Coracobrachialis Research Articles

An unusual median nerve formation; A case report and literature review

The Median nerve anatomical variation is commonly encountered. During the dissection of about 65 years of formalin-fixed male cadaver at the Department of Human Anatomy at National University Faculty of Medicine for undergraduate students in 2016-2017, the left upper limb showed that the median nerve was formed by the union of the three roots. However, the third root arose from the musculocutaneous nerve inside the coracobrachialis muscle, perforating the lower part of the muscle and joining the median nerve at the middle of the arm region. Knowledge of these variations is useful clinically, especially when evaluating symptoms of upper limb trauma, and it is also useful when performing surgical approaches.

A cadaveric analysis of anatomical variations of the musculocutaneous nerve

IntroductionVariations within musculocutaneus nerve (MCN) are very frequent. Such cases should be discussed extensively to reduce the risk of iatrogenic damage during surgery.AimIn this paper, we wanted to present the unusual variability within the brachial plexus, which is the double MCN.Case studyWe present a case of accesory MCN found during the cadaveric dissection.Results and discussionIn this paper we encountered two musculocutaneous nerves, of which MCN proper runs as standard innervating the biceps brachii and the coracobrachialis muscle, while MCN accessory extending distally from MCN proper and innervates the brachialis.ConclusionsThe case analysed by us is rare in the literature. Brachial plexus variations are very common and clinically important.

Anatomic Variations of the Musculocutaneous Nerve and Clinical Implications for Restoration of Elbow Flexion

The restoration of elbow flexion is of primary importance in the management of patients with brachial plexus injuries. Superior functional outcomes via fascicle transfer from the ulnar and median nerves have resulted in this transfer being considered the mainstay of recovery of elbow flexion in patients with intact C8 and T1 function. An understanding of the anatomy of the musculocutaneous nerve (MCN) and its branching pattern is key while performing these transfers. A prospective cohort study was conducted in patients who underwent nerve transfer for the restoration of elbow flexion following a traumatic brachial plexus injury. The anatomic course and branching pattern of the MCN were recorded in eligible cases, both as a line diagram and using intraoperative photographs. One hundred fifty patients underwent nerve transfer for the restoration of elbow flexion following an injury to the brachial plexus. The MCN in 138 patients (92%) was found to pierce the coracobrachialis muscle before emerging lateral to it. One hundred thirty-four patients (89.3%) demonstrated the "classical" anatomy. One hundred fifteen patients (76.6%) had a single primary branch to the biceps, whereas 25 patients (16.6%) demonstrated a discrete motor branch to each head. One hundred thirty-three dissections (88.6%) revealed a single muscular branch to the brachialis arising posteromedially from the MCN, distal to the origin of the branch to the biceps brachii. Notable unreported variations, such as the MCN penetrating the biceps as it descended, multiple brachialis branches, and trifurcation of divisions of the MCN, were documented. Variations in MCN anatomy are quite common, and even unreported variations can be encountered. Exploration of the MCN and its branches for nerve transfers requires knowledge of these anatomic variations and vigilance to prevent inadvertent injuries while dissecting them for nerve transfer surgery.

Six-headed coracobrachialis muscle.

The coracobrachialis muscle is the smallest muscle of the anterior compartment of the arm. It is responsible for flexion and abduction in the glenohumeral joint. The coracobrachialis muscle is morphologically variable both in its insertion and origin. Moreover, some additional heads or structures may also occur. The present report describes a six-headed coracobrachialis muscle originated as a common junctionwith the short head of the biceps brachii muscle from the coracoid process. All of these heads insert into the medial surface of the humeral shaft. It is important to note that the musculocutaneous nerve was piercing the fourth belly. Other heads were innervated by branches from the musculocutaneous nerve. Knowledge of the morphological variability of this muscle is essential not only for anatomists but for clinicians as well.

Proportional localisation of the entry point of the coracobrachialis muscle by the musculocutaneous nerve along the humerus.

