a MUSCLES ON FRONT AND INNER ASPECT OF FOREARM. 327 
a digital sheath beneath the tendon of the flexor sublimis digitorum, which it 
‘pierces opposite the first phalanx, and is finally inserted into the base of the 
terminal phalanx. Like 
the tendons of the flexor 
sublimis, those of the deep 
flexor are provided with 
vincula accessoria, viz. 
ligamenta brevia attached 
to the capsule of the 
second interphalangeal 
articulation, and liga- 
menta longa, which are in 
this case connected to the 
tendons of the subjacent 
flexor sublimis digitorum. 
Lumbricales. — Four 
small cylindrical muscles 
are associated with the 
tendons of the flexor pro- 
fundus digitorum in the 
palm of the hand. Zhe 
two outermost muscles 
arise from the radial side 
of the tendons of the 
flexor profundus digi- 
torum destined for the 
fore and middle fingers. 
The two innermost muscles 
arise, each by two heads, 
from the adjacent sides 
of the second and third, 
and third and fourth ten- 
dons. From these origins 
the muscles are directed 
downwards to the radial 
side of each of the meta- 
earpo-phalangeal joints, to 
be inserted into the cap- 
sules of these articula- 
tions, the outer border of 
the first phalanx, and 
chiefly into the outer side 
of the extensor tendon on 
the dorsum of the phalanx, 
The lumbricales vary con- 
siderably in number, and 
may be increased to six 
or diminished to two. 
In the forearm the 
flexor profundus digi- 
torum is concealed by the 
flexor sublimis digitorum 
and flexor carpi ulnaris 
~ muscles, and by the ulnar 
' nerve and artery. Under 
the anterior annular liga- 
Beh) 
Internal intermuscular septum 
COMMON ORIGIN OF PRONATOR AND 
FLEXOR MUSCLES 
BRACHIALIS ANTICUS 
Termination of musculo-spiral 
nerve 
BICEPS TENDON- 
Ulnar nerve 
SUPINATOR RADII BREVIS 
Median nerve 
ULNAR ORIGIN OF FLEXOR LONGUS POLLICIS 
FLEXOR CARPI ULNARIS 
RADIAL ORIGIN OF FLEXOR 
SUBLIMIS DIGITORUM 
FLEXOR PROFUNDUS DIGITORUM 
RADIAL ORIGIN OF FLEXOR 
LONGUS POLLICIS 
EXTENSOR OSSIS METACARPI [ 
POLLICIS (double) | - 
EXTENSOR BREVIS POLLICIS 
FLEXOR LONGUS POLLICIS 
FLEXOR CARPI RADIALIS 
ABDUCTOR POLLICIS (cut) Pests 
MINIMI 
ir 
OPPONENS POLLICIS— ~~ ae DIGITI (cut) 
FLEXOR BREVIS POLLICIS i ZF ORnON 
MINIMI 
DIGITI 
TENDON OF FLEXOR LONGUS 
POLLICIS 
ADDUCTOR TRANSVERSUS 
POLLICIS 
LUMBRICALES 
Fic. 243.—DEEP MUSCLES ON THE FRONT OF THE FOREARM 
AND HAND. 
ment the muscle is placed beneath the tendons of the flexor sublimis digitorum, 
and is enveloped in the common bursal sac. 
the lumbrical muscles, cover the deep palmar arch and the interossei muscles, and 
In the palm the tendons, along with 
