Morphological classification, anatomical variations, innervation patterns, musculocutaneous nerve relation of the coracobrachialis muscle: Anatomical study and clinical significance.

The anatomical variations of coracobrachialis muscle (CBM) are of great clinical importance. This study aimed to elucidate the morphological variations, innervation patterns and musculocutaneous nerve (MCN) relation to CBM. Upper limbs of fifty cadavers (30 males and 20 females) were examined for proximal and distal attachments, innervation pattern of CBM and its relation to MCN. Four morphological types of CBM were identified according to number of its heads. The commonest type was the two-headed (63.0%) followed by the single belly (22.0%), three-headed (12.0%) and lastly four-headed (3.0%) type. Moreover, an abnormal insertion of CBM was observed in four left limbs (4.0%); one inserting into the medial humeral epicondyle, the second into the upper third of humeral shaft, the third one in the common tendon of biceps, and the fourth one showing a bifurcated insertion. Also, four different innervation patterns of CBM were identified including MCN (80.0%), lateral cord (14.0%), lateral root of median nerve (4.0%), and median nerve itself (2.0%). The course of MCN was superficial to the single belly CBM (19.0%) and in-between the heads in the other types (71.0%). Measurements of the length and original distance of CBM muscular branches originating from MCN revealed no sex or side significant difference. Awareness of the anatomic variations, innervation patterns, and MCN relation of CBM is imperative in recent diagnostic and surgical procedures to obtain definite diagnosis, effective management and good outcome.

Possible anastomoses between the long branches of the brachial plexus and their clinical significance.

The brachial plexus consists of nerves that supply the upper limb and some nerves of the back, torso, and neck. It is formed by the ventral rami of C5 to T1 (in some cases, C4 or T2 also contribute). The anterior rami of the spinal nerves unite to the roots, trunks, divisions, cords, and terminal branches that innervate muscles and skin. An example is associated with terminal branches of the long nerves. Knowledge of this variation is necessary for enabling surgeons, orthopedists, and neurologists to avoid injury during surgical exploration in the arm or axilla region, and for achieving correct diagnoses, because such variability can evoke nonspecific responses. Awareness of this anastomosis is also mandatory for anesthetists performing anesthesia in the upper limb region. The aim of this article is to describe anastomoses between long nerves from the brachial plexus and to consider their clinical significance.

A bilateral four-headed brachialis muscle with a variant innervation: a cadaveric report with possible clinical implications.

PURPOSE: Anterior compartment muscles of the arm present high morphological variability, with possible clinical significance. The current cadaveric report aims to describe a bilateral four-headed brachialis muscle (BM) with aberrant innervation. Emphasis on the embryological background and possible clinical significance are also provided. METHODS: Classical upper limb dissection was performed on an 84-year-old donated male cadaver. The cadaver was donated to the Anatomy Department of the National and Kapodistrian University of Athens. RESULTS: On the left upper limb, the four-headed BM was supplied by the musculocutaneous and the median nerves after their interconnection. On the right upper limb, the four-headed BM received its innervation from the median nerve due to the musculocutaneous nerve absence. A bilateral muscular tunnel for the radial nerve passage was identified, between the BM accessory heads and the brachioradialis muscle. CONCLUSION: BM has clinical significance, due to its proximity to important neurovascular structures and frequent surgeries at the humerus. Hence, knowledge of these variants should keep orthopedic surgeons alert when intervening in this area. Further dissection studies with a standardized protocol are needed to elucidate the prevalence of BM aberrations and concomitant variants.

The anatomical variations of median nerve in Shiraz, Iran.

