ANTERIOR ASPECT OF THE FOREARM&

CUBITAL FOSSA

Kaan Yücel M.D., Ph.D. 26.December.2012 Wednesday

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THE ANATOMYOF FOREARM

IN

5 QUESTIONS

INTRODUCTION

1. Wheres is the forearm?

between the elbow & wrist joints

Elbow joint

Wrist jointFOREARM

2. Which structures pass between the arm & forearm?

Most major structures (nerves,veins,arteries)via cubital fossa, anterior to elbow joint Exception ulnar nerveposterior to the medial epicondyle of humerus

3. How is forearm divided?Anterior compartmentPosterior compartmentLateral intermuscular septumfrom the anterior border of the radius to deep fascia surrounding the limb

Interosseous membranelinks borders of the radius and ulna

Attachment of deep fascia along the posterior border of the ulna

4. Movements of the forearm muscles?

Muscles in the anterior compartment Flex the wrist & digits Pronate the handMuscles in the posterior compartment Extend the wrist & digitsSupinate the hand

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Muscles of the anterior compartment Mainly by median nerveThe one and a half exceptions by ulnar nerve Muscles of the posterior compartment All by radial nerve (directly or by its deep branch)

Watch out, Median nerve @median plane of the forearmUlnar nerve @ medial side

5. Innervation of the forearm muscles?

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THE ANATOMY

OF ANTERIOR ASPECT OF FOREARM

IN

12 QUESTIONS

1. Layers of anterior compartment forearm muscles?Superficial Intermediate Deep

4 muscles 3 muscles

2. Muscles of the superficial layer?

1. flexor carpi radialis2. flexor carpi ulnaris3. palmaris longus4. pronator teres

two headsUlnar headHumeral head

Medial epicondyle

2. Muscles of the superficial layer?

1. flexor carpi radialis

Medial epicondyle of humerus Base of metacarpals II & III

2. flexor carpi ulnarisHumeral head: Medial epicondyle of humerusUlnar head: Olecranon & Posterior border of ulna•Pisiform & hamate •5th metacarpal3. palmaris longusMedial epicondyle of humerus Flexor retinaculum & palmar aponeurosis

4. pronator teresHumeral head: Medial epicondyle & adjacent supraepicondylar ridgeUlnar head: Coronoid processLateral surface of radius

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3. ..the muscles of the intermediate and deep layers?

flexor digitorum superficialis

3. Muscles of the intermediate layer?

Humeroulnar head• Medial epicondyle of humerus • Adjacent margin of coronoid processRadial headSuperior half of anterior border

Shafts of middle phalanges of

medial four digits

3. ..the muscles of the intermediate and deep layers?flexor digitorum profundus

flexor pollicis longus

pronator quadratus

4. Muscles of the deep layer?

•Proximal ¾ of medial & anterior surfaces of ulna •Interosseous membrane

Bases of distal phalanges of 4th & 5th digitsBases of distal phalanges of 2nd & 3rd digits

• Anterior surface of radius• Adjacent interosseous

membrane

Base of distal phalanx of thumb

Distal ¼ of anterior surface of ulna

Distal ¼ of anterior surface of radius

5. Fxns of the anterior compartment muscles

Flexion of forearm @ the elbow jointPronator teresFlexion of hand @ the wrist jointFlexor carpi radialis et ulnaris- Palmaris longus

Abduction (radial deviation) of hand @ the wrist jointFlexor carpi radialis

Adduction (ulnar deviation) of hand @ the wrist jointFlexor carpi ulnaris

Pronation of forearmPronator teres – Pronator quadratus

5. Fxns of the anterior compartment muscles

Flexor digitorum superficialis

Flexor digitorum profundus Flexes distal phalanges 4 & 5 at distal interphalangeal joints

Flexes distal phalanges 2 and 3 at distal interphalangeal joints

Flexes proximal interphalangeal joints of the index, middle, ring, & little fingers Flexes metacarpophalangeal joints of the same fingers and the wrist joint

Flexor pollicis longusFlexes phalanges of thumb

6. Innervation of the anterior compartment muscles

All the muscles by median nerve

Except 1.5 muscles by ulnar nerveFlexor carpi ulnaris full

Flexor digitorum profundus medial half part associated w/ring & little fingers

7. Arteries in the anterior compartment of the forearm

Brachial artery

8. Veins in the anterior compartment of the forearm

deep venous palmar arch in

the hand

9. Median nerve

principal nerveno branches in the arm other than small twigs to the brachial artery. Its major branch in the forearm anterior interosseous nerve

Leaves cubital fossa by passing between 2 heads of pronator teres &humero-ulnar &radial heads of flexor digitorum superficialis

10. Ulnar nerve

Enters the anterior compartment by passing posteriorlyaround medial epicondyle of humerus &between humeral & ulnar heads of flexor carpi ulnaris muscle

Two small cutaneous branches palmar branch & dorsal branch

11. Radial nerve

motor and sensory functions in both arm & forearm but only sensory functions in the hand

Superficial (sensory)deep to brachioradialis

Deep (motor)between two heads of supinator

12. Lateral & medial cutaneous nerves of forearm

Lateral cutaneous nerve of forearmContinuation of musculocutaneous nerve

Medial cutaneous nerve of forearmBranch of medial cord of brachial plexus

Posterior cutaneous nerve of forearmBranch of radial nerve

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THE ANATOMY

IN

4 QUESTIONS

OF CUBITAL FOSSA

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An important area of transition between the arm and the forearm. seen superficially as a depression on the anterior aspect of the elbow.

Deeply, it is a space filled with a variable amount of fat anterior to the most distal part of the humerus and the elbow joint.

1. What is the cubital fossa?

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Superiorly imaginary line connecting medial &lateral epicondyles.Medially pronator teres.Laterally brachioradialis.

2. What are the boundaries of the cubital fossa?

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1) Terminal part of the brachial artery,radial and ulnar arteries 2) Biceps brachii tendon

3) Median nerve

4) Radial nerve

5) (Deep) accompanying veins of the arteries

3. What are the contents of the cubital fossa?

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Superficially, in the subcutaneous tissue overlying the fossa median cubital vein, medial and lateral antebrachial cutaneous nervesbasilic and cephalic veins.

3. What are the contents of the cubital fossa?

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median nerve lies immediately medial to the brachial artery and leaves the fossa by passing between the ulnar and humeral heads of the pronator teres

radial nerve lies under brachioradialis (lateral margin of the fossa)

gives off deep branch of the radial nerve and continues as superficial radial nerve.

4. Which nerves are in the cubital fossa?