Cadaveric investigation into the innervation of the long head of triceps brachii (726.9)

All three heads of the Triceps brachii are classically described as being innervated by the radial nerve. A previous study of 20 cadaveric shoulders revealed that in 13 specimens the long head of the triceps (LHT) was supplied by a branch of the axillary nerve, not the radial nerve. In our current study 20 cadaveric shoulders were dissected via a combined anterior and extensile dorsal approach. The dissections were photographed and nerve maps were created. Distances from proximal LHT attachment to the point of neuromuscular insertion were measured with calipers. The results indicated that in 60% of the specimens the axillary nerve contributed to the innervation of the LHT; in 15% axillary nerve alone and in 45% combined axillary and radial nerve. These findings have clinical significance in understanding why triceps brachii dysfunction is sometimes associated with axillary nerve injuries.