Possible secular trend in the incidence of an anatomical variant: median artery of the forearm

Anatomical variations of the superficial palmar arch in human fetuses

The superficial palmar arch is an important anatomical structure that contributes to the arterial supply of the palmar side of the hand in the upper extremity. However, there is limited information on the embryological morphological structure of the superficial palmar arch in the literature. We studied the types of the superficial palmar arch and determined their variations by dissecting 80 upper extremities of 40 formalin-fixed human fetuses (19 males, 21 females) 18-37 weeks of age. The types and variations of the superficial palmar arch were examined, and the median artery was imaged. The superficial palmar arch type was complete in 58 hands (72.5%) and incomplete in 22 hands (27.5%). The complete group consisted of type A (47.5%), type B (16.25%), type C (3.75%), type D (1.25%), and type E (3.75%). On the other hand, the incomplete group consisted of type F (15%), type G (8.75%), type H (2.5%), and type I (1.25%). A median artery that originated from the ulnar artery and passed through the carpal tunnel during its course was detected in two hands (2.5%). Knowledge of the superficial palmar arch variations will contribute to hand microsurgery particularly in vascular graft and free flap application interventions for arterial bleeding in the palmar region.

Radial forearm free flap in a patient with an unusual radial artery variation: a case report

Head and neck reconstruction poses unique challenges in rehabilitating surgical defects in terms of integrity, function, and form. The radial forearm free flap (RFFF) has been widely used for defect coverage, especially in the head and neck area, but its versatility allows it to be used for soft-tissue reconstruction in various parts of the body. The vascular features of the flap are quite constant and reliable. Nevertheless, abnormalities of the forearm vascular tree have been described over the decades. We report a case of intraoral reconstruction after verrucous carcinoma recurrence in a 74-year-old woman with an unusual forearm flap, which we called the median forearm free flap, based on a median branch of the radial artery that was preoperatively detected using handheld Doppler ultrasonography. The distally located skin paddle was predominantly supplied by the aberrant median vessel with its perforators. The flap was thus safely harvested with this atypical pedicle. Successful reconstruction of the intraoral defect was achieved, with an uneventful postoperative course.

The persistent median artery and its vascular patterns: A meta-analysis of 10,394 subjects

The presence of a persistent median artery (PMA) has been implicated in the development of compression neuropathies and surgical complications. Due to the large variability in the prevalence of the PMA and its subtypes in the literature, more awareness of its anatomy is needed. The aim of our meta-analysis was to find the pooled prevalence of the antebrachial and palmar persistent median arteries. An extensive search through the major databases was performed to identify all articles and references matching our inclusion criteria. The extracted data included methods of investigation, prevalence of the PMA, anatomical subtype (antebrachial, palmar), side, sex, laterality, and ethnicity. A total of 64 studies (n = 10,394 hands) were included in this meta-analysis. An antebrachial pattern was revealed to be more prevalent than a palmar pattern (34.0% vs. 8.6%). A palmar PMA was reported in 2.6% of patients undergoing surgery for carpal tunnel syndrome when compared to cadaveric studies of adult patients in which the prevalence was 8.6%. Both patterns of PMA are prevalent in a considerable portion of the general population. As the estimated prevalence of the PMA was found to be significantly lower in patients undergoing surgery for carpal tunnel syndrome than those reported in cadaveric studies, its etiological contribution to carpal tunnel syndrome is questionable. Surgeons operating on the forearm and carpal tunnel should understand the anatomy and surgical implications of the PMA and its anatomical patterns.

Anatomical variations and evolution: re-evaluating their importance for surgeons

For several decades, anatomists and biological anthropologists have made an intensive study in anatomical variations in ancestral and living humans. While many anatomical variants do not require clinical attention, some may present diagnostic problems or augur adverse symptoms. It is only in the last few decades that a plausible argument has been made that anatomical changes in human individuals and lineages demonstrate ongoing microevolution. Since the mid-19th century, there has been a reduction in differential mortality. Increased variation of heritable traits is a consequential outcome of relaxation of natural selection. Consequently, this has contributed to various anatomical variations in musculo-skeletal anatomy, vascular anatomy as well as congenital disorders such as spina bifida occulta. The authors argue that surgeons and anatomists should improve their knowledge of evolution and its continuing influence on human morphology. Simply repeating the old mantra that anatomical variations are important because knowledge of them minimizes surgical complications, albeit important, is inadequate.

