Topohistology of the cranial nerves IX-XII at the cranial base and upper parapharyngeal space: A histological study using human fetuses

The topographical relationships among the lower cranial nerves, internal carotid artery (ICA), and internal jugular vein (IJV) in the upper parapharyngeal neurovascular bundle remain obscure. Thus, details of the anatomy were examined in human fetus histology. We observed the horizontal histological sections from 20 midterm (9-18 weeks) and 12 near-term (28-40 weeks) fetuses. At the external skull base, the glossopharyngeal nerve crosses the anterior aspect of the IJV to reach the medially located Hyrtl's fissure in the petrous temporal bone. The nerve crossed the anterior aspect of the ICA medially near or below the first cervical nerve root. Below the hypoglossal nerve canal, the accessory nerve crosses the anterior or posterior aspects of the IJV and moves laterally. During the half-spiral course, the hypoglossal nerve was tightly attached to the posterolateral-anterior aspects of the vagus nerve and surrounded by a common nerve sheath. The glossopharyngeal ganglia sometimes extended inferiorly to the level of the hypoglossal nerve canal but were absent along the inferior course. The inferior vagal ganglion rarely extends above the occipital condyle. The superior cervical sympathetic ganglion occasionally extends above the first cervical nerve root. The IJV (or ICA) descends to the lateral (or medial) margins of the parapharyngeal neurovascular bundle. The glossopharyngeal (or accessory) nerve crosses the ICA (or IJV) to exit the bundle at the base of the skull (or below the hypoglossal nerve canal). The glossopharyngeal and vagus inferior ganglia differ at each site.

Thoracolumbar fascia in the lumbar region: anatomical description and topographical relationships to the cutaneous nerves: a preliminary study

BACKGROUND

The study aims to determine principal topographical relations between thoracolumbar fascia (TLF) and lateral branches derived from the dorsal (posterior) rami of lumbar spinal nerves and elucidate their potential link to lumbar region pain. The research protocol involves basic TLF morphological description, evaluating its relation to the nerves, and examining general histology.

MATERIALS AND METHODS

The research was conducted on four male cadavers fixed in 10% neutral buffered formalin.

RESULTS

The dorsal rami of the spinal nerves branched into medial and lateral divisions. The lateral divisions were about 1 mm thick and mainly visible in the subcutaneous tissue during stratigraphic dissection. They pierced the TLF superficial layer. They descended sidewards and downwards within the superficial fascia (laterally to the erector spinae muscle) to provide sensory innervation to the skin.

CONCLUSIONS

Anatomical relationships between TLF, deep (intrinsic or true) back muscles, and dorsal rami of the spinal nerves are complex and may be clinically involved in low back pain etiopathogenesis.

Surgical Anatomy of the Mesopancreas in Obese Patients: A Retrospective Study

Introduction The mesopancreas is described as a triangle formed by the superior mesenteric vein, celiac axis (CA), and superior mesenteric artery (SMA). It is the most likely site of residual cancer and local recurrence after surgical resection, making it the key site of the current radical resection of pancreatic head cancer. The surgical anatomy of the mesopancreas triangle has not been studied in detail. Furthermore, to the best of our knowledge, no information is available on the impact of obesity on the anatomy of the mesopancreas triangle. Methods Between January 2016 and August 2016, 200 consecutive triple-phase computed tomography scans of the abdomen were performed and included in this retrospective study aiming to define the anatomical relation of the left renal vein (LRV) to the root of the SMA and focusing on the relevance of the LRV as a landmark to guidance for the dissection of the mesopancreas. Furthermore, by studying six surgically relevant anatomical parameters namely the thickness of the areolar tissue separating the LRV from the root of the SMA, IVC from the root of the SMA, the left adrenal vein (LAV) from the root of the SMA, splenic vein from the aorta, and CA from the SMA at two levels, we investigated the impact of obesity on the mesopancreas anatomy. Results The mean distance from the upper border of the LRV to the root of the SMA (LRV-SMA distance) was 2.3 ± 5.4 mm. There was no correlation between this distance and patient's age (r = -0.02), height (r = -0.07), BMI (r = -0.01), visceral fat area (r = -0.04), or abdominal circumference (r = -0.02). There was no correlation between the distance from the IVC to the root of the SMA, and patient's age (r = 0.01), height (r = 0.11), BMI (r = 0.15), or abdominal circumference (r = 0.00). However, there was a negligible correlation between the IVC-SMA distance and patient's visceral fat area (r = 0.15, p = 0.036). Conclusion In the current study, the LRV was reliably identified in more than 99% of the studied patients, and in 96% of patients, the LRV crosses anterior to the aorta at the level of the second lumbar vertebra, making it easily accessible following mobilization of the duodenum and the head of the pancreas. The relationship between the LRV and SMA remains unchanged following Kocherization. Most importantly, we demonstrated that the LRV-SMA distance does not correlate with patient's age, height, BMI, visceral fat area, or abdominal circumference. This makes the LRV a reliable landmark in both obese and non-obese patients.

