Frontalis
Origen: Epicranial aponeurosis
Insertion: Skin of eyebrows and root of nose
Action:
Nerve:
Temporalis
Origen:
Insertion:
Action:
Nerve:
Occipitalis
Description:
Origen:
Insertion:
Action:
Nerve:
Latissimus Dorsi
Description: Broad, flat, triangular muscle of lower
back (lumbar region).
Origen: Indirect attachment via lumbodorsal fascia
into spines of lower six thoracic vertebrae, lumbar vertebrae, lower 3
to 4 ribs, and iliac crest; also from scapula's inferior angle
Insertion: Spirals around teres major to insert in
floor of intertubercular sulcus of humerus
Action: Prime mover of arm extension;
powerful arm adductor; medially rotates arm at shoulder
Nerve: Thoracodorsal nerve (
Pectoralis Major
Description: Large, fan-shaped muscle covering
superior portion of chest
Origen: Sternal end of clavicle, sternum, cartilage
of rib 1-6 (or 7), and aponeurosis of external oblique muscle
Insertion: Fibers converge to insert by a short
tendon into intertubercular sulcus and greater tubercle of humerus.
Action: Adducts and medially rotates arm
Nerve: Lateral and medial pectoral nerves (C5-C8 and T1)
Pectoralis Minor
Description: Flat, thin muscle directly beneath and
obscured by pectoralis major.
Origen: Anterior surfaces of ribs 3-5 (or 2-4)
Insertion: Coracoid process of scapula
Action: With ribs fixed, draws scapula forward and downward
Nerve: Medial and lateral pectoral nerves (C6-C8)
Deltoid
Description: Thick, multipennate muscle forming
rounded shoulder muscle mass
Origen: Embraces insertion of the trapezius;
lateral third of clavicle; acromion and spine of scapula
Insertion: Deltoid tuberosity of humerus
Action: Prime mover of arm abduction when all its
fibers contract simultaneously
Nerve: Axilary nerve (C5 and C6
Triceps Brachii
a) Lateral head
b) Long head
c) Medial head
Description: Large fleshy muscle, the only muscle of
posterior compartment of arm, 3 headed origin.
Origen: Long head - infragleoid tubercle of scapula,
Lateral head: posterior shaft of humerous; Medial head: posterior
humeral shaft distal to radial groove.
Insertion: by common tendon into olecranon ulna
Action: Powerful Forearm Extensor
Nerve: Radial Nerve (C6-C8)
Biceps Brachii
Description : Two headed fusiform muscle, bellies unite as insertion
point is aprproached; tendon of long head helps stabilize shoulder joint.
Origen: Short head: coracoid process. Long head: supraglenoid
tubercle and into intertubercular sulcus of humerus.
Insertion: By common tendon into radial tuberosity
Action: Flexes and supinates forearm; these actions usually occur
at same time
Nerve: Musculocutaneous nerve (Cs and C6)
Pronator Teres
Description: Two-headed muscle; seen in superficial view
Origen: Medial epicondyle of humerus, coronoid
process of ulna
Insertion: By common tendon into lateral radius, midshaft
Action: Pronates forearm
Nerve: Median nerve
Supinator
Description: Deep muscle at posterior aspect of
elbow; largely concealed by superficial muscle.
Origen: Lateral epicondyle of humerus; proximal ulna
Insertion: Proximal end of radius
Action: Assists biceps branchii to forcibly supinate
forearm. Antigonist of pronator muscle.
Nerve: Posterior interosseous nerve
Flexor Carpi Radialis
Description: Runs diagonally across forearm; midway,
its fleshy belly is replaced by a flat tendon that becomes cordlike at wrist
Origen: Medial epicondyle of humerus
Insertion: Base of second and third metacarpals;
insertion tendon easily seen and provides guide to position of radial
artery at wrist (used for taking pulse)
Action: Powerful flexor and abductor of
hand; weak synergist of elbow flexion.
Nerve:Median nerve
Palmaris Longus
Description: Small fleshy muscle with a long
insertion tendon; often absent; may be used as guide to find median
nerve that lies lateral to it at wrist.
Origen: Medial epicondyle of humerus
Insertion: Palmar aponeurosis
Action:
Tenses skin and fascia of palm during palm movement; weak wrist
flexor; weak synergist for elbow flexion
Nerve: Median Nerve
Flexor carpi ulnaris
Description: Most medial muscle of this group;
two-headed; ulnar nerve lies lateral to its tendon
Origen: Medial epicondyle of humerus; olecrenon and
posterior surface of ulna.
Insertion: Pisiform and hamate bones and base of
fifth metacarpal
Action:Powerful flexor and adductor of hand.
Nerve: Ulnar Nerve
Pronator Teres
Description: Two-headed muscle; seen in superficial
view between proximal margins of Brachioradialis and flexor carpi
radialis; forms medial boundaries of cubital fosa.
Origen: Medial epicondyle of humerous; coronoid
process of ulna
Insertion: By common tendon into lateral radius, midshaft
Action: Pronates forearm; weak flexor of elbow.
Nerve: Median Nerve
Extensor Carpi Radialis Longus
Description: Parallels brachioradialis on lateral
forearm, and my blend with it.
Origen: Lateral supracondylar ridge of humerus
Insertion: Base of second metacarpal
Action:
Extends hand in conjunction with extensor carpi
ulnaris and ABDUCTS hand in conjunction with flexor
carpi radialis.
Nerve: Radial Nerve C6 and C7
Extensor Carpi Radialis Bravis
Description: Shorter than extensor Carpi radialis
longus and lies deep to it.
Origen: Lateral epicondyle of humerus
Insertion: Base of third metacarpal
Action:
Extends and abducts hand. Acts synergistically
with extensor carpi radialis longus to steady wrist during finger flexion.
Nerve: Deep branch of redial nerve.
Extensor Digitorum
Description: Lies medial to extensor carpi radialis
brevis; a detached portion of this muscle, called extensor digit
minimi, extends little finger
Origen: Lateral epicondyle of humerus
Insertion: by four tendons into extensor expansion
and distal phalanges of second to fifth fingers.
Action:
Prime move of finger extension; extends hand can
abduct (flare) fingers.
Nerve: Posterior interosseous nerve, a branch of
radial nerve (C5 and C6)