THE SHOULDER-JOINT 



255 



The superior band, known also as the gleno-humeral ligament, runs from the edge of the glenoid 

 cavity at the root of the coracoid process, just medial to the origin of the long tendon of the 

 biceps, and, passing laterally and downward at an acute angle to the tendon, for which it forms 

 a slight groove or sulcus, is fixed to a depression, the fovea capitis humeri, above the lesser 

 tuberosity of the humerus. It is a thin, ribbon-like band, of which the superior surface is 

 attached to the capsule, while the inferior is free and turned toward the joint. In the foetus 

 it is often, and in the adult occasionally, quite free from the capsule, and may be as thick as 

 the long tendon of the biceps (fig. 289). 



The tendons of the supra- and infraspinatus, teres minor, and subscapularis muscles 

 strengthen and support the capsule, especially near their points of insertion, and can be with 

 difficulty dissected off from it. The long head of the triceps supports and strengthens the 

 capsule below. The capsule also receives an upward sUp from the pectoralis major. The 

 supraspinaius often sends a sUp into the capsule from its upper edge (fig. 288). 



The coraco -humeral Ugament (fig. 290) is a strong broad band, which is 

 attached above to the lateral edge of the root and horizontal limb of the coracoid 

 process nearly as far as the tip. From this origin it is directed backward along 

 the line of the biceps tendon to blend with the capsule, and is inserted into 

 the greater tuberosity of the humerus. 



Seen from the back, it looks like an uninterrupted continuation of the capsule, while from 

 the front it looks like a fan-shaped prolongation from it overlying the rest of the ligament. At 

 its origin there is sometimes a bursa between it and the capsule. 



The glenoid ligament or lip [labrum glenoidale] (figs. 288 and 292) is a narrow 

 rim of dense fibro-cartilage, which surrounds the edge of the glenoid socket and 

 deepens it. It is about a quarter of an inch (6 mm.) wide above and below, but 

 less at its sides. Its peripheral edge is inseparably welded, near the bone, with 



Fig. 289. — Fcetal Shoulder-joint, showing the Gleno-humeral Ligament, and also the 

 Short Head of the Biceps, being continuous with the Coraco-acromial Ligament. 



Short tendon of biceps running 

 on into anterior band of coraco- 

 acromial ligament 



Long tendon of biceps 

 Gleno-humeral ligament 

 Capsule of shoulder, turned back 



Subscapularis tendon, cut and 

 turned laterally 



the articular capsule. Its structure is almost entireh' fibrous, with, but few 

 cartilage cells intermixed. At the upper part of the fossa the biceps tendon is 

 prolonged into the glenoid ligament, the tendon usually dividing and sending 

 fibres right and left into the ligament, which may vnnd round nearly the whole 

 circumference of the socket. It may, however, send fibres into one side only, 

 usually into the lateral. 



The articular cartilage covering the glenoid fossa is thicker at the circumfer- 

 ence than in the centre, thus tending to deepen the cavity. It is usually thickest 

 at the lower part of the fossa; over the head of the humerus the cartilage is thickest 

 at and below the centre. 



The synovial membrane lines the glenoid ligament, and is then reflected over 

 the capsule as far as its attachment to the humerus, from which it ascends as 

 far as the edge of the articular cartilage. The tendon of the biceps receives a 

 long tubular sheath, which is continuous with the synovial membrane, both at 

 its attached extremity and at the bicipital groove, but is free in the rest of its 

 extent. The sj^novial cavity almost alwaj's communicates with the bursa under 

 the subscapularis, and sometimes with one under the infraspinatus muscle. 



It also sends a pouch-like prolongation beneath the coracoid process when the fibrous 

 capsule is attached wide of the margin of the glenoid fossa. A few fringes are seen near the 

 edge of the glenoid cavity, and there is often one which runs down the medial edge of the 

 biceps tendon, extending slightly below it and making a slight groove for the tendon to lie in. 



