288 INFERIOR EXTREMITY 



distance proximal to the ankle-joint, and runs transversely 

 medially under cover of the flexor hallucis longus to join the 

 posterior tibial artery. 



The perforating branch passes forwards, through the 

 interosseous membrane, and has already been dissected in 

 the anterior region of the leg (p. 271). 



Ligamentum Laciniatum (O.T. Internal Annular Liga- 

 ment). The connections of this thickened band of deep 

 fascia should be carefully studied, and also the arrangement of 

 the structures which pass under cover of it into the sole of 

 the foot. It bridges across the hollow between the promin- 

 ence of the calcaneus and the medial malleolus, and it is 

 attached to both. Its chief proximal connection is with 

 the layer of the deep fascia which intervenes between the 

 superficial and deep muscles in the posterior region of the 

 leg, but it is also continuous with the general aponeurotic 

 investment of the limb. Its distal margin gives origin to 

 the abductor hallucis, and is connected with the medial 

 portion of the plantar aponeurosis. 



Passing under cover of this ligament the dissector will 

 observe (a) the posterior tibial vessels and the tibial nerve ; 

 (fr) to the lateral side of these, the tendon of the flexor 

 hallucis longus ; (c) to their medial side, the tendons of the 

 flexor digitorum longus and tibialis posterior. From the medial 

 to the lateral side these structures lie in the following order : 



1. Tendon of tibialis posterior. 



2. Tendon of flexor digitorum longus. 



3. Posterior tibial vessels. 



4. Tibial nerve. 



5. Tendon of flexor hallucis longus. 



The tendons are isolated from each other and from the 

 vessels and nerve by septa, which pass from the deep surface 

 of the laciniate ligament to ridges on the bones. These 

 septa can be demonstrated by slitting up the ligament, for 

 a short distance, in the line of each of the tendons: each 

 of the three compartments will then be seen to be lined by 

 a glistening mucous sheath. 



Anastomosis around the Ankle-joint. The dissector 

 should next satisfy himself with regard to the anastomosis of 

 arteries which takes place around the ankle-joint. On the 

 lateral aspect of the joint he will observe inosculations taking 

 place between branches of the following arteries : (a) lateral 



