Nerve Passes Research Articles

Osteoclast activity sculpts craniofacial form to permit sensorineural patterning in the zebrafish skull.

Efforts to understand the morphogenesis of complex craniofacial structures have largely focused on the role of chondrocytes and osteoblasts. Along with these bone-creating cells, bone-resorbing osteoclasts are critical in homeostasis of adult skeletal structures, but there is currently limited information on their role in the complex morphogenetic events of craniofacial development. Fundamental aspects of skull formation and general skeletal development are conserved from zebrafish to mammals. Using a cathepsinK reporter, we documented osteoclast location in the developing zebrafish skull over several weeks, from 5.18mm to 9.6mm standard length (approximately 15 to 34 days post fertilization). While broad distribution of osteoclasts is consistent across individuals, they are sparse and the exact locations vary among fish and across developmental time points. Interestingly, we observed osteoclasts concentrating at areas associated with neuromasts and their associated nerves, in particular the hyomandibular foramina and around the supraorbital lateral line. These are areas of active remodeling. In contrast, other areas of rapid bone growth, such as the osteogenic fronts of the frontal and parietal bones, show no particular concentration of osteoclasts, suggesting that they play a special role in shaping bone near neuromasts and nerves. In csf1ra mutants lacking functional osteoclasts, the morphology of the cranial bone was disrupted in both areas. The hyomandibular foramen is present in the initial cartilage template, but after the initiation of ossification, the diameter of the canal is significantly smaller in the absence of osteoclasts. The diameter of the supraorbital lateral line canals was also reduced in the mutants, as was the number of pores associated with neuromasts, which allow for the passage of associated nerves through the bone. Our findings define important and previously unappreciated roles for osteoclast activity in shaping craniofacial skeletal structures with a particular role in bone modeling around peripheral cranial nerves, providing a scaffold for wiring the sensioneural system during craniofacial development. This has important implications for the formation of the evolutionarily diverse lateral line system, as well understanding the mechanism of neurologic sequelae of congenital osteoclast dysfunction in human craniofacial development.

Multiple dimensions of radiographic reconstruction for the optimal operative strategy of sacral meningeal cysts

Background and purposeThe contents and subtypes of sacral cysts are sophisticated in many cases. We applied multiple dimensional magnetic resonance imaging (MRI) reconstruction to preoperatively clarify the specific subtype of sacral meningeal cysts.Materials and methodsWe preoperatively used multimodal neural reconstruction MRI sequences to evaluate 76 patients with sacral cysts. The linear nerve roots were precisely traced based on sagittal or coronal images processed at various angles and levels which was conducive to the design of the operation strategy.ResultsCysts with nerve passage were detected in 47 cases (62%, 47/76), whereas cysts without nerve roots were detected in 24 cases (32%, 24/76). Five patients had mixed cysts with or without nerve roots. Intraoperative exploration results proved the high accuracy of image reconstruction; only one cyst without a nerve root was misdiagnosed prior to surgery.ConclusionMRI reconstruction based on the three-dimensional fast imaging employing steady-state acquisition T2 sequence precisely tracked the nerve roots of sacral cysts and guided the optimal strategy during surgery.

Study of suprascapular notch converted into a foramen in adult human scapulae in Karnataka region

Scapula is a triangular bone present in the back, which articulates with the humerus and clavicle forming the shoulder girdle. In the superior border of the scapula there is a notch called the suprascapular notch, through which the suprascapular nerve pass. The suprascapular nerve can be compressed by the ossified part of the transverse scapular ligament a cause for neuropathies.The present study was done on adult scapulae in department of Anatomy SUIMS & R.C. Shimoga, where the transverse scapular ligament [TSL] was ossified in 10 scapulae out of 127 adult dry scapulae [7.87%] studied of unknown sex. It was also noted that 6 out of 10 scapulae belonged to the right side & 4 to left side showing a slight preponderance to the right side. Incidence of the complete suprascapular foramen varies from one geographical region to other region, work nature of indivisuals and is variable with the samples collected by different workers for the study.The compresssion of the suprascapular nerve is an acquired neuropathy leading to neuromuscular deficits and decrease in the range of motion of the shoulder. Suprascapular nerve blocks are given in this region. The knowledge of this type of nerve compression is helpful for evaluation of patients with neurovascular deficits to orthopedicians, radiologists, anaesthetists and surgeons in their clinical practice.

