Optimizing donor fascicle selection in Oberlin's procedure: A retrospective review of anatomical variability using intraoperative neuromonitoring

BACKGROUND

Transfer of the fascicle carrying the flexor carpi ulnaris (FCU) branch of the ulnar nerve (UN) to the biceps/brachialis muscle branch of the musculocutaneous nerve (Oberlin's procedure), is a mainstay technique for elbow flexion restoration in patients with upper brachial plexus injury. Despite its widespread use, there are few studies regarding the anatomic location of the donor fascicle for Oberlin's procedure. Our report aims to analyze the anatomical variability of this fascicle within the UN, while obtaining quantifiable, objective data with intraoperative neuromonitoring (IONM) for donor fascicle selection.

METHODS

We performed a retrospective review of patients at our institution who underwent an Oberlin's procedure from September 2019 to July 2023. We used IONM for donor fascicle selection (greatest FCU muscle and least intrinsic hand muscle activation). We prospectively obtained demographic and electrophysiological data, as well as anatomical location of donor fascicles and post-surgical morbidities. Surgeon's perception of FCU/intrinsic muscle contraction was compared to objective muscle amplitude during IONM.

RESULTS

Eight patients were included, with a mean age of 30.5 years and an injury-to-surgery interval of 4 months. Donor fascicle was located anterior in two cases, posterior in two, radial in two and ulnar in two patients. Correlation between surgeon's perception and IONM findings were consistent in six (75%) cases. No long term motor or sensory deficits were registered.

CONCLUSIONS

Fascicle anatomy within the UN at the proximal arm is highly variable. The use of IONM can aid in optimizing donor fascicle selection for Oberlin's procedure.

The 2-by-2 Inch "Key Window" in the Upper Extremity: An Anatomical Appraisal of the Accessibility and Proximity of the Major Nerves and Vessels

BACKGROUND

The brachial plexus is a network of nerves located between the neck and axilla, which receives input from C5-T1. Distally, the nerves and blood vessels that supply the arm and forearm form a medial neurovascular bundle. The purpose of this study was to illustrate that a peripheral nerve dissection via a 2 × 2 inch window would allow for identification and isolation of the major nerves and blood vessels that supply the arm and forearm.

METHODS

A right side formalin-fixed latex-injected cadaveric arm was transected at the proximal part of the axillary fold and included the scapular attachments. Step-by-step anatomical dissection was carried out and documented with three-dimensional digital imaging.

RESULTS

A 2 × 2 inch window centered 2 inches distal to the axillary fold on the medial surface of the arm enabled access to the major neurovascular structures of the arm and forearm: the median nerve, ulnar nerve, medial antebrachial cutaneous nerve, radial nerve and triceps motor branches, musculocutaneous nerve and its biceps and brachialis branches and lateral antebrachial cutaneous nerve, basilic vein and brachial artery and vein, and profunda brachii artery.

CONCLUSIONS

Our study demonstrates that the majority of the neurovascular supply in the arm and forearm can be accessed through a 2 × 2 inch area in the medial arm. Although this "key window" may not be entirely utilized in the operative setting, our comprehensive didactic description of peripheral nerve dissection in the cadaver laboratory can help in safer identification of complex anatomy encountered during surgical procedures.

Comprehensive analysis and classification of retrocondylar ulnar groove morphology using CT imaging in an average population of adults

PURPOSE

Anatomical variations of the concave shaped retrocondylar ulnar groove (RUG) can contribute to ulnar nerve instability. However, there are currently limited available standardized data describing the anatomy of the RUG based on radiologic imaging, such as computed tomography (CT). This study aims to provide a comprehensive description and classification of RUG anatomy based on RUG angle measurements.

METHODS

400 CT scans of the elbows of adults showing no signs of osseous damage were evaluated. RUG angles were measured in four anatomically defined axial planes that spanned from the proximal to the distal end of the RUG. Furthermore, distance measurements at the medial epicondyle were conducted. A classification system for the RUG is proposed based on the acquired RUG angles, aiming to categorize the individual angles according to the 25th and 75th percentiles.

RESULTS

RUG angles were significantly larger in males compared to females (p < 0.001) accompanied by larger distances including the off-set and height of the medial epicondyle (p < 0.001). RUG angles decreased from proximal to distal locations (p < 0.05).

CONCLUSION

This study revealed that men exhibited larger RUG angles compared to women, indicating a less-concave shape of the RUG in men. Introducing an objective RUG classification system can improve our understanding of anatomical variations and potentially find application in diagnostics and preoperative planning.

The 3D muscle morphology and intramuscular innervation of the digital bellies of flexor digitorum profundus: Clinical implications for botulinum toxin injection sites

Spasticity of flexor digitorum profundus is frequently managed with botulinum toxin injections. Knowledge of the 3D morphology and intramuscular innervation of the digital bellies of flexor digitorum profundus is necessary to optimize the injections. The purpose of this study was to digitize and model in 3D the contractile and connective tissue elements of flexor digitorum profundus to determine muscle morphology, model and map the intramuscular innervation and propose sites for botulinum toxin injection. Fiber bundles (FBs)/aponeuroses and intramuscular nerve branches were dissected and digitized in 12 formalin embalmed cadaveric specimens. Cartesian coordinate data were reconstructed into 3D models as in situ to visualize and compare the muscle morphology and intramuscular innervation patterns of the bellies of flexor digitorum profundus. The 3rd, 4th and 5th digital bellies were superficial to the 2nd digital belly and located adjacent to each other in all specimens. Each digital belly had distinct intramuscular innervation patterns. The 2nd digital belly received intramuscular branches from the anterior interosseus nerve (AIN). The superior half of the 3rd digital belly was innervated intramuscularly by the ulnar nerve (n = 4) or by both the anterior interosseus and ulnar nerves (n = 1). The inferior half of the belly received dual innervation from the anterior interosseus and ulnar nerves in 2 specimens, or exclusively from the AIN (n = 2) or the ulnar nerve (n = 1). The 4th digital belly was innervated by intramuscular branches of the ulnar nerve. One main branch, after coursing through the 4th digital belly, entered the lateral aspect of the 5th digital belly and arborized intramuscularly. The morphology of the FBs, aponeuroses and intramuscular innervation of the digital bellies of FDP were mapped and modelled volumetrically in 3D as in situ. Previous studies were not volumetric nor identified the course of the intramuscular nerve branches within each digital belly. Based on the intramuscular innervation of each of the digital bellies, one possible optimized botulinum toxin injection location was proposed. This injection location, at the junction of the superior and middle thirds of the forearm, would be located in dense nerve terminal zones of the anterior interosseus and ulnar nerves. Future anatomical and clinical investigations are necessary to evaluate the efficacy of these anatomical findings in the management of spasticity.

Safe zones in dorsal portals for wrist arthroscopy: a cadaveric study

The standard dorsal portals are the most commonly used in wrist arthroscopy. This cadaveric study aims to determine safe zones, by quantitatively describing the neurovascular relationships of the dorsal wrist arthroscopy portals: 1-2, 3-4, midcarpal radial, midcarpal ulnar, 4-5, 6-radial and 6-ulnar. The neurovascular structures of twenty-one fresh frozen human cadaveric upper limbs were exposed, while the aforementioned portals were established with needles through portal sites. The minimum distance between portals and: dorsal carpal branch of radial artery, superficial branch of radial nerve, posterior interosseous nerve and dorsal branch of ulnar nerve, were measured accordingly with a digital caliper, followed by statistical analysis of the data. The median and interquartile range for each portal to structures at risk were determined and a safe zone around each portal was established. Free of any neurovascular structure safe zones surrounding 1-2, 3-4, midcarpal radial, midcarpal ulnar, 4-5, 6-radial and 6-ulnar portals were found at 0.46mm, 2.33mm, 10.73mm, 11.01mm, 10.38mm, 5.95mm and 0.64mm respectively. Results of statistical analysis from comparisons between 1-2, 3-4 and midcarpal radial portals, indicated that 1-2 was the least safe. The same analysis among 3-4, midcarpal radial, midcarpal ulnar and 4-5 portals indicated that midcarpal portals were safer, while 3-4 was the least safe. Results among midcarpal ulnar, 4-5, 6-radial and 6-ulnar portals indicated that 6-radial and specifically 6-ulnar were the least safe. This study provides a safe approach to the dorsal aspect of the wrist, enhancing established measurements and further examining safety of the posterior interosseous nerve.

