<p>MUSCLES OF THE POSTERIOR COMPARTMENT OF FOREARM OBJECTIVES  At the end of lecture,students will be able to:  Learn concept of the muscles of posterior compartment of forearm  Understand nerve supply of these muscles  Idea of actions of the muscles of posterior compartment of forearm.  muscles forming this compartment:</p><p>Superficial group: Anconeus. Extensor digiti minimi. Extensor carpi ulnaris Extensor digitorium Extenser carpi radialis brevis. </p><p>Deep group: Supenator. Extenser carpi radialis longus. Abductor pollicis longus. Extensor pollicis longus. Extensor pollicis brevis Extensor indices</p><p>BRACHIORADIALIS</p><p> Origin: Upper two third of supracondylar ridge.  Insertion: Styloid process of radius. Action: flexion at elbow joint. Nerve supply: Radial nerve </p><p>EXTENSER CARPI RADIALIS LONGUS</p><p> Origin: Lower third of the lateral supra- condylar ridge of humerus.  Insertion: base of second metacarpal Action: Extensor and abductor of wrist  Nerve supply: Radial nerve COMMON EXTENSOR ORIGIN</p><p> Arise from smooth area in front of the lateral epicondyle of humerus.  This fused tendon gives rise to:  Extensor carpi radialis brevis.  Extensor digitorium.  Extensor digiti minimi.  Extensor carpi ulnaris.</p><p>EXTENSOR CARPI RADIALIS BREVIS</p><p> Origin: common extensor origin.  Insertion: Base of third metacarpal. Nerve supply: Radial nerve  Action: Wrist extensor</p><p>EXTENSOR DIGITORIUM</p><p> Origin: common extensor origin  Insertion: middle and distal phalanges of medial four fingers.  Action: Extensor of the wrist, metacarpophalangeal joint and interphalangeal joints.  Nerve supply: Radial nerve</p><p>EXTENSOR DIGITI MINIMI</p><p> Origin: common extensor origin Insertion: extensor expansion of distal phalanx of little finger.  Action: Assists extensor digitorum with extension of wrist and little finger.</p><p>Nerve supply: Radial nerve.</p><p>EXTENSOR CARPI ULNARIS  Origin: Arises from the common extensor origin.  Insertion: into the base of 5th metacarpal.  Nerve supply: Radial nerve.  Action: Extend and adduct hand at wrist joint.</p><p>ANCONEUS</p><p> Origin: posterior surface of lateral epicondyle of humerus.  Insertion: lateral side of olecronon and adjacent shaft of the ulna.  Nerve supply: Radial nerve.  Action: extends elbow joint</p><p>SUPINATOR </p><p> Origin: lateral epicondyle of humerus and annular ligament of superior radioulnar joint. Insertion:Neck and shaft of radius. Action:Supination of forearm. Nerve supply: Radial nerve</p><p>ABDUCTOR POLLICIS LONGUS  Origin: Shaft of radius and ulna.  Insertion: base of first metacarpal.  Action: abduct and extend thumb.  Nerve supply: Radial nerve.</p><p>EXTENSOR POLLICIS BREVIS  Origin: Shaft of radius and interosseus membrane.  Insertion: base of proximal phalanx of thumb.  Nerve supply:Radial nerve. Action:extends MCP joints of thumb.</p><p>EXTENSOR POLLICIS LONGUS  Origin: shaft of ulna and interosseus membrane.  Insertion: into the base of distal phalanx of thumb.  Action: extends distal phalynx of thumb.  Nerve supply: Radial nerve.</p><p>EXTENSOR INDICIS  Origin: Shaft of ulna and interosseus membrane.  Insertion: extensor expansion of index finger.  Action: Extends MCP joint of index finger.  Nerve supply: Radial nerve ANATOMICAL SNUFFBOX  Anatomical snuffbox lies between extensor pollicis longus tendon on ulnar side and tendons of extensor pollicis brevis and abductor pollicis longus on radial side.</p><p>EXTENSOR RETINACULUM  A band like thickening in the deep fascia of forearm.  About 2.5 cm wide.  Passes obliquely across the extensor surface of wrist.  Medially attached to pisiform and hook of hamate bones.  Laterally attached to scaphoid trapezium.</p><p> Extensor carpal tunnel is divided in to six compartments by fibrous septa passing to bones of forearm.  Starting from lateral side.  First compartment: tendons of abductor pollicis longus and extensor pollicis brevis pass. </p><p> Second compartment: extensor longus and brevis tendons.  Third compartment: tendon of extensor pollicis longus.  Fourth compartment: extensor digitorium and indicis tendon. </p><p> Fifth compartment: tendon of extensor digiti minimi.