The origin and distribution of median nerve varies among the different individuals. The median nerve variations in axillary region were reported by many authors previously. Understanding of these variations is especially necessary for clinicians to prevent iatrogenic nerve damage. The current work aimed to evaluate the possible anatomical variations of median nerve in the axillary region in a sample of the Iranian cadavers (Shiraz, Fars). We dissected 26 upper limbs from 13 male cadavers to investigate the different variations of median and musculocutaneous nerves according to Venieratos and Anagnostopoulou classification. In 23.07% of specimens (n=6), the medial root united with 2 lateral roots and formed the median nerve proximal to the coracobrachialis muscle. In one case, a communicating branch separated from the musculocutaneous nerve distal to the coracobrachialis and connected to the median nerve in upper arm. Our results suggest that there are anatomical variations of the median nerve in terms of its origin and its communication with the musculocutaneous nerve in the population of southern Iran. The anatomical knowledge of the median nerve variations is important for clinicians to improve patient health outcome. Theses variations of the median nerve should be considered during surgical procedures of the axillary region and nerve block of the infra clavicular part of the brachial plexus.

Rare median and musculocutaneous nerve fusion with intraoperative electrical confirmation: illustrative case.

BACKGROUND: Nerve transfer is a surgical technique in which a redundant or expendable fascicle is transferred or coapted to an injured nerve distal to the site of injury for the purpose of reinnervation. Successful nerve transfer is dependent on correct intraoperative identification of donor and recipient nerves. OBSERVATIONS: An 8-year-old male was recommended for ulnar nerve fascicle to biceps branch of musculocutaneous nerve transfer to restore elbow flexion weakness after a demyelinating spinal cord injury. The biceps branch was identified approximately midway along the upper arm. Proximal musculocutaneous nerve stimulation induced hand movement and electromyography activity in the median nerve muscles. Neurolysis of the thickened proximal structure revealed fusion of the musculocutaneous and median nerves. Because of the proximity of the median and musculocutaneous nerves, median rather than ulnar nerve fascicles were used as donors for transfer. LESSONS: The authors provide the first reported intraoperative finding of an anatomical variant in which the musculocutaneous nerve and median nerve were fused in the upper arm, confirmed through intraoperative electrical stimulation. Surgeons should be aware of this rare anatomical variant to ensure correct nerve identification when performing nerve transfers in the proximal upper extremity.

Fusion of the Median and Musculocutaneous Nerves Masquerading as Biceps' Innervation from the Median Nerve.

Embryologically, the musculocutaneous nerve (MCN) comes from the lateral root of the median nerve, and thus numerous anatomical variations concerning the formation and branching pattern of these two nerves of the brachial plexus have been described. In this case study, we describe a relatively uncommon case of fusion of the median and MCNs that was identified during routine teaching dissection of a male human cadaver. The identification of this anatomical variation requires awareness of the embryological background, as it may be confused with biceps innervation from the median nerve or the existence of a communicating branch between the two nerves. In addition, awareness of such anatomical variations is of undisputable significance for the safety of surgical operations in the brachial plexus and the arm in general.

A Review of the Typical Course of the Musculocutaneous Nerve into the Coracobrachialis Muscle: Its Variability and Possible Clinical Implications.

OBJECTIVE: This literature review highlights the prevalence of the typical course of the musculocutaneous nerve (MCN) through the coracobrachialis muscle (CB), and evaluates the distance from the entrance point of the MCN to the CB, taking the coracoid process (CP) as a landmark. METHODS: PubMed (MEDLINE), Scopus, and CINAHL online databases were searched in December 2022 for studies reporting the prevalence of the MCN's typical course and the distance between the CP and the MCN entrance point to the CB. RESULTS: Twenty-eight studies were included (including 2846 subjects) investigating the MCN's typical course, and eliciting a prevalence of 93.4%. The mean distance of the CP to the entrance point of the MCN's main trunk into the CB was 5.6±2cm (median 6.1cm, in 550 subjects). In 76.12% of cases the MCN's accessory branches entered the CB proximally to the MCN's main trunk. The mean distance from the CP to the entrance point of the MCN's proximal branches to the CB was 3.8±1.2cm (median 3.7cm, in 140 subjects). CONLCUSION: In the vast majority of cases, the MCN had a typical course through the CB. In cases of altered anatomy, the MCN was either absent or passed medially to the CB (without piercing it). The average entrance point of the MCN into the CB from the CP is 5.6 cm. Proximal motor branches of the MCN to the CB are common and usually arise at a mean distance of 3.8cm from the inferior border of the tip of the CP. Surgeons should be aware of both the MCN's typical and its atypical course and these distances to avoid possible complications when operating in the area.

