76 THOMPSON YATES LABORATORIES REPORT 
My experiments on this nerve bear out the statement by Forgue and Lannegrace,* that 
the hinder parts of the diaphragm is supplied by the Vlth cervical nerve ; so also my degeneration 
obtained of the IVth cervical, bear them out that that root supplies the front of the diaphragm ; 
but the degenerations show that there is much intermingling of the two nerves, both with each 
other and with the Vth in their distribution both to back and front. 
My observations on this nerve bear out THORBURN'st statement, based on clinical 
observation, that the nerve supplies the teres major, latissimus dorsi, sternal portion of pectoralis 
major, and the triceps — a statement contrary to Forgue and Lannegrace'sJ experiments. 
The diaphragm. The degeneration in the phrenic after section of Vlth cervical in 
Macacm is heavy. Of the two main divisions into which the phrenic divides on reaching the 
diaphragm, the degeneration is considerably greater in that (dorsal) which turns backward toward 
the vertebral column than in that which turns forward (ventral). 
Degenerated fibres I found in considerable numbers in tlie phrenic twenty days after 
section of the motor root of the IVth cervical ; but in this instance the amount of degeneration 
was greater in the division of the nerve which turned forward toward the sternal border of the 
muscle than in that turning backward. The diaphragm in all my experiments proved to be a 
trimeric muscle, that is to say, drew its innervation from a scries of three consecutive spinal nerves, 
resembling in this character the majority of the limb muscles. The elements of the individual 
metamers are also, as in the limb muscles, much commingled and not strictly territorially 
arranged. 
VIIth Cervical Nerve (Figs. 4 and 5, and 7 and 8) 
This skin-field has been delimited completely in four individuals and incompletely in 
a fifth. 
Example. — M. rhesus. 9, young. At 1 1. 1 5 a.m. tlie posterior roots of the llird, IVth, 
Vth, Vlth and Vlllth cervical, and of the 1st, llnd, llird, IVth, Vth and Vlth thoracic nerves of 
the right side divided. The isolated field of response due to the VIIth cervical being intact, was 
finally delimited at 4.30 p.m. 
' The field of response is limited by a line which is traceable from the radial side of the 
cleft between tiie 3rd and 4th digits, and runs along the palm on the radial edge of the main 
longitudinal furrow. From the palm it takes an almost rectilinear course, ascending the flexor 
aspect of the forearm along the hollow between the flexor and the supinator groups of muscles. 
It attains the radial side of the biceps tendon and then mounts the swelling prominence of the biceps 
muscle ; at first it fairly bisects the surface of this prominence longitudinally, but higher up the 
line tends outward and ascends over the insertion of the deltoid muscles, and then recurves abruptly 
downward below the insertion of the deltoid, and again bends upward behind the deltoid : once 
more abruptly recurving it descends and follows the groove between extensors and flexors of elbow- 
joint. The line enters the extensor surface of the forearm closely behind the head of the radius, 
and well in front of the olecranon process of the ulna. It runs down the back of the forearm 
* ' Compt. Rend.,' vol, 98, p. 829. 
■j- 'Brain,' xxxvi, p. 510 ; xUi, p, 289. 
I Lac. cit. 
