THE LATERAL CRURAL MUSCLES 



487 



side of the first cuneiform. Occasionally it sends a slip to the base of the second 

 metatarsal bone. The tendon changes its direction at two points : first, behind the 

 lateral malleolus; secondly, on the cuboid bone; in both of these situations the ten- 

 don is thickened, and, in the -latter, a sesamoid fibrocartilage (sometimes a bone), 

 is usually developed in its substance. 



Tibialis anterior M 



Interosseous 

 membrant X 



Extensores longi digi- 

 torum et hallucis Mm. " 



Deep peroneal nerve 

 and anterior tibial--. 

 artery and vein 



Peronozi longus 

 and brevis Mm.~$ 



Superficial peroneal.- * '\ 



Fibula' 



Peroneal artery/" 

 and vein 



Gastrocncmius M/ 



,Tibia 



Flexor digitorum 

 ^/ longus M. 



Great saphenous vein 

 v-/^ and saphenous nerve 



Posterior tibial vein 

 and artery 



...Tibial nerve 



t - Soleus M. 



'Tendo m. planiaris 



*'Gastrocnemius M. 



^Median cutaneous 

 nerve 



Small saphenous vein 

 FIG. 440. Cross-section through middle of leg. (Eycleshymer and Schoemaker.) 



Lateral cutaneous'' 

 nerve 



The Peronseus brevis lies under cover of the Peronseus longus, and is a shorter 

 and smaller muscle. It arises from the lower two-thirds of the lateral surface of 

 the body of the fibula; medial to the Peronseus longus; and from the intermuscular 

 septa separating it from the adjacent muscles on the front and back of the leg. 

 The fibers pass vertically downward, and end in a tendon which runs behind the 

 lateral malleolus along with but in front of that of the preceding muscle, the two 

 tendons being enclosed in the same compartment, and lubricated by a common 

 mucous sheath. It then runs forward on the lateral side of the calcaneus, above 

 the trochlear process and the tendon of the Peronseus longus, and is inserted into 

 the tuberosity at the base of the fifth metatarsal bone, on its lateral side. 



On the lateral surface of the calcaneus the tendons of the Peronasi longus and 

 brevis occupy separate osseoaponeurotic canals formed by the calcaneus and the 

 perineal retinacula; each tendon is enveloped by a forward prolongation of the 

 common mucous sheath. 



Variations. Fusion of the two peronsei is rare. A slip from the Peronaeus longus to the base 

 of the third, fourth or fifth metatarsal bone, or to the Adductor hallucis is occasionally seen. 



Peronceus accessories, origin from the fibula between the longus and brevis, joins the tendon 

 of the longus in the sole of the foot. 



Peronceus quinti digiti, rare, origin lower fourth of the fibula under the brevis, insertion into the 

 Extensor aponeurosis of the little toe. More common as a slip of the tendon of the Peronaeus 

 brevis. 



Peronceus quartus, 13 per cent. (Gruber), origin back of fibula between the brevis and the Flexor 

 hallucis, insertion into the peroneal spine of the calcaneum, (peroneocalcaneus exlernum), or less 

 frequently into the tuberosity of the cuboid (peroneocuboideus) . 



Nerves. The Peronaei longus and brevis are supplied by the fourth and fifth lumbar and 

 first sacral nerves through the superficial peroneal nerve. 



