MUSCLES OF THE POSTERIOR LIMBS. 



303 



Action. The gastrocnemii extend the foot upon the tibia. They act as 

 a lever of the first order when the limb is raised from the ground, and as 



Fig. 137. 



MUSCLES ON INNER ASPECT OF LEFT POSTERIOR LIMB. 



1, Crest of the ilium ; 2, Section through it ; 3, Sacro-ischiatic ligament ; 4, Pyri- 

 formis ; 5, Posterior portion of sacro-ischiatic ligament ; 6, Tuberosity of ischium ; 

 7, Anterior portion of ischium, sawn through ; 8, Pubis ; 9, Obturator foramen ; 

 10, External iliac artery and vein, 11 ; 12, Obturator artery and vein ; the figures 

 are placed on the internal obturator muscle; 13, Long adductor of the leg, or 

 sartorius; 14, Small adductor of the thigh, or adductor brevis; 15, Short 

 adductor of the leg, or gracilis ; 16, Eectus of the thigh ; 17, Vastus internus ; 

 18, Patella, with insertion of rectus ; 19, Upper extremity of tibia; 20, Gas- 

 trocnemius ; 21, Popliteus ; 22, Oblique flexor of the phalanges, or flexor pedis 

 accessorius, with its tendon, 34 ; 23, Perforans muscle, with its tendon, 35 ; 24, 

 Flexor metatarsi ; 25, Anterior extensor of the phalanges, or extensor pedis ; 

 26, Annular ligament ; 27, Tendon of flexor metatarsi, and its cunean branch, 

 28 ; 29, Tendon of superficial flexor or internal gastrocuemius ; 30, Tendon of 

 gemelli or external gastrocnemius; 31, Oscalcis; 32, Astragalus ; 33, Perforatus 

 tendon ; 34, Tendon of oblique flexor joining the perforans tendon, 35 ; 36, Large 

 metatarsal bone ; 37, Extensor pedis tendon ; 38, Terminal knob of small meta- 

 tarsal bone. 



