Transcript Shoulder, Arm, and Hand

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This describes a muscle that causes specific
movement or possibly several movements to
occur through the process of its own
contraction
To be effective as a mover in the skeletal
system, it must actually cross one or more
structures that can move, typically seen where
the muscle crosses a joint by way of a tendon.
Examples:
Biceps brachii – elbow flexion
Triceps brachii – elbow extension
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Classification used to describe a muscle that acts in
opposition to the specific movement generated by
the agonist.
Responsible for returning a limb, arm or leg, to its
initial position.
Important for balance, extending limbs, holding
objects aloft, and contracting limbs.
Examples:
Flex the knee against resistance: hamstring group
(agonist) and the quadricep group (antagonist)
Elbow flexion: biceps brachii (agonist) and the
triceps brachii (antagonist)
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Kind of muscle that performs or helps performs
the same set of joint motion as the agonist.
Also called “neutralizers”, b/c they help cancel
out, or neutralize, extra motion from the agonist to
make sure that the force generated works w/in the
desired plan of motion.
Example: flex your wrist and then make a fist. See
how hard it is? Now extend your wrist and make
a fist. Easy, right? That is b/c the extensor m. of
the wrist act as a synergist in cooperation with the
flexor m. of the fingers acting as prime movers, or
agonist.
Includes head, neck, back, shoulders,
arms, hands, and fingers
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Buccinator : aids in mastification, tenses cheeks in
blowing and whistling, and aids in closure of
mouth.
Frontalis : wrinkles forehead and fixes galeal
aponeurosis, a tough layer of fibrous tissue which
covers the upper part of the cranium.
Masseter : elevates mandible ( enables forced
closure of mouth)
Orbicularis Oculi : closes eyelids, aids passage and
drainage of tears.
Orbicularis Oris : narrows orifice of mouth, purses
lips and puckers lip edges.
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Platysma : depresses and wrinkles skin of
lower face and mouth; aids in forced
depression of mandible.
Sternocleidomastoid : flexes and laterally
rotates cervical spine; protracts head when
acting together
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Thorax (Chest) Muscles:
Diaphragm: contracts for inspiration and assists in
raising intra-abdominal pressure.
 Intercostals: fix intercostal spaces during respiration.
 Pectoralis Major: b/c of different insertions,
clavicular head allows arm flexion and adduction;
sternal head allows adduction and medial rotation
arm. Also is an accessory for inspiration.
 Serratus Anterior: laterally rotates and protracts the
scapula.
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Abdomen
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External Oblique Abdominus: supports abdomen
wall, assists forced expiration, aids in raising intraabdominal pressure, and w/ muscles of opposite
side, abducts and rotates trunk.
Rectus Abdominus: flexes trunk, aids expiration and
raises intra-abdominal pressure.
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Back:
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Latissimus Dorsi: extends, abducts, and medially
rotates arm; costal attachment aids w/ deep
inspiration and forced expiration.
Rhomboid Major: retracts scapula; rotates scapula to
rest position.
Trapezius: laterally rotates, elevates and retracts
scapula; if scapula is fixed, extends and laterally
flexes neck.
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Rotator Cuff Muscles:
Supraspinatus: Abducts arm and stabilizes shoulder
joint.
 Infraspinatus: Laterally rotates arm and stabilizes
shoulder joint.
 Teres Minor: Laterally rotates arm and stabilizes
shoulder joint.
 Teres Major: Medially rotates and adducts arm.
 Subscapularis: Medially rotates arm and stabilizes
shoulder joint.
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http://www.getbodysmart.com/ap/muscular
system/armmuscles/posteriormuscles/supras
pinatus/tutorial.html
http://www.youtube.com/watch?v=LyWfR5
ZRehQ&feature=player_embedded
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Deltoid: Anterior fibers flex and medially
rotates; Middle fibers abducts arm; Posterior
fibers extend and laterally rotates arm.
Triceps brachii:
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Long Head: Extends the arm at the shoulder and
Extends the forarm at the elbow.
Medial Head: Extends the forearm at the elbow.
Lateral Head: Extends the forearm at the elbow.
Biceps brachii: Supinates the forearm, flexes the
elbow, and weakly flexes the shoulder.
Lower Arm:
 Brachialis: Flexes the elbow.
 Coracobrachialis: Flexes and weakly adducts
arm.
 Brachioradialis: Flexes the arm at the elbow
and brings the forearm into midprone, when
the hand faces inwards or medially, position.
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Supinator: Supinates forearm; only acts alone
when elbow is extended.
Pronator Teres: Pronates forearm and flexes
elbow.
Flexor Carpi Radialis: Flexes and abducts wrist.
Flexor Carpi Ulnaris: Flexes and abducts wrist.
Palmaris Longus: Flexes wrist.
Flexor pollicis brevis/longus: Flexes
metacarpophalangeal joint of thumb; Flexes
distal phalanx of thumb.
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Flexor digiti minimi brevis: Flexes
metacarpophalangeal joint of little finger, 5th
phalange.
Extensor indicis: Extends all joints of index
finger, 3rd phalange.
Extensor carpi radialis brevis/longus: Extends
and abducts hand at wrist.
Extensor pollicis brevis/longus: Extends
metacarpophalangeal joint of thumb; Extends
interphalangeal and metacarpophalangeal
joints.
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Extensor carpi ulnaris: Extends and adducts
hand at wrist.
Extensor digitorum: Extends all joints of
fingers, 2nd- 4th phalange.
Extensor digiti minimi: Extends all joints of
little finger, 5th phalange.
Adductor pollicis: Adducts carpophalangeal
joint of thumb, 1st phalange.
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Abductor pollicis brevis/longus: Abducts
thumb at metacarpophalangeal and
carpometacarpal joints; Abducts and extends
thumb at carpometacarpal joint.
Abductor digiti minimi: Abducts little finger,
5th phalange, at metacarpophalangeal joint.