Remodeling of the hyomandibular skeleton and facial nerve positioning during embryonic and postembryonic development of teleost fish

The vertebrate skeleton changes its shape during development through the activities of chondrocytes, osteoblasts and osteoclasts. Although much is known about the mechanisms for differentiation in these cells, it is less understood how they behave in a region-specific manner to acquire unique bone shapes. To address this question, we investigated the development of the hyomandibular (Hm) system in zebrafish. The Hm originates as cartilage carrying a single foramen (the Hm foramen), through which the facial (VII) nerve passes. We reveal that Schwann cells, which myelinate the VII nerve, regulate rearrangement of the chondrocytes to enlarge the Hm foramen. The Hm cartilage then becomes ossified in the perichondrium, where the marrow chondrocytes are replaced by adipocytes. Then, the bone matrix along the VII nerve is resorbed by osteoclasts, generating a gateway to the bone marrow. Subsequent movement of the VII nerve into the marrow, followed by deposition of new bone matrix, isolates the nerve from the jaw muscle insertion. Genetic ablation of osteoblasts and osteoclasts reveals specific roles of these cells during remodeling processes. Interestingly, the VII nerve relocation does not occur in medaka; instead, bone deposition distinct from those in zebrafish separates the VII nerve from the muscle insertion. Our results define novel mechanisms for skeletal remodeling, by which the bone shapes in a region- and species-specific manner.

Surgical anatomy of the lateral femoral cutaneous nerve for meralgia paraesthetica: A simple technical guide for surgeons and trainees alike

Meralgia paraesthetica is an entrapment neuropathy of the lateral femoral cutaneous nerve, usually due to compression at the inguinal ligament as the nerve passes from the pelvis into the thigh. Surgical decompression of the lateral femoral cutaneous nerve is a simple and effective treatment option, but the surgical anatomy of the area is not always familiar to neurosurgeons and neurosurgical trainees alike. This paper is a simple review of the relevant surgical anatomy and the surgical steps of lateral femoral cutaneous nerve decompression, with the aim of providing the busy surgeon and trainee a quick and easy reference guide to the procedure.

Morphometric analysis of mandibular notch in dry human mandibles- A surgeon's guide to the masseteric nerve block

Background: The mandibular notch allows passage of masseteric vessels and nerve to the deep aspect of the masseteric muscle. The existing data gives a fairer idea in locating the masseteric nerve but does not consider much of the various shapes and sizes of the masseteric notch into account. Hence the present study analyses the various size and shapes and depths of the mandibular notch to achieve a more accurate method for masseteric nerve block. Thus, this investigation intends to examine the morphology and morphometry of mandibular notch in the mandibles of the South Indian people. Methods: The morphometric parameters of the mandibular notch were examined in 102 dry mandibles of the peoples of South Indian. The morphometric parameters were estimated by a digital vernier caliper and data was analyzed statistically. Results: The results of this study showed a round-shaped mandibular notch to be the most frequent type on the right side (43.1%) whereas it was 25.5% on the left side. The length and depth from gonion to notch showed a substantial variance between right and left bone (p=0.41), (p= 0.43) respectively, but with respect to width of the notch no significant difference was observed. Conclusion: This study demonstrates that population specific and side-specific variations may be present in the mandibular notch measurements. Knowledge on variations in incisura mandibularis is of significance in maxillofacial surgeries and reconstructive operations. Keywords: Mandibular notch, masseteric vessels, masseteric nerve block, morphometry

Median Nerve Passing below the Ulnar Head of Pronator Teres in Cadavers of a Medical College in Western Nepal: A Descriptive Cross-sectional Study.

