Muscles for Practical Flashcards
Trapezius
Innervation: spinal accesory nerve (CNXI)
Action:
- Descending part elevates
- Ascending part depresses
- Middle part retracts
Rhomboid Major
Innervation: dorsal scapular nerve
Action: retract scapula, fix scapula to thoracic wall
Rhomboid minor
Innervation: dorsal scapular nerve
Action: retract scapula, fix scapula to thoracic wall
Levator scapulae
Innervation: dorsal scapular nerve
Action: elevate scapula
Deltoid
Innervation: axillary nerve
Action:
- Anterior part flexes arm
- Middle part abducts arm
- Posterior part extends arm
Teres major
Innervation: lower subscapular nerve
Action: adducts and medially rotates arm
Tricaps brachii
Innervation: radial nerve
Action: cheif extensor of forearm
Teres minor
Innervation: axillary nerve
Action: laterally rotates arm
Supraspinatus
Innervation: suprascapular nerve
Action: assists deltoid with abduction of arm
Infraspinatus
Innervation: suprascapular nerve
Action: laterally rotates arm
Subscapularis
Innervation:
- Upper subscapular nerve
- Lower sucscapular nerve
Action: medially rotates arm
Pectoralis major
Innervation:
- Lateral pectoral nerve
- Medial mectoral nerve
Action: adducts and medially rotates humerous
Pectoralis minor
Innervation: medial pectoral nerve
Action: stabalizes scapula by drawing it inferiorly and anteriorly against thoracic wall
Serratus anterior
Innervation: long thoracic nerve
Action: protracts scapula and holds it against thoracic wall and rotates scapula
Sternocleidomastoid
Innervation: accessory nerve (CN XI)
Action:
- Unilateral contraction causes lateral flexion
- Bilateral contraction causes elevation of head
Inferior belly of the omohyoid muscle
Innervation: cervical plexus (ansa cervicalis)
Action: depresses hyoid bone
Anterior, middle, and posterior scalene muscles
Coracobrachialis
Innervation: musculocutaneous nerve
Action: helps flex and adduct arm (resists dislocation of shoulder)
Biceps brachii
Innervation: musculocutaneous nerve
Action: supinates and flexes forearm
Brachialis
Innervation: musculocutaneous and radial nerves
Action: flexes forearm
Brachioradialis
Innervation: radial nerve
Action: flexion of forearm (weak)
Supinator
Innervation: radial nerve
Action: supinates forearm
Pronator teres
Innervation: median nerve
Action: pronates and flexes forearm (at elbow)
Flexor carpi ulnaris
Innervation: ulnar nerve
Action: flexes and adducts hand (at wrist)
Aconeus
Innervation: radial nerve
Action: assists tricepts in extending forearm
Flexor carpi radialis
Innervation: median nerve
Action: flex and adduct hand (at wrist)
Flexor digitorum superficialis
Innervation: median nerve
Action: flexes middle phalanges at PIP joints and flexes proximal phalanges at MCP joints
Palmaris longus
Innervation: median nerve
Action: flexes hand (at wrist) and tenses palmar apneurosis
Flexor digitorum profundus
Innervation: ulnar nerve (medial part) anterior interosseous nerve (lateral part)
Action: flexes distal phalanges 2 and 3 ar DIP joint (medial part) flexis distal phalanges 2 and 3 at DIP joint (lateral part)
Flexor pollicis longus
Innervation: anterior interosseous nerve
Action: flexes phalanges of first digit (thumb)
Abductor pollicis brevis
Innervation: recurrent branch of median nerve
Action: abducts thumb, helps oppose it
Flexor pollicis brevis
Innervation: recurrent branch of median nerve
Action: flexes thumb
Opponens pollicis
Innervation: recurrent branch of median nerve
Action: to oppose thumb, draws 1st metacarpal medially to center of palm and rotates it medially
Adductor pollicis
Innervation: deep branch of ulnar nerve
Action: adducts thumb towards lateral border of palm
Palmar interosseous muscles
Innervation: deep branch of ulnar nerve
Action: adduct 2nd, 4th, and 5th digits toward axial line, assist lumbricles in flexing MCP joints and extending interphalangeal joints
Dorsal interosseous muscles
Innervation: deep branch of ulnar nerve
Action: abduct 2nd through 4th difits from axial line, act with lumbricals in flexing MCP joints and extending interphalangeal joints
Extensor carpi radialis longus
Innervation: radial nerve
Action: extend and abduct hand at wrist joint (active during fist clenching)
Extensor carpi radialis brevis
Innervation: deep branch of radial nerve
Action: extend and abduct hand at the wrist joint
Extensor digitorum
Innervation: posterior interosseous nerve
Action: extends medial four digits primarily at MCP joints, secondarily at interphalangeal joints
Extensor digiti minimi
Innervation: posterior interosseous nerve
Action: extends 5th digit primarily at MCP joint, secondarily at interphalangeal joint
Extensor carpi ulnaris
Innervation: posterior interosseous nerve
Action: extends and adducts hand at wrist joint
Abductor pollicis longus
Innervation: posterior interosseous nerve
Action: abducts thumb and extends it at carpometacarpal joint
Extensor pollicis brevis
Innervation: posterior interosseous nerve
Action: extends proximal phalanx of thumb at MCP joint and extends carpometacarpal joint
Extensor pollicis longus
Innervation: posterior interosseous nerve
Action: extends distal phalanx of thumb at interphalangeal joint and extends MCP and CMC joints
Extensor indicis
Innervation: posterior interosseous nerve
Action: extends 2nd digit (enabling its independent extension) and helps extend hand at wrist
Pronator quadratus
Innervation: anterior interosseous nerve
Action: pronates forearm (deep fibers bind radius and ulna together)
