180 THE MUSCLES. 
tendons (Fig. 77, s’) which diverge to the insertions. The 
ulnar portion of the flexor sublimis digitorum (Fig. 77, x) takes 
origin from the common tendon before its division. 
Insertion.—Each tendon except the first gives off a branch 
which spreads out in the trilobed pad in the palm. The middle 
two of these may be traced to the integument covering the pad. 
The tendon is then inserted (Fig. 88, a) near the base of the 
first phalanx onto the outer surface of the perforated portion of 
the flexor sublimis tendon (0, 0’) at its side, except that to the 
thumb, which divides near its distal end into two which are 
inserted into the sesamoid bones at the base of the first phalanx. 
The tendons of insertion are closely united to the fibrous pulley- 
ring at the base of the first phalanx, and each may send a slip 
to the base of the phalanx at either side of the ring. 
Relations.—Outer surface with the superficial fascia and 
one head of the flexor sublimis (Fig. 77, +). Radial border 
with the flexor carpi radialis. Ulnar border with the flexor 
carpi ulnaris and a part of the flexor profundus digitorum. 
Inner surface with the flexor carpi radialis (7), the flexor carpi 
ulnaris (2), the flexor profundus digitorum (z), and the radial 
head of the flexor sublimis digitorum. 
Action.—Flexor of the first phalanx of each of the digits. 
M. flexor carpi ulnaris (Fig. 77, ¢, 7’). 
Origin. —There are two heads. The first or humeral head 
(¢’) takes origin in common with the second part of the flexor 
profundus from the median surface of the distal end of the 
humerus just distad of the medial epicondyle (Fig. 82, g). The 
second or ulnar head (¢) takes origin by fleshy fibres from the 
lateral surface of the olecranon and from the dorsal border of 
the ulna from the olecranon to a point distad of the semilunar 
notch (Fig 87, /)- The two heads join proximad of the middle 
of the forearm. The muscle passes obliquely across the ven- 
tral surface of the forearm to its 
Insertion by fleshy and tendinous fibres into the proximal 
surface of the pisiform bone. 
Relations. —Outer surface with the integument and the 
palmaris longus (Fig. 77, s). Inner surface and ulnar border 
with the flexor profundus digitorum. 
