innervation/ function / origin and insertions
Know the locations, function, and innervations of the following:
o all rotator cuff muscles
§ Supraspinatus:
§ Function: Abductor of the arm
§ Innervation: Suprascapular nerve
§ Infraspinatus:
§ Function: Lateral rotator of the arm
§ Innervation: Suprascapular nerve
§ Teres minor:
§ Function: Lateral rotator of the arm
§ Innervation: Axillary (circumflex) nerve
§ Subscapularis:
§ Function: Arm adduction and medial rotation
§ Innervation: Upper & lower Subscapular nerves
o teres major (NOT a rotator cuff muscle)
§ function: Arm adduction and medial rotation
§ innervation: lower subscapular
o latissimus dorsi
§ function: coughing muscle; pulling yourself up; adduction and medial rotation; extension of arm
§ innervation: thoracodorsal nerve
o trapezius
§ function: drawing scapula medial and stabilizing
§ innervation: accessory nerve (11); cervical plexus C3-C4
o levator scapulae
§ function: draws scapula medially, incline neck to same side
§ innervation: dorsal scapular (C4-C5)
o rhomboid major
§ function: steadies’ scapula and holds it in place
§ innervation: dorsal scapular (C4-C5)
o rhomboid minor
§ function: steadies scapula and holds it in place
§ innervation: dorsal scapular (C4-C5)
o deltoid (shoulder cap)
§ function: Most important abductor of the arm up to 90 degree
§ innervation: Axillary nerve
o coracobrachialis
§ function: flexion, adduction, internal rotation
§ innervation: musculocutaneous
o pectoralis major
§ function: adduction, internal rotation; help with respiration when shoulder is flexed
§ innervation: medial and lateral pectoral n.
o pectoralis minor
§ function: draws scapula downward, rotates glenoid inferiorly, assist in respiration
§ innervation: medial and lateral pectoral n.
o serratus anterior
§ function: Elevation of the arm over 90o; Protracts the scapula and holds it against the thoracic wall and rotates the scapula laterally to elevate the arm
§ innervation: long thoracic
o biceps brachii
§ function: elbow joint flexion, shoulder joint flexion, abduction and internal rotation of the humerus
§ innervation: musculocutaneous
o brachialis
§ function: flexion at the elbow joint
§ innervation: musculocutaneous n. and radial n.
o triceps brachii
§ function: elbow extensors
§ innervation: radial n.
o aconeus
§ function: stabilizer
§ innervation: radial n.
Know the locations, innervations, and origins/insertions of the following muscles of the Forearm:
Anterior Compartment-Superficial
Pronator teres
§ Innervation: median n.
§ Origin: humeral head à medial epicondyle of humorous; ulnar hear à coronoid process
§ Insertion à lateral radius
Flexor carpi radialis
§ Innervation: median n.
§ Origin: medial epicondyle of humorous
§ Insertion: base of 2nd metacarpal
Palmaris longus
§ Innervation: median n.
§ Origin: medial epicondyle of humorous
§ Insertion: palmar aponeurosis
§ 30% of population does not have this
Flexor carpi ulnaris
§ Innervation: ulnar n.
§ Origin: humeral head à medial epicondyle of humorous; ulnar head à olecranon
§ Insertion: pisiform; hook of hamate; base of 5th metacarpal
Anterior Compartment- Intermediate
Flexor digitorum superficialis
§ Innervation: median n.
§ Origin: humeral head à medial epicondyle of humorous; ulnar hear à coronoid process
§ Insertion: sides of middle phalanges of 2nd to 5th digits
Anterior Compartment- Deep
Flexor digitorum profundus
§ Innervation: median and ulnar
§ Origin: ulna and interosseous membrane
§ Insertion: distal phalanges of 2nd – 5th digits
Flexor pollicis longus
§ Innervation: median
§ Origin: radius and adjacent interosseous membrane
§ Insertion: distal phalanx of thumb
Pronator quadratus
§ Innervation: median
§ Origin: distal quarter of ulna
§ Insertion: distal quarter of radius
Posterior Compartment- Superficialis
Extensor digitorum
§ Innervation: radial
§ Origin: common head
§ Insertion: dorsal digital expansion of 2nd to 5th digits
Extensor digiti minimi
§ Innervation: radial
§ Origin: common head
§ Insertion: dorsal digital expansion of 5th digit
Extensor carpi ulnaris
§ Innervation: radial
§ Origin: common head and ulnar head
§ Insertion: base of 5th metacarpal
Posterior Compartment- Deep
Supinator
§ Innervation: radial
§ Origin: olecranon, lateral, epicondyle of humerus, radial collateral ligament, annular ligament of radius
§ Insertion: radius
Abductor pollicis longus
§ Innervation: radial
§ Origin: radius and ulna
§ Insertion: base of 1st metacarpal
Extensor pollicis brevis
§ Innervation: radial
§ Origin: radius and interosseous membrane
§ Insertion: base of proximal phalanx of thumb
Extensor pollicis longus
§ Innervation: radial
§ Origin: ulna interosseous membrane
§ Insertion: base of distal phalanx thumb
Extensor indicis
§ Innervation: radial
§ Origin: ulna and interosseous membrane
§ Insertion: posterior digital extension of 2nd digit
Radialis Group
Brachioradialis
§ Innervation: radial
§ Origin: distal humerus
§ Insertion: radial styloid process
Extensor carpi radialis longus
§ Innervation: radial
§ Origin: lateral supracondylar ridge of distal humerus
§ Insertion: 2nd metacarpal base
Extensor carpi radialis brevis
§ Innervation: radial
§ Origin: lateral epicondyle of humerus
§ Insertion: 3rd metacarpal base
Know the locations, functions, and innervation of the following
Thenar muscles
Adductor pollicis
- Innervation: ulnar
- Function: CMC joint of thumb à adduction and MCP joint of thumb: flexion
Abductor pollicis brevis
- Innervation: median
- Function: CMC joint of thumb à abduction
Flexor pollicis brevis
- Innervation: median and ulnar
- Function: CMC joint of thumb à flexion
Opponens pollicis
- Innervation: median
- Function: CMC joint of thumb à opposition
Hypothenar muscles
Opponens digiti minimi
- Innervation: ulnar n.
- Function: draw metacarpals in opposite direction
Flexor digiti minimi
- Innervation: ulnar n.
- Function: MCP joint of little finger: flexion
Abductor digiti minimi
- Innervation: ulnar n.
- Function: flexion, abduction, and extension
Palmaris brevis
- Innervation: ulnar n.
- Function: tightens palmer aponeurosis (protective function)