Morphology and morphometry of the ulnar nerve in the forelimb of pigs

The knowledge of the morphology and morphometry of peripheral nerves is essential for developing neural interfaces and understanding nerve regeneration in basic and applied research. Currently, the most adopted animal model is the rat, even though recent studies have suggested that the neuroanatomy of large animal models is more comparable to humans. The present knowledge of the morphological structure of large animal models is limited; therefore, the present study aims to describe the morphological characteristics of the Ulnar Nerve (UN) in pigs. UN cross-sections were taken from seven Danish landrace pigs at three distinct locations: distal UN, proximal UN and at the dorsal cutaneous branch of the UN (DCBUN). The nerve diameter, fascicle diameter and number, number of fibres and fibre size were quantified. The UN diameter was larger in the proximal section compared to the distal segment and the DCBUN. The proximal branch also had a more significant number of fascicles (median: 15) than the distal (median: 10) and the DCBUN (median: 11) segments. Additionally, the mean fascicle diameter was smaller at the DCBUN (mean: 165 μm) than at the distal (mean: 197 μm) and proximal (mean: 199 μm) segments of the UN. Detailed knowledge of the microscopical structure of the UN in pigs is critical for further studies investigating neural interface designs and computational models of the peripheral nervous system.

Ultrasound of the Ulnar Nerve: A Pictorial Review: Part 1: Normal Ultrasound Findings

This is the first of a two-part article in which we focus on the ultrasound (US) appearance of the normal ulnar nerve (UN) and its main branches. The detailed US anatomy of the UN course is presented with high-resolution US images obtained with the latest-generation US machines and transducers.

The Cutaneous Branches of the Median and Ulnar Nerves in the Palm

PURPOSE

The dermatomal distributions of the ulnar and median nerves on the palmar skin of the hand have been studied thoroughly. However, the anatomic course of the median and ulnar cutaneous nerve branches and how they supply the skin of the palm is not well understood.

METHODS

The cutaneous branches of the median and ulnar nerves were dissected bilaterally in 9 fresh cadavers injected arterially with green latex.

RESULTS

We observed 3 groups of cutaneous nerve branches in the palm of the hand: a proximal row group consisting of long branches that originated proximal to the superficial palmar arch and reached the distal palm, first web space, or hypothenar region; a distal row group consisting of branches originating between the superficial palmar arch and the transverse fibers of the palmar aponeurosis (these nerves had a longitudinal trajectory and were shorter than the branches originating proximal to the palmar arch); and a metacarpophalangeal group, composed of short perpendicular branches originating on the palmar surface of the proper palmar digital nerves at the web space. The radial and ulnar borders of the hand distal to the palmar arch were innervated by short transverse branches arising from the proper digital nerves of the index and little finger. Nerve branches did not perforate the palmar aponeurosis in 16 of 18 cases.

CONCLUSIONS

The palm of the hand was consistently innervated by 20-35 mm long cutaneous branches originating proximal to the palmar arch and shorter branches originating distal to the palmar arch. These distal branches were either perpendicular or parallel to the proper palmar digital nerves.

CLINICAL RELEVANCE

Transfer of long proximal row branches may present an opportunity to restore sensibility in nerve injuries.

Proximal forearm nerve branching patterns: an anatomical study and its clinical significance

OBJECTIVE

The aim of this study was to add to the understanding of nerve branching patterns in the proximal forearm and consider optimal nerve transfer options to address the various injuries that affect the function of the upper extremity.

METHODS

Eleven upper-extremity cadaveric specimens were dissected to expose the radial, median, and ulnar nerves in the proximal forearm. The site of origin of nerve branches from the major nerves was assessed, with measurements made in reference to the lateral epicondyle for the radial nerve branches and the medial epicondyle for the median and ulnar nerve branches. The distances to where these branches entered their respective muscles (muscle entry point) were assessed using the same landmarks. To plan a transfer, the length of the nerve branches was then calculated as the difference from the apparent origin from the main nerve trunk to the location where the nerve entered the muscle. Importantly, the nerve branch origin was established as the location of obvious separation from the main nerve trunk without additional fascicular dissection from the major nerve trunk. The number of branches was determined, and the diameter for each branch was measured using a Vernier caliper.

RESULTS

The radial nerve branch to the extensor carpi radialis brevis (ECRB) muscle had an average length of 50.7 mm and average diameter of 1.6 mm. The mean medial and lateral lengths of the radial branches to the supinator muscle were found to be 22.2 mm (diameter 1.4 mm) and 15.3 mm (diameter 1.3 mm), respectively. The anterior interosseous nerve (AIN) branch of the median nerve was found 67.8 mm distal to the medial epicondyle with a diameter of 2.3 mm. The flexor carpi ulnaris (FCU) muscle innervation from the ulnar nerve was provided by 3 or 4 branches in most specimens. The second and third of these branches were the longest, with means of 30.5 mm (diameter 1.4 mm) and 30.7 mm (diameter 1.3 mm), respectively.

CONCLUSIONS

While there is variability of the nerve branching pattern in the proximal forearm between specimens, the authors provide evidence of commonalities (branching patterns and distances) that can facilitate planning for upper-extremity nerve reconstructions. Importantly, all measurements are provided with reference to easily identified bony landmarks and to their muscle entry points to aid operative decision-making. These data complement the growing practice of nerve transfers in the upper extremity for a variety of pathologies.

Ulnar Nerve Compression at the Elbow Secondary to Intramuscular Lipoma of the Flexor Carpi Ulnaris: A Case Report

CASE

A 62-year-old right-hand-dominant woman presented with 1 year of persistent radiating pain, weakness, and paresthesias in her left forearm and hand. Electromyography findings were significant for ulnar neuropathy distal to the branch innervating the flexor carpi ulnaris (FCU), without superimposed cervical radiculopathy or other focal entrapment neuropathy. During open ulnar nerve neurolysis, an intramuscular lipoma was encountered within the FCU. Lipoma excision and cubital tunnel release with ulnar nerve transposition were performed with complete relief of neuropraxia.

CONCLUSION

We demonstrate full neurologic recovery after intramuscular lipoma excision and cubital tunnel release. Although rare, anomalous anatomy and tissue overgrowth should remain on the differential for patients presenting with atypical neuropraxia.

Lumbrical Muscles Neural Branching Patterns: A Cadaveric Study With Potential Clinical Implications

BACKGROUND

Lumbrical muscles originate in the palm from the 4 tendons of the flexor digitorum profundus and course distally along the radial side of the corresponding metacarpophalangeal joints, in front of the deep transverse metacarpal ligament. The first and second lumbrical muscles are typically innervated by the median nerve, and third and fourth by the ulnar nerve. A plethora of lumbrical muscle variants has been described, ranging from muscles' absence to reduction in their number or presence of accessory slips. The current cadaveric study highlights typical and variable neural supply of lumbrical muscles.

