Human anatomy
Muscles of the forearm
Muscles of the Forearm
 The two functional forearm muscle groups are:
those that cause wrist movement, and those that
move the fingers and the thumb
 Most anterior muscles are flexors, and posterior
muscles are extensors
 The pronator teres and pronator quadratus are not
flexors, but pronate the forearm.
 The supinator are not extensors, but supinate the
forearm.
The muscles of anterior forearm
• Primarily flexors of
the wrist and fingers
• Divided for
convenience of
description into two
groups, superficial
and deep.
Superficial muscles of the
front of the forearm
They are five:
A: pronator teres,
B: flexor carpi radialis,
C: palmaris longus,
D: flexor carpi ulnaris,
E: flexor digitorum
superficialis
Pronator teres
Common flexor origin
Origin:
The humeral head: from
the medial epicondyle
of the humerus
The ulnar head:medial
margin of the coronoid
process of the ulna.
Insertion:
Lateral surface of the shaft
of the radius.
Nerve supply:
Median nerve
Action:
pronate of the forearm
flex the elbow joint
Flexor carpi radialis
Origin:
Medial epicondyle
of the humerus
Insertion:
Palmar surface of the
bases of the second and
third metacarpal bones.
Nerve supply:
Median nerve
Action:
Flex the elbow and wrist.
abduct the wrist
Palmaris longus
Origin:
Medial epicondyle of humerus
Insertion:
distal half of flexor
retinaculum and the
apex of the palmar aponeurosis.
The flexor retinaculum
(transverse carpal ligament,
or anterior annular
ligament) is a strong,
fibrous band that arches
over the carpus
The palmar aponeurosis
(palmar fascia)
invests the muscles of the
palm, and divided into 4
band.
palmar aponeurosis
transverse carpal ligament
Nerve supply:
Median nerve
Action:
Flex the wrist and make the palmar
aponeurosis tense.
Flexor carpi ulnaris
Two heads
humeral head:
medial epicondyle of the
humerus
ulnar head:
the medial margin
of the olecranon,
posterior border of ulna
Insertion:
pisiform, and is prolonged
from this to the hamate and
fifth metacarpal bones by
the pisohamate and
pisometacarpal ligaments.
Nerve supply:
Ulnar nerve
Action:
Flex and adduct the wrist.
Flexor carpi radialis
Flexor carpi ulnaris
• Action:Flexes and
abducts hand (at wrist)
• Innervation:Median
nerve
• Arterial supply:Radial
artery
•Action:Flexes and
adducts hand (at wrist)
•Innervation:Ulnar
nerve
•Arterial supply:Ulnar
artery
Flexor digitorum Superficialis
three heads—humeral, ulnar,
and radial
Humeroulnar head: medial
epicondyle of humerus, ulnar
collateral ligament;
Ulnar head: medial side of the
coronoid process
Radial head: superior half of
anterior border of radius
Insertion:Bodies of middle
phalanges of digits 2 - 5
Action:Flexes interphalangeal joints
of medial four digits; also flexes
metacarpophalangeal joints and wrist.
Innervation:Median nerve
Muscle
Origin
Insertion
pronator teres
medial epicondyle of humerus; coronoid lateral aspect of shaft of
process of ulna
radius
flexor carpi radialis
medial epicondyle of humerus
bases of 2nd and 3rd
metacarpal bones
palmaris longus
medial epicondyle of humerus
flexor retinaculum of palm
of hand
flexor carpi ulnaris
medial epicondyle of humerus;
olecranon process and posterior border
of ulna
pisiform, hamate
base of 5th metacarpal
flexor digitorum
superficialis
medial epicondyle of humerus; coronoid tendons split to attach to
process of ulna anterior border of radius lateral sides of middle
phalanges
Deep muscles of the front of the forearm
Flexor digitorum profundus
Origins:
The anterior and medial
surfaces of the shaft of the
ulna, adjoing part of
the anterior surface of the
interosseus membrane.
Medial surfaces of the
olecranon and coronoid
processe of ulna.
Insertion:
Base of the distal phalanx of digits 2 - 5
Action:
Flexes distal phalanges at distal
interphalangeal joints of medial
four digits; assists with flexion of wrist
Nerve supply:
Medial part:ulnar nerve;
Lateral part: anterior interosseous
branch of median nerve.
