FOREARM
1
The Fore arm is divided into :
۞ Anterior / Flexor compartment
۞ Posterior / Extensor compartment
2
Contents of anterior compartment:
It is occupied by muscles, blood vessels and nerves
Muscles:
These are arranged in superficial and deep groups
Blood Vessels:
The radial and ulnar arteries form the main blood vessels
of the forearm
Nerves:
The median and ulnar nerves supply the muscles of the
anterior compartment
Flexor muscles of forearm:
Muscles are arranged into Superficial and Deep groups
Superficial flexor muscles:
ɸ Pronator teres
ɸ Flexor carpi radialis
ɸ Palmaris longus
ɸ Flexor carpi ulnaris
ɸ Flexor digitorum superficialis
4
1.Pronator teres:
Origin:
L
M
It arises by two heads:
‡ Humeral head:
Medial supracondylar
ridge of humerus and from
medial epicondyle of
humerus
‡ Ulnar head:
FLEXOR DIGITORUM
SUPERFICIALIS
PRONATOR TERES
Medial border of the
coronoid process of ulna
5
Insertion:
Middle of the lateral
surface of shaft of radius
Nerve supply:
Median nerve
Actions:
Ω Pronation of forearm
Ω Weak flexor of the elbow joint
6
2.Flexor carpi radialis:
Origin:
Medial
epicondyle as
common
origin of the
superficial
flexor muscles
Flexor carpi
radialis
7
Insertion:
Palmar surfaces of the
bases of the second and
third metacarpal bones
Nerve supply:
Median nerve
Actions:
Ω Flexor of the wrist
Ω Combined action of flexor
carpi radialis longus and brevis
produce abduction of the wrist
8
3.Palmaris longus:
Origin:
Medial epicondyle as
common origin of the
superficial flexor
muscles
Insertion:
It continuous as a
central part of
palmar aponeurosis
Palmaris
longus
9
Nerve supply:
Median nerve
Actions:
Ω Weak flexor of the wrist
10
4.Flexor carpi ulnaris:
Origin:
It arises by two heads:
‡ Humeral head:
Medial epicondyle along with
superficial group of flexor
muscles
‡ Ulnar head:
Medial margin of olecranon
process and upper two third
of the posterior border of ulna
11
Insertion:
Pisiform bone, pisometacarpal
ligament, pisohamate ligament,
hook of hamate
Piso
metacarpal
ligament
Pisohamate
ligament
12
Nerve supply:
Ulnar nerve
Actions:
Ω Flexor of the wrist
Ω Combined action of flexor
carpi and extensor carpi produces
adduction of wrist joint
13
5.Flexor digitorum superficialis:
Origin:
It arises by two heads:
‡ Humeral ulnar head:
Medial epicondyle and from
medial margin of the
coronoid process of ulna
FLEXOR DIGITORUM
SUPERFICIALIS
PRONATOR TERES
‡ radial head:
Whole length of anterior
oblique line of the radius
14
Insertion:
Sides of the shaft of middle phalanx of
the medial four digits
15
Nerve supply:
Median nerve
Actions:
Flexor of the middle phalanx at
the proximal interphalangeal joint
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Deep flexors muscles:
 Flexor pollicis longus
 Flexor digitorum profundus
 Pronator quadratus
18
1.Flexor pollicis longus:
Origin:
 Anterior
surface of shaft
of radius
 Adjacent
interosseus
membrane
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Insertion:
Palmar surface of the base
of distal phalanx of the
thumb
Nerve supply:
Anterior interosseous
branch of median nerve
Actions:
Ω Flexor of the thumb
20
2.Flexor digitorum profundus:
Origin:
 Anterior and medial
surface shaft of the
upper three fourths of
the ulna, including
coronoid and olecranon
processes
Adjacent interosseus
membrane
Upper three fourth of
the posterior border of
ulna
21
Insertion:
Palmar surface of the
base of terminal phalanx of
the medial four fingers
Nerve supply:
Medial part: Ulnar nerve
Lateral part: Anterior
interosseus
Actions:
Ω Flexes the terminal phalanges
22
3.Pronator quadratus:
Origin:
 Anterior surface
of the lower one
fourth of the ulna
Pronator
quadratus
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Insertion:
 Superficial fibers inserts
to the anterior surface of
lower one fourth of radius
 Deep fibers are inserted
to triangular area just
above the ulnar notch
Ulnar notch
25
Nerve supply:
Anterior interosseous nerve
Actions:
Ω Superficial fibers are principal
pronators of forearm
Ω Deep fibers prevents the
seperation of the lower part of
radius and ulna
26
Functional classification of flexor muscles of
forearm:
1. Flexors of the wrist:
Flexor carpi radialis and flexor carpi ulnaris
2. Flexors of the middle phalanges:
Flexor digitorum superficialis
3. Flexors of the distal phalanges:
Flexor digitorum profundus and flexor pollicis
longus
4. Pronators of the forearm:
Pronator teres and pronator quadratus
Posterior compartment of forearm:
ɸ Superficial group
ɸ Deep group
Superficial group:
They are seven in number and are divided into:
 Lateral group
Posterior group
Brachioradialis
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor digitorum
