MUSCLES OF TEE ANTERIOR LIMBS. 327 



foot ; these are the external flexor, oblique flexor, and the internal flexor of the 

 metacarpus. The other two, fixed to the digit by their inferior extremity, and 

 covered by the preceding, are designated the superficial and deep flexors of the 

 phalanges. 



Superflcial Layer. 



1. ExTEENAL Flexor of the Metacarpus (Flexor Metacarpi Externus), 

 OR Posterior UtNARis^ (Fig. 179, 18). 



Synonyms. — Epicondylo-supercarpeus — Girard. (Humero-supercarpeus externus — Leyh.) 



Situation. — The external flexor of the metacarpus is situated at the external 

 side of the forearm, between the lateral extensor of the phalanges and the 

 oblique flexor. 



Form — Structure — Attachments. — This muscle is elongated from above to 

 below, flattened on both sides, thick in the middle, and intersected by very 

 strong aponeurotic bands. It commences on the summit of the epitrochlea by 

 a very powerful, but extremely short tendon. Inferiorly, it terminates by a 

 second tendon longer than the preceding, and divides into two branches, an 

 anterior and a posterior. The latter (Fig. 179, 20), short and wide, is inserted 

 into the pisiform bone in becoming mixed with the oblique flexor. The former 

 (Fig. 179, 19), roimded and funicular in shape, glides by means of a synovial 

 bursa in the channel excavated on the external aspect of the pisiform bone, and 

 which is converted into a canal by a little fibrous apparatus ; this branch is after- 

 wards fixed on the head of the external metacarpal bone, by being confounded 

 with the external hgament of the carpus. 



Relations. — Covered by the antibrachial aponeurosis, this muscle covers the 

 two flexors of the digit. Its anterior border responds to the lateral extensor of 

 the phalanges ; the posterior to the oblique flexor. Its superior tendon lies 

 behind the external ligament of the elbow- joint, and is covered deeply by the 

 external cul-de-sac of the synovial capsule belonging to that articulation. 



Action. — It flexes the foot on the forearm. (Leyh observes that it is more 

 particularly concerned in what is known as " high action.") 



2. Oblique Flexor of the Metacarpus (Flexor Metacarpi Medius), 

 or Anterior Ulnaris (Fig. 180, 18). 



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



Situation — Form — Structure. — This muscle, situated behind and within the 

 forearm, is an exact counterpart of the preceding in form and structure. 



Direction. — Bourgelat has improperly named it an oblique flexor, for its direc- 

 tion is vertical like that of the other muscles of this region. 



Attachments. — It has its origin : 1. On the base of the epitrochlea by the 

 tendinous fibres of its superior extremity. 2. On the olecranon, by a small, very 

 thin, and very pale fleshy band, which is annexed to the principal muscular body, 

 and soon unites with its posterior border. Its inferior tendon is undivided, and 



' It is known that the bony eminences, hitherto termed in veterinary anatomy " epitrochlea " 

 and " epicondyle," correspond : the first, to the epicondyle of Man, the second, to the epi- 

 trochlea. It need excite no surprise, therefore, to see the denominations given by Girard to 

 the muscles of the posterior antibrachial region changed as above. 



