828 THE MUSCLES. 



terminates on the pisiform bone, along with the external flexor, to which it is 

 intimately attached. 



Relations. — By its superficial face, with the antibrachial aponeurosis, which 

 strongly adheres to its tendon ; by its deep face, with the flexors of the phalanges. 

 Its anterior border is covered by the internal flexor ; the posterior responds to 

 the external flexor. 



Action. — It is a congener of the preceding. 



3. Internal Flexor of the Metacarpus (Flexor Metacarpi Internus), 

 OR Palmaris Magnus (Fig. 181, 19). 



Synonyms. — Epitrochlea metacarpeus — Girard. (Humero-metacarpeus internus — Leyh.) 



Situation— Form — Structure — Attachments. — This muscle is situated within 

 the forearm, against the posterior face of the radius, and in its general features 

 resembles its congeners, the two preceding muscles. It is, however, not so wide, 

 is thinner, and less aponeurotic. Its upper extremity is fixed, by tendinous 

 fibres, to the base of the epitrochlea at the same point as the oblique flexor, with 

 which it is confounded — origin. Its inferior extremity terminates in a long, thin, 

 funicular tendon which passes through a fibrous sheath at the inner side of the 

 knee, and is inserted into the head of the internal metacarpal bone — movable 

 insertion. 



Relations. — It is covered by the antibrachial aponeurosis, and covers the 

 oblique flexor, the perforatus and perforans, as well as important blood-vessels 

 and nerves. Its anterior border responds to the radius. A synovial sheath 

 envelops its terminal tendon, and facilitates its movements in the fibrous canal 

 through which it passes. 



Action. — It is a congener of the preceding. 



4. Superficial Flexor, Sublimis of the Phalanges, or Flexor Pedis 

 Perforatus (Figs. 179, 181, 182). 



Synonyms. — Epitrochlo-phalangeus — Girard. (Humero-coronarls or humero-phalangeus — 

 Leyh.) 



Situation. — The superficial flexor of the phalanges is situated, with its fellow, 

 the perforans, beneath the flexors of the metacarpus, which form around them a 

 kind of muscular envelope. 



Form — Structure — Extent. — It is composed of a muscular and tendinous 

 portion. The first, long, thin, prismatic, and divided by a great number of 

 aponeurotic intersections, extends from the inferior extremity of the arm nearly 

 to the carpus. The tendon, continuous with the inferior extremity of the 

 muscular portion, receives at its origin an enormous fibrous production {superior 

 carpal or check ligam,ent), that arises from the eminence of insertion situated at 

 the posterior face of the end of the radius, and which contracts somewhat 

 intimate adhesions with the antibrachial aponeurosis, as well as with the 

 perforans. 



After being thus reinforced, this tendon passes through the carpal sheath 

 and arrives behind the fetlock, where it forms a ring (Fig. 183, 21) for the 

 passage of the tendon of the deep flexor. To this peculiarity is owing the de- 

 signations of mrforatus and perforans., given to the two flexors of the phalanges. 