Phrenic Nerve Transfer to Musculocutaneous Nerve: An Anatomical and Histological Study.

BACKGROUND: To restore elbow flexor muscle function in case of traumatic brachial plexus avulsion, the phrenic nerve transfer to the musculocutaneous nerve has become part of clinical practice. The nerve transfer can be done by means of video-assisted thoracic surgery without nerve graft or via supraclavicular approach in combination with an autograft. This study focuses on a detailed microscopic and macroscopic examination of the phrenic nerve. It will allow a better interpretation of existing clinical results and, thus, serve as a basis for future clinical studies. MATERIAL AND METHODS: An anatomical study was conducted on 28 body donors of Caucasian origin (female n = 14, male n = 14). A sliding caliper and measuring tape were used to measure the diameter and length of the nerves. Sudan black staining was performed on 15 µm thick cryostat sections mounted on glass slides and the number of axons was determined by the ImageJ counting tool. In 23 individuals, the phrenic nerve could be examined on both sides. In 5 individuals, however, only one side was examined. Thus, a total of 51 nerves were examined. RESULTS: The mean length of the left phrenic nerves (33 cm (29-38 cm)) was significantly longer compared to the mean length of the right phrenic nerves (30 cm (24-33 cm)) (p < 0.001). Accessory phrenic nerves were present in 9 of 51 (18%) phrenic nerves. The mean number of phrenic nerves axons at the level of the first intercostal space in body donors with a right accessory phrenic nerve was significantly greater compared to the mean number of phrenic nerves axons at the same level in body donors without a right accessory phrenic nerve (3145 (range, 2688-3877) vs. 2278 (range, 1558-3276)), p = 0.034. A negative correlation was registered between age and the nerve number of axons in left (0.742, p < 0.001) and right (-0.273, p = 0.197) phrenic nerves. The mean distance from the upper edge of the ventral ramus of the fourth cervical spinal nerve to the point of entrance of the musculocutaneous nerve between the two parts of the coracobrachialis muscle was 19 cm (range, 15-24 cm) for the right and 20 cm (range, 15-25 cm) for the left arm. CONCLUSIONS: If an accessory phrenic nerve is available, it presumably should be spared. Thus, in that case, a supraclavicular approach in combination with a nerve graft would probably be of advantage.

A Bilateral Symmetric Accessory Coracobrachialis Muscle Combined With an Interconnection of the Musculocutaneous Nerve With the Median Nerve.

This report describes a bilateral symmetric accessory coracobrachialis muscle variant coexisting with a unilateral interconnection of the musculocutaneous nerve and the median nerve. An 80-year-old female cadaver was dissected. The bilateral coracobrachialis muscle variant consisted of three heads: two superficial heads and one deep head. One superficial head arose from the tip of the coracoid process, while the other originated from the short head tendon of the biceps brachii. The deep head of the coracobrachialis muscle emerged from the base of the coracoid process. The musculocutaneous nerve bilaterally coursed between the superficial and deep heads. On the right side, the three-headed coracobrachialis muscle coexisted with an ipsilateral interconnection of the musculocutaneous nerve and the median nerve, located at the lower third of the arm. While the presence of a unilateral three-headed coracobrachialis muscle is not rare (with a prevalence range of 0-22.2%), as well as the distal interconnection between the musculocutaneous nerve and the median nerve at the lower third of the arm (with a prevalence range of 1.8-53.6%), the coexistence of the current bilateral three-headed coracobrachialis muscle variant with the distal interconnection of the musculocutaneous and median nerves is quite unusual. A similar report underscores the finding of the bilateral coracobrachialis muscle variant.

Anatomical Variations of the Musculocutaneous Nerve in the Human Fetus.

