INTERNAL ANNULAR LIGAMENT. 197 



artery ; but its position to the vessel changes, for it lies on the 

 inner side alxjve the origin of the peroneal offset, but thence to the 

 termination, on the outer side. Its branches are muscular and branches 

 cutaneous. 



Mttxrtilar brandies are furnished to the two long flexors, the to muscles, 

 tibialis posticus, and the soleus. There is an offset for each of the 

 muscles ; and they may arise either separately along the trunk, or 

 together from the upper end of the nerve. The branch to the 

 tibialis is the largest ; and that to the flexor hallucis lies on the 

 peroneal artery. 



.1 i-iitaneo'us nerve of the sole of the foot (calcaneo-plantar, fig. 74, 4 ) and to skin 

 begins above the ankle, and piercing the internal annular ligament so i e . 

 as two or more parts, ends in the integuments of the inner and 

 under-parts of the heel : this nerve will be followed to its termina- 

 tion in the dissection of the foot. 



The INTERNAL ANNULAR LIGAMENT stretches between the heel and Internal 



the inner ankle, and serves to confine the tendons of the deep layer j 

 of muscles of the foot and toes. Attached by a narrow part to the 

 internal malleolus, the fibres diverge, and are inserted into the os 

 calcis. The upper border is continuous with the fascia of the attach- 

 leg ; and the lower gives attachment to the abductor hallucis ments 

 muscle of the foot. 



Beneath it are sheaths for the tendons. The innermost sheath Sheaths : 

 encloses the tibialis posticus, lodged in a groove on the back of the their 

 malleolus. Immediately outside this is another space for the flexor P sitlou 

 digitorum. And about three-quarters of an inch nearer the os calcis 

 is the flexor hallucis, resting in a groove in the astragalus. Each 

 sheath is lined by a synovial membrane. 



Between the tendons of the two flexors of the digits are placed 

 the posterior tibial vessels and nerve. 



SECTION VI. 



SOLE OF THE FOOT. 



Position. The foot is to be placed over a block of moderate thick- Position of 

 ness with the sole towards the dissector ; and the part is to be made 

 tense by fixing the heel with hooks, and by separating and fastening 

 apart the toes. 



Dissection. The skin is to be raised in two flaps, inner and outer, Raise the 

 by means of one incision along the centre of the sole from the heel 

 to the front and by an incision across the foot at the root of the 

 toes. Afterwards the skin is to be removed from each toe, and the 

 digital vessels and nerves on the sides are to be dissected out at 

 the same time. 



In the fat near the heel the student should follow out the calcaneo- and dissect 

 plantar nerve (shown at the upper part of fig. 75, p. 200) ; and he JieJjJJ 0118 

 may trace out, at a little distance from each border of the foot, 

 some small branches of the plantar nerves and arteries. 



