198 



DISSECTION OF THE FOOT. 



Subcuta- 

 neous fat. 



Lay bare 

 the plantar 

 fascia, 



and the 

 digital ves- 

 sels and 



define the 

 ligament of 

 the toes. 



Plantar 

 fascia : 



division 

 into parts. 



Central part 



divides 

 into five 

 pieces : 



termination 

 of the 

 pieces. 



Inner piece 

 of the fascia. 



Outer piece. 



Expose the 

 septa. 



Two inter- 



mnscular 



septa. 



The subcutaneous fat is very abundant, and forms a thick cushion 

 over the parts that press most on the ground in standing, viz., over 

 the os calcis, and the metatarso-phalangeal articulations. 



Dissection. The fat should now be removed, and the plantar 

 fascia laid bare. Beginning the dissection near the heel, follow 

 forwards the fascia towards the toes, to each of which a process is 

 to be traced. In the intervals between these processes the digital 

 nerves and arteries will be detected amongst much fatty and fibrous 

 tissues ; but the vessels and nerves to the inner side of the great toe 

 and outer side of the little toe pierce the fascia farther back than 

 the rest. 



The student is next to define a fibrous band (superficial transverse 

 ligament) across the roots of toes, over the digital vessels and nerves ; 

 and when this has been displayed, he may remove the superficial 

 fascia from the toes to see the sheaths of the tendons. 



PLANTAR FASCIA. The special fascia of the sole of the foot is of a 

 pearly white colour and great strength, and sends septa between the 

 muscles. Its thickness varies in different parts of the foot ; and 

 from this circumstance, and the existence of longitudinal depressions 

 over the two chief intermuscular septa, the fascia is divided into a 

 central and two lateral pieces. 



The central part, which is much the thickest, is pointed at its 

 attachment to the os calcis, but widens and becomes thinner as it 

 extends forwards. A slight depression, corresponding with an 

 intermuscular septum, marks its limit on each side ; and opposite 

 the heads of the metatarsal bones it divides into five processes, 

 which send fibres to the integuments near the web of the foot, and 

 are continued onwards to the toes, one to each. Where the pieces 

 separate from each other, the digital vessels and nerves and the 

 lumbricales muscles become superficial, and are arched over by 

 transverse fibres. 



If one of the digital processes be divided longitudinally, and 

 its parts reflected to the sides, it will be seen to join the sheath 

 of the flexor tendons, and to be fixed laterally into the margins 

 of the metatarsal bone, and into the transverse metatarsal 

 ligament. 



The lateral pieces of the fascia are thinner than the central one. 

 On the inner margin of the foot the fascia has but little strength, 

 and is continued to the clorsum ; but on the outer side it presents 

 a strong band, which extends between the outer tubercle of the os 

 calcis and the base of the fifth metatarsal bone. 



Dissection. To examine the septa, a longitudinal incision should 

 be made along the middle of the foot through the central piece of 

 the fascia, and a transverse one near the calcaneum. On detaching 

 the fascia from the subjacent flexor brevis digitorum, by carrying 

 the scalpel from before backwards, the septal processes will appear 

 on the sides of that muscle. 



The intermuscular septa pass deeply on each side of the flexor 

 brevis digitorum, and a piece of fascia reaches across the foot from 

 one septum to the other, beneath that flexor, so as to isolate it. 



