70 ANATOMY OF THE WOOD RAT 



The muscles of the posterior limb fall naturally under 

 the following headings: 



A. Muscles of the hip 



B. Muscles of the thigh 



C. Muscles of the leg 



D. Muscles of the foot 



A. MUSCLES OF THE HIP 



The muscles segregated under this heading occur in three 

 groups; namely, 



1. Iliopsoas group 



2. Gluteal group 



3. Obturator group 



1. Iliopsoas group 

 This is composed of the 



Mm. psoas minor 

 psoas magnus 

 iliacus 



M. psoas minor (figs. 12, 33) has fleshy origin from the 

 centra apparently only of the second and third lumbar 

 vertebrae. An aponeurotic tendon develops which passes 

 superficially (ventrad) over the psoas magnus to its slender 

 insertion upon the slight psoas process ventrad of the 

 acetabulum. A very light, transparent but tough apo- 

 neurosis connects a portion of the medial border of this 

 tendon with the centra of the last lumbar and first two 

 sacral vertebrae. In Neotoma and Teonoma origin seems 

 to be from the first lumbar vertebra as well. 



M. psoas magnus (figs. 12, 33) has origin, deep to the 

 psoas minor, from the centra of all (possibly not the first) 

 of the lumbar vertebrae. The fibers are bipennated onto 

 an aponeurotic tendon and this, with some of the muscle 

 fibers, is inserted onto the cranial border of the lesser tro- 

 chanter of the femur. 



