THE MUSCLES OF TUE LIMES. 



51 



On the dorsal aspect : first, the peroyiaeus tertlus for the 

 metatarsal bone ; secondly, one tendon from the extensor digi" 

 torum brevis^ but this last is commonly absent in Man ; third* 

 ly, one tendon from the extensor digitormn longus. 



'Jlx^.2,^ 



Fig. 17. — Part of the middle digit of the manus of an Orang- with the flexors and extensors 

 of the phalanges: mcp.^ metacarpal bone; Ph. 1, Ph. 2, Ph. 3, the three phalanges; 

 Ext. 1, the deep long extensor tendon from the extetisor indicis ; Ext. 2, the supei-fl- 

 cial long extensor tendon fi-om the extensor comimmis ; I. e., the interosseous short ex- 

 tensor ; /./;, the interosseous short flexor ; E. pns., the deep long flexor (jper/orans) ; E. 

 pts., the superficial long flexor (j)er/oratus). 



On the ventral aspect : first, \kvQ peronmus hrevis.^ attached 

 to the base of the metatarsal ; secondly, two mterossei y 

 thirdly, a perforated flexor ; and fourthly, a perforating flexor, 

 like those of the manus. The divisions of the mterossei^ 

 which send tendons to the extensor sheath on the dorsum of 

 the digits of the foot in Man, are hardly distinct from the ven- 

 tral divisions of those muscles. 



In addition to the muscles which have been mentioned, the 

 fifth digit has an abductor and an adductor^ which may be 

 regarded as subdivisions of the mterossei, arising within the 

 manus or pes, and inserted into opposite sides of the proximal 

 phalanx ; and an oppo7ie7is, a muscle attached to the ventral 

 face of the carpus or the tarsus, and inserted into the post- 

 axial edge of tlie shaft of the metacarpal or metatarsal. 



Finall}^, a lumbricalls muscle proceeds from the tendon of 

 the perforating flexor, on the pre-axial side of the digit, to 

 the extensor sheath. 



None of the other digits of the manus, or of the pes, has a 

 greater number of muscles than this ; in fact, all the others 

 have fewer muscles, some of those enumerated being sup* 



