Background: A detailed description of the vascular anatomy of the shoulder capsule is lacking, yet surgical procedures may put this capsular blood supply at risk. We hypothesized that a hypovascular area is present in the capsule. The purpose of the present study was to describe the vascular anatomy of the human glenohumeral capsule and ligaments and its relevance to surgical treatment of the shoulder.

Methods: In twenty-four fresh adult cadaveric shoulders, the axillary artery proximal to the thoracoacromial branch and the suprascapular artery were injected with India ink. The specimens were sectioned and then cleared with a modified Spalteholz technique.

Results: The glenohumeral capsule demonstrates consistent arterial contributions from the anterior circumflex, posterior circumflex, circumflex scapular, and suprascapular arteries. The arterial supply is centripetal in nature. The contributing vessels enter the capsule both laterally and medially and arborize toward the middle of the capsule. The rotator cuff provides additional blood supply to the capsule through perforating vessels. The dominant capsular vessels run horizontally and form intracapsular anastomoses via vertical branches. The anterior and posterior bands of the inferior glenohumeral ligament complex are vascularized by adjacent parallel vessels. In five of twelve specimens, a hypovascular zone was located near the humeral insertion of the anterior aspect of the capsule. In these five specimens, there was an associated hypovascular zone in the underlying capsule.

Conclusion: The glenohumeral capsule is a well-vascularized structure with direct predictable contributions from four named arteries. These arteries send branches that enter the capsule superficially and from the periphery. These dominant vessels run horizontally toward the midcapsule and to deeper layers of the capsule. Vessels originating from the rotator cuff provide additional blood supply to the capsule.

Clinical Relevance: Surgical approaches to the shoulder that separate the rotator cuff from the capsule may disrupt the perforating blood supply from the overlying rotator cuff. Horizontal capsular incisions run parallel to the dominant vessels of the capsule, while vertical incisions are likely to cross these vessels. Laterally based capsular incisions may traverse the hypovascular zone when it is present.