slideshow: forearm extensors

Extensors of the forearm

The forearm is the region of the upper limb between the elbow joint proximally and wrist joint distally

Forearm Extensors


Elbow Joint

Forearm Extensors


Elbow JointWrist Joint

Forearm Extensors


Elbow JointWrist Joint

Forearm

Forearm Extensors

There are two long bones in the forearm

Forearm Extensors


Radius lies Laterally

Forearm Extensors


Radius

Ulna lies Medially

Forearm Extensors

The forearm is divided into 2 compartments by the Interosseous membrane and the Deep Fascia

Interosseous membrane

Forearm Extensors


Anterior Compartment or Flexor Compartment contain;• Superficial Flexors• Deep Flexors

Forearm Extensors


Anterior Compartment or Flexor Compartment contain;• Superficial Flexors• Deep Flexors

Posterior Compartment or Extensor Compartment contain;• Extensors• Mobile Wad of Three

Forearm Extensors

There are 2 groups of extensors;

• Superficial Extensor Compartment

• Deep Extensor compartment

Forearm Extensors

There are

• 7 muscles in the superficial group

• 5 muscles in the deep group

Forearm Extensors

Superficial Extensors

Forearm Extensors


1.Brachioradialis

Forearm Extensors


1.Brachioradialis

2.Extensor Carpi Radialis Longus

Forearm Extensors


1.Brachioradialis


3.Extensor Carpi Radialis Brevis

Forearm Extensors


1.Brachioradialis



Collectively these muscles are also called

‘The Mobile Wad of Three’

Forearm Extensors


1.Brachioradialis



4.Extensor Digitorum

Forearm Extensors


1.Brachioradialis




5.Extensor Digiti Minimi

Forearm Extensors


1.Brachioradialis





1.Extensor Carpi Ulnaris

Forearm Extensors


1.Brachioradialis





1.Extensor Carpi Ulnaris

1.Anconeus

Forearm Extensors

Deep Extensors

1.Abductor Pollicis Longus

Forearm Extensors

Deep Extensors


2.Extensor Pollicis Longus

Forearm Extensors

Deep Extensors



3.Extensor Pollicis Brevis

Forearm Extensors

Deep Extensors




4.Extensor Indicis

Forearm Extensors

Deep Extensors




4.Extensor Indicis

5.Supinator

Forearm Extensors

Tendons at the wrist

1

2345

6

RadiusUlna

There are 6 compartments on the dorsal aspect of the wrist

Forearm Extensors

First Compartment

1. Abductor Pollicis Longus

2. Extensor Pollicis Brevis

1RadiusUlna

RadiusUlna

Forearm Extensors

Second Compartment

1. Extensor Carpi Radialis Longus

2. Extensor Carpi Radialis Brevis

RadiusUlna

2

Forearm Extensors

Third Compartment

Extensor Pollicis Longus

RadiusUlna

3

Forearm Extensors

Fourth Compartment

1. Extensor Indicis

2. Extensor Digitorum

RadiusUlna

4

Forearm Extensors

Fifth Compartment

Extensor Digiti Minimi

RadiusUlna

5

Forearm Extensors

Sixth Compartment

Extensor Carpi Ulnaris

RadiusUlna

6

Forearm Extensors

1. Abductor Pollicis Longus1. Extensor Pollicis Brevis

2. Extensor Carpi Radialis Longus2. Extensor Carpi Radialis Brevis

3. Extensor Pollicis Longus

4. Extensor Indicis4. Extensor Digitorum

5. Extensor Digiti Minimi

6. Extensor Carpi Ulnaris

Forearm Extensors

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6RadiusUln

a

Nerves

Brachioradialis Extensor Carpi Radialis Longus

Anconeus are supplied by the

Radial Nerve

Forearm Extensors

All the other extensor muscles are supplied by the

Posterior Interosseous Nerve

deep branch of the Radial Nerve

Forearm Extensors

Summary of Muscles

Posterior Forearm

BrachioradialisOrigin Proximal 2/3 of lateral

supracondylar ridge of humerus

Insertion Lateral surface of distal end of radius (base of styloid process)

Action Flexes forearmNerve Supply Radial nerve (C5, C6 and C7)

Blood Supply Radial recurrent artery

Extensor Carpi Radialis Longus

Origin Lateral supracondylar ridge of humerus

Insertion Base of 2nd metacarpal

Action Extends and abducts hand at wrist joint

Nerve Supply Radial nerve (C6 and C7)

Blood Supply Radial artery

Posterior Forearm

Posterior Forearm

Extensor Carpi Radialis Brevis

Origin Lateral supracondylar ridge of humerus

Insertion Base of 3rd metacarpal

Action Extends and abducts hand at wrist joint

Nerve Supply Deep branch of radial nerve (C7 and C8)

Blood Supply Radial artery

Posterior Forearm

Extensor DigitorumOrigin Common extensor origin on

lateral epicondyle of humerusInsertion Extensor expansions of medial

four digits (not thumb)Action Extends medial four digits at

metacarpophalangeal joints; Extends hand at wrist joint

Nerve Supply Posterior interosseous nerve (deep branch of radial nerve C7, C8)

Blood Supply Interosseous recurrent and posterior interosseous arteries

Posterior Forearm

Extensor Digiti MinimiOrigin Common extensor origin on

lateral epicondyle of humerusInsertion Extensor expansion of little

fingerAction Extends 5th digit at

metacarpophalangeal and interphalangeal joints


Blood Supply Interosseous recurrent artery

Posterior Forearm

Extensor Carpi UlnarisOrigin Common extensor origin on

lateral epicondyle of humerusInsertion Base of 5th metacarpal

Action Extends and adducts hand at wrist joint

Nerve Supply Posterior interosseous nerve, (deep branch of radial nerve C7, C8)

Blood Supply Ulnar artery

Posterior Forearm

AnconeusOrigin Lateral epicondyle of humerus

Insertion Posterior olecranon process of the ulna

Action Extends the elbow joint

Nerve Supply Radial nerve (C7, C8)

Blood Supply Posterior interosseous artery

Posterior Forearm

Abductor Pollicis LongusOrigin Posterior surfaces of ulna,

radius and interosseous membrane

Insertion Base of 1st metacarpal

Action Abducts thumb, extends thumb at carpometacarpal joint



Posterior Forearm

Extensor Pollicis LongusOrigin Posterior surface of middle 1/3

of ulna and interosseous membrane

Insertion Base of distal phalanx of thumb

Action Extends distal phalanx of thumb at carpometacarpal and interphalangeal joints



Posterior Forearm

Extensor Pollicis BrevisOrigin Posterior surfaces of radius

and interosseous membraneInsertion Base of proximal phalanx of

thumbAction Extends proximal phalanx of

thumb at carpometacarpal joint



Posterior Forearm

Extensor IndicisOrigin Posterior surface of ulna and

interosseous membraneInsertion Extensor expansion of index

fingerAction Extends 2nd digit and helps to

extend handNerve Supply Posterior interosseous nerve

continuation deep branch radial nerve (C7, C8)


Posterior Forearm

SupinatorOrigin Lateral epicondyle of humerus,

radial collateral and annular ligaments, supinator fossa and crest of ulna

Insertion Lateral, posterior and anterior surfaces of proximal 1/3 of radius

Action Supinates forearm

Nerve Supply Deep branch of radial nerve (C5 and C6)

Blood Supply Recurrent interosseous artery

slideshow: forearm extensors

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