MATERIALS

Eight (3 right and 5 left) fresh frozen cadaveric hands of 3 males and 5 females of unknown age were dissected. From the palmar wrist crease, the median and ulnar nerve followed distally to their terminal branches. The ulnar nerve deep branch was dissected and lumbrical muscle innervation patterns were noted.

RESULTS

The frequency of typical innervations of lumbrical muscles is confirmed. The second lumbrical nerve had a double composition from both the median and ulnar nerves, in 12.5% of the hands. The thickest branch (1.38 mm) originated from the ulnar nerve and supplied the third lumbrical muscle, and the thinnest one (0.67 mm) from the ulnar nerve and supplied the fourth lumbrical muscle. In 54.5%, lumbrical nerve bifurcation was identified.

CONCLUSION

The complex innervation pattern and the peculiar anatomy of branching to different thirds of the muscle bellies are pointed out. These findings are important in dealing with complex and deep injuries in the palmar region, including transmetacarpal amputations.

Angiosomes of the Ulnar Nerve at the Elbow: A Cadaver Trial Using Contrast-Enhanced Ultrasound

Three major arteries supplying the ulnar nerve in the cubital tunnel are commonly known. However, their vascular territories (angiosomes) have not been described yet. Contrast-enhanced ultrasound was used to identify the angiosomes of posterior ulnar recurrent artery, inferior ulnar collateral artery and superior ulnar collateral artery in 20 fresh, non-frozen human body donors. The arteries were cannulated, and physiologic blood flow was simulated. Contrast agent was applied in each vessel in a randomized sequence, and the length of the contrast-enhancing ulnar nerve segment was measured by a radiologist blinded to the sequence. The angiosome of the posterior ulnar recurrent artery overlaps both other angiosomes. It fully covers the cubital tunnel in 63.6% of specimens. In addition, collateral flow via nerve and muscle branches of the arterial anastomotic network around the elbow (rete articulare cubiti) partly maintains the intra-neural blood flow in the absence of a vascular pedicle. The posterior ulnar recurrent artery is the dominant nutrient vessel of the ulnar nerve in the cubital tunnel. A potential watershed zone exists proximal to the Osborne ligament. Knowledge of these angiosomes may advance surgery of the ulnar nerve in the cubital tunnel.

The ulnar nerve is surrounded by the tendon expansion of the flexor carpi ulnaris muscle at the wrist: an anatomical study of Guyon's canal

The ulnar tunnel (Guyon's canal) is an osseofibrous tunnel for the ulnar nerve and artery. With regard to the proximal palmar wall (palmar carpal ligament) of the ulnar tunnel, detailed anatomical data such as attachment sites, fibrous continuity to surroundings, and variations have not been clearly described. In this study, topology of Guyon's canal was examined, especially to the palmar side of the ulnar nerve, focusing on the continuity of tendinous structures to reveal a more detailed constitution of Guyon's canal. The palmar wall of Guyon's canal was investigated in 113 forearms of 57 cadavers. The dorsal wall of the canal was also investigated in 25 subjects. The ulnar nerve passed lateral to the pisiform and the flexor carpi ulnaris tendon. At the level of the pisiform, except for one, the ulnar nerve passed dorsal to the aponeurosis expanding from the flexor carpi ulnaris tendon and the periosteum of the pisiform, and this aponeurosis laterally merged with the palmar aspect of the flexor retinaculum. Moreover, the ulnar nerve ran palmar to the pisohamate ligament and the flexor retinaculum extended from the same tendon. The present study suggests that the aponeurosis of palmar side to the ulnar nerve connected with the flexor carpi ulnaris tendon, the periosteum of the pisiform, and the palmar surface of the flexor retinaculum. These findings indicate that the ulnar nerve is surrounded by the aponeurotic portion expanding from the flexor carpi ulnaris tendon at the wrist, which is a new insight of Guyon's canal.

Safe zones in volar portals for wrist arthroscopy, evaluation of central portal : a cadaveric study

The purpose of this cadaveric study is to determine safe zones utilizing volar portals for wrist arthroscopy, by quantitatively describing the neurovascular relationships of a volar radial and a volar ulnar wrist arthroscopy portals in comparison with those of a newly described volar central portal (7) , considering the advantages in visualization of volar portals for wrist arthroscopy over the standard dorsal (19) . The neurovascular structures and the tendons of nine frozen human cadaveric upper limbs were exposed, while the aforementioned volar portal sites were pointed out with pins. The horizontal distance between the portals and the closest neurovascular branch or tendon was measured with a digital caliper, followed by statistical analysis of the data. The median interquartile range distances from portals to structures at risk were measured and safe zones around each portal were established. This study provides a safe approach to the volar radial and ulnar aspects of the radiocarpal and midcarpal joints, while volar radial and ulnar portals should be considered for inclusion in the arthroscopic examination of any patient with radial and ulnar sided wrist pain respectively (17,18) . Regarding the volar central portal, it is reproducible, safe and both the above joints can be inspected through one single incision (7) .

Quantitative Ultrasound and B-Mode Image Texture Features Correlate with Collagen and Myelin Content in Human Ulnar Nerve Fascicles

We investigate the usefulness of quantitative ultrasound and B-mode texture features for characterization of ulnar nerve fascicles. Ultrasound data were acquired from cadaveric specimens using a nominal 30-MHz probe. Next, the nerves were extracted to prepare histology sections. Eighty-five fascicles were matched between the B-mode images and the histology sections. For each fascicle image, we selected an intra-fascicular region of interest. We used histology sections to determine features related to the concentration of collagen and myelin and ultrasound data to calculate the backscatter coefficient (-24.89 ± 8.31 dB), attenuation coefficient (0.92 ± 0.04 db/cm-MHz), Nakagami parameter (1.01 ± 0.18) and entropy (6.92 ± 0.83), as well as B-mode texture features obtained via the gray-level co-occurrence matrix algorithm. Significant Spearman rank correlations between the combined collagen and myelin concentrations were obtained for the backscatter coefficient (R = -0.68), entropy (R = -0.51) and several texture features. Our study indicates that quantitative ultrasound may potentially provide information on structural components of nerve fascicles.

Locating the ulnar nerve during elbow arthroscopy using palpation is only accurate proximal to the medial epicondyle

PURPOSE

Knowledge of ulnar nerve position is of utmost importance to avoid iatrogenic injury in elbow arthroscopy. The aim of this study was to determine how accurate surgeons are in locating the ulnar nerve after fluid extravasation has already occurred, and basing their localization solely on palpation of anatomical landmarks.

METHODS

Seven cadaveric elbows were used and seven experienced surgeons in elbow arthroscopy participated. An arthroscopic setting was simulated and fluids were pumped into the joint from the posterior compartment for 15 min. For each cadaveric elbow, one surgeon was asked to locate the ulnar nerve solely by palpation of the anatomical landmarks, and subsequently pin the ulnar nerve at two positions: within 5 cm proximal and another within 5 cm distal of a line connecting the medial epicondyle and the tip of the olecranon. Subsequently, the elbows were dissected using a standard medial elbow approach and the distances between the pins and ulnar nerve were measured.

RESULTS

The median distance between the ulnar nerve and the proximal pins was 0 mm (range 0-0 mm), and between the ulnar nerve and the distal pins was 2 mm (range 0-10 mm), showing a statistically significant difference (p = 0.009). All seven proximally placed pins (100%) transfixed the ulnar nerve versus two out of seven distally placed pins (29%) (p = 0.021).

CONCLUSIONS

In a setting simulating an already initiated arthroscopic procedure, the sole palpation of the anatomical landmarks allows experienced elbow surgeons to accurately locate the ulnar nerve only in its course proximal to the medial epicondyle (7/7, 100%), whereas a significantly reduced accuracy is documented when the same surgeons attempt to locate the nerve distal to the medial epicondyle (2/7, 29%; p = 0.021). Current findings support the establishment of a proximal anteromedial portal over a distal anteromedial portal to access the anterior compartment after tissue extravasation has occurred with regard to ulnar nerve safety.

