The triceps brachii muscle and its insertion on the olecranon

The purpose of this anatomical study was to define the insertion of the tendon of the triceps brachii muscle and the course of the lateral cubital retinaculum (LCR) as an enhancement of the triceps tendon.

One hundred cadaver specimens were assessed and the widths of the triceps tendon and the olecranon and the expansion of the LCR were determined.

The width of the tendon ranged between 1.9 and 4.2 cm (mean: 2.81) and the width of the olecranon between 1.8-3.8 cm (mean: 2.5). In 65 of the 100 specimens, the width of the tendon was greater than that of the olecranon. The fibers on the medial side inserted exactly on the medial aspect of the olecranon, whereas on the lateral aspect the fibers left the olecranon to reach the posterior border of the ulna. In 28 specimens the olecranon was wider than the tendon of the triceps, and in seven extremities the tendon occupied exactly the whole area of the olecranon. The LCR measured 2.3-7.2 cm (mean: 4.04 cm).

By preserving parts of the triceps tendon on the olecranon and preserving the lateral cubital retinaculum, the extension strength will be maximized, allowing early active elbow motion. Using the triceps brachii muscle for any approach, only the medial aspect might be used as a guideline to reach the olecranon. On the lateral side the fibers of the triceps tendon fan out as the LCR to join into the ulna and the antebrachial fascia.