THE LEG 



279 



the tendons of the sartorius, the gracilis, and the semi- 

 tendinosus. 



Osteo-fascial Compartments of the posterior region of the Leg. 



Divide the fascia along the middle line and turn it laterally and medially. 

 Leave the ligamentum laciniatum intact. On raising the medial part of 

 the fascia it will be seen to be attached to the medial border of the tibia. 

 In fact, it blends with the periosteum covering the medial subcutaneous 

 surface of this bone. On turning the lateral portion of fascia laterally it 

 will be observed to be directly continuous with the fascia on the front of the 

 leg : further, the strong intermuscular septum (posterior peroneal septum) 

 which passes in to join the lateral crest of the fibula, between the peroneal 

 muscles and the muscles on the posterior aspect of the leg, will be demon- 

 strated. In this manner, then, the large posterior osteo-fascial compartment 

 is formed, and, as the dissection 

 goes on, two partitions will be 

 noticed to stretch across it so as Adductor 



to subdivide it into three portions. 

 The most superficial of these 

 holds the superficial muscles of Medial head 



of gastro- 

 cnemius 



Plantaris 



Lateral head 



astro- 

 cnemius 



Posterior crucia 

 ligament 



Anterior crucial 

 ligament 



FIG. 102. Posterior aspect of distal por- 

 tion of Femur with Attachments of 

 Muscles mapped out. 



the calf ; the intermediate portion 

 contains the flexor muscles with 

 the posterior tibial vessels and the 

 tibial nerve : whilst the deepest 

 part encloses the tibialis posterior 

 muscle (Fig. 97, p. 266). 



One of these partitions may 

 be exposed at the present moment 

 by removing the fat which is 

 usually accumulated under cover 

 of the tendo calcaneus ( Achillis). 

 Subjacent to this tendon is the 

 layer of fascia in question. It 

 stretches between the tibia and 

 fibula, and separates the super- 

 ficial from the deep group of 

 muscles. In this locality it will 



be seen to be very dense, and to be strengthened by numerous transverse 

 fibres. It becomes continuous on the medial side of the ankle with the 

 ligamentum laciniatum (O.T. internal annular ligament) indeed, the 

 dissector will not fail to observe that it takes a more prominent part in 

 the formation of this ligament than the investing aponeurosis of the limb. 

 In the proximal part of the leg it becomes very thin. 



Superficial Muscles. The superficial muscles of the calf 

 of the leg are three in number, viz. the gastrocnemius, the 

 plantaris, and the soleus. The gastrocnemius is the most 

 superficial ; the soleus is placed under cover of the gastro- 

 cnemius whilst the. slender plantaris extends distally and 

 medially between them. The tendons of insertion of the 

 gastrocnemius and soleus unite to form the tendo calcaneus 

 (Achillis). 



M. Gastrocnemius. This strong muscle arises by two heads 