An anatomical study of so-called fibrous bands around the ulnar nerve distal to the cubital tunnel

BACKGROUND

Fibrous bands (FB) are structures that cross the ulnar nerve (UN), distal to the cubital tunnel (CT). In surgical decompression of the UN in the elbow region, by endoscopy, these FB significantly impact UN visibility. The aim of the current study was to characterize the anatomical characteristics of these FB distal to the CT.

METHODOLOGY

Eighteen formalinized upper limbs were dissected, nine right and nine left, within the Department of Anatomy of the Federal University of the State of Rio de Janeiro (UNIRIO). The dissections were performed with micro techniques, under a magnifying glass and a microscope. Classical UN exposure was established in the elbow region.

RESULTS

Of the 18 upper limbs studied, 50% lacked any FB. When present, both the number and location of the FB varied, as near to the cubital tunnel as 3 cm past the UN's entrance into the tunnel, and as far away as almost 11 cm distal to it. Overall, there were no FB on either the left or right side in three cadavers (33.3%), FB on both the left and right side in three, and FB only on the left in three, meaning that FB were twice as common in left limbs (n = 6) as on the right (n = 3).

CONCLUSIONS

Our study identified FB in 50% of the dissected limbs, all within 3-11 cm of the CT, though their number and location varied. Further studies are necessary to describe FB variations associated with compressive neuropathies of the UN distal to the CT.

Evaluation of the relationship between the topographical anatomy in the axillary region of the brachial plexus and the body mass index

To investigate the topographic anatomy of the median, musculocutaneous, radial and ulnar nerves with respect to the axillary artery and to seek whether these configurations are associated with baseline descriptive data including age, gender, and body-mass index. This cross-sectional trial was carried out on 199 patients (85 women, 114 men; average age: 46.78 ± 15.45 years) in the department of anaesthesiology and reanimation of a tertiary care center. Topographic anatomy of the median, musculocutaneous, radial and ulnar nerves was assessed with ultrasonography. Localization of these nerves with respect to the axillary artery was marked on the map demonstrating 16 zones around the axillary artery. Frequencies of localizations of every nerve in these zones were recorded, and the correlation of these locations with descriptive data including age, gender and BMI was investigated. There was no difference between women and men for the distribution of the median (p = 0.74), ulnar (p = 0.35) and radial (p = 0.64) nerves. However, the musculocutaneous nerve was more commonly located in Zone A13 in men compared to women (p = 0.02). The localization of the median (p = 0.85), ulnar (p = 0.27) and radial (p = 0.88) nerves did not differ remarkably between patients with BMI < 25 kg/m² and patients with BMI ≥ 25 kg/m². Notably, the musculocutaneous nerve was more often determined in Zone A10 in cases with BMI ≥ 25 kg/m² (p = 0.001). Our results imply that the alignment of the musculocutaneous nerve may vary in men and overweight people. This fact must be considered by the anaesthetist before planning the axillary block of brachial plexus. All these informations may enlighten the planning stages of the brachial plexus blockade.

Reproducibility of Ultrasonographic Measurements of the Ulnar Nerve at the Cubital Tunnel

The cross-sectional area (CSA) of the ulnar nerve is thought to be indicative of ulnar nerve entrapment. The purpose of the study was to determine reproducibility of ultrasonographic measurements of CSA of the ulnar nerve at the cubital tunnel in healthy adults. Two sonographers tested 69 participants using a standardized protocol. The inter-rater reliability intra-class correlation coefficient was 0.63, and the intra-rater reliability intra-class correlation coefficient was 0.85 for sonographer 1 and 0.88 for sonographer 2. The smallest detectable changes were 2.47 and 2.63 mm² (25% and 26% of the mean CSA). The mean difference and 95% limits of agreement for sonographers 1 and 2 were -0.13 (-2.56 to 2.29) and -0.38 (-2.93 to 2.18). Based on the fair to good inter-rater reliability, the excellent intra-rater reliability and the clinical applicable intra-rater agreement, ultrasonography seems to be a valuable tool with which to assess the CSA of the ulnar nerve for diagnostic and evaluative purposes.

Digital Innervation Patterns Following Median or Ulnar Nerve Laceration and their Correlation to Anatomic Variations of the Communicating Branch Between these Nerves

The midline of the ring finger is classically considered as the neural watershed between the median and ulnar nerve sensory territories on the palmar surfaces of the fingers. Variations of this division exist and may be explained by a communicating branch between the third and fourth common digital nerves. The palmar sensibility patterns of fingers were assessed with Semmes Weinstein filaments after either a complete median or an ulnar nerve transection in 43 patients. Eight out of nine observed sensibility patterns could be explained by known anatomic types and subtypes of the communicating branch. The type of communicating branch, but not its subtype, could be established in the one remaining pattern.

The Innervation of the Medial Humeral Epicondyle: Implications for Medial Epicondylar Pain

The purpose of this study was identification of the innervation of the medial humeral epicondyle which has not been described before. In 20 patients, the medial intermuscular septum was evaluated histopathologically: the nerve was identified in 15 specimens without S-100 staining, and in the remaining 5 with S-100 staining. In six fresh cadavers, bilateral dissections identified the source of this nerve as the radial nerve in the axilla, coursing adjacent to the ulnar nerve in the upper arm, then moving laterally to be superficial to, or within, the medial intermuscular septum, until the nerve terminated in the periosteum of the medial humeral epicondyle, at the origin of the flexor-pronator muscle mass. In one specimen, a branch from the ulnar nerve in the axilla contributed to this nerve to the medial humeral epicondyle.

The Anatomy of the Dorsal Cutaneous Branch of the Ulnar Nerve – a Safe Zone for Positioning of the 6r Portal in Wrist Arthroscopy

The dorsal branch of the ulnar nerve passes close to the 6 Radial portal used in wrist arthroscopy. We examined 20 cadaveric limbs to establish the course of this nerve. We found it consistently crossed a line between the ulnar styloid and the fourth web space at an average of 2.4 cm from the ulnar styloid (range 1.8–2.8 cm). This represented 23% (+/−2.5 STD range 19–27%) of the distance from the styloid process to the fourth web space. Recommendations are made to help avoid iatrogenic injury to the nerve during arthroscopy. The literature on the anatomy of this nerve and its variations and the clinical relevance of this knowledge are discussed.

Peripheral nerve segmentation using Nonparametric Bayesian Hierarchical Clustering

Several cases related to chronic pain, due to accidents, illness or surgical interventions, depend on anesthesiology procedures. These procedures are assisted with ultrasound images. Although, the ultrasound images are a useful instrument in order to guide the specialist in anesthesiology, the lack of intelligibility due to speckle noise, makes the clinical intervention a difficult task. In a similar manner, some artifacts are introduced in the image capturing process, challenging the expertise of anesthesiologists for not confusing the true nerve structures. Accordingly, an assistance methodology using image processing can improve the accuracy in the anesthesia practice. This paper proposes a peripheral nerve segmentation method in medical ultrasound images, based on Nonparametric Bayesian Hierarchical Clustering. The experimental results show segmentation performances with a Mean Squared Error performance of 1.026 ± 0.379 pixels for ulnar nerve, 0.704 ± 0.233 pixels for median nerve and 1.698 ± 0.564 pixels for peroneal nerve. Likewise, the model allows to emphasize other soft structures like muscles and aqueous tissues, that might be useful for an anesthesiologist.

