Muscles of anterior compartment of forearm

D.Rania GabrD.Sama

Objectives• Name and identify the muscles in the anterior

(flexor/pronator) and posterior (extensor/supinator) compartments of the forearm, noting their relations.

• Name and identify the neurovascular structures in the anterior and posterior compartments of the forearm, noting their relations.

• Discuss the functions of the muscles in the anterior and posterior compartment of the forearm.

Functional organization

of Anterior and

posterior Compartments of

forearm.

Names of the Muscles of forearm

• Many of them• Long names: good guide to location and function• Location: ie. superficial / deep

radial / ulnar(which side is the thumb on??)

• Function: ie. flexor / extensor adductor / abductor

• Does it act on the thumb (pollux) or the fingers (digits)?

Functional Organization

• Anterior compartment – flexor / pronator• Posterior Compartment – extensor /

supinator• Flex the wrist ………[flexor]• Extend the wrist ……..[extensor]• Pronate the forearm ……..[pronator]• Acting on wrist (carpus) only ……[carpi]• Acting on fingers ……..[digiti / digitorum]• Acting on thumb (pollux) ……[pollicus]

Flexion / Extension at the wrist joint.

Flexion

Extension

Adduction / abduction at the wrist joint.

Ad-duction Ab-duction

Movements of fingers.

MCP (condyloid joints): flexion / extensionabduction / adduction

IP (hinge joints): flexion / extension

XX

Movements of the thumb – a specialized digit, occur atright angles to the fingers. Mainly at the CMC (saddle) joint.

MCP – condyloid; IP – hinge (like fingers).

Muscles of

Forearm

Anterior compartment of forearmFlexor / pronator Compartment

Divided into:• Superficial group(5)From lateral to medial:- Pronator teres - Flexor carpi radialis- Palmaris longus - Flexor digitorum superficialis, - Flexor carpi ulnaris

-And :- ……

• DEEP GROUP (3)1. Flexor pollicis

longus (FPL)2. Flexor digitorum

profundus (FDP)3. Pronator

quadratus (PQ)

Anterior compartment of forearmFlexor / pronator Compartment

SUPERFICIAL GROUP• ORIGINS:

All 5 muscles have a HUMERAL HEAD (arising from the front of medial epicondyle of humerus: Common flexor origin(CFO). • IN ADDITION:3 out of 5 muscles have an ULNAR HEAD:1. PT & FDS: arise from medial border of coronoid process

of ulna2. FCU: arises from medial surface of olecranon process &

posterior border of shaft of ulnaOne muscle has a RADIAL HEAD:• FDS: arises from oblique line & anterior border of shaft of

radius

Pronator Teres

middle of lateral surface of shaft of radius

CFO

Nerve supply: median nerve.Action: pronation of forearm

Flexor Carpi Radialis

CFO

Base of 2nd & 3rd metacarpals

Nerve supply: median nerve.Action: flexion and abduction of wrist

Palmaris Longus

CFO

Nerve supply: median nerve.Action: flexion of wrist

Palmar aponeurosis

• Insertion: • Action:• produces flexion of proximal

interphalangeal & metacarpophalangeal joints of medial 4 fingers

Flexor Digitorum Superficialis

CFOUpper 2/3 of anterior border of radius

by 4 tendons into the middle phalanges of medial 4 fingers

Nerve supply: median nerve.Action: flexion of wrist and proximal joints of fingers

Flexor Digitorum Superficialis

CFOUpper 2/3 of anterior border of radius

by 4 tendons into the middle phalanges of medial 4 fingers

Flexor Carpi Ulnaris

CFOPosterior border of ulna

Pisiform, hamate, & base of 5th metacarpal

Nerve supply: ulnar nerve.Action: flexion and adduction of wrist

FCRPalmaris Longus

Flexor Carpi Ulnaris

Flexor Pollicis Longus

DEEP GROUP

Upper 2/3 of anterior surface of radius and interosseous membrane

Base of distal phalanx of thumb

Nerve supply: median nerve.Action: flexion of wrist and thumb

Flexor Digitorum Profundus

Nerve supply: median nerve and ulnar .Action: flexion of wrist and medial 4 fingers

Proximal ¾ of anterior & medial ulna

Base of distal phalanxes of the 4 fingers

PRONATOR QUADRATUS

Lower ¼ of anterior surface of shaft of ulna

Lower ¼ of anterior surface of shaft of radius

Nerve supply: median nerve.Action: pronation of forearm

Flexor Digitorum Profundus

Nerve Supply

All forearm muscles are innervated by the MEDIAN nerve EXCEPT: 1 ½ musclesflexor carpi ulnaris ulnar side of the flexor digitorum profundus

Plus: All thenar ms except adductor pollicis

Muscles of the Forearm

Anterior Fore Arm

PassFailPassFail

Ant Fore armWrist FlexorsFCU+FCRFDSFDPPL

Wrist AddFCU

Wrist AbdFCR

Nerve Supply

Post. ForearmSuperficial disection

Nerve Supply

Radial Nerve

Anatomical snuff box

Rotators of the Radius

Supinator

Pronators

Biceps Brachii

Radio-ulnar joint

Movement: Pronation and Supination.

Types: 1. Proximal radio-ulnar joint:Head of radiusarticulates with radial notch of ulna (synovial pivot).

2. Distal radio-ulnar joint: Radius pivots around the fixed distal end of ulna (synovial pivot).

3. Middle radio-ulnar joint: interosseus membrane (fibrous).

Course of radial and ulnar arteries in forearm

Axillary vein: continuation of basilic vein

Radial & Ulnar Arteries

mediallateral

Ulnar artery

Common interosseousAnteriorPosterior

Dorsal and palmer carpal branches

Radial artery

superficial (deep)palmar arches

Deep (superficial) palmar arches

Dorsal and palmer carpal branches

RELATION OF ARTERIES, NERVES AND TENDONS AT THE WRIST NANAN

Superficial Radial Nerve Radial Artery Median Nerve Ulnar Artery Ulnar Nerve

1. Brachioradialis

2. Superficial Radial n.

3. Radial Artery

4. Flexor Carpi Radialis

5. Median Nerve

6. Flexor Digitorum Superficialis

7. Ulnar Artery

8. Ulnar Nerve

9. Flexor Carpi Ulnaris

MOVING LATERAL TO MEDIAL 1-9

Thumb

Neurovasculature (deep).

Lateral: - radial artery - radial nerve

Midline: - median nerve- anterior interosseus a. - anterior interosseus n.(deep branch of median)

Medial: - ulnar artery(gives off common interosseus artery divides into anterior and posterior branches)

- ulner nerve

Neurovasculature.

Radial nerve and its branches supplyall muscles in posterior compartment, including brachioradialis (!).

- superficial radial nerve- deep radial nerve - posterior interosseus nerve.

Posterior interosseus artery runs between superficial and deep muscles

• Medial ½ of FDP• FCU• All hand muscles

except muscle groups(lateral 2 lumbricals and thenar muscles )

Ulnar Nerve