Median nerve passes between two heads of pronator teres muscle while passing through the elbow. Detailed knowledge of these variations in the course of Median Nerve in relation to pronator teres and its neighboring structure is required for diagnosis of pronator syndrome. The aim of the study is to find out the proportion of Median Nerve passing below the ulnar head of pronator teres in cadavers of a medical college in Western Nepal. A descriptive cross-sectional study was carried out at the Department of Anatomy in a medical college of Nepal from 20th July 2021 to 2nd September 2021 after ethical clearance from the same institution (Reference number: UCMS/IRC/079/21). Variations in the course of the median nerve while passing through pronator teres were observed, recorded and photographed. Convenience sampling method was used. Data were analyzed using Microsoft Excel 2016. Point estimate at 95% Confidence Interval was calculated along with frequency and percentage. Out of 54 prosected specimens of upper limbs, 4 (7.40%) (0.418-14.38 at 95% Confidence Interval) Median Nerve passed below the ulnar head of pronator teres muscle and in 50 (92.60%) specimens Median Nerve passed between two heads of pronator teres. Our study shows that the median nerve passed below the ulnar head of pronator teres muscle is higher as compared to other studies done in similar settings. Thus, knowledge of variations in the course of Median Nerve in elbow has immense importance in the academic and clinical arena.

Trigger electromyography in endoscopic transnasal surgery of skull base tumors

Introduction . The development of minimally invasive technologies in recent decades has expanded the indications for the use of endoscopic transnasal transsphenoidal approaches in surgery of skull base tumors. It became possible to perform surgical interventions aimed at removing tumors of the base of the skull that spread to the area of the passage of cranial nerves (cavernous sinus, clival area, cerebello-pontine angle), which is associated with the risk of damage to certain cranial nerves. The study objective is to evaluate the effectiveness of trigger electromyography in providing anatomical and functional preservation of cranial nerves during endoscopic endonasal transsphenoidal removal of skull base tumors. Materials and methods . The study is based on statistical analysis and comparison of the results of surgical treatment of two groups of patients with various tumors of the base of the skull: the main group (30 patients with using trigger electromyography to identify cranial nerves intraoperatively) and the control group (43 patients without using this method). The effectiveness and safety of using the method of intraoperative identification of cranial nerves was evaluated based on a comparison of basic characteristics, treatment outcomes, and factors potentially affecting them. Results . Fifty-seven (57) cranial nerves were identified intraoperatively in the main group. The frequency of radical removal was 1.6 times higher in the main group (70 % vs 44.2 %, p = 0.03). When analyzing the dynamics of the state of motor cranial nerves after surgery in the main and control groups, it was shown that negative dynamics prevailed in the control group — 37.2 % vs 13.3 % (p = 0.03), and positive dynamics prevailed in the main group (37.3 % vs 13.9 %), 2.8 times (p = 0.08). Conclusion . The obtained data indicate that the use of the intraoperative identification method in endoscopic transnasal surgery of skull base tumors can positively affect the radical removal of tumors and the preservation of cranial nerve function in the postoperative period.

Obturator nerve block

One of the forgotten techniques of regional anesthesia is blockade of the obturator nerve, which was performed using anatomical landmarks and neurostimulation. In recent years, ultrasonic navigation methods have gained wide popularity when using regional blockades. The purpose of the review is to present the current understanding of the use of obturator nerve block in clinical practice. The review presents the anatomical features of the obturator nerve passage, surgical and therapeutic indications for the use of its blockade. The technique for performing obturator blockade using ultrasound navigation is described in detail. Blockade of the obturator nerve using ultrasound navigation can reduce the likelihood of surgical complications during transurethral resection of a tumor located on the lateral wall of the bladder, improve analgesia after hip and knee surgery, and effectively relieve spastic conditions of the adductor muscles of the hip.

ЗАКОНОМЕРНОСТИ АНАТОМИИ И ТОПОГРАФИИ ГОРТАННЫХ НЕРВОВ У ВЗРОСЛОГО ЧЕЛОВЕКА ПО ДАННЫМ ЛИТЕРАТУРЫ

Establishing the morphological regularities of laryngeal nerves of the human is extremely important in surgical and oncological practice. During surgical intervenrions on the thyroid gland, damage of the superior and inferior laryngeal nerves can occur — the second most common complication after hypoparathyroidism. Based on the studied literature data on anatomy and topography of the laryngeal nerves in an adult, a number of the morphological features have been identified. The article describes the morphometric parameters of the laryngeal nerves and their branches. Also, the article describes variants of the localisation of the internal branch of the superior laryngeal nerve relatively to the superior laryngeal artery, a number of classifications based on the localisation of the external branch of the superior laryngeal nerve relatively to the superior thyroid artery and the inferior laryngeal constrictor, variants for the inferior laryngeal nerve passage in tracheoesophageal groove, its location in relation to the trunk and branches of the inferior thyroid artery, Berry's ligament, Zuckerkandl's tubercle and also such anatomical features of the inferior laryngeal nerve as its extralaryngeal branching and cases of non-recurrent laryngeal nerve. These topographic and anatomical features of the laryngeal nerves that should be taken into account for the identification of the nerves during surgery, and also allows them to be considered prerequisites for an increased risk of iatrogenic trauma.

