32 ANTHROPOLOGY. 
vicle, descends inwards, and is inserted into the fore part of the sternum. 
The posterior ligament takes a course behind the joint, parallel to the pre- 
ceding, and adheres to the joint, restin upon the sterno-hyoid muscle. 
These two ligaments (pl. 125, fig. 8’, fig. 9") are so expanded over the joint 
as to resemble a capsular or orbicular ligament. 
The znferior costo-clavicular or rhomboid ligament (fig. 9°) passes from the 
lower surface of the sternal end of the clavicle downwards, forwards, and 
inwards, and is inserted into the cartilage of the first rib; it cee the angle 
between it and the clavicle. 
The inter-clavicular ligament (fig. 8*, fig. 9”) extends from the posterior 
surface of one clavicle to the other; its lower border is generally attached 
to the posterior lip of the sternum. Its office is to connect the clavicles 
with each other and with the sternum. The cnter-articular cartilage (fig. 9*) 
is nearly circular, very thin, and often perforated in the centre. On each 
side is a dry aap aes 
2. SCAPULO-CLAVICULAR ARTICULATION. The oval end of the clavicle 
is connected with that of the acromion process by a plain arthrodial joint, 
which is secured by a supertor and an wmferior acromio-clavicular ligament 
(fig. 10"). These are attached to the surfaces of each bone, and being 
united or continuous both before and behind, the joint may be considered 
as a strong orbicular ligament. The coraco-acromial ligament really consists 
of two, the conoid (fig. 10°) and the trapezoid (fig. 10°). The former is pos- 
terior and the smaller of the two; and while united posteriorly and exter- 
nally, anteriorly they are very distinct. 
3. PROPER LIGAMENTS OF THE SCAPULA. ‘These are two in number, an 
anterior and a posterior. The anterzor, deltoid, or coraco-acromial lgament 
(fig. 10*) arises from the coracoid process, passes upwards, and is inserted 
into the point of the acromial process. The postervor or coracoid lhgament 
arises from the superior costa of the scapula behind the notch, passes for- 
wards, and is inserted into the base of the coracoid process; it converts the 
notch into a foramen. When this ligament is wanting, as is sometimes the 
case, the notch is completed into a hole by bone. | | 
4. HUMERO-SCAPULAR OR SHOULDER ARTICULATION. This joint isa ball 
and socket (enarthrodia), with the head of the humerus retained in the 
glenoid cavity by the capsular, the coraco-humeral or accessory, and the 
glenoid ligaments, and_a synovial membrane. 
The glenoid ligament adheres to the margin of the glenoid cavity, and 
deepens the socket for the head of the humerus: it is partly continuous 
with or derived from the long tendon of the biceps muscle. The capsular 
ligament (fig. 10") arises around the head of the scapula, and increasing in 
size, encircles the head of the humerus, and is inserted into its neck and 
prolonged on the periosteum. It derives great strength from the tendons 
of the four capsular muscles which cover and are identified with it. The 
coraco-humeral or accessory ligament extends obliquely downwards and out- 
wards from the coracoid process to the anterior part of the great tuberosity. 
The synovial membrane is reflected over the glenoid surface around the 
glenoid ligament. 
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