THE BONES OP THE LOWER LIMB 245 



external condyle of the femur in extension of the joint. Behind the 

 tibial spine there is a more limited rough depression, which leads 

 backwards to the popliteal notch. The posterior comu of the 

 internal semilunar fibro- cartilage is attached to the inner part of 

 this depression, and the posterior crucial hgament is attached to 

 its back part, as well as to the popliteal notch. 



Order of Structures attached to the Head. — The structures, 

 enumerated as nearly as possible in order from before backwards, 

 are as foUows : 



I. Anterior comu of internal semilunar fibro-cartilage. 



'2. Anterior crucial ligament. 



3. Anterior comu of external semilunar fibro-cartilage. 



4. Posterior comu of external semUimar fibro-cartilage. 



5. Posterior comu of internal semilunar fibro-cartilage. 



6. Posterior cmcial ligament. 



The head is pierced all round by many nutrient foramina 

 for branches of the inferior articular arteries of the popliteal, 

 and of the posterior and anterior tibial recurrents of the anterior 

 tibial. 



The shaft is massive and triangular. It diminishes in size from 

 above downwards over its upper two-thirds, and then gradually 

 enlarges towards its lower end. It presents three borders and three 

 surfaces. The anterior border extends from the outer side of the 

 anterior tuberosity above to the anterior margin of the internal 

 malleolus below. Over the upper two-thirds, where it occupies 

 the middle line, it is prominent, and is known as the crest or shin- 

 ridge. This is doubly curved, the convexity of the upper curve 

 being directed inwards, and that of the lower outwards. Over the 

 lower third the anterior border inclines inwards, and the external 

 surface of the shaft is thus allowed to come forwards. The crest 

 is subcutaneous, and gives attachment to the deep fascia of the leg. 

 The internal border extends from the inner and back part of 

 the internal tuberosity to the posterior margin of the internal 

 malleolus. For 3 or 4 inches superiorly it is rough, and gives 

 attachment to the internal lateral ligament of the knee-joint. Over 

 its middle third it is prominent, and it here gives origin to a portion 

 of the soleus as low as the centre of the bone. The external or inter- 

 osseous border extends from the front of the fibular facet above 

 to a point about 2 inches from the lower end, where it bifurcates. 

 The two divisions pass to the front and back of the sigmoid cavity, 

 and enclose between them a rough triangular surface for the 

 inferior interosseous ligament. This border is sharp and wiry, and 

 gives attachment to the interosseous membrane. 



The internal surface is situated between the crest and internal 

 border. It is for the most part subcutaneous, and slightly 

 convex. Superiorly, where it becomes expanded and flattened, it 

 presents a vertical rough area, behind the tubercle, for the insertion 

 of the sartorius, and behind this two vertical rough impressions in 

 the same line with each other, the upper of which gives insertion 