OBJECTIVES: Knowing the motor branches and variations of the musculocutaneous nerve to the muscles along its course will facilitate the treatment of flexor spasticity and supracondylar fractures of the humerus in order to minimize nerve lesion. In fetal cadavers, the purpose of our study was to determine the number and course of the formation variations and motor branches of the musculocutaneous nerve. The significance of studying fetal nerve variations is due to injury to the brachial plexus roots during birth. METHODS: Our study was conducted using the anatomical dissection technique on 102 upper limbs from 51 fetuses ages ranged from 17 to 40 weeks. Throughout its course, the variations and motor branches of the musculocutaneous nerve were analyzed. RESULTS: In 13.7% of cases, the musculocutaneous nerve did not pierce the coracobrachialis. The musculocutaneous nerve gave the muscles 1-3 motor branches. Additionally, motor branches terminated with 1-7 fringes. The biceps brachii motor branches of the musculocutaneous nerve were typed. Accordingly, 15.6% were type 1A, 3.9% were type 1B, 35.4% were type 1C, and 19.6% were type 1D. It was determined that 23.5% of the extremities were type 2 and that 1.9% were type 3. The distance between the musculocutaneous nerve's motor branches and the acromion was proportional to the arm's length. There were no statistically significant differences between the sides and genders for any measurement. CONCLUSIONS: Our study's findings will aid in the diagnosis and treatment of pediatrics, orthopedics, surgical sciences, and radiology conditions. It reduces the risk of iatrogenic injury and postoperative complications. We also believe that our research will serve as a resource for anatomists and other scientists.

A Cadaveric Study to Define the Variant Patterns of Median Nerve Formation.

The median nerve is one of the important nerves of the upper limb which supplies the muscles of the front of the forearm, muscles of the hand, and skin of the hand. Many works of literature mentioned its formation by the fusion of two roots, the medial root from the medial cord and the lateral root from the lateral cord. But multiple variations in the median nerve formation have clinical importance from surgical and anesthetic points of view. For the study purpose, we dissected 68 axillae of 34 formalin-fixed cadavers. Out of 68 axillae, two (2.9%) showed median nerve formation by a single root, 19 (27.9%) showed median nerve formation by three roots, and three (4.4%) showed median nerve formation by four roots. A normal pattern of median nerve formation by fusion of two roots was seen in 44 (64.7%) axilla. The knowledge of variant patterns of median nerve formation will be helpful to surgeons and anesthetists while performing surgical or anesthetic procedures in the axilla to avoid any injury to the median nerve.

Coracobrachialis muscle morphology and coexisted neural variants: a cadaveric case series.

PURPOSE: The current cadaveric case series evaluates the coracobrachialis muscle morphology, the related musculocutaneous nerve origin, course, and branching pattern, as well as associated adjacent neuromuscular variants. MATERIALS AND METHODS: Twenty-seven (24 paired and 3 unpaired) cadaveric arms were dissected to identify the coracobrachialis possible variants with emphasis on the musculocutaneous nerve course and coexisted neural variants. RESULTS: Four morphological types of the coracobrachialis were identified: a two-headed muscle in 62.96% (17/27 arms), a three-headed in 22.2% (6/27), a one-headed in 11.1% (3/27), and a four-headed in 3.7% (1 arm). A coracobrachialis variant morphology was identified in 37.04% (10/27). A three-headed biceps brachii muscle coexisted in 23.53% (4/17). Two different courses of the musculocutaneous nerve were recorded: 1. a course between coracobrachialis superficial and deep heads (in cases of two or more heads) (100%, 24/24), and 2. a medial course in case of one-headed coracobrachialis (100%, 3/3). Three neural interconnections were found: 1. the lateral cord of the brachial plexus with the medial root of the median nerve in 18.52%, 2. the musculocutaneous with the median nerve in 7.41% and 3. the radial with the ulnar nerve in 3.71%. Duplication of the lateral root of the median nerve was identified in 11.1%. CONCLUSIONS: The knowledge of the morphology of the muscles of the anterior arm compartment, especially the coracobrachialis variant morphology and the related musculocutaneous nerve variable course, is of paramount importance for surgeons. Careful dissection and knowledge of relatively common variants play a significant role in reducing iatrogenic injury.

Prediction of Biceps Muscle Electromyogram Signal Using a NARX Neural Network.

