Does The Axillary Nerve Play A Role In The Innervation Of The Long Head Of The Triceps Muscle? A Cadaveric Study In A Puerto Rican Population

Abstract

The presence of an unusual innervation to the long head of the triceps brachii muscle, different as described in anatomical textbooks, may have clinical importance. The aim of this cadaveric study is to explore a possible contribution of the axillary nerve to the motor innervation of the long head of the triceps in a Puerto Rican population. We dissected the posterior cord of the brachial plexus in a supine position in embalmed cadavers, and the path of axillary nerve was followed to the quadrangular space. In a prone position, the posterior attachment of the deltoid muscle was cut to expose the long head of the triceps and its relation with the axillary nerve. After the dissection was carried out, many photographs were taken. The objective of this study was to clarify the motor innervation of the long head of the triceps brachii muscle because it has not been fully elucidated. The majority of anatomical textbooks state that the motor branch of the long head of the triceps brachii arises from the radial nerve. In our study, we found some specimens where the axillary nerve was innervating the long head of the triceps. It is very important to be aware about the presence of this variation in case the motor branch of the triceps muscle is used as a donor for nerve transfer. Recognizing this variation may also be important in radial nerve pathologies. In this clinical setting, muscle wasting would presumably be absent in the area innervated by the axillary nerve.