Recently increased prevalence of the human median artery of the forearm: A microevolutionary change

The median artery has been considered as an embryonic structure, which normally regresses around the 8th week of gestation. However, various prevalences have been reported in adults since the 18th century. Furthermore, in a study by Henneberg and George (1995; Am J Phys Anthropol 96, 329-334), has suggested that increasing prevalence of the median artery during the 20th century was a 'possible secular trend'. The present study, conducted nearly a quarter of a century later, is a continuation of that study. A total of 26 median arteries were found in 78 upper limbs obtained from Australians aged 51 to 101 years, who died in the period 2015-2016, a prevalence rate of 33.3%. Analysis of the literature showed that the presence of the median artery has been significantly increasing (p = .001) over time, from approximately 10% in people born in the mid-1880s to approximately 30% by the end of the 20th century. The significance of the prevalence increased to a p value <.0001, when the results of the present study and other studies conducted by our research team were combined. After removal of the studies that were possibly biased, because of their specific focus on the evolutionary aspects of the median artery, the significance remained at p = .018. The present study provides an example of microevolutionary changes in the internal anatomy of the human body. Second-order polynomial regression of the median artery's prevalence on dates of birth shows that it is now present in 35% of people and predicts that people born 80 years from now will all carry a median artery if the trend continues. When the median artery prevalence reaches 50% or more, it should not be considered as a variant, but as a 'normal' human structure.

Erfolgreiche freie mikrovaskuläre A. radialis-Lappenplastik zur Phalluskonstruktion bei persistierender A. mediana (PMA)

Hintergrund Anomalien des Gefäßsystems des Unterarmes können bei der mikrochirurgischen Hebung einer A. radialis-Lappenplastik von großer Bedeutung sein. Insbesondere bei der Verwendung der fasziokutanen Radialislappenplastik zur Bildung eines Penoids ist auf Grund der erforderlichen Größenausmaße der Lappenplastik eine suffiziente arterielle Versorgung von grundlegender Bedeutung. Beim Auftreten einer persistierenden A. mediana können dabei die Perfusionsverhältnisse im Versorgungsgebiet der A. radialis und der A. ulnaris verändert oder diese sogar vollständig rückgebildet worden sein.

Patienten und Methoden Es erfolgte eine retrospektive Auswertung aller in unserer Klinik durchgeführten Phalloplastiken mit Radialispenoid von Januar 2016 bis Dezember 2018. Bei allen Patienten wurde die Technik nach Gottlieb und Levine oder nach Chang angewandt.

Ergebnisse In der retrospektiv untersuchten Kohorte von 48 Patienten wurde bei zwei Patienten intraoperativ eine persistierende A. mediana gefunden, was einer Inzidenz von 4,2 % entspricht. Bei beiden Patienten gelang die hinsichtlich der Perfusion komplikationslose Bildung eines Radialispenoids ohne Einschränkungen der Lappenperfusion oder der Perfusion der Hand. Eine Literaturübersicht liefert einen Überblick über die Inzidenz auftretender Aberrationen der Vaskularisierung des Unterarmes und die daraus ableitbaren Konsequenzen für die Planung einer A. radialis-Lappenplastik.

Schlussfolgerung Auch im Falle einer verlässlichen mikrochirurgischen Lappenplastik wie der A. radialis-Lappenplastik sollten dem mikrochirurgisch tätigen Chirurgen die Möglichkeiten der anatomischen Varianten der arteriellen Versorgung des Unterarmes, wie das Vorhandensein einer persistierenden A. mediana, bekannt sein. Der standardmäßig durchzuführende Allen-Test liefert in vielen Fällen keine eindeutige Rückschlussmöglichkeit und bedingt somit häufig erst intraoperative Zufallsbefunde. Eine sorgfältige präoperative Planung und Evaluation der Perfusion sowie die Erörterung von Alternativtechniken sind hierbei notwendig.

Branches of ulnar artery in human fetuses: anatomical and morphometric study

PURPOSE

This study was conducted to demonstrate morphological pattern of the ulnar artery and to evaluate morphometrically its anatomical branching pattern in human fetuses.

METHODS

Branching pattern of ulnar artery was evaluated on 121 upper limbs of dissected 63 of formalin-fixed fetus cadavers with gestational age ranging from 17 to 40 weeks. In order to obtain second and third trimester data, according to their gestational age, two groups were determined.

RESULTS

In 79 of all 121 upper limbs (65%) ulnar artery gave anterior and posterior ulnar recurrent arteries as separate branches. In this study frequency of presence of a median artery was 46.28% among total examined 121 upper limbs. Median arteries originated from ulnar artery (3.57%) and from the common interosseous artery (53.57%) and anterior interosseous artery (42.85%). Mean distances of the measured parameters were demonstrated according to the gestational age and differences between group I (second trimester) and group II (third trimester). No statistical difference for groups was observed for gender and between right and left sides.

