28 ANTHROPOLOGY. 



projecting ridge on the articular surface of the rib, and is inserted into the 

 cavity in the intervertebral substance into which the head is received ; it 

 separates the two synovial membranes. 



In respect to the attachments of the tubercle, the external or posterior 

 rosto-transverse ligament {^pl. 12b^fi(j. 2^) arises from the posterior surface of 

 the extremity of the transverse process ; passes outwards and is inserted 

 into the rough, non-articular portion of the tubercle of the corresponding 

 rib. It exists on all the ribs. The middle cofito-transverse ligament {ßg. 2") 

 connects the back part of the rib with the front of the corresponding trans- 

 verse process. The anterior or internal costo-transverse ligament {ßg. 2 *), 

 wanting in the first and twelfth ribs, arises from the lower border of the 

 transverse process, and is inserted into the crest on the upper edge of the 

 rib beneath. 



The cartilages of the ribs at their costal ends are convex, and are very 

 closely united to the concave surfaces in the extremities of the bones by a 

 sort of gomphosis. The articular ends of the cartilages are attached to the 

 sternum by radiating ligaments, known as anterior, posterior, superior, and 

 inferior sterno-costal {pi. 124:, ßg. 14", and pi. 125, ßg. 3). 



5. Special Anatomy of the Superior Extremities. 



A. Bones of the Superior Exti-emities. 



Each superior extremity consists of the shoulder, arm, forearm, wrist, 

 and hand : the whole limb comprises thirty-two bones, the sesamoid not 

 included. The shoulder is composed of the clavicle and scapula; the arm, 

 of the humerus ; the forearm, of the radius and ulna ; the carpus, or wrist, 

 of the eight small carpal bones ; and the hand, of five metacarpal and four- 

 teen phalangeal bones. 



The clavicle, or collar hone {pi. 122, ßg. 3 '), is a long bone extending from 

 the summit of the sternum obliquely across the first rib, upwards, back- 

 wards, and outwards to the acromion process of the scapula. It is curved 

 like an italic / and presents two extremities and a body or shaft. The 

 sternal end is"*a thick, triangular, articulating surface, with the circumference 

 roughened for the attachment of ligaments. The body is rounded in the 

 middle and flattened towards the extremities. The acromial end is rough 

 above and below, and at its termination presents a small articulating sur- 

 face for the acromion scapul«. The clavicle serves to support the scapula, 

 and to prevent it from falling too far forwards or inwards ; it serves as a 

 fixed point for certain muscles, and it protects the vessels and nerves of the 

 upper extremity. 



The scapula, or shoulder blade {figs. 4", 10, 11, 12), is situated at the 

 upper, lateral, and posterior part of the chest, and extends from the 

 second to the seventh rib. It is irregularly flat and triangular, present- 

 ing an internal and external surface, three edges, and three angles. The 

 internal or anterior surface {ßg. 11) is slightly concave, and divided by 

 three or four prominent lines into several broad grooves filled by the fasci- 

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