Flexor pollicis longus
Origin:
Anterior surface of radius and anterior
surface of interosseous membrane
Insertion:
Base of distal phalanx of thumb
Action:
Flexes distal phalanges of the thumb
Nerve supply:
Anterior interosseous nerve
from median nerve
Pronator quadratus
Origin:
Distal 1/4 of anterior surface of
ulna.
Insertion:
Distal 1/4 of anterior surface of
radius.
Action:
Pronates forearm;
deep fibers bind radius and
ulna together.
• Nerve supply:
Anterior interosseous
nerve from median
nerve
• Arterial supply:
Anterior interosseous
artery
Muscles of the Forearm
1. ★ Anterior group
First layer
1) brachioradialis
2) pronator teres
3) flexor carpi radialis
4) palmaris longus
5) flexor carpi ulnaris
Muscles of the Forearm
Second layer
6) flexor digitorum
superficialis
Third layer
7) flexor pollicis
longus
8) flexor digitorum
profundus
Fourth layer
9) pronator quadratus
Arteries of Forearm
1 brachial A.
2 radial A
3 radial recurrent
4 superficial radial
5 deep radial
6 ulnar A
7 anterior ulnar recurrent
7 posterior ulnar recurrent
8 common interosseous
9 posterior interosseous
10 anterior interosseous A
11 superficial branch
12 deep branch
nerves of forearm
Cubital fossa
 The cubital fossa is the region of the upper limb
in front of the elbow joint.
 It is a triangular area with the following
boundaries:
laterally — brachioradialis
medially — pronator teres
superiorly — an imaginary line from the medial
and lateral epicondyles of humerus.
Cubital fossa
Roof : formed by the deep fascia of the
forearm, reinforced by the bicipital
aponeurosis.
Floor: formed by the brachialis muscle
and supinator.
Contents:
from medial to lateral side--- the median
nerve, brachial artery, tendon of biceps,
and futher laterally the radial nerve.
Cubital fossa
This region from superficial to deep
venous layer
 1 cephalic vein
 2 basilic vein
 3 median cubital vein
Cubital fossa
aponeurotic layer
 1 bicipital aponeurosis
 2 biceps tendon
Cubital fossa
artery-nerve layer
 1 brachial artery
 2 median nerve
Cubital fossa
muscular floor
 1 supinator
 2 brachialis
 3 biceps tendon
Cubital fossa
bony floor
 1 humerus
 2 radius
 3 ulna
Posterior muscles of the forearm
Posterior muscles of the forearm
These muscles are divided for convenience of
description into two groups, superficial and deep.
The Superficial Group:
A. Brachioradialis.
B. Extensor carpi radialis longus..
C. Extensor carpi radialis brevis.
D. Extensor digitorum.
E. Extensor digiti minimi
F. Extensor carpi ulnaris.
G. Anconeus.
For the most part, the superficial groups arise from the lateral
epicondyle of the humerus. We called common extensor origin.
Superficial group:
1.extensor carpi
radialis longus
Superficial
group
1.extensor
2.extensor carpi
radialis brevis
digitorum
2.extensor
3.extensor carpi
ulnaris
digiti minimi
Brachioradialis
Origin:
Proximal 2/3 of lateral
supracondyle ridge of
humerus
Insertion:
lateral side of radius just
above the styloid process.
Brachioradialis
Action:
Flexes forearm
Innervation:
Radial nerve
Extensor carpi radialis longus
Origin:
common extensor origin,
lateral supracondylar ridge of the
humerus
lateral intermuscular septum.
Insertion:
dorsum of the base of the 2nd
metacarpal bone
 Action:
Extension and abduction of the wrist.
 Innervation:
Radial nerve
Extensor carpi radialis brevis
Origin:
Common extensor origin and radial
collateral ligament of elbow
Insertion:
dorsal aspect of base of 3rd metacarpal bones.
Action:
Extension and abduction of the wrist
Innervation:
Posterior interosseous nerve (branch of the
Radial nerve)
Extensor digitorum
Origin:
common extensor origin
Insertion:
Extensor expansions of medial 4
digits.
Innervation:
Posterior interosseous nerve
Action:
Extension of interphalangeal,
metacarpophalangeal and wrist
joint.
Extensor digiti minimi
Origin:
common extensor origin
Insertion:
Extensor expansion of 5th digit
Innervation:
Posterior interosseous nerve
Action:
Extension of interphalangeal,
metacarpophalangeal joint of the little
finger.