Topographical Anatomy of the Rhesus Monkey (Macaca mulatta)-Part I: Thoracic Limb

Since the rhesus monkey (Macaca mulatta) is genetically closely related to man, it is generally accepted that its anatomy and physiology are largely similar to that of humans. Consequently, this non-human primate is most commonly used as a model in biomedical research. Not only the validation of the obtained research data, but also the welfare of the captive rhesus monkeys are subject to thorough anatomical knowledge of this species. Unfortunately, anatomical literature on the rhesus monkey is scarce, outdated, and hardly available at present. Furthermore, its anatomy is only illustrated by means of line drawings or black-and-white photographs. Thus, the aim of this study was to describe the anatomy of the thoracic limb of the rhesus monkey topographically, studying the various anatomical structures in relation to each other. In this manuscript, the anatomy of the thoracic limb is described per region. The structures that are visible on the different layers, from the superficial to the deepest layer, are described both in text and in numerous color images. As expected, the anatomy of the rhesus monkey is almost identical to human anatomy. However, some striking differences have been identified. This supports the necessity for an extensive publication on the anatomy of the rhesus monkey.

Cross-sectional representations of the central nervous system in Pirogov's "Ice Anatomy"

Russian surgeon Nikolay Ivanovich Pirogov (Pirogoff; 1810-1881) introduced the teaching of applied topographical anatomy in Russia. Pirogov's monumental four-part atlas, Anatome topographica sectionibus per corporis humanum congelatum triplici directione ductis illustrate (An Illustrated Topographic Anatomy of Saw Cuts Made in Three Dimensions Across the Frozen Human Body), colloquially known as the "Ice Anatomy," was published in Latin in folio in the 1850s. Pirogov sought to investigate "the normal and pathological positions of different organs and body parts using sections made in the three principal directions [anatomical planes] … throughout all regions." To accomplish this, he froze cadavers "to the density of the thickest wood" and then cut them into thin plates with a special mechanical saw. His approach was reportedly inspired by his observations of butchers sawing across frozen pig carcasses at the meat market in St. Petersburg during winter. Pirogov systemically obtained full-size representations of more than 1,000 sections. A painter made a representative copy of the cross-sectional contours of each section, using ruled glass overlain on the sections. The final lithographs were of high artistic quality and execution, resembling modern high-resolution medical imaging (i.e., CT or MRI). Moreover, structures were serially sectioned and systematically illustrated along all three anatomical planes, something that had never previously been attempted. This allowed clinicians and anatomists to scrutinize the spatial relationships of structures from multiple perspectives and at a much more detailed level than was previously possible, although the cost, massiveness, and complexity of the completed work precluded wide dissemination.

Professor Paul Jules Tillaux (1834-1904): His Contribution to Surgery and His Unknown Pioneer Work in Ophthalmic Surgery

Backround. Professor Paul Jules Tillaux (1834-1904) is considered to be a leading figure in the field of surgery during the 19th century. Methods. Although his work is mostly linked to orthopedic operations, he contributed a lot in ophthalmology and ophthalmic surgery too. Results. In addition, his masterpieces on topographical anatomy and clinical surgery became the gold standard treatises of the era.

Left/right difference in the course and division of the pulmonary arterial branches in the lung upper lobe: A study using human embryos and early fetuses

Although left/right differences in a configuration of the pulmonary artery (PA) and its branches are well known, there is little information as to when and how such differences are established. Examination of serial sagittal sections of 25 embryos and fetuses at 6-7 weeks of gestation demonstrated that, at O'Rahilly stages 18-20, the right earliest first branch of PA originated in the anterior side of the upper lobar bronchus and overlay the upper bronchi, in contrast to the left branch which was located posteriorly and constricted medially by the upper posterior bronchus B1 + 2b. The right earliest branch was most likely to correspond to the future superior trunk, while the left branch might be a lingual artery. At stages 21-23, the upper posterior parenchyma was still underdeveloped in the left lung, since the ductus arteriosus and the left common cardinal vein seemed to make the left upper thoracic cavity narrow. Conversely, in the right lung, the thick S2 seemed to require a double arterial supply from both the superior and inferior arterial trunks. On the left, A3 originated at the lung apex and took a long descending course along the lung anterior surface. This high position of A3 might soon be corrected by an increased volume of S3. Overall, in contrast to the lower and middle lobes, early-developed branches of the PA did not accompany upper segmental and subsegmental bronchi. A mechanism "differential growth" seemed to explain how to correct the fetal morphology to provide the adult morphology with variations.