Morphometric Study of Suprascapular Notch and Its Variations in Dried Human Scapulae

The study was undertaken to see the variation of the suprascapular notch. The notch is present on the superior border of the scapula near the root of coracoid process. It is roofed by the superior transverse ligament and is converted into foramen for the passage of suprascapular nerve. The study was carried out on 121 scapulae in the department of Anatomy RMC Loni, Ahmednagar. The parameters included in the study were presence of notch, shape of notch, transvers length of notch, edge of notch, ossification of transverse ligament and other finding were also noted. The parameters were measured by Vernier calliper and appropriate statistical tests were applied.
 The supra-scapular notch was present in 82.64% of scapulae. U Deep shaped notch was most common shape followed by J shallow shaped notch. Round edge at the depth of the notch was more common.
 The knowledge of suprascapular notch variations is of great importance for surgeons performing suprascapular nerve decompression especially by means of endoscopic techniques. Our anatomical study helps the clinicians before planning a surgery.

Defining the proximity of the axillary nerve from defined anatomic landmarks: an in vivo magnetic resonance imaging study

The location of the axillary nerve in the shoulder makes it vulnerable to traumatic or iatrogenic injury. Cadaveric studies have reported the location of the axillary nerve but are limited because of tissue compression, dehydration, and decay. Three-Tesla (T) magnetic resonance imaging (MRI) allows high anatomic resolution of neural structures. The aim of our study was to better define the location of the axillary nerve from defined bony surgical landmarks invivo, using MRI scan. Using MRI, we defined a number of anatomic points and measured the distance from these to the perineural fat surrounding the axillary nerve using simultaneous tracker lines on both images. Two observers were used. A total of 187 consecutive 3-T MRI shoulder scans were included. Mean age was 57.9 years (range 18-86). The axillary nerve was located at a mean of 14.1 mm inferior from the bony glenoid at the anterior border, 11.9 mm from the midpoint, and 12.0 mm from the posterior border. There was a significant difference between distance at the anterior border and midpoint (P < .001), and between the anterior and posterior borders (P < .001). The axillary nerve was located at a mean of 12.6 mm medial to the humeral shaft at the anterior border, 9.9 mm at the midpoint, and 8.6 mm from the posterior border. There was a significant difference between distance at the anterior border and midpoint (P = .008) and between the anterior and posterior borders (P = .002). The mean distance of the axillary nerve from the anterolateral edge of the acromion was 53.3 mm (95% confidence interval [CI] 52.3, 54.2; range 33.9-76.3). The mean distance of the axillary nerve from the inferior edge of the capsule was 2.7 mm (95% CI 2.9, 3.1; range 0.3-9.9). There was a positive correlation between humeral head diameter and axillary nerve distance from the inferior glenoid (R2 = 0.061, P < .001). There was a positive correlation between humeral head diameter and distance from the anterolateral edge of the acromion (R2 = 0.140, P < .001). Our study has defined the proximity of the axillary nerve from defined anatomic landmarks. The proximity of the axillary nerve to the inferior glenoid and medial humeral shaft changes as the axillary nerve passes from anterior to posterior. The distance of the axillary nerve from the anterolateral edge of the acromion remains relatively constant. Both sets of distances may be affected by humeral head size. The study has relevance to the shoulder surgeon when considering "safe zones" during arthroscopic or open surgery.

