FOREARM

The Fore arm is divided into : Anterior / Flexor compartment Posterior / Extensor compartment

Contents of anterior compartment: It is occupied by muscles, blood vessels and nerves Muscles: These are arranged in superficial and deep groups Blood Vessels: The radial and ulnar arteries form the main blood vessels of the forearm Nerves: The median and ulnar nerves supply the muscles of the anterior compartment

Flexor muscles of forearm: Muscles are arranged into Superficial and Deep groups Superficial flexor muscles: Pronator teres Flexor carpi radialis Palmaris longus Flexor carpi ulnaris Flexor digitorum superficialis

1.Pronator teres: Origin: It arises by two heads: Humeral head: Medial supracondylar ridge of humerus and from medial epicondyle of humerus Ulnar head: Medial border of the coronoid process of ulna FLEXOR DIGITORUM SUPERFICIALIS PRONATOR TERES

Insertion: Nerve supply: Actions: Middle of the lateral surface of shaft of radius Nerve supply: Median nerve Actions: Pronation of forearm Weak flexor of the elbow joint

2.Flexor carpi radialis: Origin: Medial epicondyle as common origin of the superficial flexor muscles Flexor carpi radialis

Insertion: Nerve supply: Actions: Palmar surfaces of the bases of the second and third metacarpal bones Nerve supply: Median nerve Actions: Flexor of the wrist Combined action of flexor carpi radialis longus and brevis produce abduction of the wrist

3.Palmaris longus: Origin: Insertion: Medial epicondyle as common origin of the superficial flexor muscles Insertion: Palmaris longus It continuous as a central part of palmar aponeurosis

Nerve supply: Median nerve Actions: Weak flexor of the wrist

4.Flexor carpi ulnaris: Origin: It arises by two heads: Humeral head: Medial epicondyle along with superficial group of flexor muscles Ulnar head: Medial margin of olecranon process and upper two third of the posterior border of ulna

Insertion: Pisiform bone, pisometacarpal ligament, pisohamate ligament, hook of hamate Piso metacarpal ligament Pisohamate ligament

Nerve supply: Actions: Ulnar nerve Flexor of the wrist Combined action of flexor carpi and extensor carpi produces adduction of wrist joint

5.Flexor digitorum superficialis: Origin: It arises by two heads: FLEXOR DIGITORUM SUPERFICIALIS Humeral ulnar head: Medial epicondyle and from medial margin of the coronoid process of ulna radial head: Whole length of anterior oblique line of the radius PRONATOR TERES

Insertion: Sides of the shaft of middle phalanx of the medial four digits

Nerve supply: Actions: Median nerve Flexor of the middle phalanx at the proximal interphalangeal joint

Deep flexors muscles: Flexor pollicis longus Flexor digitorum profundus Pronator quadratus

1.Flexor pollicis longus: Origin: Anterior surface of shaft of radius Adjacent interosseus membrane

Insertion: Nerve supply: Actions: Palmar surface of the base of distal phalanx of the thumb Nerve supply: Anterior interosseous branch of median nerve Actions: Flexor of the thumb

2.Flexor digitorum profundus: Origin: Anterior and medial surface shaft of the upper three fourths of the ulna, including coronoid and olecranon processes Adjacent interosseus membrane Upper three fourth of the posterior border of ulna

Insertion: Nerve supply: Actions: Palmar surface of the base of terminal phalanx of the medial four fingers Nerve supply: Medial part: Ulnar nerve Lateral part: Anterior interosseus Actions: Flexes the terminal phalanges

3.Pronator quadratus: Origin: Anterior surface of the lower one fourth of the ulna Pronator quadratus

Insertion: Ulnar notch Superficial fibers inserts to the anterior surface of lower one fourth of radius Deep fibers are inserted to triangular area just above the ulnar notch Ulnar notch

Nerve supply: Actions: Anterior interosseous nerve Superficial fibers are principal pronators of forearm Deep fibers prevents the seperation of the lower part of radius and ulna

Functional classification of flexor muscles of forearm: 1. Flexors of the wrist: Flexor carpi radialis and flexor carpi ulnaris 2. Flexors of the middle phalanges: Flexor digitorum superficialis 3. Flexors of the distal phalanges: Flexor digitorum profundus and flexor pollicis longus 4. Pronators of the forearm: Pronator teres and pronator quadratus

Posterior compartment of forearm: Superficial group Deep group

They are seven in number and are divided into: Lateral group Superficial group: They are seven in number and are divided into: Lateral group Posterior group Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris Anconeus

1.Brachioradialis: Origin: Upper two – third of lateral supracondylar ridge and from the lateral intermuscular septum

