Chapter 10
The Muscular System
355
10
MUSCLE
DESCRIPTION
ORIGIN (O) AND
INSERTION (I)
ACTION
NERVE
SUPPLY
Flexor digitorum
superficialis
(dı˘
0
jı˘-tor
9
um
soo
0
per-fish
0
e-al
9
is)
(
digit
5
finger, toe;
superficial
5
close to
surface)
Two-headed muscle;
more deeply placed
(therefore, actually forms
an intermediate layer);
overlain by muscles above
but visible at distal end of
forearm
O—medial epicondyle
of humerus, coronoid
process of ulna; shaft of
radius
I—by four tendons into
middle phalanges of
fingers 2–5
Flexes wrist and middle
phalanges of fingers 2–5
;
the important finger
flexor for speed and
flexion against resistance
Median nerve (C
7
, C
8
,
and T
1
)
Deep Muscles
Flexor pollicis longus
(pah
9
lı˘-kis)
(
pollix
5
thumb)
Partly covered by flexor
digitorum superficialis;
parallels flexor digitorum
profundus laterally
O—anterior surface of
radius and interosseous
membrane
I—distal phalanx of
thumb
Flexes distal phalanx of
thumb
Branch of median
nerve (C
8
,T
1
)
Flexor digitorum profundus
(pro-fun
9
dus)
(
profund
5
deep)
Extensive origin; overlain
entirely by flexor digitorum
superficialis
O—coronoid process,
anteromedial surface of
ulna, and interosseous
membrane
I—by four tendons into
distal phalanges of
fingers 2–5
Flexes distal
interphalangeal joints
;
slow-acting flexor of any
or all fingers; helps flex
wrist
Medial half by ulnar
nerve; lateral half by
median nerve
MUSCLE GALLERY
Table 10.11
(continued)
Biceps brachii
Medial head of
triceps brachii
Tendon of
biceps brachii
Pronator
teres
Brachio-
radialis
Extensor carpi
radialis longus
Flexor pollicis
longus
Pronator
quadratus
Flexor
retinaculum
(a)
Medial epicondyle
of humerus
Flexor carpi
radialis
Palmar
aponeurosis
Superficial
transverse
ligament of palm
Palmaris longus
Flexor carpi
ulnaris
Flexor digitorum
superficialis
(b)
(c)
Tendon of biceps
brachii (cut)
Flexor
digitorum
superficialis
Flexor pollicis
longus
Supinator
Flexor digitorum
profundus
Thenar muscles
of thumb
Tendon of flexor
pollicis longus
Lumbricals
Tendon of
flexor
digitorum
superficialis
Tendon of flexor
digitorum superficialis
(cut)
Tendon of
flexor digitorum
profundus
Pronator quadratus
Tendon of flexor
carpi ulnaris (cut)
Extensor carpi
radialis longus
Tendon of flexor
carpi radialis (cut)
Tendon of
brachioradialis
(cut)
Figure 10.16
Muscles of the anterior
fascial compartment of the forearm
acting on the right wrist and fingers.
(a)
Superficial view.
(b)
The brachioradialis,
flexors carpi radialis and ulnaris, and palmaris
longus muscles have been removed to reveal
the flexor digitorum superficialis.
(c)
Deep
muscles of the anterior compartment. The
lumbricals and thenar muscles (intrinsic hand
muscles) are also illustrated. (For a related
image, see
A Brief Atlas of the Human Body
,
Figure 37.)
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