24S MUSCLES OF THE LOWER LIMB. 



Nerves.— All the mnscles in front of tlie leg', tog'etlier with the extensor brevis 

 digitorum, are supplied by the anterior tibial nen^e. 



EXTERNAL REGIOX. 



The psronens longus muscle arises from the head of the fibula, and 

 from the upper two-thirds of the external surface of that bone ; from the 

 fascia of the leg ; and from the intermuscular septa on either side. It 

 ends above the ankle in a tendon which passes downwards behind that 

 of the peroneus brevis in the hollow behind the external malleolus, and 

 in the same sJieath of the external annular ligament with it ; it then 

 inclines forwards over the outer margin of the foot, and enters the groove 

 on the lower surface of the cuboid bone, proceeding inwards and forwards 

 to be inserted into the lower part of the internal cuneiform and the 

 tarsal end of the first metatarsal bone : an oflset is continued from it 

 to the base of the second metatarsal bone. 



Bdathiis. — At its origin the peroneus longns lies between the extensor com- 

 munis digitorum in front and the soleus and flexor longus poUicis behind ; in the 

 lower part of the leg it lies behind the peroneus brevis. Beneath the external 

 annular ligament the tendons of both peronei are sm'rounded by the same 

 sjTiovial sheath. In the sole of the foot the tendon of the peroneus longus lies 

 in a filjrous sheath formed by the long plantar ligament, and is enclosed by a 

 tubular sheath of synovial membrane. A small sesamoid cartilage is sometimes 

 foimd m that part of the tendon which lies in the groove of the cuboid. 



The peroneus brevis arises fi"om the lower two-thirds of the external 

 surface of the fibula, internal to the peroneus longus, and from the 

 intermuscular septa on either side. Its tendon passes behind the 

 external malleolus, and inclining forwards, is inserted into the projec- 

 tion at the base of the fifth metatarsal bone. 



Eelat'iom^. — In front it is in contact with the extensor longus digitoram and 

 the peroneus tertius, and behind with the peroneus longus and flexor longus poUicis. 

 Behind the malleolus it is enclosed in the same filjrous and spiovial sheaths with 

 the tendon of the peroneus lougiis, but over the calcaneum. it traverses a separate 

 sheath above that for the peroneus longTis, but lined by an offset of the same 

 synovial membrane. 



Yarict'ic'i. — The following are the most common : — The lycrnncns acecaitoriiis 

 (Henle) arises from the fibula between the peroneus longus brevis and joins the 

 tendon of the former in the sole of the foot. The 2>''ro>icH.^ qiiinfi diffiti arises 

 from the lower fourth of the fibula midcr the i:)eroneus bre-vis, and is inserted 

 into the aponeurosis on the upper surface of the little toe : or it may aiise from 

 the tendon of the peroneus brevis itself. (Hallet. "Wood, Macalister.) Pnvnnis 

 tjiiartii.-: (Otto) arises from the back of the fibula, between the i^eroneus brevis 

 and the flexor pollicis, and is inserted into a tubercle on the os calcis, behmd the 

 tendons of the peroneal muscles. (Macalister.) 



Nerves. — The peroneus longus and brevis are supplied by the musculo-cutaneous 

 branch of the popliteal nerve. 



rOSTERIOR REGION. 



The muscles at the back of the leg consist of a superficial group 

 inserted into the extremity of the calcaneum, and a deeper group 

 covered in by a deep fascia and descending to the sole. 



The SUPERFICIAL GROUP consists of three muscles ; two of them, 

 placed one on the surface of the otlier, are of large size, the r/asfro- 

 cncniiK.'^ and soleus, form the bulk of the calf of tlie leg, and are 

 inserted into the heel by a common tendon — the tendo Achillis ; the 

 third, a small muscle, the jJlantan's, descends between the other two. 



