is ANATOMY IX A NUTSHELL. 



the one for the inferior angle appear aboul the 15th year and join the body of 

 the scapula the 25th year. There are two for the acromion process which ap- 

 pear the l">tli year and join the body of the scapula the 20th year. The cor- 

 acoid process has two centers, the one a1 the base of the process appearsatthe 

 linh year and the other during the 1st year; they both join the body of the scap- 

 ula the 25th year. 



Articulation. It articulates with the clavicle, (a description of which is 

 given in Lesson Vll.) and with the humerus, making the shoulder-joint. This 

 joint is a diarthro dial joint and belongs to the sub-class enarthrodial (ball-and- 

 socket.) Plate XIII.) 



Blood supply of the shoulder-joint is ( 1 ) suprascapular from the thyroid 

 axis, ('_) anterior circumflex, (3) posterior circumflex, and (4) subscapular. 

 The last three are from the third part of the axillary artery. 



Nerve supply. (1) Suprascapular and (2) circumflex, both are branches 

 formthe Brachial plexus. 



Ligaments. The true ligaments of the scapula are the transverse or supra- 

 scapular which passes o\cr the suprascapular notch separating the suprascap- 

 ular nerve from the suprascapular vessels above. The coraco-acromial lig- 

 ament, which is triangular, is attached by its base to the entire outer border of 

 the coracoid process, and by its apex to the tip of the acromion process. 



The ligaments of the shoulder- joint are (1) The capsular which is very 

 loose and permits free movements of the joint. It is attached to the circum- 

 ference of the glenoid cavity and to the anatomical neck of the humerus. This 

 is thickesl above. It may have three openings in it. one for the long head of 

 i he Biceps between the two tuberosities, another below the coracoid process, 

 partially filled by the tendon of the Subscapulars and a third (which is not 

 always present) for the tendon of the Infraspinatus muscle. These openings 

 are for the communication between the synovial membranes of the joint and 

 the bursa' beneath the tendons. A bursa is a sac or pouch. 



The long head of the Biceps is a ligament. On the inner and anterior as- 

 pect of the capsular ligament are three gleno-humeral ligaments, thickened 

 portions of the capsular ligament, (a) The upper one of these is called Flood's 

 ligament, (b) the middle one is the interna] brachial of Schlemm and (e) the 

 inferior is called the broad ligament of Schlemm. (2) The coraco-humeral 

 or accessory ligament, is also a part of the capsular ligament; it is attached to 

 the outer border of the base of the coracoid process above and to the ureal 

 tuberosity of the humerus below. (3) The transverse ligament passes over the 

 bicipital groove, holding down the long head of the Biceps. (4) The glenoid 

 I i 'j a men i i- a continuation of the long head of the Biceps which makes the glenoid 

 fossa deeper ;i 1 1 • 1 it join.- the long head of the Triceps below. It is narrow at 

 tin' circumference, but broad at its base. It is a fibro-cartilaginous rim. A 

 synovia! membrane lines these joints ami is reflected through the opening in 

 the capsule and oxer the long head of the Biceps in the groove. 