CONCLUSIONS

Ulnar artery shows predictable patterns during second and third trimester of fetal period and can be suitable access effective alternative for diagnostic and therapeutic coronary interventions. Persistent median artery is important variation and knowledge of its incidence is important for diagnostic difficulties and also during awareness of its injury during surgical approaches.

The estrogen hypothesis of obesity

The explanation of obesity as a simple result of positive energy balance fails to account for the scope of variable responses to diets and lifestyles. It is postulated that individual physiological and anatomical variation may be responsible for developing obesity. Girls in poor families develop greater adiposity than their male siblings, a trend not present in richer environments. This indicates strong influence of estrogen on fat accumulation irrespective of poor socioeconomic conditions. Obesity rates in males and females of developed nations are similar, while in poorer nations obesity is much more prevalent in females. Female to male ratio of obesity correlates inversely with gross domestic product. Therefore, the parity of male and female obesity in developed countries may result from male exposure to environmental estrogen-like substances associated with affluence. These hormonally driven mechanisms may be equally active within both sexes in more developed areas, thereby increasing overall obesity.

New perspectives on evolutionary medicine: the relevance of microevolution for human health and disease

Evolutionary medicine (EM) is a growing field focusing on the evolutionary basis of human diseases and their changes through time. To date, the majority of EM studies have used pure theories of hominin macroevolution to explain the present-day state of human health. Here, we propose a different approach by addressing more empirical and health-oriented research concerning past, current and future microevolutionary changes of human structure, functions and pathologies. Studying generation-to-generation changes of human morphology that occurred in historical times, and still occur in present-day populations under the forces of evolution, helps to explain medical conditions and warns clinicians that their current practices may influence future humans. Also, analyzing historic tissue specimens such as mummies is crucial in order to address the molecular evolution of pathogens, of the human genome, and their coadaptations.

MRI of the median nerve and median artery in the carpal tunnel: prevalence of their anatomical variations and clinical significance

OBJECTIVE

Anatomical variations of the median nerve and the persistent median artery (PMA) in the carpal tunnel (CT) are important to understand for their clinical and surgical significance. The aim of this cohort retrospective study was to investigate the prevalence of aberrant median nerve branches and persistent median artery in the CT in a selected population using magnetic resonance imaging (MRI).

MATERIALS AND METHODS

MR wrist images of 194 patients, 77 males and 117 females, aged 12-80 years were randomly selected and retrieved from our clinical and radiology data base. The MR examinations were performed using either 1.5-T or 3.0-T magnet using a cylindrical receive-transmit wrist coil for all cases. The course of the bifurcation of the median nerve was followed on axial T2-weighted and axial proton density fat saturated images and classified as either proximal, within, or distal to the CT. The flexor retinaculum proximally and the metacarpal bases were used as anatomic landmarks to subdivide these three categories. In addition, the median artery was searched in order to assess the prevalence of its presence inside the CT. A total of 194 wrists were analyzed by two musculoskeletal-trained radiologists. They were blinded on the population age, gender, and the sides of the wrists. Agreement was reached by consensus.

RESULTS

Among the 194 wrists, there was bifurcation of the nerve proximal to the CT in 12 (6.1%) wrists. There was nerve bifurcation within the CT in 36 (18%) wrists. Nerve bifurcation distal to the CT was more frequently observed, occurring in 147 (75%) wrists. Only one nerve trifurcation was seen within the CT. There was no gender predominance for the nerve bifurcation within the tunnel. There were 107 right wrists and 87 left wrists. On the right side, bifurcation of the nerve within the CT was seen in 21 (19.6%) wrists; and on the left side bifurcation of the nerve was present in 15 (17.2%) wrists. Statistically, we found no significant difference in the prevalence of the bifid nerve within the tunnel in the subgroups based on age, gender, or side of the wrists. A persistent median artery (PMA) within the tunnel was observed in 21 (11%) wrists--10 males and 11 females. Of these, four (19%) cases were presented with coexistent PMA and bifid median nerve within the tunnel. Statistically, we found that the two variations are not independent traits, and their covariance is not null.

CONCLUSION

There was a high prevalence of bifid median nerve (19%) and PMA (11%) within the tunnel regardless of gender or age. The PMA was more frequent on the left side.

Secular trend in the opening of the sacral canal: an Australian study

STUDY DESIGN

Computer tomography scans were used to asses the opening of the sacral canal.

OBJECTIVE

We investigated the prevalence of sacral spina bifida occulta in 2 population groups: born 1940 to 1950 and 1980 to 1990.

SUMMARY OF BACKGROUND DATA

Comparison of the prevalence of spina bifida occulta in the first-century Pompeii with that in 20th century European and Mediterranean populations indicates that the degree of the closure of vertebral arches in the sacrum has undergone changes and the prevalence of spina bifida occulta is increasing.