To project the distance between the tip of the greater tubercle (GT), respectively, the proximal border of the tip of the coracoid process (CP) and the entry point of the coracobrachialis by the musculocutaneous nerve (MCN) proportionally onto the humeral length. Sixty-six upper extremities were included in the study. The distance between the tip of the GT and the distal tip of the lateral humeral epicondyle (LE) was evaluated as the humeral length (HL). The interval between the tip of the GT and the entry point of the coracobrachialis muscle by the MCN was measured. The distance between the proximal border of the tip of the CP and the distal portion of the medial humeral epicondyle (ME) and the entry point of the MCN into the coracobrachialis were evaluated. Proportions were used to project the entry point of the coracobrachialis by the MCN along the HL, respectively, the interval between the proximal border of the tip of the CP and the distal tip of the ME. The entry point of the MCN into the coracobrachialis muscle can be expected at an interval between 14.9 and 33.9% of the HL (between the tip of the GT and the LE), starting from the tip of the GT. Regarding the reference line between the proximal border of the CP and the ME, the nerve's entry point was located between 14.2 and 34.4%, starting from the CP. Results represent easily applicable intervals for intraoperative localisation of the MCN.

A Proposal for a New Classification of the Supernumerary Heads of the Biceps Brachii Muscle.

Introduction The anterior compartment of the arm consists of three muscles: the biceps brachii (BB), brachialis, and coracobrachialis muscle. The aim of the present study was to characterize possible variations in the supernumerary heads of the biceps brachii and use these to prepare an accurate classification of the area that could be used for planning surgical procedures in the region. Material and Methods. One hundred (51 left and 49 right, 52 females and 48 males) upper limbs fixed in 10% formalin solution were examined. Results Four types of supernumerary BB heads were identified, with subtypes. Type I was the most common type, characterized by the two heads (64%); this was subdivided into Type IA, with a single muscle belly, and Type IB with two muscle bellies. The second most common type was Type II, which was characterized by the three BB heads (26%). This type was divided into four subtypes (A-D): Type IIa characterized by attachment to the middle part of the shaft of the humerus; Type IIb characterized by the origin to the coracoid process together with the short head of the BB; Type IIc characterized by origin to the tendon of the pectoralis major muscle; and Type IId characterized by the attachment to the capsule of the humeral joint. The third most common type was Type III, which was characterized by four heads (6%); this was divided into Type IIIa, where two heads originated from the humerus bone, and Type IIIb, where one head originated from the short heads and the second from the long head of the BB. The rarest type was Type IV (4%) which was characterized by five heads: the short head originated from the coracoid process and the long head originated from the supraglenoid tubercle, the third and fourth head originated from the shaft of the humerus, while the fifth head originated from the pectoralis major muscle. Conclusion The biceps brachii is characterized by very high morphological variability. The new classification proposes four types of supernumerary head arrangement (I-IV), divided into subtypes. This classification has both clinical and anatomical significance.

Relationships among Coracobrachialis, Biceps Brachii, and Pectoralis Minor Muscles and Their Correlation with Bifurcated Coracoid Process.

The aim of this study is to demonstrate the relationship between the proximal attachment of the coracobrachialis muscle and the short head of the biceps brachii and the distal attachment of the pectoralis minor. Their correlation with the bifurcated coracoid process (CP) will be also assessed. On the basis of these observations, a new classification of structures attached to the coracoid process is proposed. Classical anatomical dissection was performed on one hundred forty-five upper limbs. Three types of relationship between the coracobrachialis muscle and the short head of the biceps brachii were observed in the cadavers. In type I (occurring in 54%), the coracobrachialis and the short head of the biceps brachii created a common junction attached to a single CP. Type II was divided into two subtypes (a and b). Subtype IIa (frequency 10%) was represented by independent proximal attachments of the short head of the biceps brachii and the coracobrachialis muscles to the CP. In subtype IIb (frequency 5%), the coracobrachialis muscle was two-headed (the first head located under the second) and not connected to the short head of the biceps brachii; all heads were attached to a single CP. Type III (frequency 31%) was characterized by a two-headed coracobrachialis muscle, the first head originating from a bifurcated CP laterally to the short head of the biceps brachii and the second medially to this structure. Different variations connected with the mentioned structures could be problematic for surgeons during operations, so detailed knowledge of them could contribute to more efficient procedures.

The Structure of the Brachial Plexus in Selected Representatives of the Caniformia Suborder.

