Branch Of Axillary Nerve Research Articles

The Axillary Nerve Danger Zone in Percutaneous Fixation in the Pediatric Shoulder: The "1-Mountain-3-Valleys" Principle.

Adult literature cites an axillary nerve danger zone of 5 to 7 cm distal to the acromion tip for open or percutaneous shoulder surgery, but that may not be valid for younger patients. This study sought to quantify the course of the axillary nerve in adolescent patients with reference to easily identifiable intraoperative anatomic and radiographic parameters. A single-institution hospital database was reviewed for shoulder magnetic resonance images (MRIs) in patients 10 to 17 years old. One hundred and one MRIs from patients with a mean age of 15.6 ± 1.2 years (range, 10 to 17 years) were included. Axillary nerve branches were identified in the coronal plane as they passed lateral to the proximal humerus and were measured in relation to identifiable intraoperative surface and radiographic landmarks, including the acromion tip, apex of the humeral head, lateral physis, and central apex of the physis. The physeal apex height (i.e., 1 "mountain") was defined as the vertical distance between the most lateral point of the humeral physis (LPHP) and the central intraosseous apex of the physis. Axillary nerve branches were found in all specimens, adjacent to the lateral cortex of the proximal humerus. A mean of 3.7 branches (range, 2 to 6) were found. The mean distance from the most proximal branch (BR1) to the most distal branch (BR2) was 11.7 mm. The pediatric danger zone for the axillary nerve branches ranged from 6.6 mm proximal to 33.1 mm distal to the LPHP. The danger zone in relation to percent of physeal apex height included from 62% proximal to 242% distal to the LPHP. All branches were found distal to the apex of the physis (1 "mountain" height proximal to the LPHP). Distal to the LPHP, no branches were found beyond a distance of 3 times the physeal apex height (3 "valleys"). In children and adolescents, percutaneous fixation of the proximal humerus should be performed with cortical penetration outside of this range. These parameters serve as readily identifiable intraoperative radiographic landmarks to minimize iatrogenic nerve injury. This study provides valuable landmarks for percutaneous approaches to the proximal humerus. The surgical approach for the placement of percutaneous implants should be adjusted accordingly (i.e., performed at least 1 mountain proximal or 3 valleys distal to the LPHP) in order to prevent iatrogenic injury to the axillary nerve.

C6 and not C5 nerve fibers more commonly contribute most to deltoid muscle innervation: anatomical study with application to better diagnosing cervical nerve injuries.

Most anatomical textbooks list both the C5 and C6 spinal nerves as contributing to the deltoid muscle's innervation via the axillary nerve. To our knowledge, no previous study has detailed the exact spinal nerve components of the axillary nerve terminating in the deltoid via cadaveric dissection. Twenty formalin-fixed cadavers (40 sides) underwent dissection of the brachial plexus. The fascicles making up the axillary nerve branch that specifically terminated in the deltoid muscle were traced proximally. The axillary nerve branch to the deltoid muscle was most commonly (70%) made up of three spinal nerve segments and less commonly (30%) by two spinal nerve segments. For all axillary nerve branches to the deltoid muscle, C4 spinal nerves contributed 0-5%, C5 spinal nerves contributed 1-80%, C6 spinal nerve contributed 15-99%, C7 spinal nerves contributed 0-30%, and C8 and T1 spinal nerves were not found to contribute any fibers to any deltoid muscle branches. The nerve to the deltoid muscle was contributed to equally by C5 and C6 nerve fibers on 10% of sides. On 16% of sides, C5 contributed the most nerve fibers to this muscle. On 35% of sides, C6 contributed the majority fibers found in the axillary nerve branches to the deltoid. Based on our anatomical study, C6 is more often than not the main level of innervation. C5 was never the sole component of the axillary nerve branches to the deltoid muscle. Such anatomical data will now need to be reconciled with clinical studies.

Definition of a Risk Zone for the Axillary Nerve Based on Superficial Landmarks.

