ANATOMY IN A NUTSHELL. 1 ")7 



tins is superficial to the Peroneus brevis. It is situated at the upper part and 



outside of the leg. The external popliteal or peroneal nerve passes between 

 the fibula and this muscle near the upper part of the bone between the head and 

 the shaft. As its tendon passes behind the external malleolus it lies behind the 

 tendon of the Peroneus brevis in a common groove which is converted into a 

 canal by a fibrous band. These two tendons have synovial membranes. Its 

 tendon passes across the outer side of the os calcis, below its peroneal tubercle, 

 then it runs in a groove on the under surface of the cuboid bone after which it 

 crosses the sole of the foot obliquely. Behind the external malleolus and on 

 the outer side of the cuboid bone the tendon changes its direction, and in these 

 places it is thickened. A sesamoid fibro-eartilage (sometimes a bone) is in its 

 substance where it crosses the cuboid bone. 



Origin. — (Plate LI.) — (1) Head and upper two-thirds of outer surface of 

 fibula; (2) deep surface of fascia; (3) intermuscular septa and occasionally by 

 few fibers from outer tuberosity of tibia. 



Insertion. — (Plate LIII.) — Outer side of base of metatarsal of meat toe 

 and internal cuneiform. Occasionally send- dip to base of second metatarsal 

 bone. 



Action. — Extends and everts foot and steadies leg upon foot. 



Nerve Supply. — Fourth and fifth lumbar and first sacral through musculo- 

 cutaneous branch of the external popliteal. 



Blood Supply. — Peroneal. 



Peroneus brevis. — Description. — (Plate LXXIX.) — This muscle is shorter 

 and smaller than the Peroneus longus and lies behind it. Its tendon passes 

 behind the external malleolus in front of that of the Peroneus longus. On the 

 outer side of the os calcis it is separated from the tendon of the Peroneus longus 

 by the peroneal tubercle. 



Origin. — (Plate L.) — Lower two-thirds of external surface of shaft of 

 fibula, and intermuscular septa. 



Insertion. — (Plate LIII.) — Tuberosity at base of metatarsal of little tee 

 on its outer side. 



Action. — Extends foot and helps to steady leg upon foot. 



\ki;\ e Supply. — Fourth and fifth lumbar and hist sacral through musculo- 

 cutaneous branch of external popliteal. 



Blood Supply. — Peroneal. 



LESSON Xidl. 



Extensor brevis digitoruin. — Description.— (Plate LXXV.)— This is a 

 broad, thin muscle which passes obliquely across the dorsum of the foot and 

 divides into four tendons. Beneath this muscle lie the tarsal and metatarsal 

 arteries and bones and the Dorsal interossei muscles. The innermost tendon 

 crosses the dorsalis pedis artery. 



Origin. — (Plate LI I.) — (1) Fore part of upper and outer surface of < s calcis; 

 (2) external calcaneo-astragaloid ligament; (3) horizontal portion of anterior 

 annular ligament. 



