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Forearm muscles.pptx
- 1.
- 2. Compartments • Forearm isdivided into • Anterior and posterior compartments by • Aninterosseousmembrane • Lateral intermuscular septum • Attachment of deepfasciaalongtheposterior border of theulna
- 3. Anterior compartment offorearm • Eight muscles present • Five muscles cross the elbow joint • Three musclesdonot • Flexor compartment is much more bulky • Necessary power of grip • Movementsofwristjoint • Flexionoffingers • Pronation • All are innervated by median nerve • Except • Flexor carpi ulnaris muscle • Medial half of Flexor digitorum profundus muscle • Innervated byulnarnerve
- 4. Anterior compartment offorearm • Deep (3) • Has been arranged in 2 groups • Superficial (5)
- 5. Superficial muscles • 5muscles • Have common origin • Anterior surface of medial epicondyle • 3 muscles have additional origin • Pronator teres • Flexor carpi ulnaris • Flexor digitorum superficialis
- 6. Pronator Teres • Origin •Humeral head • Medial epicondyle of humerus (CFO) • Ulnar head • Medial border of coronoid process of ulna • Insertion • Middle of lateral aspect of shaft of radius • Nerve supply • Median nerve • Action • Pronation and flexion of elbow
- 7. Flexor carpi radialis •Origin • Medial epicondyle of humerus (CFO) • Insertion • Bases of second and third metacarpal bones • Nerve supply • Median nerve • Action • Flexes elbow & wrist • Abducts hand at wrist joint
- 8. Palmaris longus • Origin •Medial epicondyle of humerus (CFO) • Insertion • Flexor retinaculum and palmar aponeurosis • Nerve supply • Median nerve • Action • Flexes elbow & wrist
- 9. Flexor Carpi Ulnaris •Origin • Humeral head • Medial epicondyle of humerus (CFO) • Ulnar head • Medial aspect of olecranon process and posterior border of ulna • Insertion • Pisiform bone, hook of the hamate, base at fifth metacarpal bone • Nerve supply • Ulnar nerve • Action • Flexes and adducts hand at wrist joint
- 10. Flexor Digitorum Superficialis •Origin • Humeroulnar head • Medial epicondyle of humerus (CFO); medial border of coronoid process of ulna • Radial head • Oblique line on anterior surface of shaft of radius • Insertion • Middle phalanx of medial four fingers • Nerve supply • Median nerve • Action • Flexes middle phalanx of fingers and assists in flexing proximal phalanx and hand
- 11. Deep group • 3muscles • Flexor digitorum profundus • Flexor pollicis longus • Pronator quadratus
- 12. Flexor digitorum profundus •Origin • Anteromedial surface of shaft of ulna • Insertion • Base of distal phalanges • of medial four fingers • Action • Flexion of middle and proximal phalanges and wrist • Nerve supply • Ulnar (medial half) • Anterior interosseous branch of median nerve (lateral half)
- 13. Flexor pollicis longus •Origin • Anterior surface of shaft of radius • Insertion • Distal phalanx of thumb • Action • Flexes distal phalanx of thumb • Nerve supply • Anterior interosseous branch of median nerve
- 14. Pronator quadratus • Origin •Lower ¼ of anterior surface of shaft of ulna • Insertion • Lower ¼ of anterior surface of shaft of radius • Action • Pronates radioulnar joint • Nerve Supply • Anterior interosseous • Branch of median nerve
- 15. Space of Parona •Space in front of pronator quadratus • Deep to long flexor tendons of fingers and their synovial sheaths • Limited proximally by • Oblique origin of flexor digitorum superficialis • Space involved in proximal extensions of synovial sheath infections • Can be drained through radial and ulnar incisions to the side of the flexor tendons
- 16. • Flexors ofWrist • Fl. Carpi Radialis • Fl. Carpi Ulnaris • Flexors of Middle Phalanges • Fl. Digitorum Superficialis • Flexors of Distal Phalanges • Fl. Digitorum Profundus • Fl. Pollicis Longus • Pronator of the Forearm • Pronator Teres • Pronator Quadratus
- 17. Flexor Retinaculum • Strong,fibrous band that covers the carpal bones on palmar side of hand near wrist • Attachment • Ulnar side • Pisiform bone and hook of hamate bone • Radial side • Tubercle of scaphoid bone and ridge of trapezium bone
- 18. Structures passing superficialto flexor retinaculum • Tendon of Palmaris longus • Palmer cutaneous branch of Median nerve • Palmer cutaneous branch of Ulnar nerve • Ulnar vessels • Ulnar nerve