Background: This study was conducted to compare the response between the results of experimental data and the results achieved by the NARX neural network model to predict the electromyogram (EMG) signal on the biceps muscle in nonlinear stimulation conditions as a new stimulation model. Methods: This model is applied to design the controllers based on functional electrical stimulation (FES). To this end, the study was conducted in five stages, including skin preparation, placement of recording and stimulation electrodes, along with the position of the person to apply the stimulation signal and recording EMG, stimulation and recording of single-channel EMG signal, signal preprocessing, and training and validation of the NARX neural network. The electrical stimulation applied in this study is based on a chaotic equation derived from the Rossler equation and on the musculocutaneous nerve, and the response to this stimulation, i.e., the EMG signal, is from the biceps muscle as a single channel. The NARX neural network was trained, along with the stimulation signal and the response of each stimulation for 100 recorded signals from 10 individuals, and then validated and retested for trained data and new data after processing and synchronizing both signals. Results: The results indicate that the Rossler equation can create nonlinear and unpredictable conditions for the muscle, and we also can predict the EMG signal with the NARX neural network as a predictive model. Conclusion: The proposed model appears to be a good method to predict control models based on FES and to diagnose some diseases.

Correlation between Elbow Flexor Muscle Strength and Needle Electromyography Parameters after Musculocutaneous Nerve Injury.

OBJECTIVES: To explore the changes of elbow flexor muscle strength after musculocutaneous nerve injury and its correlation with needle electromyography (nEMG) parameters. METHODS: Thirty cases of elbow flexor weakness caused by unilateral brachial plexus injury (involving musculocutaneous nerve) were collected. The elbow flexor muscle strength was evaluated by manual muscle test (MMT) based on Lovett Scale. All subjects were divided into Group A (grade 1 and grade 2, 16 cases) and Group B (grade 3 and grade 4, 14 cases) according to their elbow flexor muscle strength of injured side. The biceps brachii of the injured side and the healthy side were examined by nEMG. The latency and amplitude of the compound muscle action potential (CMAP) were recorded. The type of recruitment response, the mean number of turns and the mean amplitude of recruitment potential were recorded when the subjects performed maximal voluntary contraction. The quantitative elbow flexor muscle strength was measured by portable microFET 2 Manual Muscle Tester. The percentage of residual elbow flexor muscle strength (the ratio of quantitative muscle strength of the injured side to the healthy side) was calculated. The differences of nEMG parameters, quantitative muscle strength and residual elbow flexor muscle strength between the two groups and between the injured side and the healthy side were compared. The correlation between elbow flexor manual muscle strength classification, quantitative muscle strength and nEMG parameters was analyzed. RESULTS: After musculocutaneous nerve injury, the percentage of residual elbow flexor muscle strength in Group B was 23.43% and that in Group A was 4.13%. Elbow flexor manual muscle strength classification was significantly correlated with the type of recruitment response, and the correlation coefficient was 0.886 (P<0.05). The quantitative elbow flexor muscle strength was correlated with the latency and amplitude of CMAP, the mean number of turns and the mean amplitude of recruitment potential, and the correlation coefficients were -0.528, 0.588, 0.465 and 0.426 (P<0.05), respectively. CONCLUSIONS: The percentage of residual elbow flexor muscle strength can be used as the basis of muscle strength classification, and the comprehensive application of nEMG parameters can be used to infer quantitative elbow flexor muscle strength.

The utility of selective partial neurectomy of the musculocutaneous nerve in children with bilateral spastic elbow.

