DISSECTION OF THE LOWER KXTIiK.MITV 



bones, and a lateral pillar, formed by the calcam-mn, 

 the cuboid, and the two lateral metatarsal bones. 



(b) Transverse arch. Where is this arch to be found and what function 



does it subserve? 



(c) Lateral arch. This arch is convex laterally and extends from the 



heel to the base of the little toe. Determine in what directions 

 pressure exerted from above is radiated by this arrangement of 

 the arches. What factors assist in the maintenance of the aivh 

 of the foot? Study, in this connection, especially the tendon 

 of the M. peronaeus. What is flat-foot? Where is the sprin.i: 

 of the foot? In flat-foot the line of tenderness generally corre- 

 sponds to the line of Chopart's joint. 



Examine the medial margin of the foot and determine the 

 position of the following : 



(a) Sustentaculum tali. 



(b) Tuberositas ossis navicularis. 



(c) Line of calcaneo-astragaloid joint (articulatio talocalcanea) . 



(d) Line of tarsometatarsal joints (articulationes tarsometatarseae) . 



(e) Lines of metatarsophalangeal joints (articulationes metatarsopha- 



langeae). 



Examine upon the lateral margin of the foot 



(a) Trochlear process (processus trochlearis) , not always present. 



(b) Line of calcaneocuboid joint (articulatio calcaneocuboidea) . In con- 



nection with Chopart's amputation it is important to know the 

 structures which serve as guides in finding the mid-tarsal joint. 



(c) Tuberositas ossis metatarsalis. What is its relation to the articula- 



tiones tarsometatarseae? What is Lisfranc's ligament? (Vide 

 Cunningham's Systematic Anatomy, p. 1218.) 



Examine now the skin covering the sole of the foot. Note its 

 general characteristics and compare it with the skin of the palm 

 of the hand. How does it compare with the skin over the dorsum 

 of the foot ! Which is the more mobile, and which is the thinner ? 

 Note the callosities that form about the heel and the ball of the 

 toes. In standing which parts of the sole come in contact with 

 the floor? 



The foot should be firmly fixed and the toes extended, thus 

 rendering the plantar aponeurosis tense. Make the following 

 incisions : 



(1) A perpendicular incision extending down the middle of the sole. 



(2) A transverse incision across the sole at the clefts of the toes. 



(3) A medial incision extending the length of each toe. 



Reflect the flaps of skin and study the fascia beneath. 