METHODS

Transverse computer tomograph scans and multiplanar reconstruction images of sacra of 100 males and 100 females born 1940 to 1950 and 100 males and 100 females born 1980 to 1990 were used after ethics committee approval.

RESULTS

The individuals born later have significantly more open sacral arches when compared with those born 40 years earlier, especially in the midsacral region. Also, males have open sacral arches in the rostral segments of the sacrum more than females.

CONCLUSION

This study demonstrates a secular trend in the opening of the sacral canal in both sexes that occurred within 2 generations. Also, the increased prevalence of open sacral canal in males suggests a different response between sexes to the forces of evolution.

Hyperostosis frontalis interna: archaeological evidence of possible microevolution of human sex steroids?

Hyperostosis frontalis interna is a restricted bilateral thickening of the frontal endocranial surface, which is frequently found in postmenopausal females today. Surprisingly, this condition had a higher male prevalence in its rare archaeological records. This is again highlighted by the oldest known male European hyperostosis frontalis interna case in an adult Celtic from 100 BC presented here. This unique specimen supports earlier suggestions of the possible microevolution of human endocrine regulation, e.g. by sex steroids, and its pathoanatomical impact.

High prevalence of tarsal coalitions and tarsal joint variants in a recent cadaver sample and its possible significance

Tarsal coalitions (TC) are defined as fibrous (beyond normal ligaments), cartilaginous, or osseous unions of at least two tarsal bones. Most of the clinical studies report the prevalence of TC as <1%, but they disregard the asymptomatic coalitions. Because TC have been associated with pathologic conditions, including degenerative arthritic changes, knowledge of their prevalence has clinical importance. The aim of our study was to establish the prevalence of TC and tarsal joint variants. A total of 114 feet from 62 cadavers (average age = 78 years) without obvious foot pathologies were dissected at the Department of Anatomical Sciences, The University of Adelaide. Ten non-osseous TC in eight subjects were identified: two talocalcaneal and eight calcaneonavicular (occurred twice bilaterally). Variant calcaneonavicular and cuboideonavicular joints were found in 8% and 31% of feet, respectively. Other joint variants included a variable number of talocalcaneal joint surfaces and sesamoid bones. No secondary TC (due to trauma, infections, or neoplasm) were found. Our study demonstrated that the overall prevalence of TC is higher (13%) than previously thought; tarsal joint variations (39%) and sesamoid bones (42%) were common as well. The supposed secular increase in the prevalence of TC as well as the high number of anatomical variants could reflect a short-term response to altered life-style or a microevolutionary trend due to relaxed selection.

Surgical anatomy of the sural and superficial fibular nerves with an emphasis on the approach to the lateral malleolus

The aim of this study was to investigate the risk and to analyse the significance of laceration of the sural and superficial fibular nerves during the surgical approach to the lateral malleolus. The sural and the superficial fibular nerves, and their branches were dissected under x 3 magnifying lenses in 68 embalmed leg-ankle-foot specimens. The specimens were measured, drawn and photographed. In 35% of specimens the superficial fibular nerve branched before piercing the crural fascia, and in all these specimens the medial dorsal cutaneous nerve of the foot was located in the anterior compartment while the intermediate dorsal cutaneous nerve of the foot was located in the lateral compartment. In 35% of specimens the intermediate dorsal cutaneous nerve of the foot was absent or did not innervate any toe. The deep part of the superficial fibular nerve was in contact with the intermuscular septum. Its superficial part was parallel with the lateral malleolus when the nerve pierced the fascia more proximally and oblique to the lateral malleolus when the nerve pierced the fascia distally. In one case the intermediate dorsal cutaneous nerve of the foot was in danger of laceration during a subcutaneous incision to the lateral malleolus. In 7 cases (10%) the sural nerve overlapped or was tangent to the tip of the malleolus. Malleolar nerve branches were identified in 76% of the cases (in 28% from both sources). The sural nerve supplies the lateral 5 dorsal digital nerves in 40% of cases. Our study indicates that during the approach to the lateral malleolus there is a high risk of laceration of malleolar branches from both the sural and the superficial fibular nerves. There is less risk of damage to the main trunk of these nerves, but the 10% chance of laceration of sural nerve at the tip of the malleolus is significant. As the sural nerve supplies the superficial innervation to the lateral half of the foot and toes in 40% of cases, the risk of its laceration is even more important than indicated by the common anatomical teaching.

Anatomically aberrant forearm arteries: an absent radial artery with co-dominant median and ulnar arteries

A radial-artery free flap was dissected from a traumatically amputated forearm. During dissection the arterial tree was found to be abnormal, with no radial artery. The arterial supply was based on co-dominant median and ulnar arteries. This description raises issues regarding anatomical vascular aberrations when planning forearm flaps.