ABSTRACT
Background: Traditionally the axillary nerve innervates the Deltoid and the Teres minor(TM) muscle. Axillarynerve injuries are common in shoulder dislocation, fracture surgical neck of humerus, brachial plexus injuriesand neuropathies. Traumatic injuries of axillary nerve have also shown weakness of Long head of triceps and insurgical practice, the nerve to long head of triceps is utilized for nerve transfer to neurotise the deltoid muscle inpatients with axillary nerve injuries. Hence the aim of the study was to find out the prevalence of contribution ofaxillary nerve to the innervation of Long head of triceps brachii (LHT).Materials and Methods: Nine embalmed adult human cadavers (bilaterally) and twelve disarticulated upperextremities were dissected. Total of thirty upper extremities were dissected. The axillary nerve was observedemerging from the quadrangular space. Anterior and posterior branches of axillary nerve were noted. Themuscular branches to deltoid, TM and LHT were traced to their point of innervation. The focus was on the branchof axillary nerve supplying the LHT. The branching configuration was classified into three types. Type I- posteriorbranch of axillary nerve supplying the LHT, Type II- Branch to TM supplying the LHT and Type III- A branch from thebifurcation of anterior & posterior branch of axillary nerve supplying LHT.Results: The present study showed that axillary nerve innervated the LHT in 8 out of 30 limbs (26.66%). Amongstthese, in 4 limbs(50%) posterior branch of axillary nerve supplied the LHT(type I ), in 3 limbs(37.5%) branch to TMsupplied the LHT(type II) and in 1 limb(12.5%) a branch from the bifurcation of axillary nerve into anterior andposterior branch supplied the LHT( type III). It was also observed that in 2 (6.66%) specimens, axillary nerve wasthe only supply to LHT and in 6 (20%) specimens both axillary nerve & radial nerve supplied the LHT and in theremaining 22 (73.3%) specimens, only the radial nerve supplied the LHT.Conclusion: Awareness of the variation of axillary nerve supplying the LHT is important for surgeons,orthopaedicians and anaesthetists for surgical treatment of traumatic nerve injuries.