Arterial blood supply of the proximal humeral epiphysis.

The arterial blood supply of the proximal humeral epiphysis is known to derive mainly from the anterior humeral circumflex a. (ACA), but this description may minimize the role of the posterior circumflex humeral a. (PCA). The studies of Laing [9] and Gerber [3] emphasized the role of the ACA and of its branches, the ascending anterolateral artery and arcuate artery Thus, this description could not explain either the necrosis or the absence of necrosis in all the cases of fracture or dislocation of the glenohumeral joint. The evaluation of the risk of a vascular post-traumatic necrosis of the humeral head requires a knowledge of its arterial vascularization, and the aim of this study was to determine the respective areas of vascularization of both the humeral circumflex aa. 32 shoulders of adult cadavers were studied: the ACA and the PCA were injected with latex containing two differently colored fluids. The proximal humeral epiphysis was removed with the arteries. The extraosseous vessels and the coloration of the capsule were noted; then the epiphysis was sectioned in 5 mm horizontal scans, and the bone staining was studied in order to define the distribution of the arterial supplies. The origin of the ACA and PCA was common in only 10 cases. The mean diameters were: ACA 0.8 mm (0.3 to 2) and PCA 2.1 mm (1.5 to 4). The subchondral bone was colored in 29 specimens by the PCA, and by both the ACA in the cranial part and PCA in the caudal part in 3. The apex of the head was colored by the ACA in 7 cases, the PCA in 7 and both ACA and ACP in 1 case; the head was colored by the PCA in 17 and the ACA in 12 cases; the lesser tubercle by the ACA in 23, the PCA in 2 and both arteries in 7 cases; the greater tubercle by the PCA in 19, the ACA in 5 cases and both in 1 case; the intertubercular groove by the ACA in 29, the PCA in 1 and both arteries in 2 specimens. The arcuate a. was distributed along the metaphyseal side of the epiphyseal plate, and small branches crossed the plate to reach the epiphyseal side and give numerous anastomoses to the branches of the ACA or the PCA. The diameter of the ACA was constantly smaller than that of the PCA. Exclusive vascularization of the humeral head by the ACA was not confirmed. The roles of both the ACA and PCA remain important, and must be taken into account in evaluating the risk of necrosis after a fracture, by carefully considering the topography of the separation and the displacement of the different parts.