The muscular axillary arch: an anatomic study and clinical considerations.
OBJECTIVE
The muscular axillary arch is a musculotendinous structure that arises from the latissimus dorsi muscle and crosses the axilla before inserting to the humerus, brachial fascia, or coracoid process. Case reports have described the neurovascular compression symptoms caused by this anatomic variant and have reported that the symptoms can be relieved by division of the muscle. However, there has been little information published regarding this topic in the neurosurgical literature.


METHODS
We evaluated 70 axillary dissections in 35 cadavers to assess for the presence of this anomaly.


RESULTS
The muscular axillary arch was identified unilaterally in 3 (8.6%) of the 35 cadavers. All 3 arches arose from the anterior border of the latissimus dorsi muscle and inserted at a point along a line extending from the coracoid process to the intertubercular groove deep to the insertion of the pectoralis major muscle. All 3 arches crossed over the neurovascular bundle in the axilla.


CONCLUSIONS
Compression by the muscular axillary arch should be considered in the differential diagnosis of patients with thoracic outlet and hyperabduction syndromes.
Rizk
Elias
E
Department of Neurosurgery, Pennsylvania State Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA.
Harbaugh
Kimberly
K
D000369:Aged, 80 and over; D001365:Axilla / Q000033:anatomy & histology* / Q000294:innervation; D002102:Cadaver; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000002:abnormalities* / Q000033:anatomy & histology*; D009408:Nerve Compression Syndromes / Q000209:etiology; D012782:Shoulder / Q000033:anatomy & histology*