ARCHES OF THE FOOT 



73 



connect the various tarsal bones to each other to complete the 

 instep, and there is one elastic ligament upon which the head of the 

 talus rests. It assists to prevent excessive jarring as the foot 

 strikes the ground. (This is the only ligament containing elastic 

 tissue in the extremities.) 



Metatarsal. Like the metacarpal, except that the heads are 

 all joined together by a transverse band; the great toe is not free. 



Phalangeal. Like those of the hand. 



Arches of the foot. The principal arch is from the heel to 

 the ball of the foot; a second one, the transverse, is equally im- 



Tendo Achillia 

 Talus Vessels and nerve 



Scaphoid 

 First cuneiform 



First metatarsal 



Calcaneus 



Muscles of plartar region 



FIG. 68. MEDIAL BORDER OF RIGHT FOOT, SHOWING BONES IN POSITION. (Morris.} 



portant. The arteries and nerves in the sole of the foot are pro- 

 tected from pressure by these arches, which are preserved not 

 only by the ligaments and the shape of the bones, but by the 

 tendons of certain muscles. 



Practical points. In walking the weight is transmitted principally through 

 the talus, the navicular, and three cuneiform bones to the three medial toes, 

 giving the "springy" step to the well-arched foot. In standing, it falls more 

 upon the calcaneus, and is distributed through the cuboid to the two lateral 

 toes as well. 



RESUME 



Comparing the joints in the upper and lower extremities, note 

 that both the shoulder and hip are ball-and-socket joints; that 



