THE ROLE OF REFLEX INHIBITION 



599 



joint enhances the effect oi another muscle crossing that joint 

 to act on a more distant one is termed the pseud-antagonist 



Fig. 5. — Muscles ascertained by direct analysis to be engaged in the flexion-reflex 



of hind-limb (cat). 

 A. Lateral aspect of limb ; B. Medial aspect. 

 Muscles engaged in construction (dotted Hnes). 



N. Pectineus. 



P. Peroneus longus. 



R. Rectus femoris. 



S. Sartorius, lateral band, S' medial band. 



T. Semitendinosus. 



Y. Psoas parvus. 



A. Tibialis anticus. 



B. Biceps femoris posterior. 



E. Extensor brevis digitorum. 



F. Tensor fasciae femoris longus, F' brevis. 



G. Gracilis. 

 I. Psoas magnus. 



L. Extensor longus digitorum. 



M. Gluteus minimus (a second dotted line indi- 

 cates its posterior part). 



Muscles relaxed by reflexed inhibition (interrupted lines). 



1. Crureus. 6. Biceps femoris anterior. 



2. Vastus lateralis. 7. Gastrocnemius ext. 7' int. 



3. Adductor minor. 8. Soleus. 



4. Adductor major (in part). 9. Vastus medialis. 



5. Semimembranosus. o. Quadratus femoris. 



(This figure serves also to illustrate the crossed extension-reflex. In that reflex the muscles marked 

 with numerals contract, and A, S, S, T oi the alphabet-group are relaxed by inhibition — and none of the 

 alphabet-group contract.) 



of the latter. Pseud-antagonists, unlike true antagonists, are 

 dealt with by " identical innervation " — that is, contract together 



and relax 



together. 



Thus, in reflex flexion at hip, when the 



