82 THOMPSON YATES LABORATORIES REPORT 
Man the 1st thoracic sends a branch back to join the Ilnd thoracic (cutaneous), but it does not do 
so in the Macaques I have dissected. 
2. Motor Root. 1st Thoracic. {See Conspectus, p. 114 infra.) 
Two experiments, both by degeneration method : one performed on Macacus rhesus, one 
on Macacus sinicus. The muscular distribution was in this way found to include the following : — 
scaleni. 
pectoralis major (lower body only). 
pectoralis minor. 
triceps (inner head, long head less). 
latissi?nus dorsi (in part). 
serratus posticus superior. 
' palmaris longus. 
flexor carpi ulnaris. 
flexor profundus digitorum, 
flexor suhlimis digitorum, 
flexor longus polUcis. 
pronator quadratus. 
(xtensor ossis metacarpi poUicis. 
extensor longus pollicis. 
extensor hrevis pollicis. 
extensor communis digitorum. 
extensor indicts, 
extensor minimi digiti. 
extensor carpi ulnaris. 
intrinsic muscles of the hand., including the inter ossei. 
A further examination of the distribution of this motor root was carried out as before by 
degeneration and teasing nerve-trunks. Degenerate nerve-fibres were traced to the following 
muscles : — 
flexor carpi radialis. 
palmaris longus. 
extensor communis digitorum. 
flexor profundus digitorum. 
flexor sublimis digitorum. 
pronator quadratus. 
extensor carpi ulnaris. 
extensor indicis (not always). 
extensor internodii pollicis (not always). 
extensor minimi digiti. 
superficial short muscles of the thumb. 
