110 BONES OF THE LOWER LIMB. 



for the patella. The patellar surface is of a trochlear form, beinp: 

 marked by a vertical hollow and two prominent ridges ; the external 

 portion of this surface is more prominent, and rises higher than the 

 internal. The tibial surfaces are nearly parallel, except in front, where 

 the internal turns obliquely outwards to reach the patellar surface. 

 Above the condvlcs are two^'ough tuberosities, one on each side of the 

 bone, which give attachment to the external and internal lateral liga- 

 ment's of theknee-joint. Between the external tuberosity and the back 

 part of the external condyle is a smooth groove directed downwards 

 and forwards, and ending anteriorly in a pit, in which the popliteus 

 muscle takes origin. 



In the female the angle made by the neck of the femur with the shaft is less 

 obtuse tiian in the male ; and from the greater Avidth of the i^elvis. and the 

 shortness of the limbs, the convergence of the thigh bones inferiorly is more 

 apparent. 



In adrancrd ngr the neck comes to be placed at a less obtuse angle than in 

 middle life, and at last may almost assume a rectangular position in regard to 

 the shaft. (See Holdens Osteology.) 



THE PATELLA. 



The patella, rotula, or knee-pan, is situated at the front of the knee 

 joint, is attached inferiorly by a ligament or tendon to the tibia, and 



Fig. 98.— Right Patella. (A. T.) ^ Fig. 98. 



A from lief ore ; B, from behind. 



Botli views .show the lower extremity pointing slightly inwards ; 

 the posterior view shows the articular cartilaginous surface, divided 

 by an elevated ridge into a smaller internal and a large)- external 

 pkrt. 



may be considered as a sesamoid bone developed in 

 the tendon of the quadriceps extensor cruris. It is 

 compressed from before backwards, and has the form 

 of a triangle with the apex below. Its anterior sur- 

 face is subcutaneous ; the superior border is broad, 

 and gives attachment to the extensor muscles ; its 

 inferior angle, together with a rough depression on 

 its deep aspect, gives attachment to the ligamcutum 

 patellfe. The deep surface, except at the inferior 

 angle, is coated with cartilage for articulation with the 

 femur, and is divided by a vertical elevation into two parts, the ex- 

 ternal of which, the larger, is transversely concave, while the internal 

 is convex. 



THE TIBIA. 



The tibia, or shin bone, is, next to the femur, the longest bone in 

 the skeleton. It is the anterior and inner of the two bones of the leg, 

 and alone communicates the weight of the trunk to the foot. It arti- 

 culates with the femur, fibula, and astragalus. 



The superior extremity is thick and expanded, broader from side to 

 side than fi'om before backwards, and slightly hollowed posteriorly. 

 On its superior aspect are placed two sliglitly concave articular sur- 

 faces, which sustain the femur. These are the condylar surfaces; they 



