The long head of the biceps muscle is vulnerable and receptive to both specific and nonspecific infections. This vulnerability is based on a number of factors.
—The long head of the biceps muscle is inserted into the supraglenoid tuberosity and the glenoid ligament by a long tendon (9 cm.), which glides over the head of the humerus, within the capsule of the joint. It is invested with a synovial sheath, which is an evagination of the capsule, and then slides down the bicipital groove. This bursa is closed at its lower end and is 5 cm. long. Codman1 stated: "To my mind it is more properly called a sheath, but is in fact merely an extension of the joint cavity with which it freely communicates."Constant movement of the tendon in a rather shallow groove and relative instability of the shoulder make it possible for
SCHRAGER VL. SYPHILIS OF TENDON OF LONG HEAD OF BICEPS MUSCLE AND OF OLECRANON BURSA. Arch Surg. 1944;48(6):423-428. doi:10.1001/archsurg.1944.01230010436001