OF THE DIFFERENT MUSCLES. 155 



arises from the internal condyle of the os humeri, and is in- 

 serted into the os trapezium. 

 Use. — To bend the leg. 



FLEXOR METACARPI INTERNETS 



Takes its course along the inner and back part of the leg. 

 It originates from the internal condyle of the os humeri, 

 adhering to the capsular ligament of the elbow joint. 



Insertion. — Into the head of the internal small metacar- 

 pal bone. 



DEEP POSTERIOR BRACHIAL REGION. 



The following muscles constitute the deep-seated flexors ; 

 they lie anterior to, and are concealed by, the superficial. 



FLEXOR PEDIS PERFORATES. FLEXOR PEDIS PERFORANS. 



Both these muscles originate from the internal condyle. 



Insertion. — The former, at the pastern joint, divides into 

 two parts, which are fixed into the upper and back part of 

 the os coronas. 



The perforans continue over the os naviculare — having 

 a bursa between them; an expanded termination passes to 

 the concavity of the os pedis. 



ANTERIOR BRACHIAL REGION. 



These muscles form the prominent part of the arm in front, 

 take their origin from the external condyle, and operate in 

 the extension of the leg and foot. 



EXTENSOR METACARPI MAGNUS. 



Origin. — From the external condyle of the os humeri : 

 its fibres also adhere to the capsular ligament ; at the knee 

 its tendon passes under the annular ligament, within a syno- 

 vial sheath, where we find a bursa mucosa. 



Insertion. — Into the front and upper part of the large 

 metacarpal bone. 



Use. — To extend the leg. 



