Chap. 8.] Knee Pan 3 &?r/ 123 



is turned directly backwards, and one of the angles is 

 placed directly at the fore-part of the bone, and is 

 that iharp ridge which is felt by the finger, being only 

 covered by the common integuments of the body. 

 Another angle is called the pofterior and internal, and 

 terminates in the inner ankle-bone ; and the third is 

 called the pofterior and external angle, and gives 

 connection to the interofleous ligament, which pafles 

 from this bone to the fibula. 



The fibula, which is nearly oppofed to the lad- 

 mentioned angle of the tibia, is a triangular and very 

 thin bone, nearly as long as the tibia. Its fuperior 

 extremity is united to the head of the tibia by means 

 of cartilage. Its head does not rife quite fo high as 

 that of the tibia, and has therefore no connection with 

 the os femoris ; its lower extremity is flightly con- 

 nected to the aftragalus, and forms the external ankle. 

 Its chief ufes are to afford room for the connection 

 of mufcies, to extend the interofleous ligament, and to 

 give greater firmnefs to the connection of the tibia 

 with the foot. 



The patela, rotula, or knee-pan, is a fmall flat 

 bone of a fomewhat triangular form, which is placed 

 at the fore part of the leg, where the tibia is con- 

 nected with the os femoris. The anterior convex 

 furface of the patella is pierced by a great num- 

 ber of holes, into which enter fibres of the ftrong 

 ligament which is fpread over it. Behind, its furface 

 is fmooth, covered with cartilage, and divided by a 

 middle convex ridge into two cavities, both of which 

 are exactly adapted to the pulley of the os femoris. 

 The fubftance of the patella is cellular, but the ceils 

 are fo fmall that it is a very ftrong bone. Its ufes 

 are to protect the joint, and to aniwer the purpofe 

 of a pulley to the muicles which extend the '^. 



The 



