Anatomy of the scapulothoracic articulation.

Four fresh frozen human cadavers (eight extremities) consisting of the head, neck, thorax, and entire upper extremities were used for dissection of the scapulothoracic articulation. In each specimen, the spinal accessory nerve, all relevant muscle insertions, and bursae were identified and measured. The structures of the scapulothoracic articulation can be divided into superficial, intermediate, and deep layers. The superficial layer consists of the trapezius, latissimus dorsi, and an inconsistent bursa between the inferior angle of the scapula and the latissimus dorsi. The intermediate layer consists of the levator scapulae, rhomboid minor and major, spinal accessory nerve, and scapulotrapezial bursa located between the superomedial scapula and the overlying trapezius. In all specimens, the spinal accessory nerve traveled intimately along the wall of the scapulotrapezial bursa, an average of 2.7 cm lateral to the superomedial angle of the scapula. The deep layer consists of the serratus anterior, subscapularis, and two bursae: one between the serratus and the thorax, the scapulothoracic bursa; and one between the subscapularis and the serratus, the subscapularis bursa.