Myology of the Wrist and Hand Flashcards
Anatomical snuff box
Triangular depression above the thumb. Bordered by 3 tendons: - Extensor pollicis longus. - Extensor pollicis brevis. - Abductor pollicis longus. Radial nerve, radial artery and cephalic vein pass through.
Extrinsic muscles
Longer muscles.
Origin in the forearm, insertion in the hand or fingers.
Intrinsic muscles
Small muscles with origin and insertion in the area of the hand.
Polyarticular muscles
Cross multiple articulations. Therefore can produce movement in multiple areas.
Thenar muscles
Anterior, most lateral part of the hand (underneath the thumb). M. abductor pollicis brevis M. adductor pollicis M. flexor pollicis brevis M. opponens pollicis
Hypothenar muscles
Anterior, medial part of hand. Provide movement to the 5th finger. M. abductor digiti minimi M. flexor digiti minimi brevis M. opponens digiti minimi M. palmaris brevis
Flexor vs. extensor muscles
Flexor muscles on medial side.
Extensor muscles on lateral side.
Flexor pollicis longus
- Origin: Interosseus membrane, anterior surface of the
radius. - Insertion: Palmar surface of the distal phalanx I.
- Action: Wrist: flexion and abduction. MCP and IP I: flexion.
Carpometacarpal I: opposition. - Innervation: Median nerve.
Abductor pollicis longus
- Origin: Dorsal surface of radius and ulna. Interosseus membrane. - Insertion: Base metacarpal I. - Action: Wrist: flexion and abduction. Carpometacarpal joint I: abduction. - Innervation: Radial nerve.
Extensor pollicis brevis
- Origin: Dorsal surface of radius. Interosseus membrane.
- Insertion: Base phalanx prox I.
- Action: Wrist: extension, abduction.
Carpometacarpal and MCP joint I: extension. - Innervation: Radial nerve.
Extensor pollicis longus
- Origin: Dorsal surface of ulna. Interosseus membrane.
- Insertion: Base phalanx distal I.
- Action: Carpometacarpal joint I: adduction. MCP and IP I:
extension. Wrist: extension, abduction. - Innervation: Radial nerve.
Extensor digiti minimi
- Origin: Lateral epicondyle of humerus.
- Insertion: Medial and distal phalanges V via dorsal
aponeurosis. - Action: Wrist: extension, ulnar deviation.
MCP, PIP, DIP V: extension, abduction. - Innervation: Radial nerve.
Extensor indicis
- Origin: Dorsal surface of ulna. Interosseus membrane.
- Insertion: Dorsal aponeurosis II.
- Action: II: extension, adduction. Wrist: extension, abduction.
- Innervation: Radial nerve.
Abductor pollicis brevis
Intrinsic, Thenar muscle.
From lateral carpal bones to thumb.
Action: Art. trapezium-MC: abduction. Art. MCP: synergic action with flexor.
Adductor pollicis
Intrinsic, Thenar muscle.
From 3rd metacarpal to thumb.
Action: CMC I: opposition. MCP: flexion.
Flexor pollicis brevis
Intrinsic, thenar muscle.
From carpal bones to to thumb.
Action: CMC I: flexion, opposition.
Opponens pollicis
Intrinsic, thenar muscle.
From proximal carpal bones to 1st metacarpal.
Action: CMC I: opposition.
Abductor digiti minimi
Intrinsic, hypothenar muscle.
From proximal carpal to 5th phalange.
Action: MCP V: flexion, ABD (PIP and DIP V: extension).
Palmaris brevis
Intrinsic, hypothenar muscle.
Proximal part of 5th metacarpal. Horizontally.
Action: Tightens aponeurosis.
Opponens digiti minimi
Intrinsic, hypothenar muscle.
From distal carpal to distal 5th metacarpal.
Action: MC: Opposition.
Flexor digiti minimi
Intrinsic, hypothenar muscle.
From distal carpal to proximal 5th phalange.
Action MCP V: flexion, abduction.
Lumbricales I-IV
Intrinsic muscle.
From middle tendons to phalanges 2-5.
Action: MCP II-V: flexion. PIP and DIP II-V: extension.
Interossei dorsales I-IV
Intrinsic muscles.
From metacarpal 1-5 to phalanges 2-5.
Action: MCP II-IV: flexion. PIP and DIP II-IV: extension, ABD of II and IV.
Interossei palmares I-III
Intrinsic muscles.
From metacarpal 2,4,5 to phalanges 2,4,5.
Action: MCP II, IV, V: flexion. PIP and DIP II, IV, V: extension and adduction for II and IV.
