Mi'SCLES OF Tin: .( \Ti:i;i< >i; /./.v/;v >i<r, 



U iiinl nerves. Its anterior border responds to the radius. A syuovial 

 sheath en\vlop> its terminal teiidon, 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 Perforatus. ''Figs. 

 89, 119, 121, 122.) 



!'. Epitrochlo-phalangeus Girard. (Flexor pedit perforatue Ptrclcnll. 

 llumero-coroiiaris 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 

 apoiicurotic 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 

 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. 89, 14) for the 

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

 designations of perforatus and perforans, given to the two flexors of the 

 phalanges. Afterwards it is inflected forwards over the sesamoid groove, 

 and terminates by two branches towards the middle of the digital region. 



Attachments. It hikes its origin, in common with the perforans, at the 

 summit of the epitroehlea, and is inserted, by the bifurcations of its tendon, 

 into the extremities of the pulley formed behind the superior extremity of the 

 second phalanx. 



Relations. The muscular portion, covered by the external and the 



oblique flexors of the metacarpus, may be said to be incrusted in the perforans, 



to which it adheres in the most intimate manner. The tendon covers that 



of tin lutt.-r muscle, and is in turn covered by the fibrous expansions of the 



uictacarpal and metacarpo-phalangeal sheaths which are now to bo 



IM .1. 



The Carpal sheath is the name given to a very remarkable annular 



apparatus, formed by the superficial face of the common posterior ligament of 



tin; carpus, and by a thick expansion of inelastic white fibrous tissue, together 



: ituting a perfect arch thrown across like a bridge, from the supercarpnl 



to the inner side of the carpus. This arch is continuous, above, with 



the antibrachial apoueurosis, and is prolonged, below, over the metacarpal 



jMirtion of the flexor tendons. An extensive synovial membrane covers the 



internal aspect of the carpal sheath, envelops the perforatus and perforaus 



in their passage through this canal, ascends above the carpus, and descends 



as far as the lower third of the metacarpal region. 



The Metacarpo-phalangeal sheath is formed by the sesamoid groove, the 

 posterior face of the principal uavicular ligaments, that of the glenoid fibro- 

 i-artilago of the first interphalaugeal articulation, and by the posterior pulley 

 of tin srroml phalanx. It is completed by a very wide membranous expansion 

 applied against the flexor tendons, closely adherent to the perl'ipi-atus on the 

 median line of the digit, and fixed, laterally, to the phalaugcal bones by the 