Extensor carpi ulnaris
Origin:
common extensor origin and posterior
border of the ulna
Insertion:
The base of the 5th metacarpal bone
Innervation:
Posterior interosseous nerve
Action:
Extension and adduction the wrist joint.
Anconeus
Origin:
posterior aspect of Lateral
epicondyle of the humerus
Insertion:
olecranon process of ulna
Innervation:
radial nerve
Action:
Weak Extension the elbow joint.
Muscle
Origin
Insertion
brachioradialis
lateral supracondylar ridge
styloid process of
radius
extensor carpi
radialis longus
lateral supracondylar ridge
base of 2nd metacarpal
extensor carpi
radialis brevis
lateral epicondyle
base of 3rd metacarpal
extensor carpi
ulnaris
lateral epicondyle
base of 5th metacarpal
extensor digitorum
lateral epicondyle
extensor expansion
over fingers
extensor digiti
minimi
extensor expansion over
fingers
extensor expansion of
little finger
posterior border of ulna
Deep muscles of the back of the forearm
From lateral to median :
 Supinator.
 Abductor pollicis longus.
 Extensor pollicis brevis.
 Extensor pollicis longus.
 Extensor indicis.
Supinator
Origin:
supinator crest of the ulna,
lateral epicondyle of humerus, radial
collateral ligament and annular
ligament.
Insertion:
Lateral surface of proximal 1/3 of
radius.
Nerve supply: posterior interosseus
nerve.
Action: supination of forearm.
Abductor pollicis longus
Origin: Posterior surfaces of ulna,
radius and interosseous membrane
Insertion:Base of 1st metacarpal
Nerve Supply:Posterior interosseus
Nerve.
Action: Abduction and extension of
the thumb.
Extensor pollicis brevis
Origin: Posterior surface of the
radius and interosseus membrane.
Insertion: Base of proximal
phalanx of thumb.
Nerve Supply:Posterior interosseus
Nerve.
Action: Extends the proximal phalanx
and metacarpal of the thumb.
Extensor pollicis longus
Origin: Posterior surface of middle 1/3
of ulna and interosseous embrane
Insertion:Base of distal phalanx of
thumb
Nerve Supply:Posterior interosseus
Nerve.
Action: Extension at all joints of the
thumb.
Extensor indicis
Origin: Posterior surface of ulna
and interosseous membrane
Insertion: Extensor expansion of
2nd digit.
Nerve Supply:Posterior
interosseus Nerve.
Action: Extends the index finger.
Deep group
1.supinator
2.abductor pollicis longus
3.extensor pollicis brevis
4.extensor pollicis longus
5.extensor indicis
Anterior compartment
Demarcated medially
from the posterior
compartment
by the olecranon
pocess and the
the ulna,
and is demarcated laterally by the radius
and intermuscular septum.
Contain:
• radial and ulnar
arteries and their
venous
concomitant
• median and ulnar
nerve
• anterior
interosseous
vessles and nerve.
The contents of the posterior compartment
posterior interosseous nerve and blood
vessels.
Anatomical snuff box
It is a triangular
depression on
the radial side of
the wrist.
Boundaries:
Laterally, tendon of abductor pollicis longus
and extensor pollicis brevis;
Medially, tendon of extersor pollicis longus.
• The cutaneous
branches of the
radial nerve cross
the tendons and
supply to the skin.
• The cephalic vein
begins in the roof
of the snuff- box,
The radia artery lies
on the floor.
Extensor retinaculum
Its lateral attachment is to the
anterolateral border of the
radius above the styloid process.
Its medial attachment is to the
pisiform and triquetral bores.
Nine tendons to form 6 mucous
Sheaths beneath the extensor
retinaculum.
(1) on the lateral side of the styloid process, for the
tendons of the Abductor pollicis longus and Extensor
pollicis brevis; (2) behind the styloid process, for the
tendons of the Extensores carpi radialis longus and
brevis; (3) about the middle of the dorsal surface of the
radius, for the tendon of the Extensor pollicis longus; (4)
to the medial side of the latter, for the tendons of the
Extensor digitorum communis and Extensor indicis
proprius; (5) opposite the interval between the radius and
ulna, for the Extensor digiti quinti proprius; (6) between
the head and styloid process of the ulna, for the tendon
of the Extensor carpi ulnaris.