Surgical exposures of the hand

Surgical approaches to the hand are commonly executed in the treatment of fractures, ligament injuries, and less commonly in the resection of bony tumors. Careful design and execution of these surgical approaches translates into superior functional and aesthetic outcomes. We have provided a thorough review of commonly used approaches to the hand by evaluating each of these approaches in the context of core principles including safety, versatility, preservation of stability, and aesthetic outcomes.

C7 nerve root sensory distribution in peripheral nerves: a bold functional magnetic resonance imaging investigation at 9.4 T

INTRODUCTION

In this study we used a rat model to elucidate the linear make-up of each major nerve of the upper limb by the C7 root through sensory stimulation and functional magnetic resonance imaging (fMRI).

METHODS

The C7 nerve root and major nerves of the right forelimb were stimulated electrically. Blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) was performed concurrently. Voxel overlap within the primary sensory cortex was calculated.

RESULTS

C7 comprised sensation in <1% in the musculocutaneous nerve, 6% in the ulnar nerve, 16% in the radial nerve, and 19% in the median nerve (P<0.005 for each). The overlap was always <25% for each major nerve.

CONCLUSIONS

This study helps explain why C7 is a suitable donor for brachial plexus injury treatment and why there is only a transient sensory deficit after transfer.

Topography of ulnar nerve and its variations with special respect to carpal region

Ulnar nerve supplies small muscles of the hand and apart from the median nerve is the main coordinator of precise movements performed both in the medical and dental practice. Based on their anatomical and clinical experience, authors revised a knowledge on this nerve with special respect to its topography, variation in the wrist.

Anterior translation and morphologic changes of the ulnar nerve at the elbow in adolescent baseball players

The effect of repetitive throwing on the ulnar nerve is not clear. There are no published imaging studies regarding this issue in adolescent baseball players. The purpose of this cross-sectional ultrasonographic study was to use 5- to 10-MHz frequency ultrasonography to define the anterior translation and flattening of the ulnar nerve in different elbow positions. We divided 39 adolescent baseball players into two groups, 19 pitchers and 20 fielders, according to the amount of throwing. Twenty-four non-athlete junior high school students were also included as controls. We ultrasonographically examined each participant's ulnar nerve in the cubital tunnel with the elbow extended and at 45°, 90° and 120° of flexion. Anterior translation and flattening of the ulnar nerve occurred in all groups. Pitchers had larger-scale anterior translation than did controls. In pitchers, the ulnar nerve exhibited more anterior movement on the dominant side than on the non-dominant side. The anterior subluxation of the ulnar nerve occurred in players without ulnar nerve palsy and was not correlated with elbow pain. In addition to the known musculoskeletal adaptations of pitchers' elbows, ultrasonography revealed new changes in the ulnar nerve, anterior translation and subluxation, after repetitive throwing. These changes might also be physiologic adaptations of throwing elbows.

[Ultrasound-guided axillary block: anatomical variations of terminal branches of the brachial plexus in relation to the brachial artery]

OBJECTIVES

To describe the distribution of the terminal branches of the brachial plexus at the axillary level and define distribution patterns after ultrasound evaluation.

MATERIAL AND METHOD

Fifty volunteers underwent ultrasound bilateral axillary brachial plexus scanning exploration. Nerve distribution around the humeral artery was described and the distance between each nerve and the center of the artery was measured. The distance and relationship between the ulnar nerve and the humeral vein were also recorded.

RESULTS

The median nerve was located in the anterolateral quadrant (-29±40°) and at a mean distance of 2.1±0.9mm from the artery (85%). The ulnar nerve was found at 53±26° and at 4.2±2.1mm from the artery in the anteromedial quadrant (90%), anterolateral to the vein in 46% of cases, and deep to it in 54%. The radial nerve was at 122±38° and at 3.3±1.7mm from the artery in the posteromedial quadrant (86%). The musculocutaneous nerve was found at -103±22° and 9.3±5.6mm from the artery in the posterolateral quadrant (90%) and in the anterolateral quadrant (-55±16°) at 4.8±2.7mm (10%). There were no differences regarding laterality, gender or overweight patients.

CONCLUSIONS

Our results allow defining four different anatomical patterns, two based in the position of the musculocutaneous nerve and two based on the disposition of the ulnar nerve with respect to the humeral vein. These patterns were not related to laterality, gender or body weight.

[Anatomic structure of "Shaoze" (SI 1), "Qiangu" (SI 2), "Houxi" (SI 3), "Yanggu" (SI 5) and Xiaohai" (SI 8) regions of Hand-Taiyang Meridian in the rabbit's forelimb]

OBJECTIVE

To observe the anatomic structure of the Five Shu-acupoints: "Shaoze" (SI 1) ,"Qiangu" (SI 2), "Houxi" (SI 3),"Yanggu" (SI 5) and "Xiaohai" (SI 8) regions of the Taiyang Meridian in the rabbit's forelimb.

METHODS

Thirty rabbits (half male and half female) were used in the present study. The Five Shu-acupoints regions were located first based on the atlas of rabbits, stimulated by needling and confirmed later by using an electronic acupoint detector. Under anesthesia, the rabbit was perfused with warm normal saline via the common carotid artery and the internal jugular vein, followed by arterial perfusion of dental base acrylic resin powder(30 g), dibutylphthalate(6 mL), red couring agent liquid for denture acrylic and acetoacetate (2 mL), respectively; and venous perfusion of 30% gelatin (filtered) and black ink (filtered) and formaldehyde (8%). After fixing in 8% formaldehyde for 10 days, the rabbit's forelimb containing the aforementioned Five Shu-acupoints were carefully dissected layer by layer, followed by observing the local anatomic structure under microscope.

RESULTS

The superficial layers of these acupoint regions mainly contained the basilic vein and its branches, and the superficial branch of the ulnar nerve. The deep layers chiefly comprised of the ulnar artery, the ulnar vein and their branches, and the ulnar nerve.

CONCLUSION

In "Shaoze"(SI 1 ), "Qiangu" (SI 2), "Houxi" (SI 3), "Yanggu" (SI 5) and "Xiaohai" (SI 8) acupoint regions, the ulnar artery, basilic vein, ulnar vein and their branches, the ulnar nerve and its superficial branches are found, which constitute the morphological basis of the five acupoints of the Hand-Taiyang Meridian for treating some related clinical disorders.

Ultrasound anatomy of the brachial plexus nerves in the neurovascular bundle at the axilla in patients undergoing upper-extremity block anesthesia

PURPOSE

Familiarity with the localization of the nerves in the neurovascular bundle that constitutes the axillary segment of the brachial plexus (BP) is important when applying ultrasound (US)-guided block anesthesia. Therefore in this study we aimed to delineate the anatomy of the median, radial, and ulnar nerves of the BP at the axilla with US and electrical stimulation.

MATERIALS AND METHODS

The study included 60 patients who were scheduled to undergo upper-arm surgery with axillary block anesthesia. Prior to anesthesia, ulnar, radial, and median nerves were localized with US using a 12-h quadrant identification system that placed the axillary artery (AA) in the middle. The nerves were then functionally tested using a neurostimulator.

RESULTS

The radial nerve was mainly located in the 4-6 o'clock arc (posterior and posteromedial to AA) in 50 (83 %) of patients. Ulnar nerve was mainly at the 12-3 o'clock arc (anteromedial to AA) in 51 (85 %) of patients. Ulnar nerve showed a second peak at 9-10 o'clock quadrant (anterolateral to AA) in 11 % (7) of patients. Median nerve location was most common in the 12 and 9 o'clock arc (anterior and anterolateral to AA) in 53 (88 %) of the patients.