- 19. Structures passing deepto Flexor retinaculum Median nerve Tendon of flexor digitorum superficialis Tendon of flexor digitorum profundus Tendon of flexor pollicis longus Ulnar bursa Radial bursa
- 20. Posterior compartment offorearm • Muscles are arranged in 2 layers • Superficial • Deep • Muscles are associated with • Movement of the wristjoint • Extension of the fingers and thumb • Supination • All the muscles of posterior compartment are supplied by • Radial nerve
- 21. Arrangement of posteriorcompartment muscles • Upper part • Anconeus (superficial) • Supinator (deep) • Lateral part of humerus • Pass along the radial side • Brachioradialis • Extensors carpi radialis longus • Extensors carpi radialis brevis • Passing along posterior surface of the forearm • Extensor digitorum • Extensor digiti minimi and • Extensor carpi ulnaris • At lower end of forearm • These two groups are separated by three muscles • They emerge from deeply in between them and go to the thumb • Abductor pollicis longus • Extensors pollicis longus and • Extensors pollicis longus brevis • One muscle for the forefinger runs deeply to reach the back of the hand • Extensor indicis
- 22. Superficial muscles ofthe back of forearm • There are 7 muscles • Common extensor origin • Four of the superficialmuscles • Arise from the tip of lateral epicondyle of the humerus • Extensor carpi radialis brevis • Extensor digitorum • Extensor digiti minimi, and • Extensor carpi ulnaris • All seven muscles cross elbow joint
- 23. Superficial muscles ofback of forearm • Categorized into two groups • Lateral and posterior • Each group consists of three muscles • Lateral group • Brachioradialis • Extensor carpi radialis longus • Extensor carpi radialis brevis • Posterior group • Extensor digitorum • Extensor digiti minimi • Extensor carpi ulnaris • In the upper end • Anconeus
- 24. Brachioradialis • Origin • Upper2/3rd of lateral supracondylar ridge of humerus • Insertion • Into base of styloid process of radius • Nerve Supply • Radial nerve • Action • Flexion of the forearm (specially in midprone position)
- 25. Extensor carpi radialislongus • Origin • From the lower 1/3rd of the lateral supracondylar ridge of the humerus • Insertion • Into posterior surface of base of 2nd metacarpal bone • Nerve Supply • Radial nerve • Action • Extension & Abduction of wrist joint • Extension of elbow joint
- 26. • Common extensororigin • 4 out of 7 superficial muscles • Extensor carpi radialis brevis • Extensor digitorum • Extensor digiti minimi • Extensor carpi ulnaris
- 27. Extensor carpi radialisbrevis • Origin • Lateral epicondyle of humerus (common extensor origin) • Insertion: • Posterior surface of base of 3rd metacarpal bone • Nerve Supply • Posterior interosseous nerve • Action • Extension & abduction of the hand at wrist joint
- 28. Extensor digitorum • Origin •Lateral epicondyle of humerus (common extensor origin) • Insertion • Extensor expansion of the medial 4 fingers • Nerve Supply • Posterior interosseous nerve • Action • Extension of metacarpophalangeal and interphalangeal joints of the medial 4 fingers • Extension of the hand at wrist joint
- 29. Dorsal digital expansion •Tendons of extensor digitorum expands • Covers dorsal surface of • Head of metacarpal & proximal phalanx • Triangular shape • Base • Forms a hood over metacarpal head • Apex • At proximal phalanx • Trifurcates into median & two lateral bands
- 30. Dorsal digital expansion The tendon splits into three parts: One Central: inserted into the base of Middle phalanx Two laterals: inserted into the base of the Distal phalanx Receives the insertions of: Corresponding Interosseous muscle (on each side) Lumbrical muscle (on the lateral side) Also receives Extensor indicis Extensor digiti minimi
- 31. Dorsal digital expansion •Muscles inserted • Index finger • 1st lumbrical • 1st dorsal interosseous • 2nd palmar interosseous • Middle finger • 2nd lumbrical • 2nd & 3rd dorsal interossei • Ring finger • 3rd lumbrical • 4th dorsal interosseous • 3rd palmar interosseous • Little finger • 4th lumbrical • 4th palmar interosseous
- 32.
