296 FASCIA OF THE LOWER LIMB. 



The fascia on the dorsum of the foot is reduced to a thin membrane pro- 

 longed from the anterior annular ligament over the extensor tendons. 

 Beneath it, deep fasciae are placed over the short extensor of the toes and 

 the interossei muscles. 



The plantar fascia is stronger and thicker than any other of the fibrous 

 membranes. It is composed of dense, white, glistening fibres, the greater 

 number of which are ranged in a longitudinal direction, and extend 

 from the under surface of the os calcis forwards to the heads of the meta- 

 tarsal bones. It presents a central and two lateral portions, clearly 

 marked off from each other by two strong internmscular septa, indicated 

 on the surface by grooves. The inner portion, very thin and unlike the 

 others, invests the abductor pollicis, and is often partly removed with the 

 skin in dissection. It is continuous round the inner border of the foot 

 with the dorsal fascia and with the internal annular ligament. The outer 

 part covers the abductor minimi digiti, and is much stronger, particularly 

 between the outer tubercle of the calcaneum and the base of the fifth 

 metatarsal bone, between which points it forms a strong ligament. It is 

 continuous round the outer border of the foot with the dorsal fascia, and 

 sends a thin prolongation forwards over the insertion of the abductor and 

 the short flexor of the little toe. The central portion, like the corre- 

 sponding part of the palmar fascia, is narrow behind, and becomes wider 

 and thinner towards the toes. At the back, where it is thickest, the fascia 

 is attached to the inner tubercle on the under surface of the calcaneum 

 immediately behind the origin of the flexor brevis digitorum, with which 

 muscle it is closely connected. Nearly opposite the middle of the meta- 

 tarsal bones, this fascia, becoming broader and thinner as it advances, 

 begins to divide into five processes, one for each of the toes ; and from this 

 point forwards to the base of the toes, numerous strong transverse fibres 

 are superadded, which bind the processes together, and connect them 

 closely with the skin. Near the articulation of the toes with the metatarsal 

 bones, each of the five processes divides, to permit the passage of the flexor 

 tendons ; and the two bundles of fibres resulting from the division of each 

 process, after strengthening the sheath of the tendons over which they pass, 

 are attached to the sides of the metatarsal bone, and are blended with the 

 transverse ligament uniting those bones. From the point of splitting of 

 each process, as in the hand, fibrous bands are continued forwards to the 

 skin in the division between the toe?. 



The two intermuscular septa which lie between the middle and lateral 

 portions of the plantar fascia are prolonged deeply upwards into the sole 

 of the foot ; they separate the flexor brevis digitorum from the abductor 

 pollicis on the inner side, and from the abductor minimi digiti on the outer 

 side, and give partial origin to each of these muscles. 



In both the foot and the hand there is a band of transverse fibres across 

 the roots of the digits, placed immediately beneath the skin, and connected 

 with the subjacent sheaths of the tendons. The digital nerves and vessels 

 are covered by this structure, which receives the name of transverse liga- 

 ment of the toes or fingers. In the foot a somewhat similar baud, but con- 

 sisting merely of a stronger part of the dorsal aponeurosis, crosses the place 

 of the metatarso-phalangeal articulations. 