The aim of this study was to investigate the axillary nerve's location along superficial anatomical landmarks, and to define a convenient risk zone. A total of 123 upper extremities were evaluated. After dissection of the axillary nerve, the vertical distance between the upper border of the anterolateral edge of the acromion and the proximal border of the nerve was measured. Furthermore, the interval between the proximal border and the distal border of the axillary nerve's branches was evaluated. The interval between the distal border of the branches and the most distal part of the lateral humeral epicondyle was measured. The distance between the anterolateral edge of the acromion and the lateral humeral epicondyle was evaluated. Measurements were expressed as proportions with respect to the distance between the acromion and the lateral humeral epicondyle. The distance between the acromion and the proximal border of the axillary nerve's branches was at a height of 10 percent of the distance between the acromion and the lateral humeral epicondyle, starting from the acromion (90 percent when starting from the lateral humeral epicondyle). The interval between the proximal and distal margins of the axillary nerve's branches was between 10 percent and 30 to 35 percent of this interval, starting from the acromion (65 to 70 percent when starting from the lateral humeral epicondyle). The authors were able to locate the branches of the axillary nerve at an interval between 10 and 35 percent of the distance between the acromion and the lateral humeral epicondyle, starting from the acromion. This makes the proximal third of this distance an easily applicable risk zone during shoulder surgery.

Use of the Humeral Head as a Reference Point to Prevent Axillary Nerve Damage during Proximal Fixation of Humeral Fractures: An Anatomical and Radiographic Study.

IntroductionTreatment of proximal humeral fractures with plate osteosynthesis or intramedullary nail fixation in humeral shaft fractures with a proximal locking bolt carries the risk of iatrogenic injury of the axillary nerve. The purpose of this anatomical study is to define a more reliable safe zone to prevent iatrogenic axillary nerve injury using the humeral head instead of the acromion as a (radiographic) reference point during operative treatment.Materials and methodsAnatomical dissection and labeling of the axillary nerve and branches was performed on 10 specially embalmed human specimens. Standard AP and straight lateral radiographs were made. The distances were measured indirectly from the cranial tip of the humerus to the axillary nerve on radiographs.ResultsThe median distance from the cranial tip of the humerus to the axillary nerve was 52 mm. The mean number of axillary nerve branches was 3. The distances from the cranial tip of the humerus to the nerve (branch) varied from 23 to 78 mm. The median distance from the proximal (anterior) branch was 36 mm, to the second branch 47 mm, 54 mm to the third branch and 73 mm to the fourth branch. The axillary nerve moves along with the humerus in cranial and caudal direction when the subacromial space varies.ConclusionThis study shows that the position of the axillary nerve can be better determent using the cranial tip of the humerus as a reference point instead of the acromion. Furthermore, it is unsafe to place the proximal locking bolts in the zone between 24 mm and 78 mm from the cranial tip of the humerus. The greatest chance to cause a lesion of the main branch of the axillary nerve is in the zone between 48 mm and 58 mm caudal from the tip of the humeral head.How to cite this articleTheeuwes HP, Potters JW, Bessems JHJM, et al. Use of the Humeral Head as a Reference Point to Prevent Axillary Nerve Damage during Proximal Fixation of Humeral Fractures: An Anatomical and Radiographic Study. Strategies Trauma Limb Reconstr 2020;15(2):63–68.

Transfers of the Ipsilateral C7 Plus the Spinal Accessory Nerve Versus Triple Nerve Transfers for Treatment of C5-C6 Avulsion of the Brachial Plexus

To compare the long-term results of transfers of the ipsilateral C7 (IC7) plus spinal accessory nerve (SAN) with those of triple nerve transfers (TNT) using one fascicle of the ulnar nerve to the biceps motor branch (Oberlin's procedure), SAN transferred to the suprascapular nerve, and transfer of the long head of triceps nerve branch to the anterior branch of axillary nerve to treat C5-C6 avulsion of the brachial plexus. The IC7 group included 9 patients undergoing transfers of IC7 to the upper trunk and SAN to the suprascapular nerve. Median age at surgery was 26 years and interval between injury and surgery was 2.8 months. Patients were observed for a median of 118 months. The TNT group contained 13 patients, median age 33 years; interval between injury and surgery was 3.1 months. Patients were observed for a median of 103 months. In the IC7 group, median shoulder abduction was 105° and median external rotation of the shoulder was 64°, which was similar to that of the TNT group (89° abduction and 58° external rotation). Eight of nine patients recovered at least M3 (Modified Narakas scale) strength of deltoid in the IC7 group, which was similar to that in the TNT group (11 of 13 patients). Six of nine patients achieved at least Medical Research Council grade 3 (MRC3) strength of biceps in the IC7 group, which was similar to that in the TNT group (11 of 13 patients). Of 4 patients in the IC7 group with a preoperative latissimus dorsi strength of MRC3 or less, 3 gained a deltoid strength of M3 or less, and 3 a biceps strength of MRC2 or less. Transfers of IC7 plus SAN provide results comparable to those of TNT for treatment of C5-C6 avulsion. Therapeutic IV.