- 33. Extensor digiti minimi •Origin • Lateral epicondyle of the humerus (common extensor origin) • Insertion • Extensor expansion of the little finger • Nerve Supply • Posterior interosseous nerve • Action • Extension of metacarpophalangeal and interphalangeal joints of the little finger
- 34. Extensor carpi ulnaris •Origin • Lateral epicondyle of the humerus (common extensor origin) • Insertion • Posterior surface of the base of the 5th metacarpal bone • Nerve Supply • Posterior interosseous nerve • Action • Extension & Adduction of the hand at wrist joint
- 35. Anconeus • Origin • Posterioraspect of the lateral epicondyle of the humerus • Insertion • Lateral surface of olecranon process of ulna • Nerve Supply • Posterior interosseous nerve • Action • Helps the triceps in extension of the elbow joint
- 36. Deep Layer • Thereare five deep muscles • Three deep extensorsof the forearm • Function on thumb • Abductor pollicis longus(APL) • Extensor pollicis brevis (EPB) • Extensor pollicis longus (EPL) • To acquire insertion on the three bones of thumb ‘crop out’ • From furrow in lateralelementof forearmbetweenlateral andposterior groupsof superficialextensor • One muscle • Functiononindexfinger • Extensor indicis • In the upper part • Supinator
- 37. Supinator • Origin • Lateralepicondyle of the humerus • Radial collateral lig • Annular ligament of the superior radio-ulnar joint • Supinator fossa and crest of the ulna • Insertion • Upper 1/3rd of the lateral surface of shaft of radius • Nerve Supply • Posterior interosseous nerve • Action • Supination of the forearm • At radio-ulnar joint
- 38. Abductor pollicis longus •Origin • Middle of the posterior surface of radius and ulna • Interosseus membrane • Insertion • Posterior surface of the base of the 1st metacarpal bone • Nerve Supply • Posterior interosseous nerve • Action • Abduction and extension of the thumb at the carpo-metacarpal joint
- 39. Extensor pollicis brevis •Origin • Posterior surface of the shaft of radius • Insertion • Posterior surface of the base of the proximal phalanx of the thumb • Nerve Supply • Posterior interosseous nerve • Action • Extension of the metacarpophalangeal joint of the thumb
- 40. Extensor pollicis longus •Origin • Posterior surface of ulna • Insertion • Posterior surface of the base of the distal phalanx of the thumb • Nerve Supply • Posterior interosseous nerve • Action • Extension of the interphalangeal joints of the thumb
- 41. Anatomical snuff box •Triangular depression • On lateral aspect of wrist • Boundaries • Medial • Extensor pollicis longus • Lateral • Abductor pollicis longus • Extensor pollicis brevis • Roof • Superficial fascia contains • Cephalic vein • Superficial branch of radial nerve • Floor • Scaphoid • Content • Radial artery
- 42. Extensor indicis • Origin •Posterior surface of ulna (below extensor pollicis longus) • Insertion • Extensor expansion of the index finger. • Nerve Supply • Posterior interosseous nerve • Action • Extension of the interphalangeal joints of the thumb
- 43. Wrist Drop • Signof radial nerve injury • There are two common characteristic sites of damage • Axilla • Injured viahumeral dislocationsor fractures of the proximalhumerus • Radial groove of the humerus • Injured via a humeral shaft fracture • Radial nerve innervates • All muscles in extensor compartment of forearm • In radial nerve lesion • These muscles are paralysed • Muscles that flex the wrist • Innervated by median nerve • Flexor muscles produces unopposed flexion at the wrist joint – wrist drop
- 44. Supination and pronation •These movements occur at • Radioulnar joint • Head of radius & ulna rotate in their sockets • Supination • Movement of forearm • Radius is rotating along a longitudinal axis • Pronation • Movement of forearm • Radius is rotating along the longitudinal axis • Thumb directed medially • Palm faces backwards • Body of radius lies obliquely across ulna
- 45. Dorsal interossei • 4in number • Present in middle 3 fingers • Middle finger has 2 muscles • Ring and index finger has one each • Numbered from lateral to medial • Bipennate in nature • Origin from adjacent sides of shaft of metacarpals • Inserts on dorsal digital expansion and base of proximal phalanx • Abductors • Supplies by deep branch of ulnar nerve
- 46. Palmar interossei • 4in number • No palmar interossei for middle finger • Unipennate • Origin from • Medial side of 1st metacarpal bone • Medial half of palmar aspect of shaft of 2nd metacarpal • Lateral part of palmar aspect of shaft of 4th and 5th metacarpal bones • Inserted to • Medial side of dorsal digital expansion of thumb • Medial side of dorsal digital expansion of index • Lateral side of dorsal digital expansion of ring • Lateral side of dorsal digital expansion of little