THE LEG 263 



fascial compartments, corresponding to the anterior, lateral, 

 and posterior crural regions. The anterior compartment is 

 bounded by the investing deep fascia, the anterior peroneal 

 septum, the anterior part of the medial surface of the fibula 

 (that part which lies anterior to the interosseous crest), 

 the interosseous membrane, and the lateral surface of the 

 tibia. The lateral compartment is bounded by the lateral 

 surface of the fibula, the investing fascia, and the two peroneal 

 septa. The posterior compartment is much the largest, and 

 its walls are formed by the posterior surface of the tibia, the 

 posterior part of the medial surface and the whole of the 

 posterior surface of the fibula, the interosseous membrane, the 

 posterior peroneal septum, and the investing deep fascia. 

 This compartment'is still further subdivided by two partitions ; 

 but these will be studied later. 



Dissection. The anterior compartment of the leg should now be opened 

 by removing the deep fascia. The transverse and cruciate ligaments, 

 however, must be retained, and their borders should be separated artificially, 

 by the knife, from the deep fascia with which they are continuous. In 

 the proximal part of the leg it will be found impossible to raise the fascia 

 from the subjacent muscles without lacerating their surfaces. It should 

 therefore be left in position. At a lower level it can readily be separated. 

 Divide it in a longitudinal direction midway between the tibia and fibula. 

 On throwing the medial piece medially its firm attachment to the anterior 

 border of the tibia will become evident ; and as the lateral piece is turned 

 laterally the anterior peroneal septum will come into view. 



Contents of the Anterior Crural Compartment. Four 

 muscles are brought into view by the above dissection, viz. 

 the tibialis anterior, the extensor digitorum longus, the 

 extensor hallucis longus, and the peronseus tertius. The 

 tibialis anterior lies in relation to the tibia ; the extensor digitorum 

 longus is placed along the fibula; and on separating these 

 muscles from each other, the extensor hallucis longus will be 

 seen in the interval between them. The peronceus tertius 

 lies upon the distal portion of the fibula, and in most cases 

 is incorporated with the extensor digitorum longus. The 

 anterior tibial vessels and the deep peroneal nerve (O.T. anterior 

 tibial) proceed distally in this compartment. At first they 

 are deeply placed, but as they approach the ankle they come 

 nearer to the surface. 



Dissection. To expose the anterior tibial vessels and the deep peroneal 

 nerve in their entire course, on the front of the leg, the tibialis anterior 

 and the extensor digitorum longus must be separated from each other, 

 along the line of a strong intermuscular septum which dips posteriorly 



i 17 c 