VARIATIONS OF ORIGIN AND DISTANCE OF AXILLARY NERVE: A DESCRIPTIVE STUDY

Background: Axillary nerve, one of the terminal branches of posterior cord of brachial plexus is more prone for injuries. Lack of proper anatomical knowledge and variations of axillary nerve leads to risk of nerve injuries. The present study describes the origin of axillary nerve, its distance of origin from tip of coracoids process. Method: Thirty brachial plexuses from fifteen formalin fixed human cadavers of both the sexes were studied by dissection method. Origin and branching pattern of axillary nerve and its distance of origin from the anteromedial aspect of tip of coracoid process & posterolateral aspect of acromion process was recorded. Results: Out of the 30 specimens studied, axillary nerve was originating from the posterior cord of brachial plexus in 90% of specimens, remaining 10% specimens showed a common trunk of origin of axillary nerve from posterior cord of brachial plexus. The mean distance of origin of axillary nerve from the anteromedial aspect of tip of coracoid process and posterolateral aspect of acromion process is 3.98cm & 6.30cm respectively. The axillary nerve terminated into anterior and posterior branch within quadrangular space in 29 specimens. In one specimen articular branch for shoulder joint was not directly arising from axillary nerve instead it is arising from anterior branch of axillary nerve. Conclusion: In studied population Axillary nerves display variations in the origin and distance of origin. Knowledge of this variation in axillary nerve is very important to clinicians, anaesthetists and orthopaedic surgeons during surgical exploration of neck, axilla and upper arm, shoulder dislocation, infraclavicular brachial plexus block and fracture of surgical neck of humerus.
 Keywords: Axillary nerve; Posterior cord; Coracoid process; Acromion process.

Results of Distal Nerve Transfers in Restoration of Shoulder Function in C5 and C6 Root Avulsion Injury to the Brachial Plexus

Background The lack of shoulder function following brachial plexus injury is a debilitating condition. Nerve root avulsion injury precludes a direct nerve repair. Under these circumstances, distal nerve transfer is a well-established technique in the restoration of shoulder abduction and external rotation. Methods Thirty patients with C5 and C6 root avulsion injury were treated with distal nerve transfers in the period between February 2009 and December 2012.The average denervation period was 5.6 months. Shoulder function was restored by posterior transfer of distal part of the spinal accessory nerve into the suprascapular nerve and transfer of the long head triceps branch of radial nerve to the anterior branch of axillary nerve. An additional nerve transfer was performed in four patients with winged scapula by transferring a part of thoracodorsal nerve into the long thoracic nerve. Results Twenty-seven patients recovered shoulder abduction; 18 scored M4 and 9 scored M3. Range of abduction averaged 118 degrees (range, 90–170 degrees). Nineteen patients restored external rotation with an average of 53 degrees (range: 30–70 degrees). Three patients failed to recover shoulder abduction though the joint regained stability. External rotation remained severely restricted in 11 patients. At final follow-up, winging of scapula improved in three of four patients following reinnervation of the serratus anterior muscle. Conclusion Nerve transfers, when performed close to the target muscles, restore good range and strength of shoulder abduction in most patients with C5 and C6 root avulsion injuries. However, return in external rotation is not as good as the recovery in abduction.

