Fig. 190. Region behind the Internal Malleolus. 



Right Leg of a girl aged 75 years. The region around the Internal Malleolus 

 is exposed in layers. ^ windows have been made in the Deep Fascia and Internal 



Annular Ligament. 



The Long Saphenous Vein runs in the Superficial Fascia as far as the 

 Internal Malleolus accompanied by the Long Saphenous Nerve. The Fascia of 

 the Leg is strengthened behind the Internal Malleolus by thick bands of fibres 

 which radiate from the Malleolus towards the inner surface of the Os Calcis and 

 Plantar Fascia — the Internal Annular Ligament. This Ligament forms a bridge 

 under which tlie Flexor Tendons, Nerves and Vessels pass to the sole of the foot. 



Nearest to the Internal Malleolus under this fascia and in a strong Apo- 

 neurotic Canal the Tendon of the Posterior Tibial Muscle passes, next to this the 

 Tendon of the Long Flexor of the Toes. The Tendon of this muscle crosses the 

 Posterior Tibial Muscle in the Leg from within outwards. 



Nextly, the Posterior Tibial Vessels lie between the Long Flexor of the 

 Toes and the Long Flexor of the Big Toe so that, for ligature of this vessel, the 

 mid-point between Internal Malleolus and Tendo Achillis serves as the landmark. 



Directly posterior to the Artery is the Posterior Tibial Nerve or its ter- 

 minal branches. — Internal and External Plantar Nerves. — The space posterior 

 to this and extending as far back as the Tendo Achillis is occupied by fat; in 

 this is found the Tendon of the Plantaris which is inserted into the posterior part 

 of the Os Calcis, along side of the Tendo Achillis. 



By pushing the Vessels and Nerves forwards, the posterior segment of the 

 Ankle-joint can be reached. The Long Flexor of the Big Toe passes over the 

 middle of the joint. Between this and the other tendons, posterior to the Inner 

 Malleolus on the one side and the Peroneal Tendons behind the outer Malleolus 

 on the other side, the Capsule of the Joint may bulge in cases of effusion into the 

 joint, because it is not strengthened at these points. For operations, such as Ex- 

 tirpation of the Capsule in Tuberculosis, the joint is accessible from behind. The 

 arrangement is analogous with that on the Anterior Aspect of the joint near the 

 Extensor Tendons (cf. Fiy. 193), there is, however, the difference that, owing to 

 its deeper position, the swelling of the joint is only noticed posteriorly when 

 extensive. It becomes visible when the hollow next to the Tendo Achillis is 

 filled out. 