CONCLUSIONS

Ultrasound is a useful tool for depicting BP anatomy in the axillary fossa prior to block anesthesia. Median, ulnar, and radial nerves form a highly consistent triangular pattern around the axillary artery that is easily recognizable with US.

Anatomical study of the dorsal cutaneous branch of the ulnar nerve using ultrasound

OBJECTIVES

To determine whether ultrasound allows precise assessment of the course and relations of the dorsal cutaneous branch of the ulnar nerve (DCBUN).

METHODS

This work, initially undertaken in cadavers, was followed by high-resolution ultrasound study in 20 healthy adult volunteers (40 nerves) by two musculoskeletal radiologists in consensus. Location and course of the DCBUN and its relations to adjacent anatomical structures were analysed.

RESULTS

The DCBUN was consistently identified along its entire course by ultrasound. Mean cross-sectional area of the nerve was 1.6 mm(2) (range 1.1-2.2). The level at which the DCBUN branches from the ulnar nerve was located a mean of 57 mm (range 40-80) proximal to the ulnar styloid process and 11 mm (range 7-15) radial to the medial border of the ulna. The DCBUN then crossed the medial border of the ulna a mean of 14 mm (range 6-25) proximal to the ulnar styloid process.

CONCLUSION

The DCBUN is clearly depicted by ultrasound. Precise mapping of its anatomical course could have significant clinical applications, such as preventing injury during surgery of the ulnar side of the wrist or helping in the diagnosis of chronic pain of the ulnar side of the hand.

KEY POINTS

• The dorsal cutaneous branch of the ulnar nerve (DCBUN) is often injured. • The DCBUN originates from the ulnar nerve in the distal third of the forearm. • It can be clearly depicted by ultrasound. • The level at which the DCBUN crosses the ulna is variable. • Precise mapping of its anatomical course could have significant clinical applications.

The study of intramuscular nerve distribution patterns and relative spindle abundance of the thenar and hypothenar muscles in human hand

Background

The intramuscular nerve distribution and relative spindle abundance of the human hand have not been well defined, although this is important in guiding hand surgery.

Methods

Forty human hands were dissected and subjected to modified Sihler’s stain and haematoxylin and eosin stain to investigate intramuscular nerve distribution and relative spindle abundance, respectively.

Results

The flexor pollicis brevis (FPB), adductor pollicis (AP), and abductor digiti minimi (ADM) contain separate nerve compartments. Neural anastomoses were observed in the thenar and hypothenar muscles, including the Y-like, O-like, H-like, and U-like appearance. We found that U-like neural anastomoses may be the characteristic of the opponens muscles. The relative spindle abundance was the greatest in the opponens muscles which may coordinate fine movements.

Conclusion

Except for the two opponens muscles, the rest of the thenar and hypothenar muscles could be used as whole muscle or half-muscle donors for muscle transplant. Our nerve map of the hand offers valuable guidance for hand reconstruction.

Dorsal cutaneous innervation of the hand with respect to anatomical landmarks: is there a safe zone?

OBJECTIVES

In this study, we aimed to define the borders of the triangular area between the radial and dorsal nerves on the dorsum of the hand and to determine its dimensions using measurements between anatomic landmarks.

MATERIALS AND METHODS

We statistically analyzed the relation between the distance from Lister's tubercle to the blending point of the central branches of radial and ulnar nerves and the distance between styloids on 14 hands of seven adult human cadavers (5 males, 2 females). The distances of nerve branches to vertical lines drown distally from both styloid processes were also compared with interstyloid distances to help in presuming the course of these nerves.

RESULTS

No statistical constant correlation was determined between the measurements. Neither the height of the triangular area nor the courses of both nerves seemed to be quantitatively related to any measurements between the anatomical landmarks.

CONCLUSION

Variability in these measurements in our study indicates that there is no surgical safe zone on the dorsum of the hand.

Ulnar nerve component to innervation of thumb carpometacarpal joint

PURPOSE

Thumb carpometacarpal (CMC) joint arthritis is one of the most common problems addressed by hand surgeons. The gold standard of treatment for thumb CMC joint arthritis is trapeziectomy, ligament reconstruction and tendon interposition. Denervation of the thumb CMC joint is not currently used to treat arthritis in this joint due to the failure of the procedure to yield significant symptomatic relief. The failure of denervation is puzzling, given that past anatomic studies show the radial nerve is the major innervation of the thumb CMC joint with the lateral antebrachial nerve and the median nerve also innervating this joint. Although no anatomic study has ever shown that the ulnar nerve innervates the CMC joint, due to both the failure of denervation and the success of arthroscopic thermal ablation, we suspect that previous anatomic studies may have overlooked innervation of the thumb CMC joint via the ulnar nerve.

METHODS

We dissected 19 formalin-preserved cadaveric hand-to-mid-forearm specimens. The radial, median and ulnar nerves were identified in the proximal forearm and then followed distally. Any branch heading toward the radial side of the hand were followed to see if they innervated the thumb CMC joint.

RESULTS

Eleven specimens (58%) had superficial radial nerve innervation to the thumb CMC joint. Nine specimens (47%) had median nerve innervation from the motor branch. Nine specimens (47%) had ulnar nerve innervation from the motor branch.

CONCLUSIONS

We believe this is the first study to demonstrate that the ulnar nerve innervates the thumb CMC joint This finding may explain the poor results seen in earlier attempts at denervation of the thumb CMC, but the more favorable results with techniques such as arthroscopy with thermal ablation.

Imaging and anatomic study of the pisiform bone/ulnar nerve relationship-evaluation of the preferred surgical approach for the excision of the pisiform bone

This study examines the role of the pisiform bone/ulnar nerve relationship in determining the preferred surgical approach for the excision of the pisiform bone. An anatomic dissection of Guyon's canal on 10 fresh frozen cadaver wrists evenly divided between males and females was combined with magnetic resonance imaging (MRI) scans of 10 volunteer wrists. The 3 reported data points include the axial images determined on the MRI, the anatomic dissection related to the proximity of the ulnar nerve relative to the pisiform in defined positions of the wrist and the soft tissue envelope that surrounds the pisiform, and the proximity of the ulnar nerve as recorded, measured, and analyzed. An analysis of variance of the recorded data points was performed and the statistical results were presented (P value of P 05). Dissection and the MRI scans determined that the soft tissue envelope between the pisiform and ulnar nerve at Guyon's canal with neutral dorsiflexion was 2.5 mm. Palmar flexion was 3.0 mm and neutral flexion was 4.5 mm. The thinnest area was adjacent to the ulnar nerve proper on the volar radial aspect of the pisiform, on the basis of clock-faced analysis, between the 3 : 00 and 6 : 00 positions (the pisiform as a circle). The proximity of the pisiform in relation to the ulna and the limit of the soft tissue envelope would suggest that the preferred surgical approach, or that least likely to cause injury to the ulnar nerve, is one that is volar and includes excising the pisiform after exposing Guyon's canal.

[Anatomical studies on low end-to-side anastomosis of median nerve and ulnar nerve in repair of Dejerine Klumpke type paralysis or high ulnar nerve injury]

OBJECTIVE

To investigate the anatomical evidence of low end-to-side anastomosis of median nerve and ulnar nerve in repair of Dejerine Klumpke type paralysis or high ulnar nerve injury.

METHODS

Twelve formaldehyde anticorrosion specimens (24 sides) and 3 fresh specimens (6 sides) were observed. There were 9 males (18 sides) and 6 females (12 sides). The specimen dissected under the microscope. S-shape incision was made at palmar thenar approaching ulnar side, the profundus nervi ulnaris and superficial branch of ulnar nerve were separated through near end of incision, and the recurrent branch of median nerve and common digital nerve of the ring finger were separated through far end of incision. The distances from pisiform bone to the start point of the recurrent branch of median nerve, and to the start point of common digital nerve of the ring finger were measured. The width and thickness of the profundus nervi ulnaris and superficial branch of ulnar nerve, and the recurrent branch of median nerve and common digital nerve of the ring finger were measured, and the cross-sectional area was calculated. The number of nerve fiber was determined with HE staining and argentaffin staining.

