The neurovascular bundle to the upper limb passes posterior to the coracoid process and the pectoralis minor muscle. In 1945, Wright observed that in normal individuals, excessive abduction of the upper limb causes compression of the neurovascular bundle. This occurs because the neurovascular bundle is both stretched and compressed by the pectoralis minor muscle. The site of compression is at the transition from the subclavian pulse to the axillary pulse. This mechanism of compression can be demonstrated both in anatomical specimens and on the operating table.

bubble_chart Etiology

Under normal circumstances, excessive abduction of the upper limb does not cause symptoms despite compression of the neurovascular bundle. However, symptoms may appear when there is malunion of the coracoid process or thickening of the pectoralis minor muscle.

bubble_chart Clinical Manifestations

It commonly occurs in muscular, stocky, short-necked young adults, often during work. There is a sensation of fullness in the hands and fingers, with numbness and tingling in the forearms and fingers.

The most obvious sign is tenderness under the coracoid process of the pectoralis minor muscle. Applying pressure here can reproduce symptoms such as numbness and tingling in the forearms, hands, and fingers. Excessive abduction of the affected limb can block the pulsation of the radial stirred pulse.

bubble_chart Treatment Measures

Changing jobs may provide some relief. Tuina has a certain therapeutic effect. If conservative treatment fails, surgical treatment can be considered. The main procedure involves cutting the pectoralis minor muscle at its insertion point to release compression and alleviate or eliminate symptoms.