146 
THOMPSON YATES LABORATORIES REPORT 
Excitation of the lateral cutaneous branch of the Ilnd thoracic only with difficulty evokes any pupil 
reflex, the entire afferent root of Ilnd thoracic evokes reflex dilatation fairly readily. In the same way 
lateral cutaneous branch of Ilnd thoracic evokes retraction of shoulder very easily, but only with 
difficulty any contraction in the intercostal muscles. 
Again, of the muscles of the front of the thigh, some tend to be brought into reflex play by 
the internal saphenous nerve — playing upon the spinal segments of those muscles via their own proper 
afi"erent roots — much more readily than others ; the rectus femoris (its upper part especially), sartoris and 
fascialis much more readily than the crureus and vasti. Excitation of the central end of the nerve to one 
of the vasti evokes contraction of its own fellow vastus and the associated crureus less easily than sartorius 
and a part of the rectus femoris. 
Again, excitation of the central end of the nerve to one head of the gastrocnemius evokes contraction 
in the hamstring muscles more readily than in the gastrocnemius itself ^nd. the soleus. 
Again, excitation of the plantar nerves evokes contraction more readily in the pre-tibial muscles 
than in the post-tibial group, though segmentall}- they belong rather to the post-tibial group than to the 
pre-tibial. 
It can be said, that of the movements of the limb, some are easily provoked by spinal reflex 
action, some only rarely and with difficulty. Among those induced as primary spinal reflexes (the 
cord being transected above) are, in order of facility of production in my experience : — 
In the upper limb : 
retraction of upper arm. 
flexion-adduction of thumb, 
extension of wrist (especially in Cat), 
adduction at shoulder, 
flexion of elbow. 
flexion (less often extension) of digits (always in accompaniment to flexion-adduction 
of thumb). 
slight pronation of forearm (especially in Cat), 
abduction at shoulder, 
extension of elbow (rare). 
less common is flexion and some pronation of wrist. 
In the lower limb : 
flexion of hip. 
flexion of hallux, 
flexion of knee, 
adduction at hip. 
flexion (less often extension) of digits (always in accompaniment to flexion-adduction 
of hallux). 
flexion — less commonly plantar flexion — of ankle, 
less common is extension of hip. 
abduction of hip (not common), 
extension of knee (rare). 
The preponderance of the above movements over others in the limb is exemplified in the 
following summary of movements, commonly evoked by excitation of various peripheral nerves in 
