Bilateral Additional Slips of Triceps Brachii Forming Osseo-Musculo-Fibrous Tunnels for Ulnar Nerves
During routine dissection for undergraduate students at department of anatomy, at our institution, we observed bilateral variation of triceps muscle in a South Indian male cadaver of a 62 year old. On left side, the variant additional slip of triceps muscle took origin from the lower part of the medial intermuscular septum, about 4 cm proximal to the medial epicondyle. From its origin, the muscle fibres were passing over the ulnar nerve and were joining the triceps muscle to get inserted on the upper surface of olecranon process of ulna []. On right side, the additional slip was larger and bulkier and in addition to its attachment to the medial intermuscular septum, it was arising from the lower part of the medial border of the humerus about 4 cm proximal to the medial epicondyle and then joined the triceps muscle, to get inserted on the upper surface of olecranon process of ulna []. The additional slips on both sides were supplied by twigs from the radial nerve.\nOn both sides, the ulnar nerve was passing between variant additional slip, medial intermuscular septum and the lower part of the shaft of the humerus in an osseo-musculo-fibrous tunnel and then was passing behind the medial epicondyle of humerus to enter the forearm [Figures and ].