Three-dimensional analysis of the segmental arrangement of lower lung lobes in human fetuses: is this arrangement a miniature version of adult morphology?

Knowledge of the lung segment system is essential for understanding human anatomy and has great clinical relevance. The arrangement of 11 segments, including the S* or subsuperior segment, and its individual variations, are considered to be the same in fetal and adult lungs. The present study assessed the topographical anatomy of lower segmental and subsegmental bronchi by computer-assisted three-dimensional imaging of serial sagittal sections of both lungs of 22 embryos and fetuses of gestational age 6-7 weeks (crown-rump length 15.0-28.5 mm). Long inferior courses of B8b (basal) and B10c (medial) were observed in sagittal sections of both lungs. B8a (lateral) and B10b (lateral) in the right lungs were consistently underdeveloped, with S9 occupying most of the lateral half of the lower lobe. In some samples, B6b (lateral) did not reach the lateral surface. The lateral dominance of S9 was also seen in the left lungs. Some B* candidates were present, but B7 candidates were absent. Lateral and posterior expansions of S6b, S8a and S10b to cover S9 were observed in additional midterm and near-term lung sections, indicating that the original S9 dominance was 'corrected' by an increase in lung volume. Delayed growth of the lower lateral subsegments might induce mechanical stress, resulting in aberrant notches or fissures, such as those separating an independent posterior lobe. The segmental arrangement of fetal lungs was not stable, but was altered over a long fetal period after the complete subsegmental division of the bronchi, except for the minor bronchi B* and B7.

Estimating the Mobility of the Michaelis Sacral Rhombus in Pregnant Women

Pelvic mobility is the cornerstone of an adequate birth canal for safe childbirth, and midwives invite pregnant women to assume loading positions to facilitate delivery. Biomechanics asserts that pelvic space changes in shifting positions from erect to the squat position. The current standard practice in obstetrics and osteopathy provides a qualitative observational assessment of the dimension of Michaelis sacral rhombus in shifting positions; a previous report presented a clinical method and instrument to estimate the pelvic range of motion through finger contact on bone landmarks. The present study aims to match the measurement of the diameters of the sacral area of Michaelis from skin marks with the amount from bone landmarks. Methods estimate the sacral area from 100 pregnant women in the late trimester, considering the dimension of the diameters, the range of motion, and the patterns of mobility. Differences resulted in the methods: measuring the skin marks in shifting positions revealed a not significant difference between starting position and squat position. The measurements through the finger contact on the bone landmarks seem to be adequate to estimate pelvic mobility fulfilling the expectation from biomechanics literature.

Vermiform Appendix During the Repackaging Process from Umbilical Herniation to Fixation onto the Right Posterior Abdomen: A Study of Human Fetal Horizontal Sections

The anatomical position of the vermiform appendix varies among adults, and these variations are responsible for differences in the symptoms of appendicitis. However, to date no study has examined how and when these variations occur during fetal development. The present study examined horizontal sections of 27 midterm fetuses (crown rump length [CRL] 38-97 mm, gestational age approximately 8-15 weeks). There were 10 fetuses (CRL 56 mm or more) in which the cecum and appendix were in a posterosuperior site near the right kidney (postmigration phase), and 12 fetuses (CRL 39-72 mm) in which the ileocecal junction and appendix remained on the visceral surface of the liver in the anterior or anterolateral abdominal cavity (migration phase, after physiological umbilical herniation). Analysis of the 12 fetuses in the migration phase indicated that the appendix extended inferiorly in eight fetuses and superiorly in four fetuses. Likewise, a "preileal" appendix (a morphology in which the distal part of the appendix was in front of the terminal ileum) was present in eight of these fetuses. Extension of the appendix superiorly or inferiorly during the migration phase seems unrelated to the topographical relationship of the appendix with the terminal ileum at the postmigration phase in fetuses and in adults. Conversely, it seems likely that a retroileal appendix leads to a coiled appendix behind the ileocecal junction. "Guidance" by the liver surface seemed to be important for posterior migration, which ended with the ascent of the liver. Clin. Anat., 33:667-677, 2020. © 2019 Wiley Periodicals, Inc.