Insertion: Nerve supply: Action: Base of the styloid process of the radius Nerve supply: Radial nerve Action: Flexor of elbow joint Styloid process

Extensor carpi radialis longus: Origin: Extensor carpi radialis longus Lower one – third of lateral supracondylar ridge and from the lateral intermuscular septum Extensor carpi radialis brevis

Insertion: Nerve supply: Dorsal surface of the base of second metacarpal bone Nerve supply: Radial nerve Insertion of Extensor carpi radialis longus

Extensor carpi radialis brevis Origin: Common extensor origin from the front of the lateral epicondyle Extensor carpi radialis brevis

Insertion: Nerve supply: Dorsal surface of second and third metacarpal bones Nerve supply: Posterior interosseous nerve Insertion of Extensor carpi radialis brevis

Action: Actions of extensor carpi radialis longus and brevis Both radial extensors along with extensor carpi ulnaris produce extension of the wrist Both radial extensors along with flexor carpi radialis act as abductors of the wrist

Extensor digitorum: Origin: Front of lateral epicondyle as common extensor origin Extensor digitorum

Insertion: Each extensor tendon covers the dorsal surface of the metacarpal head and proximal phalanx and forms a triangular dorsal digital expansion

Nerve supply: Action: Posterior interosseous nerve Prime movers for extension at metacarpo-phalangeal and interphalangeal joints

Extensor digiti minimi: Origin: From common extensor tendon Extensor digiti minimi Insertion: Dorsal digital expansion

Nerve supply: Action: Posterior interosseous nerve It extends the little finger and assists the action of extensor digitorum

Extensor carpi ulnaris Origin: From lateral epicondyle as common extensor tendon From subcutaneous posterior border of ulna Extensor carpi ulnaris

Insertion: Nerve supply: Tubercle on the medial side of the base of fifth metacarpal bone Insertion of Extensor carpi ulnaris Nerve supply: Posterior interosseous nerve

Action: Simultaneous contraction with extensor carpi radialis longus and brevis produces extension of wrist Combined actions of extensor and flexor carpi ulnaris produce adduction of the wrist

Anconeus: Origin: Posterior surface of the lateral epicondyle

Insertion: Nerve supply: Action: Posterior view of Ulna Insertion: Lateral surface of the olecranon process and upper one-fourth of the posterior surface of the shaft of ulna Anconeus Nerve supply: Radial nerve Action: Extensor of elbow joint

Deep group of extensor muscles: Supinator Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indices

Supinator: Origin: Superficial fibers arises from lateral epicondyle Superficial head Origin: Deep head Superficial fibers arises from lateral epicondyle Deep fibers arises from supinator crest of ulna Lateral view of ulna

Insertion: Superficial and deep fibers are attached to the upper one-third of the anterior part of the lateral surface of radius

Nerve supply: Action: Posterior interosseous nerve Supinator in extended elbow

Abductor pollicis longus Origin: Posterior surface of radius and ulna and intervening interosseous membrane Abductor pollicis longus Posterior view

Nerve supply: Action: Posterior interosseous nerve Abductor and extensor of the thumb

Origin of Extensor policis brevis Extensor pollicis brevis: Origin: Posterior surface of radius and adjacent interosseous membrane Origin of Extensor policis brevis

Insertion of Extensor policis brevis Dorsal surface of the proximal phalanx of the thumb Nerve supply: Posterior interosseous nerve Action: Extends the proximal phalanx of the thumb Insertion of Extensor policis brevis

Extensor policis longus Extensor pollicis longus: Origin: Posterior surface of ulna and adjacent interosseous membrane Origin of Extensor policis longus

Extensor policis longus Insertion: Base of distal phalanx of the thumb Nerve supply: Posterior interosseous nerve Action: Extends the distal phalanx of the thumb Insertion of Extensor policis longus

Extensor indices: Origin: Posterior surface of ulna and adjacent interosseous membrane Origin of Extensor indices

Insertion: Nerve supply: Action: Dorsal digital expansion Posterior interosseous nerve Action: Extends the index finger

END THANK YOU

Anatomical snuff box: Boundaries: Laterally: Medially: It is a triangular depression on the radial side of the wrist Boundaries: Laterally: Tendons of abductor pollicis longus and extensor pollicis brevis Medially: Tendon of extensor pollicis longus

Content: Radial artery Roof: Skin and fasciae Floor: Styloid process of radius, scaphoid, trapezium and base of first metacarpal bone Content: Radial artery

Extensor retinaculum: Ulna Derived from deep fascia Attachments: Laterally: Anterior border of radius Medially: Pisiform and Triquetral bone