Comp. Vert. Part II

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Triceps brachii: three heads- arm

Action: powerful forearm extensor; prime mover; antagonist of forearm flexors; long head assists in arm adduction
- O: infraglenoid tubercle of scapula (long head); posterior shaft of humerus (lateral head); posterior humeral shaft distal to radial groove (medial head)
- I: by common tendon into olecranon porcess of ulna
Anconeus: elbow

Action: abducts ulna during forearm pronation; synergist of triceps brachii in elbow extension
- O: lateral epicondyle of humerus
- I: lateral aspect of olecranon process of ulna
Biceps brachii: two heads- arm

Action: flexes elbow joint and supinates forearm; weak fleor of arm at shoulder
- O: coracoid process (short head); tubercle above and lip of glenoid cavity, tendon runs into intertubercular groove of humerus (long head)
- I: by common tendon into radial tuberosity
Brachialis: arm

Action: a major forearm flexor
- O: front of distal humerus; embraces insertion of deltoid muscle (deltoid tuberosity of humerus)
- I: coronoid process of ulna
Brachioradialis: arm- radius

Action: synergist in forearm flexion; stabilizes the elbow
- O: lateral supracondylur ridge at distal end of humerus
- I: base of styloid process of radius
Pronator teres: turning palm posteriorly- round

Action: pronates forearm; weak elbow flexor
- O: medial epicondyle of humerus; coronoid process of ulna
- I: common tendon into lateral radius, midshaft
Flexor carpi radialis: decrease angle between two bones- wrist- radius

Action: powerful flexor of wrist; abducts hand; weak synergist of elbow flexion
- O: medial epicondyle of humerus
- I: base of second and third metacarpals; insertion tendon easily seen
Palmaris longus: palm- long

Action: weak wrist flexor; tenses skin and fascia of palm during hand movements; weak synergist for elbow flexion
- O: medial epicondyle of humerus
- I: palmar aponeurosis; skin and fascia of palm
Flexor carpis ulnaris: decrease angle between two bones- wrist- ulna

Action: powerful flexor of wrist; adducts hand with extensor carpi ulnaris
- O: medial epicondyle; olecronon process of and posterior surface of ulna
- I: pisiform and hamate bones and base of 5th metcarpal
Flexor digitorum superficialis: decrease angle between two bones- fingers- close to surface

Action: flexes wrist and middle phalanges of fingers 2-5; important flexor
- O: medial epicondyle of humerus, coronoid process of ulna; shaft of radius
- I: by four tendons onto middle phalanges of fingers 2-5
Flexor pollicis longus: decrease angle between two bones- thumb- long

Action: flexes distal phalynx of thumb
- O: anterior surface of radius and interosseus membrane
- I: distal phalynx of thumb
Flexor digitorum profundus: decrease angle between two bones- finger- deep

Action: slow-acting flexor of any or all fingers; assists in flexing wrist; only muscle that can flex distal interphalangeal joints
- O: coronoid porcess, anteromedial surface of ulna and interosseus membrane
- I: by four tendons into distal phalanges of fingers 2-5
Pronator quadratus: turning palm down- square

Action: prime mover of forearm pronation; acts with pronator teres
- O: distal portion of anterior ulnar shaft
- I: distal surface of anterior radius
Extensor carpi radialis longus: increase angle between two bones- wrist- radius- long

Action: extends wrist in conjunction with extensor carpi ulnaris and abducts wrist in conjunction with flexor carpi radialis
- O: lateral supracondylar ridge of humerus
- I: base of second metacarpal
Extensor carpi radialis brevis: increase angle between two bones- wrist- radius- short

Action: extends and abducts wrist; acts synergistically with extensor carpi radials longus to steady wrist during finger flexion
- O: lateral epicondyle of humerus
- I: base of third metacarpal
Extensor digitorum: increase angle between two bones- fingers

Action: prime mover of finger extension; extends wrist; can abduct (flare) fingers
- O: lateral epicondyle of humerus
- I: by four tendons into extensor expansions and distal phalanges of fingers 2-5
Extensor carpi ulnaris: decrease angle between two bones- wrist- ulna

Action: extends wrist in conjunction with the extensor carpi radials and adducts wrist in conjunction with flexor carpi ulnaris
- O: lateral epicondyle of humerus and posterior border of ulna
- I: base of fifth metacarpal
Supinator: turning palm upward

Action: assists biceps brachii to forcibly supinate forearm; atagonist of pronator muscles
- O: lateral epicondyle of humerus; proximal ulna
- I: proximal end of radius
Abductor pollicis longus: movement away from median plane- thumb-long

Action: abducts and extends thumb; abducts wrist
- O: posterior surface of radius and ulna; interosseus membrane
- I: base of first metacarpal and trapezium
Extensor pollicis brevis and longus: increase angle between two bones- thumb- short and long

Action: extends thumb
- O: dorsal shaft of radius and ulna; interosseus membrane
- I: base of proximal (brevis) and distal (longus) phalanx of thumb
Extensor indicis: increase angle between two bones- index finger

Action: extends index finger and assists in wrist extension
- O: posterior surface of distal ulna; interosseus membrane
- I: extensor expansion of index finger; joins tendon of extensor digitorum
Abductor pollicis brevis: movement away from median plane- thumb- wrist

Action: abducts thumb
- O: flexor retinaculum and nearby carpals
- I: lateral base of thumb's proximal phalanx
Flexor pollicis brevis: decrease angle between two bones-thumb- short

Action: flexes thumb
- O: flexor retinaculum and trapezium
- I: lateral side of base of proximal phalanx of thumb
Adductor pollicis: movement towards median plane- thumb

Action: adducts and helps to oppose thumb
- O: capitate bone and bases of metacarpals 2-4; front of metacarpal 3
- I: medial side of base of proximal phalanx of thumb
Flexor digiti minimi brevis: decrease angle between two bones- little finger- short

Action: flexes little finger at metacarpophalangeal joint
- O: hamate bone and flexor retinaculum
- I: medial side of proximal phalanx of little finger
Abductor digiti minimi: movement away from median plane- little finger

Action: abducts little finger at metacarpophalngeal joints
- O: pisiform bone
- I: medial side of proximal phalanx of little finger
Opponens digiti minimi: opposistion- little finger

Action: helps in opposition: brings metacarpal 5 towards thumb
- O: hamate bone and flexor retinaculum
- I: most length of medial side of metacarpal 5
Lumbricalis: earthworm

Action: flex fingers at metacarpophalangeal joints but extends fingers at interphalangeal joints
- O: lateral side of each tendon of flexor digitorum profundus in palm
- I: lateral edge of extensor expansion on first phalanx of fingers 2-5
Palmar interossei: palm- between bones

Action: adductors of fingers; pull fingers in toward third digit; act with lumbricalis to extend fingers and interphalangeal joints and flex the at metacarpophalangeal joints
- O: the side of each metacarpal that faces the midaxis of the hand (except finger 3)
- I: extensor expansion on first phalanx of each finger (except 3) on side facing midaxis of heand
Dorsal Interossei: back- between bones

Action: abduct (diverge) fingers; extend fingers at interphalangeal joints and flex them at metacarpophalangeal joints
- O: sides of metacarpals
- I: extensor expansion over first phalanx of fingers 2-4 on side opposite midaxis of hand (except finger 3) but on both side of finger 3

Author

hw.hair

284647

Card Set

Comp. Vert. Part II

Description

muscles

Updated

2014-10-01T23:40:31Z

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