BIOL 310 Practical 2 MUSCLES OIAI

Trapezius: origin

Superior nuchal line, external occipital protuberance, medial margin of the ligamentum nuchae, spinous processes of CVII to TXII and the related supraspinous ligaments

Trapezius: insertion

Superior edge of the crest of the spine of the scapula, acromion, posterior border of lateral one-third of clavicle

Trapezius: action

Powerful elevator of the scapula; rotates the scapula during abduction of humerus above horizontal; middle fibers retract scapula; lower fibers depress scapula

Trapezius: innervation

Motor—Accessory nerve (cranial nerve [XI]). Sensory—(proprioception) anterior rami of C3 and C4

Latissimus dorsi: origin

Spinous processes of lower six thoracic vertebrae and related interspinous ligaments; via the thoracolumbar fascia to the spinous processes of the lumbar vertebrae, related interspinous ligaments, and iliac crest; lower 3–4 ribs

Latissimus dorsi: insertion

Floor of intertubercular sulcus

Latissimus dorsi: innervation

Thoracodorsal nerve (C6, C7 , C8)

Latissimus dorsi: action

Adduction, medial rotation, and extension of the arm at the glenohumeral joint

Levator scapulae: origin

Transverse processes of CI and CII vertebrae and posterior tubercles of transverse processes of CIII and CIV vertebrae

Levator scapulae: insertion

Posterior surface of medial border of scapula from superior angle to root of spine of the scapula

Levator scapulae: action

Elevates the scapula

Levator scapulae: innervation

Branches directly from anterior rami of C3 and C4 spinal nerves and by branches ( C5 ) from the dorsal scapular nerve

Rhomboids: origin

Lower end of ligamentum nuchae and spinous processes of CVII and TI vertebrae; Spinous processes of TII–TV vertebrae and intervening supraspinous ligaments

Rhomboids: insertion

Posterior surface of medial border of scapula from the root of the spine of the scapula to the inferior angle

Rhomboids: action

Elevates and retracts the scapula

Rhomboids: innervation

Dorsal scapular nerve ( C4, C5 )

Deltoid: origin

Inferior edge of the crest of the spine of the scapula, lateral margin of the acromion, anterior border of lateral one-third of clavicle

Deltoid: insertion

Deltoid tuberosity of humerus

Deltoid: action

Major abductor of arm; clavicular fibers assist in flexing the arm; posterior fibers assist in extending the arm

Deltoid: innervation

Axillary nerve ( C5 , C6)

Pectoralis major: origin

Clavicular head—anterior surface of medial half of clavicle; sternocostal head—anterior surface of sternum; first seven costal cartilages; sternal end of sixth rib; aponeurosis of external oblique

Pectoralis major: insertion

Lateral lip of intertubercular sulcus of humerus

Pectoralis major: action

Flexion, adduction, and medial rotation of arm at glenohumeral joint; clavicular head—flexion of extended arm; sternocostal head—extension of flexed arm

Pectoralis major: innervation

Medial and lateral pectoral nerves; clavicular head ( C5 , C6); sternocostal head (C6, C7 , C8, T1)

Pectoralis minor: origin

Anterior surfaces and superior borders of ribs III to V; and from deep fascia overlying the related intercostal spaces

Pectoralis minor: insertion

Coracoid process of scapula (medial border and upper surface)

Pectoralis minor: action

Pulls tip of shoulder down; protracts scapula

Pectoralis minor: innervation

Medial and lateral pectoral nerve (C5, C6, C7, C8 , T1)

Serratus anterior: origin

Lateral surfaces of upper 8–9 ribs and deep fascia overlying the related intercostal spaces

Serratus anterior: insertion

Costal surface of medial border of scapula

Serratus anterior: action

Protraction and rotation of the scapula; keeps medial border and inferior angle of scapula opposed to thoracic wall

Serratus anterior: innervation

Long thoracic nerve ( C5 , C6, C7)

Supraspinatus: origin

Medial two-thirds of the supraspinous fossa of the scapula and the deep fascia that covers the muscle

Supraspinatus: insertion

Most superior facet on the greater tubercle of the humerus

Supraspinatus: action

Rotator cuff muscle ; participates in abduction of the glenohumeral joint; stabilization of glenohumeral joint

Supraspinatus: innervation

Suprascapular nerve ( C5 , C6)

Infraspinatus: origin

Medial two-thirds of the infraspinous fossa of the scapula and the deep fascia that covers the muscle

Infraspinatus: insertion

Middle facet on posterior surface of the greater tubercle of the humerus

Infraspinatus: action

Rotator cuff muscle ; lateral rotation of arm at the glenohumeral joint; stabilization of glenohumeral joint

Infraspinatus: innervation

Suprascapular nerve ( C5 , C6)

Teres minor: origin

Upper two-thirds of a flattened strip of bone on the posterior surface of the scapula immediately adjacent to the lateral border of the scapula

