ANTERIOR ASPECT OF THE FOREARM & CUBITAL FOSSA 26.December.2012 Wednesday Kaan Yücel M.D., Ph.D.

THE ANATOMY OF FOREARM IN 5 QUESTIONS INTRODUCTION

between the elbow & wrist joints 1. Wheres is the forearm? between the elbow & wrist joints Elbow joint FOREARM Wrist joint

2. Which structures pass between the arm & forearm? Most major structures (nerves,veins,arteries) via cubital fossa, anterior to elbow joint Exception ulnar nerve posterior to the medial epicondyle of humerus

Posterior compartment 3. How is forearm divided? Anterior compartment Posterior compartment Lateral intermuscular septum from the anterior border of the radius to deep fascia surrounding the limb Interosseous membrane links 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 hand Muscles in the posterior compartment Extend the wrist & digits Supinate the hand

5. Innervation of the forearm muscles? Muscles of the anterior compartment Mainly by median nerve The 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 forearm Ulnar nerve @ medial side

OF ANTERIOR ASPECT OF FOREARM 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? flexor carpi radialis flexor carpi ulnaris palmaris longus pronator teres two heads Ulnar head Humeral head Medial epicondyle

2. Muscles of the superficial layer? flexor carpi radialis Medial epicondyle of humerus Base of metacarpals II & III 2. flexor carpi ulnaris Humeral head: Medial epicondyle of humerus Ulnar head: Olecranon & Posterior border of ulna •Pisiform & hamate •5th metacarpal 3. palmaris longus Medial epicondyle of humerus Flexor retinaculum & palmar aponeurosis 4. pronator teres Humeral head: Medial epicondyle & adjacent supraepicondylar ridge Ulnar head: Coronoid process Lateral surface of radius

Shafts of middle phalanges of 3. ..the muscles of the intermediate and deep layers? 3. Muscles of the intermediate layer? flexor digitorum superficialis Humeroulnar head • Medial epicondyle of humerus • Adjacent margin of coronoid process Radial head Superior half of anterior border Shafts of middle phalanges of medial four digits

4. Muscles of the deep layer? 3. ..the muscles of the intermediate and deep layers? flexor digitorum profundus flexor pollicis longus pronator quadratus Proximal ¾ of medial & anterior surfaces of ulna Interosseous membrane Anterior surface of radius Adjacent interosseous membrane Distal ¼ of anterior surface of ulna Distal ¼ of anterior surface of radius Bases of distal phalanges of 4th & 5th digits Bases of distal phalanges of 2nd & 3rd digits Base of distal phalanx of thumb

5. Fxns of the anterior compartment muscles Flexion of forearm @ the elbow joint Pronator teres Flexion of hand @ the wrist joint Flexor carpi radialis et ulnaris- Palmaris longus Abduction (radial deviation) of hand @ the wrist joint Flexor carpi radialis Adduction (ulnar deviation) of hand @ the wrist joint Flexor carpi ulnaris Pronation of forearm Pronator teres – Pronator quadratus

Flexor pollicis longus 5. Fxns of the anterior compartment muscles Flexor digitorum superficialis Flexes proximal interphalangeal joints of the index, middle, ring, & little fingers Flexes metacarpophalangeal joints of the same fingers and the wrist joint Flexor digitorum profundus Flexes distal phalanges 4 & 5 at distal interphalangeal joints Flexes distal phalanges 2 and 3 at distal interphalangeal joints Flexor pollicis longus Flexes phalanges of thumb

6. Innervation of the anterior compartment muscles All the muscles by median nerve Except 1.5 muscles by ulnar nerve Flexor 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

deep venous palmar arch in the hand 8. Veins in the anterior compartment of the forearm deep venous palmar arch in the hand

9. Median nerve principal nerve no 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 posteriorly around 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 forearm Continuation of musculocutaneous nerve Medial cutaneous nerve of forearm Branch of medial cord of brachial plexus Posterior cutaneous nerve of forearm Branch of radial nerve

THE ANATOMY OF CUBITAL FOSSA IN 4 QUESTIONS

1. What is the cubital fossa? 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.

2. What are the boundaries of the cubital fossa? Superiorly imaginary line connecting medial &lateral epicondyles. Medially pronator teres. Laterally brachioradialis.

3. What are the contents of the cubital fossa? 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? Superficially, in the subcutaneous tissue overlying the fossa median cubital vein, medial and lateral antebrachial cutaneous nerves basilic and cephalic veins.

4. Which nerves are in the cubital fossa? 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.