RESULTS

The cross-sectional area and the number of nerve fiber were (2.46 +/- 1.03) mm2 and 1305 +/- 239 for the profundus nervi ulnaris, (2.62 +/- 1.75) mm2 and 1634 +/- 343 for the recurrent branch of median nerve, (1.60 +/- 1.39) mm2 and 1201 +/- 235 for the superficial branch of ulnar nerve, and (2.19 +/- 0.89) mm2 and 1362 +/- 162 for the common digital nerve of the ring finger. There were no significant differences (P > 0.05) in the cross-sectional area and the number of nerve fiber between the profundus nervi ulnaris and the recurrent branch of median nerve, between the superficial branch of ulnar nerve and the common digital nerve of the ring finger; and two factors had a linear correlation (P < 0.05) with correlation coefficients of 0.68, 0.66 and 0.56, 0.36. The distances were (36.98 +/- 4.93) mm from pisiform bone to the start point of the recurrent branch of median nerve, and (28.35 +/- 6.63) mm to the start point of common digital nerve of the ring finger.

CONCLUSION

Low end-to-side anastomosis of median nerve and ulnar nerve has perfect match in the cross-sectional area and the number of nerve fiber.

Anatomical and electrophysiological myotomes corresponding to the flexor carpi ulnaris muscle

This study was designed to investigate the incidence of lateral root of the ulnar nerve through cadaveric dissection and to analyze its impact on myotomes corresponding to the flexor carpi ulnaris (FCU) assessed by electrodiagnostic study. Dissection of the brachial plexus (BP) was performed in 38 arms from 19 cadavers, and the connecting branches between the lateral cord and medial cord (or between lateral cord and ulnar nerve) were investigated. We also reviewed electrodiagnostic reports from January 2006 to May 2008 and selected 106 cases of single-level radiculopathy at C6, C7, and C8. The proportion of abnormal needle electromyographic findings in the FCU was analyzed in these patients. In the cadaver study, branches from the lateral cord to the ulnar nerve or to the medial cord were observed in 5 (13.1%) of 38 arms. The incidences of abnormal electromyographic findings in the FCU were 46.2% (36/78) in C7 radiculopathy, 76.5% (13/17) in C8 radiculopathy and 0% (0/11) in C6 radiculopathy. In conclusion, the lateral root of the ulnar nerve is not an uncommon anatomical variation of the BP and the FCU commonly has the C7 myotome. Needle EMG of the FCU may provide more information for the electrodiagnosis of cervical radiculopathy and brachial plexopathy.

[Anatomic study on injury of simple deep branch of ulnar nerve]

OBJECTIVE

To provide anatomy evidence of the simple injury of the deep branch of the ulnar nerve for clinical diagnosis and treatments.

METHODS

Fifteen fresh samples of voluntary intact amputated forearms with no deformity were observed anatomically, which were mutilated from the distal end of forearm. The midpoint of the forth palm fingerweb was defined as dot A, the midpoint of the hook of the hamate bone as dot B, the ulnar margin of the flexor digitorum superficialis of the little finger as OD, and the superficial branch of the ulnar nerve and the forth common finger digital nerve as OE, dot O was the vertex of the triangle, dot C was intersection point of a vertical line passing dot B toward OE; dot F was the intersection point of CB's extension line and OD. OCF formed a triangle. OCF and the deep branch of the ulnar nerve were observed. From May 2000 to June 2007, 3 cases were treated which were all simple injury of the deep branch of the ulnar nerve by glass, diagnosed through anatomical observations. The wounds were all located in the hypothenar muscles, and passed through the distal end of the hamate bone. Muscle power controlled by the ulnar nerve got lower. The double ends was sewed up in 2 cases directly intra operation, and the superficial branch of radial nerve grafted freely in the other 1 case.

RESULTS

The distance between dot B and dot O was (19.20 +/- 1.30) mm. The length of BC was (7.80 +/- 1.35) mm. The morphia of OCF was various, and the route of profundus nervi ulnaris was various in OCF. OCF contains opponens canales mainly. The muscle branch of the hypothenar muscles all send out in front of the opponens canales. The wounds of these 3 cases were all located at the distal end of the hook of the hamate bone, intrinsic muscles controlled by the ulnar nerve except hypothenar muscles were restricted without sensory disorder or any other injuries. Three cases were followed up for 2 months to 4 years. Postoperation, the symptoms disappeared, holding power got well, patients' fingers were nimble. According to the trial standard of the function of the upper limb peripheral nerve established by Chinese Medical Surgery of the Hand Association, the synthetical evaluations were excellent.

CONCLUSION

Simple injuries of the deep branch of the ulnar nerve are all located in OCF; it is not easy to be diagnosed at the early time because of the little wounds, the function of the hypothenar muscles in existence and the normal sense.

[Anatomic bases of surgical approaches to the nerves of the upper limb: tips for young surgeons]

Peripheral nerve surgery requires a certain level of specialization. Surgeons must have solid knowledge of morphological anatomy of the different segments to be explored, decompressed, repaired, or even neurotized. This paper describes the most common approaches to the peripheral nerves of the upper limb.

Variation in relation of cords of brachial plexus and their branches with axillary and brachial arteries--a case report

Anatomical variations in the formation, course and distribution of brachial plexus are well documented. The present report describes some rare variations with regard to relation of cords of brachial plexus, median and ulnar nerves with the third part of axillary artery and brachial artery in the left upper limb of an adult male cadaver. All three cords of brachial plexus were noted to be lateral to all three parts of axillary artery. Median nerve was lateral to brachial artery and ulnar nerve was between the brachial artery and median nerve. Further distribution of median and ulnar nerves was normal. The arterial pattern in left arm (axillary and brachial arteries) was also normal. The findings were noted after thorough and meticulous dissection of both the upper limbs (axilla, arm, cubital fossa, forearm and palm) of the same cadaver in the Department of Anatomy, College of Medical Sciences, Bharatpur, Nepal. The right upper limb revealed no abnormality. It is important to be aware of such variations while planning a surgery in the region of axilla and arm as these nerves are more liable to be injured during surgical procedures. Possible embryological explanations and clinical significance have been discussed.

[Two different methods of supracondylar lateral wedge osteotomy in cubitus varus deformity in adults]

OBJECTIVES

We reviewed the results of a transverse osteotomy for cubitus varus deformity in adults stabilized by two different methods of fixation with either Kirschner wire (K-wire) or Y plate.

PATIENTS AND METHODS

Sixteen soldiers were treated by a lateral closing wedge osteotomy of the distal humerus for cubitus varus deformity in the military infirmary. Two different methods of fixation were used for the osteotomy. The osteotomies were stabilized with K-wires in the initial five cases. Because of loosening of the pins and loss of correction in these five cases, Y plates were introduced for fixation in the other patients.

RESULTS

Three patients in the K-wire group, and one case in the Y plate fixation group had poor results. Lateral closing wedge osteotomy is technically easy and allows three dimensional correction. Accompanying displaced ulnar nerves and snapping triceps tendons were spontaneously corrected by the osteotomy.

CONCLUSION

Y plates provide rigid fixation that permits early active motion and prevents possible complications related to implant failure or loss of fixation.

[3D visualization research on microstructure of human ulnar nerve]

OBJECTIVE

To explore the application of 3D nerve visualization system in processing 2D image information of human ulnar nerve acquired by series freezing tissue section, staining and scanning. And to draw the 3D anatomical atlas of human ulnar nerve through 3D Nerve visualization software system.

