The origin of the long head of the triceps: A cadaveric study

HypothesisThere is a paucity of literature examining the origin, size, and capsular contribution of the long head of the triceps brachii muscle. We hypothesize that there is a more extensive origin and capsular contribution than previously described.Materials and methodsTwenty fresh, frozen cadaveric specimens were dissected from a posterior and anterior approach exposing the long head of the triceps and the inferior capsule. The origin and size of the long head of the triceps and contribution to the capsule was documented.ResultsThe average age of the specimens was 65.8. At the scapula, the tendon width averaged 2.69 cm at the insertion and the thickness averaged 0.47 cm laterally and 0.29 cm medially. The bony origin extended on the lateral border dorsal surface of the scapula in addition to the infraglenoid tubercle. The long head of the triceps gave a capsular contribution in each specimen. This contribution measured 1.43 cm from superior to inferior and 1.01 cm from anterior to posterior after dissecting the capsule off the glenoid.DiscussionWe found the origin of the long head of the triceps had a more extensive bony attachment on the scapula then previously described. In addition, the long head of the triceps has a consistent contribution to the inferior shoulder capsule.ConclusionThe anatomic origin of the long head of the triceps gives a capsular contribution to the inferior glenohumeral capsule. The triceps may be affected by open and arthroscopic procedures that release or shift the posterior inferior glenohumeral capsule.Level of evidenceCadaveric study.