J. Playfair McMurrich A97 
tively, along with the radial (or ulnar, as the case may be) slip of that 
digit. Furthermore, the first and fourth intermetacarpals become asso- 
ciated with the combined muscles so formed, the three portions thus 
associated constituting the first and fourth dorsal interossei. ‘The sec- 
ond and third intermetacarpals unite with the flexor brevis profundus 
slips of the third digit to form the second and third dorsal interossei, 
and the flexor brevis profundus slips of the first, second, fourth and fifth 
digits which do not unite with intermetacarpals form the palmar inter- 
ossei. A diagram (Fig. 11) will, I trust, make this description clear 
and at the same time demonstrate the significance of the mutually com- 
plementing arrangement of the two sets of interossei. 
Ly 
FZ 
$ 
Fie. 11. Diagram showing the composition of the interossei of the human hand. 
id, dorsal interossei; ip, palmar interossei. 
V. SUMMARY. 
It is difficult and tedious to follow a lengthy description involving 
reference to a number of separate structures even when an abundance of 
illustrations accompanies it. Owing to my results having been based 
very largely on the study of the serial sections it would require an undue 
number of figures to demonstrate all the points to which reference has 
been made in the preceding pages, and hence, I fear, only those who are 
especially interested in the subject will have the patience necessary for 
the thorough perusal of what I have written. And yet it seems that the 
