THE STRUCTURE AND VASCULARIZATION OF THE BICEPS BRACHII LONG HEAD TENDON

In the present study we examined the structure and the blood supply of the long biceps tendon as well as the surface of the intertubercular sulcus, using tissue samples from children and adults. The applied met hods were light and electron microscopy, immunohistochemistry, and art erial injection techniques. The tendon represents a sliding tendon wit h the intertubercular sulcus and humeral head as hypomochlion. The par ts facing the humerus show some ultrastructural features of fibrous ca rtilage, the ovoid chondrocyte-like cells of the tendon lying within f elt-like matrix. In the opposite part adjacent to the capsule, the ten don resembles a traction tendon. The intertubercular sulcus is covered by fibrous cartilage. The tendon is supplied with arteries from three different sources. The density of intratendinous vessels in the tract ion zone is comparable to that of other tendons, while in the sliding zone it is markably decreased. The immediate vicinity of the sliding s urface is avascular. Our findings show that the long biceps tendon is structurally adapted to both its functions as sliding and traction ten don. The blood supply seems to be related to the metabolic requirement s of the different parts of the tendon.