PURPOSE: This study aims to determine the utility of selective partial neurectomy of the musculocutaneous nerve (MCN) in pediatric patients with bilateral spastic elbow. METHODS: A prospective, cross-sectional, case series study was performed in nine pediatric patients (four females and five males) with bilateral spastic elbow, all with a 11.4-year-old average age, where 18 selective partial neurectomies of the MCN were carried out. They were evaluated with goniometry of both spastic elbows at resting position and active amplitude, and staging spasticity employing the Modified Ashworth Scale (MAS) in the preoperative and postoperative period. The results are reported 1 year after surgery. RESULTS: The etiology of the spasticity was secondary to cerebral palsy in eight patients (88.8%) and in one patient (11.11%) secondary to traumatic brain injury. A clinical improvement was observed in goniometry comparing the preoperative and postoperative resting position, a mean preoperative of 44.38 degrees (SD ± 7.61) versus 98.05 degrees (SD ± 24.44), respectively, and preoperative active amplitude a mean of 86.55 degrees (SD ± 15.97) versus the mean postoperative of 47.33 (SD ± 17.86). A relevant decrease on the MAS after surgical intervention was observed, resulting from an average preoperative state according to MAS of 3.78 (SD ± 0.42) to a postoperative state according to MAS of 1.44 (SD ± 0.51), these changes being statistically significant (p ≤ 0.001). No postoperative complications were observed. CONCLUSIONS: Selective partial neurectomy of the MCN has shown good results in patients with bilateral spastic elbow in whom antispastic drugs and physical therapy have failed, and has prove permanent effects.

Restoring musculocutaneous nerve function in 146 brachial plexus operations - A retrospective analysis.

INTRODUCTION: A brachial plexus lesion is a devastating injury often affecting young, male adults after traffic accidents. Therefore, surgical restoration of elbow flexion is critical for establishing antigravity movement of the upper extremity. We analyzed different methods for musculocutaneous reconstruction regarding outcome. METHODS: We conducted a retrospective analysis of 146 brachial plexus surgeries with musculocutaneous reconstruction performed at our department from 2013 to 2017. Demographic data, surgical method, donor and graft nerve characteristics, body mass index (BMI) as well as functional outcome of biceps muscle based on medical research council (MRC) strength grades before and after surgery were analyzed. Multivariate analysis was performed using SPSS. RESULTS: Oberlin reconstruction was the procedure performed most often (34.2%, n = 50). Nerve transfer and autologous repair showed no significant differences regarding outcome (p = 0.599, OR 0.644 CI95% 0.126-3.307). In case of nerve transfers, we found no significant difference whether reconstruction was performed with or without a nerve graft (e.g. sural nerve) (p = 0.277, OR 0.619 CI95% 0.261-1.469). Multivariate analysis identifies patient age as a strong predictor for outcome, univariate analysis indicates that nerve graft length > 15 cm and BMI of > 25 could lead to inferior outcome. When patients with early recovery (n = 19) are included into final evaluation after 24 months, the general success rate of reconstructions is 62,7% (52/83). CONCLUSION: Reconstruction of musculocutaneous nerve after brachial plexus injury results in a high rate of clinical improvement. Nerve transfer and autologous reconstruction both show similar results. Young age was confirmed as an independent predictor for better clinical outcome. Prospective multicenter studies are needed to further clarify.

Bifurcated distal biceps brachii tendon coexisting with separated bicipital aponeurosis: a complex variational case report.

Variations appearing in biceps brachii muscle are common with accessory head, different origins, variant insertion, and different pattern of nerve innervation. However, variations appearing in both origin and insertion, and with other anomalous morphology at the same time are seldom. Here we report a complex variational case on the right arm of a 91-year-old Japanese female cadaver. The complex variations included (1) the biceps brachii muscle bifurcated at its distal ending; (2) the long head had its own tendon, which divided into two parts, i.e., a lateral part fused into the fascia between the brachioradialis and extensor carpi brevis, and a medial part attached to the radius about one centimeter ahead of the radial tuberosity; (3) the short head had an accessory origin from the shoulder capsule; (4) the bicipital aponeurosis was of two parts with an anterior superior layer formed by the long head and a posterior deep one formed by the short head; (5) the musculocutaneous nerve was especially underdeveloped that only innervated the coracobrachialis; (6) the existence of communicating branch between the musculocutaneous and median nerves, and the median nerve issued muscular branches to the biceps brachii and brachialis muscles, and (7) the brachioradial muscle had two accessory muscular bundles that originated from the fascia of the brachial muscle (proximal one) and from the bicipital aponeurosis (distal one).

