EXTENSOR BREVIS DIGITORUM. 



247 



digitornra, from the lower fourth of the inner surface of tlie fibula, 

 from the lower part of the interosseus membrane, and from the inter- 

 muscular septum which connects it on 

 the outer side with the peroneus brevis. 

 Its tendon is inserted into the upper sur- 

 face of the base of the fifth metatarsal 

 bone. 



Fig. 192.— Superficial I\rtiscLES and Tendoxs on 



THE Dorsum of the Foot and Lower Part op 



THE Front of the Leq (after Bourgery). i 



a, the tibia ; h, the fibula ; c, the scaphoid boue ; 

 d, internal cuneiform bone ; 1, the tibialis anticus 

 muscle ; 1', its tendon descending in the groove of 

 the internal cuneiform bone ; 2, extensor longus pol- 

 licis ; 2', its expansion on the dorsum of the great 

 toe ; 3, extensor communis digitorum dividing into 

 its four tendons for the toes ; 3', its expansion, and 

 3", final insertion (upon the second toe) ; 4, peroneus 

 tertius ; 4', its expanded insei-tion on the base of 

 tlie fifth metatarsal bone ; 5, soleus ; 6, peroneus 

 lirevis ; 7, extensor brevis digitorum ; 7', 7", placed 

 on the ti-ansverse band of aponeurosis, marks the 

 first and fourth tendons of the extensor brevis muscle 

 passing to join those of the long extensor ; S , 9, 

 part of anterior annular ligament, and ligamentum 

 cruciatum ; between 8 and c, the slings enclosing the 

 extensor longus pollicis and tibialis anticus ; below 

 9, the outer part of the ligamentum cruciatum 

 enclosing the tendons of the extensor communis and 

 peroneus tertius ; 10, 11, dorsal transverse meta- 

 tixrsal baud of aponeurosis. 



liclntlons. — It is placed to the outer side of 

 the long extensor of the toes, with which it is 

 usually united at its origin, and iti:).isses through 

 the same compai-tment of the annular ligament 

 with that muscle. 



Vtvlctirs — The peroneus tertius is sometimes as large as the extensor long-us 

 digitorum ; it has been obsei-ved to terminate on tlie fouith metatarsal bone ; 

 and it is sometimes altogether wanting. 



The extensor brevis digitorum pedis arises from the outer surfoce 

 of the OS calcis in front of the liToove for the peroneus brevis muscle, 

 and from the lower band of the anterior annular ligament. It divides into 

 four tapering slips each of which terminates in a tendon ; the first or 

 most internal of these, sometimes reckoned as a distinct muscle, is 

 inserted separately into the dorsal surface of the first phalanx of the 

 great toe near its tarsal extremity ; and the other three become severally 

 united to the outer border of the extensor tendons proceeding to the 

 three next toes. 



Hdnfiom. — It crosses the dorsum of the foot somewhat obliquely, resting on 

 the tarsus and metatarsus, and lying beneath the tendons of the peroneus tertius 

 and long extensor of the toes. Its inner tendon also crosses the dorsalis pedis 

 artery and the anterior tibial nerve. 



Viirictica. — The tendons of this muscle vary considerably both as to number 

 and position, they may be reduced to two, or one of them may be doubled. The 

 inner part of the muscle very commonly forms a distinct extensor hrevh Mlhtcls 

 being separate at its origin from the rest of the muscle ; this is regarded by 

 Henle as the normal arrangement. 