</p><p> Sixth compartment: tendon of extensor carpi ulnaris. Word of thanks to following great authors of Books of Anatomy: The reading material is taken from , Last’s Anatomy, Gray’s anatomy, Keith L Moore’s Anatomy, Clinical Anatomy by Richard S Snell and Atlas of human anatomy by Frank H Netter with thanks. The end</p><p>MUSCLES OF THE POSTERIOR COMPARTMENT OF FOREARM OBJECTIVES  At the end of lecture,students will be able to:  Learn concept of the muscles of posterior compartment of forearm  Understand nerve supply of these muscles  Idea of actions of the muscles of posterior compartment of forearm. </p><p> muscles forming this compartment: Superficial group: Anconeus. Extensor digiti minimi. Extensor carpi ulnaris Extensor digitorium Extenser carpi radialis brevis. </p><p>Deep group: Supenator. Extenser carpi radialis longus. Abductor pollicis longus. Extensor pollicis longus. Extensor pollicis brevis Extensor indices</p><p>BRACHIORADIALIS</p><p> Origin: Upper two third of supracondylar ridge.  Insertion: Styloid process of radius. • Action: flexion at elbow joint. Nerve supply: Radial nerve </p><p>EXTENSER CARPI RADIALIS LONGUS  Origin: Lower third of the lateral supra-condylar ridge of humerus.  Insertion: base of second metacarpal Action: Extensor and abductor of wrist  Nerve supply: adial nerve </p><p>COMMON EXTENSOR ORIGIN  Arise from smooth area in front of the lateral epicondyle of humerus.  This fused tendon gives rise to:  Extensor carpi radialis brevis.  Extensor digitorium.  Extensor digiti minimi.  Extensor carpi ulnaris. EXTENSOR CARPI RADIALIS BREVIS  Origin: common extensor origin.  Insertion: Base of third metacarpal.</p><p>Nerve supply: Radial nerve  Action: Wrist extensor EXTENSOR DIGITORIUM  Origin: common extensor origin  Insertion: middle and distal phalanges of medial four fingers.  Action: Extensor of the wrist, metacarpophalangeal joint and interphalangeal joints.  Nerve supply: Radial nerve</p><p>EXTENSOR DIGITI MINIMI  Origin: common extensor origin Insertion: extensor expansion of distal phalanx of little finger.  Action: Assists extensor digitorum with extension of wrist and little finger. Nerve supply: Radial nerve.</p><p>EXTENSOR CARPI ULNARIS  Origin: Arises from the common extensor origin.  Insertion:into the base of 5th metacarpal.  Nerve supply: Radial nerve.  Action: Extend and adduct hand at wrist joint.</p><p>ANCONEUS  Origin: posterior surface of lateral epicondyle of humerus.  Insertion: lateral side of olecronon and adjacent shaft of the ulna.  Nerve supply: Radial nerve.  Action: extends elbow joint SUPINATOR  Origin: lateral epicondyle of humerus and annular ligament of superior radioulnar joint. Insertion: Neck and shaft of radius. Action: Supination of forearm. Nerve supply: Radial nerve</p><p>ABDUCTOR POLLICIS LONGUS  Origin: Shaft of radius and ulna.  Insertion: base of first metacarpal.  Action: abduct and extend thumb.  Nerve supply: Radial nerve.</p><p>EXTENSOR POLLICIS BREVIS  Origin: Shaft of radius and interosseus membrane.  Insertion: base of proximal phalanx of thumb.  Nerve supply: Radial nerve. Action: extends MCP joints of thumb.</p><p>EXTENSOR POLLICIS LONGUS  Origin: shaft of ulna and interosseus membrane.  Insertion: into the base of distal phalanx of thumb.  Action: extends distal phalynx of thumb.  Nerve supply: Radial nerve. EXTENSOR INDICIS  Origin: Shaft of ulna and interosseus membrane.  Insertion: extensor expansion of index finger.  Action: Extends MCP joint of index finger.  Nerve supply: Radial nerve</p><p>ANATOMICAL SNUFFBOX  Anatomical snuffbox lies between extensor pollicis longus tendon on ulnar side and tendons of extensor pollicis brevis and abductor pollicis longus on radial side. EXTENSOR RETINACULUM  A band like thickening in the deep fascia of forearm.  About 2.5 cm wide.  Passes obliquely across the extensor surface of wrist.  Medially attached to pisiform and hook of hamate bones.  Laterally attached to scaphoid trapezium.</p><p> Extensor carpal tunnel is divided in to six compartments by fibrous septa passing to bones of forearm.  Starting from lateral side.  First compartment: tendons of abductor pollicis longus and extensor pollicis brevis pass. </p><p> Second compartment: extensor longus and brevis tendons.  Third compartment: tendon of extensor pollicis longus.  Fourth compartment: extensor digitorium and indicis tendon. </p><p> Fifth compartment: tendon of extensor digiti minimi.</p><p> Sixth compartment: tendon of extensor carpi ulnaris. Word of thanks to following great authors of Books of Anatomy: The reading material is taken from , Last’s Anatomy, Gray’s anatomy, Keith L Moore’s Anatomy, Clinical Anatomy by Richard S Snell and Atlas of human anatomy by Frank H Netter with thanks. The end</p>