Extensor digiti minimi
Extensor carpi ulnaris
Anconeus
1.Brachioradialis:
Origin:
Upper two – third of
lateral supracondylar
ridge and from the lateral
intermuscular septum
Insertion:
Base of the
styloid process
of the radius
Nerve supply:
Radial nerve
Action:
Flexor of elbow joint
Styloid process
Extensor carpi radialis longus:
Origin:
Lower one – third of
lateral supracondylar
ridge and from the lateral
intermuscular septum
Extensor carpi
radialis longus
Extensor carpi
radialis brevis
Insertion:
Dorsal surface of the base
of second metacarpal
bone
Nerve supply:
Radial nerve
Insertion of
Extensor carpi
radialis longus
Extensor carpi radialis brevis:
Origin:
Common extensor origin
from the front of the lateral
epicondyle
Extensor carpi
radialis brevis
Insertion:
Dorsal surface of second
and third metacarpal
bones
Nerve supply:
Posterior
interosseous nerve
Insertion of
Extensor carpi
radialis brevis
Action:
Actions of extensor carpi radialis longus and brevis
Both radial extensors along with extensor carpi
ulnaris produce extension of the wrist
Both radial extensors along with flexor carpi radialis
act as abductors of the wrist
Extensor digitorum:
Origin:
Front of lateral
epicondyle as common
extensor origin
Extensor
digitorum
Insertion:
Each extensor tendon covers the dorsal surface of the metacarpal head
and proximal phalanx and forms a triangular dorsal digital expansion
Nerve supply:
Posterior interosseous nerve
Action:
Prime movers for extension at metacarpo-phalangeal and
interphalangeal joints
Extensor digiti minimi:
Origin:
From common extensor
tendon
Insertion:
Extensor digiti
minimi
Dorsal digital expansion
Nerve supply:
Posterior interosseous nerve
Action:
It extends the little finger and assists the action of
extensor digitorum
Extensor carpi ulnaris:
Origin:
 From lateral epicondyle as
common extensor tendon
From subcutaneous posterior
border of ulna
Extensor
carpi ulnaris
Insertion:
Tubercle on the medial side
of the base of fifth metacarpal
bone
Insertion of Extensor
carpi ulnaris
Nerve supply:
Posterior interosseous nerve
Action:
♥ Simultaneous contraction with extensor carpi
radialis longus and brevis produces extension of
wrist
♥ Combined actions of extensor and flexor carpi
ulnaris produce adduction of the wrist
Anconeus:
Origin:
Posterior surface of the lateral
epicondyle
Insertion:
Lateral surface of the
olecranon process and
upper one-fourth of the
posterior surface of the
shaft of ulna
Nerve supply:
Radial nerve
Action:
Extensor of elbow joint
Posterior view of
Ulna
Anconeus
Deep group of extensor muscles:
1. Supinator
2. Abductor pollicis longus
3. Extensor pollicis longus
4. Extensor pollicis brevis
5. Extensor indices
Supinator:
Origin:
Deep head
 Superficial fibers arises from
lateral epicondyle
 Deep fibers arises from
supinator crest of ulna
Lateral view of
ulna
Superficial head
Insertion:
Superficial and deep fibers are
attached to the upper one-third
of the anterior part of the lateral
surface of radius
Nerve supply:
Posterior interosseous nerve
Action:
Supinator in extended elbow
Abductor pollicis longus:
Origin:
Posterior surface of radius and
ulna and intervening
interosseous membrane
Abductor
pollicis longus
Posterior view
Nerve supply:
Posterior interosseous nerve
Action:
Abductor and extensor of the thumb
Extensor pollicis brevis:
Origin:
Posterior surface of radius and
adjacent interosseous membrane
Origin of Extensor policis
brevis
Insertion:
Dorsal surface of the proximal
phalanx of the thumb
Nerve supply:
Posterior interosseous nerve
Action:
Extends the proximal phalanx of
the thumb
Insertion of
Extensor policis
brevis
Extensor pollicis longus:
Origin:
Posterior surface of ulna and
adjacent interosseous membrane
Origin of
Extensor policis longus
Insertion:
Base of distal phalanx of the
thumb
Nerve supply:
Posterior interosseous nerve
Action:
Extends the distal phalanx of the
thumb
Insertion of
Extensor policis longus
Extensor indices:
Origin:
Posterior surface of ulna and
adjacent interosseous membrane
Origin of
Extensor indices
Insertion:
Dorsal digital expansion
Nerve supply:
Posterior interosseous nerve
Action:
Extends the index finger
END
THANK YOU
Anatomical snuff box:
It is a triangular depression on the
radial side of the wrist
Boundaries:
Laterally:
Tendons of abductor
pollicis longus and
extensor pollicis brevis
Medially:
Tendon of extensor
pollicis longus
Roof:
Skin and fasciae
Content: Radial artery
Floor:
Styloid process of radius,
scaphoid, trapezium and
base of first metacarpal
bone
Derived from deep fascia
Attachments:
Laterally:
Anterior border of
radius
Medially:
Pisiform and
Triquetral bone
Ulna