Simple SummaryThe brachial plexus of animals is an ongoing topic of research interest among the scientific community. Research in this area allows scientists to select model animals for laboratory studies. In this way, the research contributes to the improvement of techniques for performing various procedures, not only on animals but also on humans. The most important information about the brachial plexus is the number of roots that form the plexus, from which roots the individual nerves arise, their course, and the extent of innervation of the individual nerves. In this paper, we have analysed the brachial plexus of five species of animals that commonly live in forests. In the study, we show similarities to the domestic dog but also present the individual anatomical features of the brachial plexus. Our results increase knowledge of the nervous system anatomy of wild animals and provide important information for veterinarians dealing with wild and exotic animal species.Like most structures, the brachial plexus is subject to species variation. Analysing this structure over a wide spectrum of species, we can obtain a complex view of the changes–in a given group of animals. The aim of this study was to describe the brachial plexus anatomy of species from two families of Caniformia. We analysed the brachial plexus structure of five species from two families of Caniformia: Canidae and Mustelidae. The cadavers were obtained from breeders and hunters. All were fixed by being kept in a 10% formaldehyde solution for two weeks. This study allows us to present the similarities as well as the differences between species and families. Our study reveals different trends in the course of the individual nerves and innervations of the thoracic limb. A species-specific feature is the extent of the brachial plexus, as each species has a specific number of ventral branches of the spinal nerves in the brachial plexus. However, a characteristic of the family Mustelidae is the course of the median nerve through the epicondylar foramen. Within the Canidae, two species are characterised by a very long branch for the coracobrachialis muscle. The general conclusion is that the brachial plexus of species belonging to the Caniformia is subject to variation within families and species, as well as individual variation while maintaining a general schematic for the group.

Musculocutaneous nerve as a branch from median nerve: A case report

The brachial plexus is the most variable part of the peripheral nervous system. The Musculocutaneous nerve is a terminal branch of the lateral cord of the brachial plexus in a normal individual. It is not uncommon for variations in the origin, branching termination, and connection patterns. During routine dissection in the Anatomy Department, College of Medicine, King Saud University, we found the lateral cord after giving a small branch to the coracobrachialis muscle join the medial root of the medial cord to form the median nerve. Knowledge of these variations is essential for anatomists, orthopedics, neurologists, and anesthesiologists.

A proposal for a new classification of the Coracobrachialis longus: A rare case or a new, distinct muscle?

BackgroundThe coracobrachialis muscle, along with the brachialis and biceps brachii muscles, belong to the anterior group of the brachial region. It is characterized by high level of morphological variabilities, with a common variation being the coracobrachialis longus (CBL) muscle. The CBL may be recognized as a distal part of the coracobrachialis muscle, originating from the anteromedial surface of the humerus, however, the two muscles are distinct from each other, and the distal attachment of the CBL is longer and located closer to the elbow joint. The CBL muscle may also be inserted on to various structures. The aim of the present study was to determine the frequency of the CBL muscle among a studied population, and to prepare a classification based on its morphological features. Material and MethodsClassical anatomical dissection was performed on 100 upper limbs from fifty human cadavers (30 female and 20 male) fixed in 10% formalin solution. ResultsThe coracobrachialis muscle was found in all individuals, and the CBL muscle was present in 11%, i.e. 11 upper limbs: four women, and seven men; five left and six right. Significantly, in all cadavers in which the coracobrachialis longus was found, its presence was unilateral (five left and six right). A new classification of the CBL can be proposed based on its insertion: Type I characterized by a distal attachment located on the medial epicondyle (73% of all cases of the CBL) and Type II by an insertion into the olecranon (27% of all cases of the CBL). ConclusionThe CBL muscle is morphologically variable. More studies focused on the course of this muscle among various populations are needed. Nevertheless, our findings indicate that the CBL muscle could be classified as a distinct muscle.

Indirect traumatic musculocutaneous nerve injury confused with static line injury: A case report

The musculocutaneous nerve is rarely injured because it is short and is located deep in the shoulder and arm. Damage is usually caused by direct injuries, including stabbing, explosion, and surgery in a war setting. Although indirect injury of the musculocutaneous nerve is extremely rare, it occurs in various situations. In military parachuting-related activities, musculoskeletal injury occurs most commonly, and static line injury is known as rupture of the biceps brachii tendon. However, musculocutaneous neuropathy can also result from secondary injury by the static line. The musculocutaneous nerve goes together with the biceps brachii muscle, and the musculocutaneous nerve could overstretch and compress within the coracobrachialis muscle where the nerve is relatively fixed due to the overloading of the upper arm with shoulder extension. This report focuses on the indirect musculocutaneous nerve injury with axonotmesis following an overloading event by the static line during military parachuting. In this case, some physicians may confuse nerve injury with static line injury, leading to delays in the diagnosis of neuropathy. If the biceps brachii muscle is damaged due to trauma, checking for the accompanying musculocutaneous nerve injury is necessary.

