236 SKELETON. 



moris is also highly favourable to the erect attitude and to loco- 

 motion. The neck of the bone, by its length and oblique posi- 

 tion in regard to its body, enlarges transversely the base of its 

 support, and gives great stability in preventing the trunk from 

 falling either to the right or left; while it contributes at the same 

 time to the facility of progression, in permitting the os femoris to 

 bend forwards and backwards. The laterat or transverse extent 

 of the base, thus obtained, cannot be supplied with equal effect 

 in any other way, as a certain proportion between the diameters 

 of the pelvis and the length of the neck of the thigh bone is in- 

 dispensable. In females, where the transverse diameter of the 

 pelvis is greater than in males, though standing is equally secure 

 as in the latter, yet their progression is always marked by a 

 want of firmness strongly characteristic of the sex. The strength 

 of articular connexion of the os femoris with the innominatum is 

 confirmed by the acetabulum being placed where the latter is 

 re-enforced by the linea ilio pectinea, and by the anterior infe- 

 rior spinous process; and as the principal weight of the trunk is 

 sustained by the acetabulum, immediately below the latter pro- 

 cess, we accordingly find it at this point of the greatest depth. 

 It is also to be stated, that the capsular ligament at this part is 

 stronger than elsewhere, thereby conforming strictly to the gene- 

 ral purposes of the articular connexion. The capsular ligament 

 is assisted by the ligamentum teres, which, by arising from the 

 lower margin of the acetabulum and passing upwards to the 

 head of the os femoris, prevents the head from sliding upwards, 

 while it permits it to swing freely backwards and forwards in 

 its socket. 



In erection, the bones of the leg are in a line with the vertical 

 diameter of the trunk: in this "respect they differ very materially 

 from the os femoris, which not only inclines forwards in its de- 

 scent, but also leans towards its fellow internally, and almost 

 touches it at the knee. This relative position of the leg and 

 thigh is obtained by the greater length of the internal condyle of 

 the os femoris, and also by the other peculiarities of form in the 

 latter; \\hereas the tibia is nearly straight in the direction of its 

 long diameter, and has a horizontal articular surface above, 

 whereby it and the os femoris make an entering angle externally 

 and a salient one internally. Under common circumstances, the 