Anatomy Teaching, a "Model" Answer? Evaluating "Geoff", a Painted Anatomical Horse, as a Tool for Enhancing Topographical Anatomy Learning

Development of new methods for anatomy teaching is increasingly important as we look to modernize and supplement traditional teaching methods. In this study, a life-sized equine model, "Geoff," was painted with surface and deep anatomical structures with the aim of improving students' ability to convert theoretical knowledge into improved topographical anatomy knowledge on the live horse. Third and fourth year veterinary medicine students (n = 45) were randomly allocated into experimental (used "Geoff") and control (used textbook) groups. The efficacy of the model was evaluated through a structured oral exam using a live horse. Questionnaires gathered information on student confidence and enjoyment of the task. There was no significant difference in the performance of experimental and control groups either immediately (44±20% vs. 40±21%; P = 0.504) or 9 weeks after the learning intervention (55±17% vs. 55±20%; P = 0.980). There were however specific questions on which the experimental group performed better than controls, and for which gender effects were apparent. The students using "Geoff" showed a transient gain in confidence following the session (Likert scale 2.7 to 3.6) however the initial increase was no longer present at the second test. There was a significant influence of gender on confidence with greater confidence gains in females in the Experimental group. The students found the model to be extremely useful and both groups found the sessions enjoyable. The model will be of benefit as a complementary learning tool for students.

Changes in topographical relation between the ductus arteriosus and left subclavian artery in human embryos: a study using serial sagittal sections

BACKGROUND

At birth, the ductus arteriosus (DA) merges with the aortic arch in the slightly caudal side of the origin of the left subclavian artery (SCA). Since the SCAs (7th segmental arteries) were fixed on the level of the 7th cervical-first thoracic vertebral bodies, the confluence of DA should migrate caudally. We aimed to describe timing and sequence of the topographical change using serial sagittal sections of 36 human embryos and foetuses (CRL 8-64 mm; 5-10 weeks), Those made easy evaluation of the vertebral levels possible in a few section.

MATERIALS AND METHODS

The DA or 6th pharyngeal arch artery seemed to slide down in front of the sympathetic nerve trunk along 1.0-1.2 mm from the second cervical vertebral level at 5-6 weeks and, at 6 weeks (CRL 14-17 mm), the DA confluence with aorta reached the 7th cervical level. Because of the highly elongated common carotid artery, the sliding of DA confluence seemed to be much shorter than the cervical vertebrae growing from 1 mm to 2.4 mm.

RESULTS

At the final topographical change at 6-7 weeks, the DA confluence further descended to a site 1-vertebral length below the left SCA origin. From 6 to 9 weeks, a distance from the top of the aortic arch to the left SCA origin was almost stable: 0.3-0.5 mm at 6 weeks and 0.4-0.6 mm at 9 weeks.

CONCLUSIONS

The heart descent and the caudal extension of the trachea and bronchi, those occurred before the DA sliding, were likely to be a major driving force for the sliding.

Nikolay Ivanovich Pirogov (1810-1881): A pioneering Russian surgeon and medical scientist

Nikolay Pirogov qualified as a physician from Moscow University in 1828 and then studied surgery and anatomy at University of Dorpat. He developed new surgical techniques, including the eponymous osteoplastic foot amputation. His application of scientifically based techniques extended surgery from a craft to a science. During the Crimean War he initiated the deployment of women as nurses and used triage for dealing with mass casualties. His textbook on field surgery became the standard reference on the subject and his principles remained virtually unchanged until the Second World War. Pirogov died on 5 December 1881 at his estate in Vishnya.

Anatomical relationship and positions of the lumbar and sacral segments of the spinal cord according to the vertebral bodies and the spinal roots

Segments of the spinal cord generally do not correspond to the respective vertebral level and there are many anatomical variations in terms of the segment and the level of vertebra. The aim of this study is to investigate the variations and levels of lumbar and sacral spinal cord segments with reference to the axilla of the T11, T12, and L1 spinal nerve roots and adjacent vertebrae. Morphometric measurements were made on 16 formalin fixed adult cadaveric spinal cords. We observed termination of the spinal cord between the axilla of the L1 and L2 spinal nerve roots in 15 specimens (93.8%). In all cadavers the emergence of the T11, T12, and the L1 spinal nerve roots was at the level of the lower one-third of the same vertebral body. In 15 specimens (93.8%), the beginning of the lumbar spinal cord segment was found to be above the T11 spinal nerve root axilla and corresponded to the upper one-third of the T11 vertebral body. The beginning of the sacral spinal cord segment occurred above the L1 spinal nerve root axilla and corresponded to the upper one-third of the L1 vertebral body. The results of this study showed that when the conus medullaris is located at the L1-L2 level, the beginning of the lumbar spinal cord segment always corresponds to the body of T11 vertebra. This study provides detailed information about the correspondence of the spinal cord segments with reference to the axilla of the spinal nerve roots.