Is it the coracobrachialis superior muscle, or is it an unidentified rare variant of coracobrachialis muscle?

The coracobrachialis muscle (CBM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. The CBM demonstrates variability in both the proximal and distal attachment, with some extremely rare varieties, such as the coracobrachialis superior, coracobrachialis longus and coracocapsularis muscle. This case report describes an extremely rare variant of the coracobrachialis superior muscle, or a very rare variant of the CBM. Our findings highlight the importance of muscle variants in the shoulder region, especially the coracoid region, and are significant for radiologists, anatomists, physiotherapists and surgeons specializing in the shoulder joint.

Effective stretching position of the coracobrachialis muscle

An increase in the stiffness of the coracobrachialis muscle can restrain proper movement of the glenohumeral joint and scapula during arm elevation. Therefore, muscle stiffness should be reduced through stretching. The aim of this study was to determine the effective stretching position of the coracobrachialis muscle using ultrasound shear wave elastography imaging to evaluate the stiffness of individual muscles. Eighteen healthy young men participated in this study. The shear modulus of the coracobrachialis muscle was measured at the following eight shoulder positions: i) 20° abduction (Rest), ii) maximal external rotation at 90° abduction (ER2), iii) maximal internal rotation at 90° abduction (IR2), iv) maximal flexion (Flex), v) maximal extension (Ext), vi) maximal horizontal abduction at 90° abduction (Hab), vii) maximal horizontal abduction and maximal external rotation at 90° abduction (HabER), and viii) maximal horizontal abduction and maximal internal rotation at 90° abduction (HabIR). The shear modulus in each position was compared with that of Rest using the Wilcoxon signed-rank test, and a multiple comparison test was performed among the positions that exhibited significant difference. The shear modulus of all stretching positions was significantly higher than that of Rest, except for Flex. Moreover, the shear moduli of IR2, Ext, Hab, HabER, and HabIR were significantly higher than that of ER2. The shear modulus of Ext was significantly higher than that of HabIR. The coracobrachialis muscle could be stretched effectively at IR2, Ext, Hab, HabER, and HabIR. Among these positions, Ext, Hab, and HabER are recommended for clinical settings.

A proposal for a new classification of coracobrachialis muscle morphology

IntroductionThe coracobrachialis muscle (CRM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. It inserts to the medial part of the humerus between the attachment of the medial head of the triceps brachii and the brachial muscle. Both the proximal and distal attachments of the CRM, as well as its relationship with the musculocutaneus nerve, demonstrate morphological variability.Material and methodsOne hundred and one upper limbs (52 left, and 49 right) fixed in 10% formalin solution were examined.ResultsThree main types, with subtypes, were identified. The most common was Type I (49.5), characterized by a single muscle belly with a classical origin from the coracoid process, medially and posteriorly to the tendon of the biceps brachii. Type II (42.6%), characterized by two heads, was divided into two subtypes (A-B) depending on its origin: Type IIA, where one head originated from the coracoid process posteriorly to the tendon of the biceps brachii and the second head from the short head of the biceps brachii, and Type IIB, in which both heads originated from the coracoid process; however, the superficial head fused with the insertion of a short head of the biceps brachii, while the deep head was directly originating. Finally, Type III (7.9%) was characterized by three heads: two originated from the coracoid process (superficial and deep), and the third from a short head of the biceps brachii. Two types of insertion and two types of musculocutaneous nerve (MCN) relative to CRM could be distinguished.ConclusionAn adapted classification is needed for all clinicians working in this area, as well as for anatomists. The CRM demonstrates morphological variability in both its proximal and distal attachments, as well as the variable course of the MCN relative to the CRM.What is known about this subject "and" What this study adds to existing knowledgeNot much is known about the variability of coracobrachialis muscle. The present paper introduces a completely new classification, both clinical and anatomical.

