THE KNEE-JOINT. 



403 



posterior horn, moreover, joins the posterior crucial hgament. There is not more 

 than one centimetre between the two horns, so that this cartilage is almost circular. 

 The internal cartilage ' is C-shaped. The anterior horn, thin and fibrous, is in- 

 serted into the rough surface near the anterior border at no very definite point. 

 Sometimes it runs into the transverse ligament without any fixed ending ; some- 

 times the extreme point is free. The posterior horn is attached to the back of the 

 tibial facet of the spine and to the edge of the articular facet behind it. The 



Fig. 418. 



Femur 



Inner head of 

 gastrocnemius 



Popliteus tendon and 

 opening into joint 



Long external lateral 

 ligament 



Tendon of biceps' 



Extensor tendon 



Siibrectal bursa 



Superficial band to patella 



Ligamentum patellae 



Anterior tibio-fibular ligament 



Head of fibula 



Right knee-joint, external aspect. The extensor tendon is drawn forward and upward. 



distance between the horns is about three centimetres. The anterior horn of the 

 internal cartilage may not come into contact with the femur. The vertical diameter 

 of the cartilages at the periphery is from six to eight millimetres. The breadth 

 varies in different joints, ranging from one to nearly t\vo centimetres.^ The broadest 

 part is near the back of the internal one, but the external is, on the whole, the 

 broader. It is said sometimes to completely divide that half of the joint. The 

 free border is very thin and may present fine prolongations with scalloped edges. 



^ For various statistics, consult Higgins : Journal of Anatomy and Physiology', vol. xxix., 

 1895- 



' Meniscus medialis. 



