INTRODUCTION 217 



of it, about seven and a half centimetres anterior to the 

 lateral malleolus, is the prominent posterior end of the fifth 

 metatarsal bone, and the joint between the posterior surface 

 of the cuboid and the anterior end of the calcaneus is about 

 midway between the lateral malleolus and the posterior end 

 of the fifth metatarsal (Fig. 103). 



All the metatarsal bones can be felt from the dorsum of 

 the foot, but the large first and the fifth are the most easily 

 distinguishable. The first lies in the medial border of the 

 foot between the first cuneiform and the first phalanx of the 

 great toe. The second and third lie respectively between the 

 second and third cuneiform and the first phalanges of the 

 second and third toes. The fourth and fifth extend from 

 the cuboid behind to the first phalanges of the fourth and 

 fifth toes respectively. 



All the above-mentioned points can be verified by the 

 dissector upon his own person whilst he is waiting to 

 commence the dissection of his "part." 



Since many students commence dissecting before they 

 have attended lectures or demonstrations on anatomy, they 

 are unacquainted with terms which must be used in the 

 instructions given regarding the dissections which are to be 

 made. Fortunately most of the terms used refer to things 

 which can be seen and felt. They, therefore, are easily 

 understood. There are, however, certain terms used when 

 branches of spinal nerves are under consideration which are 

 not self-explanatory, and it is necessary, therefore, that the 

 student should possess a knowledge of the terms used in 

 connection with spinal nerves before the actual work of 

 dissection is commenced. The following points should be 

 noted : (i) Every spinal nerve is attached to the spinal 

 medulla (spinal cord) by two roots, an anterior and a 

 posterior-, (2) as they are leaving the vertebral canal through 

 an intervertebral foramen the two roots unite to form 

 a nerve trunk (3) immediately after its exit from the 

 intervertebral foramen the trunk breaks up into a posterior 

 ramus and an anterior ramus, of which except in a few cases 

 the posterior is the smaller ; (4) each posterior ramus divides 

 into a medial branch and a lateral branch \ (5) each anterior 

 ramus divides into a lateral branch and an anterior branch (Fig. 

 4, p. 6). 



Every anterior root consists of nerve fibres passing from 