Safety-driven master's technique of the Latarjet-Walch procedure and its short-term complications: experience in a study of 150 consecutive patients.

Background: Although the classic open Latarjet has a low recurrence rate in unstable shoulders, this advantage may be offset by the higher number of complications. We aimed to report the safety-driven nuanced steps and the resulting short-term complications of the Latarjet-Walch technique. Methods: Between 2016 and 2022, 150 patients who underwent the Latarjet procedure following the key safety-driven technical steps were retrospectively evaluated for intraoperative and short-term (3 months) complications. The complications were divided into 3 types: Any adverse event that did not need a change in the treatment protocol was a type 1 complication. An event that resulted in a prolongation of rehabilitation protocol or an additional medical line of treatment was classified as type 2, and an event that resulted in readmission, a resurgery, or one that affected the outcome was classified as a type 3 complication. Results: There were 12 (8%) short-term complications in 9 patients. Neurological complications were noted in 3 (2%) patients (1 axillary nerve injury, 1 suprascapular nerve injury, and 1 musculocutaneous nerve injury). Type 1 complications were noted in 2 patients: 2 patients had hematoma that was detected as superficial swelling, but no surgical drainage was needed, and both resolved at their 1-month follow-up. Type 2 complications were noted in 4 patients. One patient had surgical site infection and a second patient had superficial wound dehiscence in the lower part of the wound. The third patient had suprascapular nerve paresis and the fourth had musculocutaneous nerve paresis and shoulder stiffness. Both nerve injuries recovered completely after 6 months of rehabilitation. Type 3 complications were noted in 3 patients. One patient had axillary nerve paresis and shoulder stiffness. The axillary nerve palsy had recovered partially by 8 months. One patient had an intraoperative graft fracture and postoperative shoulder stiffness, and the third patient had shoulder stiffness. Conclusion: Following the safety-driven nuanced steps in the Latarjet-Walch procedure, the short-term complication rate was 8%, and the neurological complication was 2% (n = 3). The musculocutaneous and suprascapular nerves completely recovered, and the axillary nerve had partially recovered.

A rare bilateral variant of the coracobrachialis muscle with supernumerary heads and coexisted variant branching patterns of the brachial plexus and the axillary artery.

PURPOSE: The study report describes a rare bilateral variant of a six- and five-headed coracobrachialis muscle (CB). The musculocutaneous nerve (MCN) (bilaterally) and the median nerve (MN) lateral root (unilaterally) pierced CB heads, separating superficial from deep heads. METHODS: The variant bilateral CB was identified in a 78-year-old formalin-embalmed male cadaver, derived from a body donation program after a signed informed consent. RESULTS: At the right side: The 6-headed CB was pierced by the MCN, while the MN lateral root pierced the one superficial and deep head. CB was supplied by the lateral cord and the MCN. At the left side: A 5-headed CB was identified with three superficial distinct origins that fused into a common superficial head coursing anterior to MCN. The variant CB bilaterally (with 11 heads in total) coexisted with a MN variant formation, an atypical course of the MN lateral root through CB (right side), a connection of the MN lateral root with the MCN (left side) and a variant axillary artery branching pattern (bilaterally). CONCLUSIONS: Course and direction of the accessory CB heads may occasionally entrap the MCN and/or adjacent structures (brachial artery and MN). The MCN compression results in problems in the glenohumeral joint flexion and adduction, and tingling or numbness of the elbow joint, the forearm lateral parts and the hand.

Unilateral accessory brachialis muscle and its functional significance: a case report of rare variation.

Variations of the brachialis muscle are uncommon in the literature. During regular cadaveric dissection, we observed the unilateral presence of an accessory muscle in the front of the right arm of a female cadaver, taking its origin from the medial aspect of the brachialis and the adjacent intermuscular septum. The muscle belly descended downwards, crossed the neurovascular bundle in the cubital fossa and merged with the fibres of the pronator teres. There is no doubt regarding its significance in the etiogenesis of numerous compression syndromes due to its close topographical relationship with the neurovascular bundle. In our report, we consider the potential developmental process and therapeutic implications of this variation, which can aid surgeons in their strategy and management.