Background and Objectives: The extensor compartment of the arm is occupied by triceps muscle, through which runs the radial nerve and profunda brachii artery. Triceps arises by three heads namely long head, lateral head and medial head. Triceps is innervated by radial nerve (C6, C7 and C8) with separate branches for each head. Triceps muscle and its main motor nerve namely the radial nerve have multiple connection modalities. Each of the motor branches to triceps might be used as a donor for nerve transplantation. Axillary nerve, ulnar nerve and ulnar collateral branch of the radial nerve are previously unrecognized sources of triceps brachii innervation. Additional study was directed towards exploring the anatomy of motor branches to three heads of triceps brachii. Methods: The present study was performed on 52 upper limbs of 26 formalin embalmed cadavers from department of anatomy, at PMCH, Patna. Study duration of Two and half years, by dissection method. The nerve supply to each head of triceps was traced and carefully followed to the source of each nerve branch and noted. Conclusion: Gross anatomical knowledge of innervations pattern of triceps brachii and variations of its motor supply are important to medical personnel especially to orthopaedic surgeons, radiologists, neurophysicians and physiotherapists for surgical treatment of traumatic nerve injuries, nerve grafting, neurophysiologic evaluation to diagnose peripheral neuropathy.