Anatomical Study of the Musculocutaneous Nerve in Relation to the Coracoid Process.

OBJECTIVE The authors performed an anatomical study on the path of the musculocutaneous nerve by dissecting 20 shoulders from 10 fresh adult cadavers. METHOD The distance from the lower edge of the coracoid process to the point of penetration of the most proximal branch of the musculocutaneous nerve in the coracobrachialis muscle was measured and named the base. Starting from the inferomedial edge of the coracoid process, a second measurement was made to the point at which the lateral fascicle of the brachial plexus crossed the subclavius muscle, and was named the height. The third measurement was of the triangular area formed by the two first measurements, and was named the area. RESULTS The mean base length was 3.42 cm, ranging from 2.38 cm to 4.40 cm. The mean height measurement was 2.74 cm, ranging from 1.03 cm to 3.80 cm. The mean area was 4.92 cm(2), ranging from 1.22 cm(2) to 7.99 cm2. CONCLUSION These measurements are very important because of the risk of injury to the musculocutaneous nerve in surgical approaches to the shoulder.