Bilateral variation in origin of thoracodorsal artery along with non-piercing variant of musculocutaneous nerve on left side

Subclavian artery continues as axillary artery in the axilla and is the principal source of blood supply of the lateral thoracic wall, axilla, scapular region, and upper limb. Thoracodorsal artery is one of the terminal branches of subscapular artery, which in turn is branch from the third part of axillary artery. Musculocutaneous nerve, a branch from lateral cord of brachial plexus, is the chief nerve supply of anterior compartment of arm, commonly seen piercing the coracobrachialis muscle before continuing as lateral cutaneous nerve of forearm. In the current case report, thoracodorsal arteries on both sides were arising from lateral thoracic artery, branch of second part of axillary artery and the left musculocutaneous nerve was not piercing the coracobrachialis muscles. Also, there was a communication between left musculocutaneous nerve and left median nerve. The knowledge about normal and variant pattern of origin and course of branches of axillary artery is very important as it may help the surgeons to identify the source of bleeding during surgeries in region of shoulder or axilla. Also, post-surgical complication or symptoms of nerve repair can be explained by the variation in course of musculocutaneous nerve and its communication with median nerve.

Anatomical aspects of the use of the thoracodorsal nerve as a donor in musculocutaneous nerve ­injury

Aim. To assess the anatomical possibility of the use of the thoracodorsal nerve as a donor for nerve transfer to the musculocutaneous nerve.
 Methods. Anatomical dissection of the brachial plexus with layer-by-layer dissection of secondary bundles, short and long branches was performed in 121 male and female corpses. The localization of the origin of thoracodorsal and musculocutaneous nerves relative to the clavicle, the takeoff angle (degrees) from the secondary bundle, the length (in centimeters) of the nerves from the site of origin to the latissimus dorsi muscle entry point and the perforation of the coracobrachialis muscle, respectively, were investigated. The length of the thoracodorsal nerve with and without extramuscular branches was studied separately.
 Results. It was revealed that, in 58.7% of cases, the thoracodorsal nerve has the optimal length required for transposition to the musculocutaneous nerve. The excess length of the thoracodorsal nerve was between 0.1 and 9.1 cm. In 41.3% of cases, the length of the thoracodorsal nerve is not enough for transposition. Of these, in 17.4% of cases, the shortage of the length of the thoracodorsal nerve was 2 cm or less, which categorically does not allow its transfer to the musculocutaneous nerve. Only in 5% of cases, the length of the nerve was not enough for transposition in the use of the thoracodorsal nerve with extramuscular branches.
 Conclusion. Due to tension in many cases, the thoracodorsal nerve transfer to the musculocutaneous nerve can be performed with difficulty, and in some cases it is impossible, solving the problem in this category of people dictates the development of new surgical techniques with the thoracodorsal nerve or the use of another nerve as a donor.

The co-occurrence of a four-headed coracobrachialis muscle, split coracoid process and tunnel for the median and musculocutaneous nerves: the potential clinical relevance of a very rare variation

The coracobrachialis muscle (CBM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. Both the proximal and distal attachment of the CBM, as well as its relationship with the musculocutaneus nerve demonstrate morphological variability, some of which can lead to many diseases. The present case study presents a new description of a complex origin type (four-headed CBM), as well as the fusion of both the short biceps brachii head, brachialis muscle and medial head of the triceps brachii. In addition, the first and second heads formed a tunnel for the musculocutaneus and median nerves. This case report has clear clinical value due to the split mature of the coracoid process, and is a significant indicator of the development of interest in this overlooked muscle.

An Absent Subscapular Artery Co-Existing with Multiple Variants of the Brachial Plexus and Clinical Implications.