Fetal topography of branches of the cervical and thoracic divisions of the vagus nerves

The study of age and individual anatomical variability of vagus nerves and their branches in different age periods of human ontogenesis causes interest among both morphologists and doctors of different specialties.The aim of the study. To find out the topography of the cervical and thoracic divisions of the vagus nerves in human fetuses aged from 4th to 10th gestational months.Materials and methods. The research was conducted on 75 preparations of human fetuses ranging from 81.0 to375.0 mm in parietal-coccygeal length (PCL) using methods of macro-microscopic dissection and morphometry.Results. In human fetuses, the left vagus nerve is placed anteriorly to the left subclavian artery, then on the lateral surface of the Botallo’s arterial duct and the aortic arch. In the neck region, the superior cardiac branch departs from the left vagus nerve and goes to the anterior surface of the left common carotid artery.In the inferior part of the left common carotid artery, the superior cardiac branch gives off two branches: the middle one reaches the aortic arch wall, and the lateral one runs along the anterior surface of the left common carotid artery. The left recurrent laryngeal nerve departs from the left vagus nerve at the level of the inferior border of the aortic arch. The right vagus nerve passes from the right subclavian artery anteriorly and gives rise to the right recurrent laryngeal nerve, which continues inferiorly and posteriorly around the subclavian artery. The superior cardiac branch originates from the right vagus nerve at the level of the inferior border of the thyroid gland. The inferior cardiac branch departs inferiorly and medially from the right laryngeal nerve and is located on the right anterolateral surface of the trachea.Conclusions. During the fetal period of human ontogenesis, age and individual anatomical variations of the branches of the cervical and thoracic vagus nerves is observed, which is manifested by the variability of the structure, asymmetry of the topography of the recurrent laryngeal nerves, bronchial, esophageal and cardiac branches. The left recurrent laryngeal nerve departs from the left vagus nerve at the level of the inferior border of the aortic arch, the right recurrent laryngeal nerve departs from the right vagus nerve at the level of the right subclavian artery. The esophageal nervous plexus is formed by esophageal branches of the vagus nerves, which then forms mainly the posterior vagal trunk. The anterior vagal trunk is a direct continuation of the left vagus nerve branches. The innervation of the aortic arch involves the common cardiac trunk, which is formed by the superior cardiac branch and the superior cardiac nerve and also anastomoses both with vagus nerve and with recurrent laryngeal nerves.

Effect of Nd: YAG laser irradiation to the temporomandibular joint on taste threshold

Background/purposeThe tissue absorption laser has been clinically applied to alleviate pain in various areas. It is used for pain relief from temporomandibular disease (TMD) in dentistry. Although the facial and trigeminal nerves are distributed around the temporomandibular joint, the effects of laser irradiation and absorption on the neural functions have not been directly studied. In this study, the Nd:YAG laser was applied to an area where the facial nerve passes with photonic radiation for the treatment of TMD. Materials and methodsTen volunteers including seven males and three females were selected as subjects. Nd:YAG laser was irradiated area included several internal and external standard and associated acupuncture points. The chorda tympani nerve, a branch of facial nerve is distributed to the front two thirds of the tongue and is associated with the sense of taste. We evaluated the effect of laser irradiation and absorption on the taste function by means of an electric taste meter. ResultsNo significant difference was identified in the values between before and after laser irradiation (Wilcoxon signed-rank test). ConclusionIt was confirmed that there was no effect on taste function while applying Nd:YAG laser irradiation around the TMD joint.

Anatomy of the posterior branch of the medial antebrachial cutaneous nerve: A cadaveric study

PurposeThe posterior branch of the medial antebrachial cutaneous nerve (MACN) is at risk to be damaged during cubital tunnel surgery. The purpose of this study was to identify the location of the posterior branch of the MACN (PBMACN) in relation to surgical landmarks pertinent in cubital tunnel surgery. MethodsWe performed an anatomical study on 20 limbs from 13 fresh cadavers. The nerve was dissected from 10cm proximal to 10cm distal of the medial epicondyle. We measured the distance between the nerve and the medial epicondyle, and also the distance separating the PBMACN from the ulnar nerve passage between the two heads of the flexor carpi ulnaris. Measurements were performed with the elbow at 45° and 90° of flexion, as well as in full pronation and supination. ResultsAfter its emergence from the main trunk of the MACN, the posterior branch ran anteriorly to the medial epicondyle, taking an oblique direction toward the ulnar shaft. The PBMACN was in average 2.53cm under the medial epicondyle when the elbow was flexed at 45°, and 2.96cm when the elbow was flexed at 90°. Average distance between the PBMACN and the penetrating point of the ulnar nerve within the flexor carpi ulnaris was 1.54cm when the elbow was flexed at 45°, and 1.62cm when the elbow was flexed at 90°. Pronation and supination positions of the forearm did not significantly modify our measurements. ConclusionsUnderstanding the position of MACN posterior branch during ulnar nerve release surgery at the elbow may help in preventing iatrogenic injury. According to our measurements, incision and superficial dissection anterior to the medial epicondyle or distal to the ulnar nerve penetrating point between the two heads of the flexor carpi ulnaris should be avoided or done with an elbow flexed at 90°.