Axon Counts Yield Multiple Options for Triceps Fascicular Nerve to Axillary Nerve Transfer

To evaluate the relative axonal match between potential donor and recipient nerves, so that maximal reinnervation potential may be reached with the least chance of donor site morbidity. In 10 fresh-frozen cadaveric specimens, the main trunk and anterior, posterior, sensory and teres minor branches of the axillary nerve were identified, as were the radial nerve branches to the long, medial, and lateral heads of the triceps. The swing distances of thetriceps fascicular nerve branches and the axillary nerve branches relative to the inferior border of the teres major muscle were recorded. Histomorphological analysis and axon counts were performed on sections of each branch. The median number of axons in the main axillary trunk was 7,887, with 4,052, 1,242, and 1,161 axons in the anterior, posterior, and teres minor branches, respectively. All specimens had a single long head triceps branch (median, 2,302 axons), a range of 1 to 3 branches to the medial head of the triceps (composite axon count, 2,198 axons), and 1 to 3 branches to the lateral head of the triceps (composite average, 1,462 axons). The medial and lateral head branches had sufficient swing distance to reach the anterior branch of the axillary nerve in all 10 specimens, with only 4 specimens having adequate long head branch swing distances. It is anatomically feasible to transfer multiple branches of the radial nerve supplying the medial, lateral, and sometimes, long head of the triceps to all branches of the axillary nerve in an attempt to reinnervate the deltoid and teres minor muscles. Understanding the axon counts of the different possible transfer combinations will improve operative flexibility and enable peripheral nerve surgeons to reinnervate for both abduction and external rotation with the highest donor/recipient axon count ratios.

Surgical anatomy of the axillary nerve branches to the deltoid muscle

Variations in the innervation of the posterior deltoid muscle by the anterior branch of the axillary nerve have been reported. The objective of this study is to clarify the anatomy of the axillary nerve branches to the deltoid muscle. One hundred and twenty-nine arms (68 right and 61 left) from 88 embalmed cadavers (83 male and 46 female) were included in the study. The anterior and posterior branches of the axillary nerve were identified and their lengths were measured from the point of emergence from the axillary nerve to their terminations in the deltoid muscle. In all cases, the axillary nerves split into two branches (anterior and posterior) within the quadrangular space and none split within the deltoid muscle. In all specimens, the anterior and middle parts of the deltoid muscle received their nerve supplies from the anterior branch of the axillary nerve. The posterior part of the deltoid muscle was supplied only by the anterior branch of the axillary nerve in 2.3% of the specimens, from the posterior branch in 8.5%, and from both branches in 89.1%. There were two sub-branches of the anterior branch in 4.7% of the specimens. The anterior branch of the axillary nerve supplied not only the anterior and middle parts of the deltoid muscle but also the posterior part in most cases (91.5%).

Single-Stage Surgery Combining Nerve and Tendon Transfers for Bilateral Upper Limb Reconstruction in a Tetraplegic Patient: Case Report

A 39-year-old tetraplegic patient had paralysis of elbow, thumb, and finger extension and thumb and finger flexion. We transferred axillary nerve branches to the triceps long and upper medial head motor branches, supinator motor branches to the posterior interosseous nerve, and brachioradialis tendon to the flexor pollicis longus and flexor superficialis of the index finger. Surgery was performed bilaterally 18 months after spinal cord injury. At 12 months after surgery, we performed bilateral distal radioulnar arthrodesis percutaneously. By 22 months postoperatively, we observed triceps strength scoring M3 bilaterally and full metacarpophalangeal joint extension scoring M4 bilaterally. The thumb span was 53 and 66 mm from the proximal index phalanx on the right and left sides, respectively. Pinch strength measured 1.5 kg on the left side and 2.0 kg on the right. Before surgery, the patient was incapable of grasping; after surgery, a useful grasp had been restored bilaterally.

Transfer of axillary nerve branches to reconstruct elbow extension in tetraplegics: A laboratory investigation of surgical feasibility

In spinal cord injuries at the C6 level, elbow extension is lost and needs reconstruction. Traditionally, elbow extension has been reconstructed by muscle transfers, which improve function only moderately. We have hypothesized that outcomes could be ameliorated by nerve transfers rather than muscle transfers. We anatomically investigated nerve branches to the teres minor and posterior deltoid as donors for transfer to triceps motor branches. In eight formalin-fixed cadavers, the axillary nerve, the teres minor branch, the posterior deltoid branch, the triceps long and upper medial head motor branches, and the thoracodorsal nerve were dissected bilaterally, their diameters measured and their myelinated fibers counted. To simulate surgery, using an axillary approach in two fresh cadavers, we transferred the teres minor or the posterior deltoid branch to the triceps long head and to the thoracodorsal nerve. The posterior division of the axillary nerve gave off the teres minor motor branch and then the branch to the posterior deltoid, terminating as the superior lateral brachial cutaneous nerve. The diameters of the teres minor motor branch, posterior deltoid, triceps long and upper medial head branches, and the thoracodorsal nerve all were ∼2 mm, with minimal variation. The nerves varied little in their numbers of myelinated fibers, being consistently about 1,000. Via an axillary approach, either the teres minor or the posterior deltoid branch could be transferred directly to the thoracodorsal nerve or to triceps branches without any tension.