Knowledge of neurovascular variants in the upper limb is important to neurologists in explaining unusual neurological presentations, to trauma surgeons in the selection of appropriate surgical interventions, and to neuroradiologists in the interpretation of images. Here we present the case of an absent subscapular artery coexisting with multiple variants of the brachial plexus nerves in the left limb of a 71-year-old female cadaver. The median nerve was formed from 3 roots, 2 contributed by the lateral cord and one from the medial cord. The thoracodorsal branch shared a common trunk of origin with the lateral thoracic artery, while the circumflex scapular arose directly from the axillary artery. The musculocutaneous nerve did not penetrate the coracobrachialis muscle, but coursed superior to the second lateral root, and about the proximal and middle third of the brachium supplied the flexor arm muscle, continuing distally as the lateral cutaneous nerve of the forearm. The first lateral root coursed initially within the medial root proximally, exiting about 3 cm distally before travelling superolaterally to join the second lateral root. Final formation of the median nerve was in the distal third brachium. There is uniqueness in this median nerve formation; a variant or a reverse of Le Minor Type 2 was observed except that this lateral root joined the medial root initially, unlike in Type 2 in which the medial root joins the musculocutaneous nerve, both re-exiting to join in median nerve formation. Clinically, unexplained sensorimotor deficits in the flexor compartments distal to the elbow may be explained by inadvertent ligation to any of these median nerve roots.

A RARE CASE OF TENDINOUS INSERTION OF CORACOBRACHIALIS ASSOCIATED WITH VARIANT MUSCULOCUTANEOUS NERVE

We report a rare case of the tendinous insertion of coracobrachialis muscle which has not been reported in the literature. The insertion of the novel coraco-brachialis muscle is usually into the medial border of the humerus in a 3-5cm impression at the mid-shaft level. Contrary to this, in the present case, it was seen getting inserted as a sharp slender tendon in the middle of the medial border of the humerus. Variable insertion of coracobrachialis muscle may be responsible for the causation of compression of surrounding structures like median nerve, musculocutaneous nerve, and brachial artery. This article aims to point out a rare case of the unusual tendinous insertion of coracobrachialis and its association with musculocutaneous nerve, providing necessary information to surgeons performing surgical reconstruction using coracobrachialis.

The Branching Pattern and Internal Topography of the Musculocutaneous Nerve

BackgroundPrevious research on the musculocutaneous nerve (MCN) has focused on its motor and sensory branching pattern. Defining the branching pattern is important for selective neurectomy in the treatment of elbow flexor spasticity (EFS). Very limited data, however, exists regarding its internal topography, which is important for surgical procedures. Several neurotization techniques of the MCN, such as intercostal nerve transfer, rely on the location of motor and sensory fascicles of the MCN from the lateral cord. The purpose of this study is to confirm the MCN branching pattern and define its internal topography.ResultsThe study was performed on 15 arms (9 left and 6 right) in 12 Caucasians cadavers. Branches of the MCN nerve to the coracobrachialis, biceps brachii and brachialis muscles were assessed and presented as a percentage of the distance from the coracoid process to the medial epicondyle. The internal topography of each fasciculus was identified at proximal, middle and distal levels following blunt intraneural dissection from the respective branch termination up to the lateral cord. It was found that the coracobrachialis muscle was innervated by 1–3 primary branches arising from MCN at an average of 17.7% of the arm length. The biceps brachii was innervated by 1–2 primary branches arising at an average 45% of the arm length. The brachialis was innervated by a single branch arising at an average 60% of the arm length. Regarding its internal topography, the lateral cutaneous nerve to the forearm occupied the medial and anteromedial one fourth at proximal and middle levels, but the lateral and posterolateral one fourth at the distal level. The branches to the coracobrachialis and biceps brachii occupy the anterior and anterolateral one fourth at the proximal level, and the branches to the brachialis occupy the lateral and posterolateral one fourth at proximal and middle levels, and the medial and posteromedial one fourth at the distal level.ConclusionsCompared to the respective data found in the literature, our present results indicate that the branching points of the nerves to coracobrachialis, biceps brachii, and brachialis are relatively constant at approximately 20%, 40%, and 60% respectively, of the distance between the coracoid process and the medial epicondyle. Additionally, regarding the internal topography, our results indicate that while at the distal level the lateral cutaneous nerve to the forearm was located lateral and the brachialis branch was located medial, at the proximal level of MCN the nerves to the coracobrachialis, biceps brachii and brachialis occupy the lateral three fourths and lateral cutaneous nerve of the forearm occupies the medial one fourth. Based on the data obtained, it appears that the lateral half of the proximal and middle levels and the medial half of distal level of MCN would be the preferred site for any motor nerve transfer. These findings are important for the development of more efficient microsurgical procedures to treat EFS and for neurotization of the MCN.Support or Funding InformationCenter for Anatomical Science and Education, Department of Surgery, Saint Louis University School of Medicine