438 



HUMAN ANATOMY. 



On the sole of the foot between the tuberosity of the os calcis and the heads of 

 the metatarsals the bones cannot be felt distinctly. The internal sesamoids are 

 directly beneath the hrst metatarso-phalangeal articulation. 



On the dorsum of the foot, when at right angles to the leg, the bones of the 

 tarsus form a smooth rounded convexity, with a slight elevation between its middle 

 and inner thirds, made up of the head of the astragalus, the scaphoid, the middle 

 cuneiform, and the second metatarsal. With the foot in full extension the head of 

 the astragalus projects, and the extreme anterior ends of the ridges between the upper 

 and lateral articular surfaces of that bone can be felt. The internal cuneiform at the 

 summit of the instep is easily recognized. The other cuneiforms, the cuboid, and 

 the metatarsals can be felt in thin feet. 



THE ANKLE-JOINT. 



The articulation is between the bones of the leg and those of the foot as a 

 whole, — i.e., between the tibia and fibula above and the astragalus below. It is a 

 hinge-joint, although the mortise of the leg bones and the top of the astragalus are 

 both broader in front than behind. The ligaments are : the capsular, supporting 



Fig. 456. 



Superior astragalo- 

 scaphoid ligament 



Tibialis posticus 



Groove for tibialis posticus 



Sustentaculum tali 

 Groove for flexor communis digitorum 



Groove for flexor longus hallucis 1 



Right ankle-joint, inner aspect. 



the synovial membrane, and itself strengthened by very strong bands at the sides 

 {lateral ligaments') and by a weak one at the back. There is also a m.iddle external 

 lateral ligament quite distinct from the capsule. 



The capsule (Fig. 456) arises from the front of the tibia nearly one centi- 

 metre above the lower border, from the edge of the anterior tibio-fibular ligament, 