Teres minor: insertion

Inferior facet on the posterior surface of the greater tubercle of the humerus

Teres minor: action

Rotator cuff muscle ; lateral rotation of arm at the glenohumeral joint; stabilization of glenohumeral joint

Teres minor: innervation

Axillary nerve ( C5 , C6)

Subscapularis: origin

Medial two-thirds of subscapular fossa

Subscapularis: insertion

Lesser tubercle of humerus

Subscapularis: action

Rotator cuff muscle ; medial rotation of the arm at the glenohumeral joint

Subscapularis: innervation

Upper and lower subscapular nerves (C5, C6 , (C7))

Teres major: origin

Elongate oval area on the posterior surface of the inferior angle of scapula

Teres major: insertion

Medial lip of the intertubercular sulcus on the anterior surface of the humerus

Teres major: action

Medial rotation and extension of the arm at the glenohumeral joint; stabilization of glenohumeral joint

Teres major: innervation

Inferior subscapular nerve ( C5, C6, C7 )

Biceps brachii: origin

Long head—supraglenoid tubercle of scapula; short head—apex of coracoid process

Biceps brachii: insertion

Tuberosity of radius

Biceps brachii: action

Powerful flexor of the forearm at the elbow joint and supinator of the forearm; accessory flexor of the arm at the glenohumeral joint

Biceps brachii: innervation

Musculocutaneous nerve ( C5, C6 )

Coracobrachialis: origin

Apex of coracoid process

Coracobrachialis: insertion

Linear roughening on midshaft of humerus on medial side

Coracobrachialis: action

Flexor of the arm at the glenohumeral joint; adducts arm

Coracobrachialis: innervation

Musculocutaneous nerve ( C5, C6, C7 )

Brachialis: origin

Anterior aspect of humerus (medial and lateral surfaces) and adjacent intermuscular septae

Brachialis: insertion

Tuberosity of the ulna

Brachialis: action

Powerful flexor of the forearm at the elbow joint

Brachialis: innervation

Musculocutaneous nerve (C5, C6 ); small contribution by the radial nerve (C7) to lateral part of muscle

Brachioradialis: origin

Proximal part of lateral supraepicondylar ridge of humerus and adjacent intermuscular septum

Brachioradialis: insertion

Lateral surface of distal end of radius

Brachioradialis: action

Accessory flexor of elbow joint when forearm is midpronated

Brachioradialis: innervation

Radial nerve (C5, C6 ) before division into superficial and deep branches

Triceps brachii: origin

Long head—infraglenoid tubercle of scapula; medial head—posterior surface of humerus; lateral head—posterior surface of humerus

Triceps brachii: insertion

Olecranon

Triceps brachii: action

Extension of the forearm at the elbow joint; long head can also extend and adduct the arm at the shoulder joint

Triceps brachii: innervation

Radial nerve (C6, C7 , C8)

Pronator quadratus: origin

Linear ridge on distal anterior surface of ulna

Pronator quadratus: insertion

Distal anterior surface of radius

Pronator quadratus: action

Pronation

Pronator quadratus: innervation

Median nerve (anterior interosseous nerve) (C7, C8 )

Pronator teres: origin

Humeral head—medial epicondyle and adjacent supra-epicondylar ridge; ulnar head—medial side of coronoid process

Pronator teres: insertion

Roughening on lateral surface, midshaft, of radius

Pronator teres: action

Pronation

Pronator teres: innervation

Median nerve (C6, C7 )

Supinator: origin

Superficial layer—lateral epicondyle of humerus, radial collateral and anular ligaments; deep layer—supinator crest of the ulna

Supinator: insertion

Lateral surface of radius superior to the anterior oblique line

Supinator: action

Supination

Supinator: innervation

Posterior interosseous nerve ( C6 , C7)

Flexors of the hand and wrist: origin

Medial epicondyle of humerus

Flexors of the hand and wrist: insertion

base of metacarpals

Flexors of the hand and wrist: action

flex and abduct wrist

Flexors of the hand and wrist: innervation

median nerve

Extensors of the hand and wrist: origin

Lateral epicondyle of humerus

Extensors of the hand and wrist: insertion

Dorsal surface of base of metacarpals

Extensors of the hand and wrist: action

extend and abduct wrist

Extensors of the hand and wrist: innervation

radial nerve

Iliopsoas: origin

Posterior abdominal wall (lumbar transverse processes, intervertebral discs, and adjacent bodies from TXII to LV and tendinous arches between these points, iliac fossa)

Iliopsoas: insertion

Lesser trochanter of femur

Iliopsoas: action

Flexes the thigh at the hip joint

Iliopsoas: innervation

Anterior rami ( L1, L2 , L3); Femoral nerve (L2, L3)

Tensor fascia latae: origin

Lateral aspect of crest of ilium between anterior superior iliac spine and tubercle of the crest

Tensor fascia latae: insertion

Iliotibial tract of fascia lata

Tensor fascia latae: action

Stabilizes the knee in extension

Tensor fascia latae: innervation

Superior gluteal nerve ( L4, L5 , S1)