Right Aortic Arch with Mirror Image Branching and Situs Solitus: A case report on anatomic variation

During a routine cadaver dissection performed by first year medical students at Oakland University William Beaumont School of Medicine, a 60‐year‐old female cadaver was found to have right aortic arch with mirror image branching (RAMI). The descending aorta was observed to pass to the right of the midline and subsequently to cross left, anterior to the esophagus, returning to its typical orientation at the aortic hiatus. This defect involves a mirror image branching in which a left brachiocephalic trunk, right common carotid artery, and right subclavian artery emerging directly from the aortic arch proximal to distal. The right recurrent laryngeal nerve passes under the aortic arch while the left recurrent laryngeal nerve was located more superiorly, passing underneath the left subclavian artery. The heart presented in its typical orientation with the apex located to the left of midline with no noted abnormalities of the pulmonary trunk or vascular ring surrounding the trachea. The aortic arch was studied in 24 formalin fixed cadavers (13 female, 11 male, average age 80) which had been dissected by first year medical students. Only 1 of the 24 specimens (4.17%) had a congenital aortic arch and branching defect while the remaining 23 did not display any aortic arch or branching abnormalities. After review of the published clinical literature, this variation appears consistent with RAMI and situs solitus which has been found in &lt;0.1% of the general population. Studies have shown that 75–85% of cases with this defect are associated with cyanotic congenital heart disease, which makes early detection and follow‐up with pediatric cardiology essential. Other considerations for cardiac patients presenting with RAMI and situs solitus include accurate procedural imaging to provide safe and effective interventional care.

Simple approach to a complex problem: Abdominal cutaneous nerve entrapment

The aim was to show the efficacy of simple ultrasound-guided trigger point injection of local anesthetic in combination with steroid for the management of postoperative abdominal cutaneous nerve entrapment syndrome (ACNES). Abdominal cutaneous nerve entrapment can be the cause of severe, undiagnosed, abdominal pain. The entrapment of the nerve can be secondary to various conditions which cause increased abdominal pressure, leading to herniation of fat or connective tissue into the fibrous ring in the rectus abdominis muscle through which the nerve passes. Due to the compression of the nerve, there is ischemia which leads to pain. The nerve can be entrapped in scar tissue causing the compromised blood flow to the nerve and hence leading to postoperative pain. None of the available radiological investigations is helpful in diagnosing the abdominal cutaneous nerve entrapment. Clinical examination looking for tender trigger point on the abdominal wall and the eliciting a positive clinical sign, i.e., Carnett's sign can lead to the possible diagnosis of this frustrating condition. We successfully managed three cases of abdominal cutaneous nerve entrapment following laparoscopic meshplasty of abdominal hernia. All these cases were injected with a mixture of local anesthetic and steroid, i.e., 1 ml of 2% lignocaine and 1 ml of 10 mg triamcinolone at each trigger point under ultrasound guidance. The patients were prescribed pregabalin for 3 months and an anti-inflammatory COX-2 inhibitor for 10 days postprocedure. All the 3 patients were pain free at 6 months following the injections. A simple approach to a very disturbing problem of managing the severe pain due to abdominal cutaneous nerve entrapment in the postoperative period is a trigger point injection of local anesthetic and steroid under ultrasound guidance. Ultrasound-guided trigger point injections using a local anesthetic and a steroid offer an almost noninvasive option to the management of a very complex problem of ACNES.

