LIGAMENTS OF THE ANKLE. 253 



posterior internal, manufacture the word AEPI, from which 

 the memory may derive assistance. 



The semi-lunar fibro-cartilages are two crescentic plates 

 of cartilage placed upon the margins of the head of the 

 tibia, and attached externally to the capsule of the joint ; 

 they are thick along their convex borders and thin at their 

 concave, being hollowed out to receive the condyles of the 

 femur; they are connected anteriorly with the front of the 

 tibia, and posteriorly with its spine. The internal cartilage 

 forms the segment of a larger circle than the external, and 

 is more ovoidal in shape. 



The transverse ligament unites these cartilages anteri- 

 orly ; sometimes it hardly exists. 



The tibia and fibula are articulated together at their two 

 extremities, and connected between their shafts by an inter- 

 osseous membrane. 



The union between the bones superiorly is effected by 

 anterior and posterior bands from the tuberosity of the, 

 tibia to the head of the fibula. Inferior! y, an anterior band 

 crosses in front from the fibula to the tibia, and a posterior 

 one is similarly disposed behind the ankle-joint; an inferior 

 interosseous ligament closes the space between the ends of 

 the two bones below, and may be seen by forcibly tearing 

 them apart. 



The interosseous membrane is attached to the contiguous 

 sides of the shafts of the tibia and fibula, and separates 

 the muscles of the back from those of the front of the leg ; 

 its fibres are directed downward and outward, and are 

 crossed by a few passing in the opposite direction ; they 

 are deficient above, at the point where the anterior tibial 

 artery enters, and below, where the anterior peroneal artery 

 comes forward from the back of the leg, to be distributed 

 upon the tarsus. 



The TIBTO-TARSAL ARTICULATION, or ANKLE-JOINT, is 

 formed by the fibula, the tibia, and the astragalus, and is 

 maintained by four ligaments, anterior, posterior, external, 

 and internal. 



The anterior ligament is a thin membranous layer, ex- 

 tending from the front of the tibia to the upper part of 

 the astragalus, and continuous by its sides with the lateral 

 ligaments. 



The internal lateral, or deltoid ligament, expands, fan- 

 22 



