1Kaan Yücel M.D., Ph.D 12.January.2012 Thursday

POSTERIOR ASPECT OF THE FOREARM&

ANATOMY OF THE HAND

IN 19 QUESTIONS

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THE ANATOMY OFPOSTERIOR ASPECT OF

THE FOREARMIN

7 QUESTIONS

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1. How are the muscles in the posterior compartment estabslihed?

In two layers: a superficial layera deep layer.

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2. Which muscles are in the superficial layer?

Common origin from the supraepicondylar ridge and lateral epicondyle of the humerus Except for the brachioradialis and anconeus, extend as tendons into the hand.

Brachioradialis

Extensor carpi radialis longus

Extensor carpi radialis brevis

Extensor carpi ulnaris

Extensor digitorum

Extensor digiti minimi

Base of 2nd metacarpal

Base of 3rd metacarpalBase of 5th metacarpal

Anconeus

Supraepicondylar ridge of humerus

Lateral surface of distal end of radius proximal to styloid process

flexion of forearmSupraepicondylar ridge of humerus

Base of 2nd metacarpal

extend and abduct hand at the wrist joint

Lateral epicondyle of humerus (common extensor origin)

Base of 3rd metacarpal

Extend and abduct hand at the wrist join

Lateral epicondyle of humerus; posterior border of ulna

Base of 5th metacarpal

Extends and adducts hand at wrist joint

Lateral epicondyle of humerus (common extensor origin)

Extensor expansions of medial four digits

extends medial four digits primarily at metacarpophalangeal joints, secondarily at interphalangeal joints

Extensor expansion of 5th digit

Lateral surface of olecranon and superior part of posterior surface of ulna

Lateral epicondyle of humerus

assists triceps in extending forearmstabilizes elbow joint;may abduct ulna during pronation

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3. Which muscles are in the deep layer?

Except for the supinator muscle, all these deep layer muscles originate from the posterior surfaces of the radius, ulna, and interosseous membrane and pass into the thumb and fingers.

Supinator

Abductor pollicis longus

Extensor pollicis brevis

Extensor pollicis longus

Extensor indicis

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4. What movements do these muscles do?

EXTENSION OF THE HAND & FINGERSABDUCTION OF THE FINGERSSUPINATION

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5. How are the muscles of the posterior compartment of the forearm innervated?Supinator Extensor carpi radialis brevisDeep branch of radial nerve

RestPosterior interosseous nervecontinuation of deep branch of radial nerve

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6. ....arteries in the posterior compartment of the forearm?Radial artery

Posterior interosseous artery

origin: common interosseous branch of

the ulnar arteryrecurrent interosseous arteryEnd by joining to dorsal carpal arch of the wrist

Anterior interosseous artery

origin: common interosseous branch of the ulnar artery

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7. ...radial nerve in the posterior compartment of forearm?Deep branch becomes posterior interosseous nerve after emerging from between 2 heads of supinator

Posterior interosseous nerve passes deep to extensor pollicis longus to reach the wrist.

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THE ANATOMY

IN

12 QUESTIONS

OF THE HAND

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1. ...bones of the hand ?

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2. What are flexor retinaculum & carpal tunnel?The carpal tunnel formed anteriorly at wrist by a deep arch formed bycarpal bones & flexor retinaculum (transverse carpal ligament)

Flexor digitorum/superficialis Flexor pollicis longus Median nerve

Pass through the carpal tunnel

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3. What is extensor retinaculum (dorsal carpal ligament)?

abductor pollicis longus & extensor pollicis brevisextensor carpi radialis longus & extensor carpi radialis brevisextensor pollicis longus

through three compartments on the lateral surface of the wrist.

The extensor tendons pass into the hand in six compartments defined by an extensor retinaculum:

extensor digitorum & extensor indicis posterior surface of the wrist

extensor carpi ulnaris & extensor digiti minimi medial side of the wrist

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4. What is palmar aponeurosis?A triangular condensation of deep fascia that covers the palm and is anchored to the skin in distal regions.

Continuous with the palmaris longus tendon, when present; otherwise, anchored to the flexor retinaculum.

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5. What are extensor hoods for?Tendons of the extensor digitorum extensor pollicis longus muscles expand over the proximal phalanges to form "extensor hoods" or "dorsal digital expansions".

Tendons of the extensor digiti minimi, extensor indicis, extensor pollicis brevis join these hoods.

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6. Which are the intrinsic muscles of the hand?Palmaris brevis

Interossei

Thenar muscles

Hypothenar muscles

Adductor pollicis

Lumbrical

Abductor pollicis brevis

Flexor pollicis brevis

Opponenspollicis

Abductordigiti minimi

Flexordigiti minimi

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7. How are the intrinsic muscles innervated?All of the intrinsic muscles of the hand by deep branch of the ulnar nerve

Exceptthree thenar & two lateral lumbrical musclesby median nerve

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8. ....arteries of the hand?

Superficial palmar archDeep palmar arch

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9. ....veins of the hand?Cephalic vein originates from lateral side of dorsal venous network. Basilic vein originates from medial side of dorsal venous network.

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10. ...sensory innervation of the hand?

Ulnar nerve medial side of the palm, medial half of the dorsum of the hand, the 5th finger, and the medial half of the 4th finger, anterior surfaces of the medial one and a half digits,Median nerve thumb,index,middle fingers,lateral side of the ring [distal parts on the dorsum of the hand]Radial nerve dorsolateral side

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11. ...carpal tunnel?

Homework:

1. Which structures pass through the carpal tunnel and their anatomical relationships with each other in the tunnel?2. The incidence of carpal tunnel syndrome in the world and/or in Turkey?3. The risk factors, higher in whom? Any gender disperancies in its incidence?Please send answers to yeditepeanatomy@yahoo.com

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12. ....anatomical snuffbox?