METHODS

One left ulnar nerve (from medial fasciculus of brachial plexus to transverse carpal ligament, about 50 cm) was taken from a fresh donated cadaver. After marked with human hair and embedded in OCT, series freezing tissue sections were made and stained with acetylcholinesterase histochemically. Series 2D image information was obtained through high resolution scanner. Then the microstructure of ulnar nerve was reconstructed with 3D Nerve visualization software system.

RESULTS

Different cross sections of ulnar nerve have different numbers, positions and characters of the internal nerve fibers. The microstructure of ulnar nerve could be observed in magnifying visual field at any cross section after reconstructed in 3D Nerve visualization soft ware system, which made it possible to track stereo course of fascicles.

CONCLUSION

Reconstructed 3D Nerve visualization software system shows the whole microstructure of ulnar nerve and the 3D stereo-structure of its internal fascicles, thus provides exact topography atlas for medical teaching and facilitates precise repair of ulnar nerve injury to improve therapeutic effect.

Sonographic appearances of the normal ulnar nerve in the cubital tunnel

PURPOSE

To investigate the sonographic characteristics of the normal ulnar nerve in the cubital tunnel, as well as any differences related to age, sex, and dominant arm.

METHOD

Two hundred twelve elbows in healthy volunteers were evaluated sonographically. The cross-sectional area (CSA) of the ulnar nerve within the cubital tunnel was measured with the elbow in extension and in flexion. The presence and number of fascicles was determined. The displacement of the ulnar nerve out of the cubital tunnel in full elbow flexion was also investigated.

RESULTS

The mean +/- SD CSA of the ulnar nerve was 6.6 +/- 1.7 mm(2) (6.7 +/- 1.8 mm(2) in men and 6.5 +/- 1.7 mm(2) in women). The mean CSA of the ulnar nerve was highest for subjects aged 50-59 years, and lowest for subjects aged 30-39 years. Forty-two of 212 (19.8%) ulnar nerves had 2 fascicles, and 5 (2.4%) had 3 fascicles. The remaining 165 (77.8%) nerves had 1 fascicle. During elbow flexion, 49 of 212 (23.1%) ulnar nerves showed subluxation, and 18 (8.5%) were dislocated.

CONCLUSION

There were differences in the CSA of the ulnar nerve between some age groups, but there was no variation with sex or handedness. Sonography can evaluate the morphologic changes of the nerve during flexion of the elbow.

[Anatomical study on anterior transposition of ulnar nerve accompanied with arteries for cubital tunnel syndrome]

OBJECTIVE

To investigate the blood supply of the ulnar nerve in the elbow region and to design the procedure of anterior transposition of ulnar nerve accompanied with arteries for cubital tunnel syndrome.

METHODS

The vascularity of the ulnar nerve was observed and measured in 20 adult cadaver upper limb specimens. And the clinical surgical procedure was imitated in 3 adult cadaver upper limb specimens.

RESULTS

There were three major arteries to supply the ulnar nerve at the elbow region: the superior ulnar collateral artery, the inferior ulnar collateral artery and the posterior ulnar recurrent artery. The distances from arterial origin to the medial epicondyle were 14.2+/-0.9, 4.2+/-0.6 and 4.8+/-1.1 cm respectively. And the total length of the vessels travelling alone with the ulnar nerve were 15.0+/-1.3, 5.1+/-0.3 and 5.6+/-0.9 cm. The external diameter of the arteries at the beginning spot were 1.5+/-0.5, 1.2+/-0.3 and 1.4+/-0.5 mm respectively. The perpendicular distance of the three arteries were 1.2+/-0.5, 2.7+/-0.9 and 1.3+/-0. 5 cm respectively.

CONCLUSION

It is feasible to perform anterior transposition of the ulnar nerve accompanied with arteries for cubital tunnel syndrome. And the procedure preserves the blood supply of the ulnar nerve following transposition.

Superficial palmar communications between the ulnar and median nerves in Turkish cadavers

The superficial palmar communicating branch between the ulnar and median nerves, the ramus communicans (RC), has been investigated by anatomical dissections in 30 hands of 15 cadavers in the Turkish population. A communicating branch between the ulnar and median nerves was found in 18 hands (60%). It was classified into 4 types: Type 1-RC emerging from the ulnar 4th common digital nerve (CDN) and uniting with the median 3rd CDN, Type 2-RC emerging from the median 3rd CDN and uniting with the ulnar 4th CDN, Type 3-RC extending horizontally between the 3rd and 4th CDN, Type 4-a plexiform RC formed by multiple twigs. Twelve hands (40%) showed the Type 1 arrangement, one was Type 2 (3.3%), two were Type 3 (6.7%) and three (10%) were Type 4, based on the classification devised by Meals and Shaner ([1983] J Hand Surg Am 8:411-414) and modified by Bas and Kleinert ([1999] J Hand Surg Am 24:1171-1184). Knowledge of the anatomical characteristics of this branch is important for surgical interventions, especially in carpal tunnel release operations.

Location of nerve entry points of flexor digitorum profundus

The aim of this study was to elucidate the anatomical location of nerve entry points of Flexor digitorum profundus (FDP) and its implications for non-surgical neurolysis. A total of 21 amputated forearms of 11 Korean fresh cadavers were dissected. Two transverse x-axes joined the medial and lateral epicondyles and the radial and ulnar styloid processes. The longitudinal y-axis joined the midpoints of the proximal and distal transverse x-axes. The locations of the points were marked relative to the forearm length (x) and forearm width (y). The number of nerve entry points from median nerve and ulnar nerve were average 3.91 +/- 0.62 (range 3-5, median 4) and 2.14 +/- 0.65 (range 1-3, median 2) respectively. Most (82.9%) nerve entry points of FDP from the median nerve were within two circles, with 15 mm diameter. The two circles were on medial 1/10 of forearm width from the y-axis, and on proximal 1/3 (1:2) and 2/5 (2:3) of forearm length on x-axis. Most (80.0%) nerve entry points of the ulnar nerve innervating FDP were within a 15 x 30 mm rectangle. Its center was located at +26.5% on x-axis and -36.0% on y-axis. The nerve entry points used to be selected in performing non-surgical neurolysis with either ethyl alcohol (50%) or phenol (5-12%).

Innervation of the triangular fibrocartilage complex of the human wrist: Quantitative immunohistochemical study

The distribution of neural elements in the triangular fibrocartilage complex (TFCC) of the human wrists was studied via immunohistochemical staining of protein gene product (PGP) 9.5 and calcitonin gene-related peptide (CGRP). Articular branches projecting to the TFCC arose from the dorsal branch of the ulnar nerve in all wrists examined. The TFCC is subdivided into the following six regions: the articular disc proper (ADP), meniscus homolog (MH), radio-ulnar ligament (RUL), loose part of ulnar collateral ligament (lUCL), dense part of ulnar collateral ligament (dUCL), and internal portion (IP). The IP consists of a mixture of dense and loose connective tissues enclosed by the ADP, MH, RUL, and UCL, and resides deep in the prestyloid recess, which is a pit in the MH. The densities of PGP 9.5-positive neural elements, including free nerve endings, single nerve fibers, nerve fascicles, and perivascular neural nets, were significantly higher in the IP than in other regions. Some of the neural elements except for the perivascular neural nets were positive for CGRP. The high density of neural elements in the IP suggests that sensory nerves projecting to the TFCC enter into the IP and from there distribute to adjacent regions such as the MH and RUL. Free nerve endings are responsible for pain transmission. The high density of free nerve endings in the IP suggests that the IP is a source of ulnar side wrist pain.