Man Ther. 1996 Jun; 1(3): 133-139.

The muscular arch of the axilla revisited: its possible role in the thoracic outlet and shoulder instability syndromes.

Clarys JP, Barbaix E, Van Rompaey H, Caboor D, Van Roy P.

Experimental Anatomy and Manual Therapy Departments, Vrije Universiteit, Brussels, Belgium

SUMMARY. The thoracic outlet syndrome and shoulder instability provoke well known and partly similar sensations, often described by the patient as "my arm feels deadellipsisI have no strength in my armellipsisI feel pins and needles in my armellipsis". In axillary surgery, there are sometimes reports of a fibromuscular band or string crossing the axilla. In the dissection room these bands are well known. Their reported incidence being about 10% at post mortem. Generally they are variations of the latissimus dorsi or the pectoralis major muscles, the most common form being known as the axillary arch or the arch of Langer. Simulations of abduction in combination with external rotation on dissected cadaveric material suggest a possible neurovascular compression at the transition from the axilla to the upper end of the brachial neurovascular bundle. Dissection confirms that the band is innervated by branches from the ansa pectoralis with a blood supply from the lateral thoracic artery. Following a case study, where the axillary arch negatively influenced the patients occupational skills, an extensive echographic study of 1321 subjects (1179 male, 142 female) was undertaken. A total of 188 arches was detected in 112 subjects (8.50%), mostly occurring bilaterally (incidence 5.80%). The incidence of the arch of Langer suggests that it should be considered in the differential diagnoses of thoracic outlet and shoulder instability syndromes. Copyright 1996 Harcourt Publishers Ltd.