J. Playfair McMurrich 465 
From the ulnar border of the muscle an additional portion is sepa- 
rated off which becomes intimately associated with the large ulnar slip 
of the flexor brevis profundus minimi digiti and forms what may be 
regarded as an abductor minimi digiti. At its origin it is associated 
with the insertion of the flexor carpi ulnaris, indeed, the fibres of this 
latter muscle are to a certain extent continued directly into the 
abductor, additional fibres being added, however, from the ulnar carpal 
bone. ; 
The flerores digitorum breves medi 
have essentially the same arrangement 
as do the superficiales. They arise from 
the dorsal surface of the palmar apo- 
neurosis and are inserted into the fibro- 
cartilages of the metacarpo-phalangeal 
joints of each of the four digits. The 
slips for the medius and annulus arise 
together and at first form a single mus- 
cle, but later on they separate and that 
for the annulus divides into three slips 
(Fig. 2, F. M., F. M’. and 1) which he- 
come associated with three correspond- 
ing slips of the flexor brevis profundus 
and are inserted with them. The por- 
tion for the medius divides into two slips 
only, comparable to the ulnar and me- 
dian slips of the annulus, and in the in- 
dex and minimus only two slips are 
formed, a radial one being lacking in the 
index and an ulnar one in the minimus. 
The insertion in both these digits is, 
however, in association with the corre- 
Ino eline c “or are ss Fia.2. Transverse section through 
Sg OS ‘ } Ss 5 3 oes = 
sponding slips of the flexor brevis pro- eee a eee ea ot ane 
c = blystoma tigrinum. EF. M., flexor 
s ystor grin B 
fundus. brevis es J ikegad eee flexor brevis 
Thea Ie nrpe faator "27)P° “1. profundus; F’.S.. flexor brevis super- 
Phe fle LOres digitor um breves pro ficialis; 1, one of the lateral portions 
fund are four distinct muscles. ‘They, coire eee er ociae ae eloeenc al 
arise from the carpal bones and as they P#!mar aponeurosis. 
are traced distally each is divided into 
two lateral slips (Fig. 2, F. P.) by a median slip which arises 
from the palmar surface of the metacarpal (/. P’.), so that dis- 
tally three profundus slips may be recognized in each digit. These 
unite, as has already been stated, with-slips from the medii and super- 
ficiales to insert into the metacarpo-phalangeal fibro-cartilages. The 
