434 THE MUSCLES AND FASCIAE. 



III. MUSCLES AND FASCLE OF THE LEG. 



These may be divided into three groups : those on the anterior, those on the 

 posterior, and those on the outer side of the leg. 



5. Anterior Tibio-fibular Region. 



Tibialis anticus. Extensor longus digitorum. 



Extensor proprius hallucis. 1 Peroneus tertius. 



Dissection (Fig. 252). The knee should be bent, a block placed beneath it, and the foot 

 kept in an extended position ; then make an incision through the integument in the middle 

 line of the leg to the ankle, and continue it along the dorsuni of the foot to the toes. Make a 

 second incision transversely across the ankle, and a third in the same direction across the bases 

 of the toes ; remove the flaps of integument included between these incisions in order to examine 

 the deep fascia of the leg. 



The Deep Fascia of the Leg forms a complete investment to the muscles, 

 but is not continued over the subcutaneous surfaces of the bones. It is con- 

 tinuous above with the fascia lata, receiving an expansion from the tendon 

 of the Biceps on the outer side, and from the tendons of the Sartorius, Gracilis, 

 and Semitendinosus on the inner side ; in front it blends with the periosteum 

 covering the subcutaneous surface of the tibia, and with that covering the head 

 and external malleolus of the fibula ; below it is continuous with the annular 

 ligaments of the ankle. It is thick and dense in the upper and anterior part 

 of the leg, and gives attachment, by its deep surface, to the Tibialis anticus 

 and Extensor longus digitorum muscles, but thinner behind, where it covers 

 the Gastrocnemius and Soleus muscles. Over the popliteal space it is much 

 strengthened by transverse fibres which stretch across from the inner to the outer 

 hamstring muscles, and it is here perforated by the external saphenous vein. Its 

 deep surface gives off, on the outer side of the leg, two strong intermuscular septa 

 which enclose the Peronei muscles, and separate them from the muscles on the an- 

 terior and posterior tibial regions and several smaller and more slender processes 

 which enclose the individual muscles in each region ; at the same time a broad 

 transverse intermuscular septum, called the deep transverse fascia of the leg, inter- 

 venes between the superficial and deep muscles in the posterior tibio-fibular region. 



Remove the fascia by dividing it in the same direction as the integument, excepting oppo- 

 site the ankle, where it should be left entire. Commence the removal of the fascia from below, 

 opposite the tendons, and detach it in the line of direction of the muscular fibres. 



The Tibialis anticus is situated on the outer side of the tibia ; it is thick and 

 fleshy at its upper part, tendinous below. It arises from the outer tuberosity and 

 upper two-thirds of the external surface of the shaft of the tibia ; from the adjoin- 

 ing part of the interosseous membrane ; from the deep surface of the fascia ; and 

 from the intermuscular septum between it and the Extensor longus digitorum : 

 the fibres pass vertically downward, and terminate in a tendon which is apparent 

 on the anterior surface of the muscle at the lower third of the leg. After passing 

 through the innermost compartment of the anterior annular ligament, it is inserted 

 into the inner and under surface of the internal cuneiform bone and base of the 

 metatarsal bone of the great toe. 



Relations. By its anterior surface, with the fascia and with the annular liga- 

 ment ; by its posterior surface, with the interosseous membrane, tibia, ankle-joint, 

 and inner side of the tarsus: this surface also overlaps the anterior tibial vessels 



1 There is no such word as " Hallux, -cis." It is the result of some ignorant blunder, copied 

 until it has become established by usage ; it has been thought better, therefore, to retain it. Accord- 

 ing to Lewis and Short the word is ALLEX, masculine ; genitive, ALLICIS, the great toe, and the cor- 

 rect rendering would be Extensor proprius alllcis. It is a rare word, and is sometimes spelt, but not 

 so correctly, " Hallex." It is used by Plautus, in the " Poenulus" V., v. 31, of a little man, as we 

 might say " a hop-o'-my-thumb." " Tune hie amator audes esse, allex viri" (To think of you daring 

 to make up to her, you hop-o'-my-thumb!). The word " alex," sometimes spelt "allex," a fish 

 sauce, is probably a different word altogether. It is used by Horace and Pliny. 