Multiple nerve transfers for the reanimation of shoulder and elbow functions in irreparable C5, C6 and upper truncal lesions of the brachial plexus

In irreparable C5, C6 spinal nerve and upper truncal injuries the proximal root stumps are not available for grafting, hence repair is based on nerve transfer or neurotization. Between Feb 2004 and May 2006, 23 patients with irreparable C5, C6 or upper truncal injuries of the Brachial Plexus underwent multiple nerve transfers to restore the shoulder and elbow functions. Most of them (16 patients) sustained injury following motor cycle accidents. The average denervation period was 5.3 months. Shoulder function was restored by transfer of distal part of spinal accessory nerve to suprascapular nerve, and transfer of radial nerve branch to long head of triceps to the anterior branch of axillary nerve. Elbow function was restored by transfers of ulnar and median nerve fascicles to the biceps and brachialis motor branches of musculocutaneous nerve. All patients recovered shoulder abduction and external rotation; 7 scored M4 and 16 scored M3. Range of abduction averaged 1230(range, 800-1700). Full elbow flexion was restored in all 23 patients; 15 scored M4 and 8 scored M3. Patients with excellent results could lift 5 kgs of weight. Selective nerve transfers close to the target muscle provide an early and good return of functions. There is negligible morbidity in donor nerves. These intraplexal transfers are suitable in all cases of upper brachial plexus injuries.

Transferring intercostal nerves to the anterior branch of axillary nerve through a posterior approach

Objective To provide anatomical evidence for restoring the deltoid function by trans- ferring 2 intercostal nerves to the anterior branch of the axillary nerve through a posterior approach. Methods Fifteen adult human cadavers embalmed by formalin were used.Microsursical longitudinal con- tradissection of the axillary nerves by tracing their terminal braches was conducted.The lengths of the 3rd, 4tth,5th and 6th intercostal nerves from tlle costochondral junction to the midaxillary line were recorded.The distance from the pivot point at the midaxillary line to the anterior branch of the axillary nerve was recorded as the tunnel length.Results The axillary nerve to the deltoid muscle is divided into 2 branches mostly. The anterior branch of the axillary nerve innervates about 4/5 of the dehoid muscle.The distancos from the costochondral junctions of the 3rd,4th,5th and 6th intercostal nerves to the pivot points average 11.41± O.35 cm,15.8l±1.12 cm,16.54±1.18 cm and 16.85±0.90 cm,respectively.The tunnel distances of the 3rd,4th,5th and 6th intercostal nerves average 11.53±0.47 cm,12.24±0.65 cm,13.22±1.15 cm and 13.82±1.02 cm,respectively. Conclusion Transfer of any two of the 4th,5th and 6th(except the 3rd)intercostal nerves to the anterior branch of the axillary nerve through a posterior approach call be an al- temative method for reconstruction of the deltoid muscle. Key words: Intercostal nerve; Nerve transfer; Anterior branch of axillary nerve

Lesion of the anterior branch of axillary nerve in a patient with hereditary neuropathy with liability to pressure palsies

We report the case of a 30-year-old woman affected by hereditary neuropathy with liability to pressure palsies (HNPP), who developed a painless left axillary neuropathy after sleeping on her left side, on a firm orthopaedic mattress, in her eighth month of pregnancy. Electromyography (EMG) showing neurogenic signs in the left anterior and middle deltoid, and normal findings in the left teres minor, posterior deltoid and other proximal upper limb muscles, demonstrated that the lesion was at the level of the axillary anterior branch. A direct compression of this branch against the surgical neck of the humerus seems the most likely pathogenic mechanism. This is the first documented description of an axillary neuropathy in HNPP. Knowledge of its possible occurrence may be important for prevention purposes.