290 FASCLE OF THE LEG. 



ligament, beneath which the tendons of the extensor muscles pass into 

 the dorsum of the foot, in distinct sheaths lined by synovial bursae. 

 Upon the outer side it forms a distinct sheath which envelopes the 

 peronei muscles, and ties them to the fibula. The anterior annular 

 ligament is attached by one extremity to the outer side of the os calcis, 

 and divides in front of the joint into two bands ; one of which is in- 

 serted into the inner malleolus, while the other spreads over the inner 

 side of the foot, and becomes continuous with the internal portion of 

 the plantar fascia. 



The fascia of the dorsum of the foot is a thin layer given off from 

 the lower border of the anterior annular ligament ; it is continuous at 

 each side with the lateral portions of the plantar fascia. 



The fascia of the posterior part of the kg is much thinner than the 

 anterior, and consists of two layers, superficial and deep. The super- 

 ficial layer is continuous with the posterior fascia of the thigh, and is 

 increased in thickness upon the outer side of the leg by an expansion 

 derived from the tendon of the biceps ; it terminates inferiorly in the 

 external and internal annular ligaments. The deep layer is stretched 

 across between the tibia and fibula, and forms the intermuscular fascia 

 between the superficial and deep layer of muscles. It covers in 

 superiorly the popliteus muscle, receiving a tendinous expansion from 

 the semi-membranosus muscle, and is attached to the oblique line of 

 the tibia. 



The internal annular ligament is a strong fibrous band attached 

 above to the internal malleolus, and below to the side of the inner 

 tuberosity of the os calcis. It is continuous above with the posterior 

 fascia of the leg, and below with the plantar fascia, forming sheaths 

 for the passage of the flexor tendons and vessels, into the sole of the 

 foot. 



The external annular ligament, shorter than the internal, extends 

 from the extremity of the outer malleolus to the side of the os calcis, 

 and serves to bind down the tendons of the peronei muscles in their 

 passage beneath the external ankle. 



The PLANTAR FASCIA consists of three portions, a middle and two 

 lateral. 



The middle portion is thick and dense, and is composed of strong 

 aponeurotic fibres, closely interwoven with each other. It is attached 

 posteriorly to the inner tuberosity of the os calcis, and terminates 

 under the heads of the metatarsal bones in five fasciculi. Each of 

 these fasciculi divides into two slips, which are inserted one on each side 

 into the bases of the first phalanges of the toes, leaving an interval be- 

 tween them for the passage of the flexor tendons. The point of 

 division of this fascia into fasciculi and slips, is strengthened by trans- 

 verse bands, which preserve the solidity of the fascia at its broadest 

 part. The intervals between the toes give passage to the digital 

 arteries and nerves and the lumbricales muscles. 



The lateral portions are thin, and cover the sides of the sole of the 

 foot ; they are continuous behind with the internal and external an- 



