Improved knowledge of the distal triceps insertion is needed as a result of an increase in procedures involving this area, including distal triceps repair, posterior capsulectomy, and olecranon tip osteotomy for coronoid reconstruction.
Materials and methods:
Five pair-matched upper limbs were dissected to study the morphology and dimension of the distal triceps tendon, triceps tendon insertion, capsular insertion on the olecranon, and triceps lateral retinaculum. Muscle origins of the triceps insertions were identified proximally.
Three distinct insertional areas were found in the olecranon corresponding to the posterior capsular insertion, the deep muscular portion, and the superficial tendinous portion of the triceps with areas of 1.5, 1.2, and 2.8 cm2, respectively. The deep muscular head corresponded to the medial head of the triceps and the tendinous portion corresponded to the long and lateral heads and correlated with the height of the specimen. The triceps width at insertion was 2.6 ± 0.5 cm (standard deviation), and the triceps lateral retinaculum extended the tendon laterally for 2.5 ± 0.7 cm. The tendinous portion of the triceps tendon extended proximally 15.3 ± 1.4 cm. The triceps inserted at a mean of 1.1 cm from the tip of the olecranon.
The distinct insertional heads of the triceps provides additional knowledge that can aid in diagnosing and treating partial triceps tears. In addition, a safe zone for capsulectomy and olecranon tip osteotomy is described that can be used to increase the safety of these procedures.