244 



THE SKELETON. 



Fig. 176. Bones of the Eight Leg. Anterior Surface. 



ffty7eirt vroet 



broader, flatter, and more circular, 

 to articulate with the external 

 condyle. Between the two arti- 

 cular surfaces, and nearer the 

 posterior than the anterior aspect 

 of the bone, is an eminence, the 

 spinous process of the tibia, sur- 

 mounted by a prominent tubercle 

 on each side, which gives attach- 

 ment to the extremities of the 

 semilunar fibro-cartilages ; in front 

 and behind the spinous process 

 is a rough depression for the at- 

 tachment of the anterior and pos- 

 terior crucial ligaments and the 

 semilunar cartilages. The ante- 

 rior surfaces of the tuberosities 

 are continuous with one another, 

 forming a single large surface, 

 which is somewhat flattened: it 

 is triangular, broad above, and 

 perforated by large vascular fora- 

 mina, narrow below, where it ter- 

 minates in a prominent oblong 

 elevation of large size, the tuber- 

 cle of the tibia; the lower half 

 of this tubercle is rough, for the 

 attachment of the ligamentum pa- 

 tellae ; the upper half is a smooth 

 facet corresponding, in the recent 

 state, with a bursa which sepa- 

 rates the ligament from the bone. 

 Posteriorly, the tuberosities are 

 separated from each other by a 

 shallow depression, the popliteal 

 notch, which gives attachment to 

 the posterior crucial ligament. 

 The posterior surface of the inner 

 tuberosity presents a deep trans- 

 verse groove, for the insertion of 

 the tendon of the Semi-membra- 

 nosus ; and the posterior surface 

 of the outer one, a flat articular 

 facet, nearly circular in form, di- 

 rected down wards, backwards, and 

 outwards, for articulation with the 

 fibula. The lateral surfaces are 

 convex and rough : the internal 

 one, the most prominent, gives 

 attachment to the internal lateral 

 ligament. 



The Shaft of the tibia is of a 

 triangular prismoid form, broad 

 above, gradually decreasing in 

 size to the commencement of 

 its lower fourth, its most slender 