Una visión evolutiva del síndrome supracondilar. Sobre atavismos y la aparición de los primeros tetrápodos

Understanding the evolution and function of structures in the past is key to understanding current biodiversity. This paper shows how an evolutionary perspective can help us to understand supracondylar syndrome. This pathology is caused by compression of the median nerve and/or the brachial artery in the arm and affects a significant percentage of the human population. We propose that this neuropathy is an atavism (the reappearance of an ancestral characteristic that had been lost along our evolutionary lineage) of the entepicondylar foramen: a channel present at the lower end of the humerus through which the brachial artery and the median nerve pass in some mammals. The origin of the foramen has been identified in the first tetrapods, and we propose that its original function could be linked to the evolutionary innovation of the cervical brachial plexus as well as the subsequent evolution of the entepicondylar foramen in amniotes – a group of terrestrial vertebrates that encompasses current reptiles and amphibians – and that it may be vestigial.

When and why was the phrenicoabdominal branch of the left phrenic nerve placed into the esophageal hiatus in German textbooks of anatomy? An anatomical study on 400 specimens reevaluating its course through the diaphragm

BackgroundThe phrenicoabdominal branch of the left phrenic nerve passes between muscle fiber bundles within the costal part of the diaphragm near the pericardium. In most German textbooks of anatomy, however, its passage is described to be found in the esophageal hiatus. The aim of this study was to reevaluate its topography relative to the diaphragm in a multicentric study and to identify the initiation of this description. MethodsIn this multicentric study, the most dorsomedial branch of the left phrenic nerve was identified as the phrenicoabdominal branch in 400 embalmed anatomic specimens of Caucasian origin. The distance between its passage and the apex of the pericardium, the left border of the esophageal hiatus, and the inner aspect of the left sixth rib was measured on the cranial aspect of the diaphragm. Textbooks on human anatomy published in German language between 1700 and 2018 were reviewed for their description of the passage of the left phrenicoabdominal branch through the diaphragm. ResultsThe first statement on the passage of the left phrenicoabdominal branch through the esophageal hiatus was given in 1791 by Sömmering. Since then, in German textbooks of anatomy, a duality in the description of the passage of the left phrenicoabdominal branch persists. In none of the individuals examined in this study, the left phrenicoabdominal branch passed through the esophageal hiatus. In 99.5% of all cases, it pierced the costal part of the diaphragm dorsal to or at the same level as the apex of the pericardium. The mean distances (standard deviations) were 3.4 (±1.5) cm to the apex of the pericardium, 5.8 (±2.2) cm to the esophageal hiatus, and 5.5 (±1.6) cm to the inner aspect of the left sixth rib. ConclusionThe findings on the position of the left phrenicoabdominal branch relative to the diaphragm help to improve topographical knowledge and prevent inadvertent nerve injury during surgical interventions on or near the diaphragm. Further to this, these results may form a substantial basis to adopt the correct description of the passage of the left phrenicoabdominal branch to anatomical textbook knowledge.

RELATION OF MEDIAN NERVE WITH BRACHIAL ARTERY: A CADAVERIC STUDY

Introduction: Variation in neurovascular structure are commonly encountered in routine dissection. Brachial artery is the main artery of upper limb. In the arm, the median nerve passes at first lateral to brachial artery (near the insertion of coracobrachialis muscle), then crosses in front of the artery, descending medial to it in the cubital fossa. The knowledge of these variation could be helpful to vascular, plastic, general surgeons and orthopedicians. It is also important to prevent iatrogenic injuries. The aim of this study was to evaluate anatomical variations in course and relation of median nerve to brachial artery in the arm. Material &amp; Methods: The study was conducted in 50 cadavers (100 upper limbs) in duration of two years. Proper cadaveric dissection was done in the Department of Anatomy, Dr. RML Institute of Medical Sciences, Lucknow, and Era’s Lucknow Medical College, Lucknow. Observation &amp; Results: In the present series, median nerve was found to cross behind the brachial artery at about the middle of the arm in 8% cadavers. Median nerve entered the arm at first lateral to brachial artery, near the insertion of coracobrachialis. In 46 cadavers (96 upper limbs), it crossed in front of the artery from lateral to medial side. In four cadavers (5 upper limbs), it passed posterior to the brachial artery in the arm. Conclusion: Knowledge of the brachial artery and their variations are of clinical and surgical importance. An awareness of such a presence is valuable for the surgeons and radiologists in evaluation of angiographic images, vascular and re-constructive surgery or appropriate treatment for compressive neuropathies.