EXAM 3 - MUSCLES

Pectoralis major — Origins (2)

clavicular head = clavicle; sternocostal head = sternum and adjacent costal cartilages

Pectoralis major — Insertion

Lateral lip of intertubercular sulcus of humerus

Pectoralis major — Innervation

Clavicular head: lateral pectoral nerve; Sternocostal head: medial pectoral nerve

Pectoralis major — Action

clavicular head: flexion, adduction, and medial rotation of arm

Sternocostal head: extension (when arm is flexed), adduction, and medial rotation of arm

Deltoid — Origin

Anterior part: clavicle; Middle part: acromion; Posterior part: scapular spine

Deltoid — Insertion

Deltoid tuberosity on the humerus

Deltoid — Innervation

Axillary nerve

Deltoid — Actions (3)

Anterior: flexion of arm

Middle: abduction of arm

Posterior: extension of arm

Latissimus Dorsi — Origin

Thoracolumbar aponeurosis

Latissimus Dorsi — Insertion

Intertubercular sulcus of the humerus

Latissimus Dorsi — Innervation

Thoracodorsal nerve (middle scapular nerve)

Latissimus Dorsi — Action

Extension, adduction, and medial rotation of arm

Teres Major — Origin

Inferior angle of scapula

Teres Major — Insertion

Medial lip of intertubercular sulcus of humerus

Teres Major — Innervation

Lower subscapular nerve

Teres Major — Action

Extension, adduction, and medial rotation of arm

Supraspinatus — Origin

Supraspinous fossa of scapula

Supraspinatus — Insertion

Greater tubercle of humerus

Supraspinatus — Innervation

Suprascapular nerve

Supraspinatus — Action

Abduction of arm

Infraspinatus — Origin

Infraspinous fossa of scapula

Infraspinatus — Insertion

Greater tubercle of humerus

Infraspinatus — Innervation

Suprascapular nerve

Infraspinatus — Action

Lateral rotation of arm

Teres Minor — Origin

Lateral border of scapula

Teres Minor — Insertion

Greater tubercle of humerus

Teres Minor — Innervation

Axillary nerve

Teres Minor — Action

Lateral rotation of arm

Subscapularis — Origin

Subscapular fossa of scapula

Subscapularis — Insertion

Lesser tubercle of humerus

Subscapularis — Innervation

Upper and lower subscapular nerves

Subscapularis — Action

Medial rotation of arm

which 4 muscles reinforce fibrous capsule of glenohumeral joint for stabilization?

Supraspinatus

Infraspinatus

Teres minor

Subscapularis

which muscles act on the scapula? (6)

trapezius, levator scapulae, rhomboid major, rhomboid minor, serratus anterior, pectoralis minor

Trapezius — Origin

Superior nuchal line of occipital bone, nuchal ligament, and spinous processes of thoracic vertebrae

Trapezius — Insertion

Clavicle, acromion, and scapular spine

Trapezius — Innervation

Accessory nerve (CN XI) and ventral rami of C3-C4

Trapezius — Action

Upper part - Scapular elevation

Middle part - retraction of scapula

Lower part - depression of scapula

upper and lower parts together: glenoid up rotation of scapula

Levator Scapulae — Origin

Transverse processes of upper cervical vertebrae

Levator Scapulae — Insertion

Superior angle of scapula

Levator Scapulae — Innervation

Dorsal scapular nerve

Levator Scapulae — Action

Elevation of scapula

Rhomboids (Minor and Major) — Origin

Nuchal ligament and spinous processes of upper thoracic vertebrae.

Rhomboids (Minor and Major) — Insertion

Medial border of scapula.

Rhomboids (Minor and Major) — Innervation

Dorsal scapular nerve

Rhomboids (Minor and Major) — Action

Retraction, elevation, and glenoid down rotation of scapula

Serratus Anterior — Origin

Upper 9 ribs

Serratus Anterior — Insertion

Medial border of scapula

Serratus Anterior — Innervation

Long thoracic nerve

Serratus Anterior — Action

Protraction and glenoid up rotation of scapula

Pectoralis Minor — Origin

Ribs 3-5

Pectoralis Minor — Insertion

Coracoid process of scapula

Pectoralis Minor — Innervation

Medial pectoral nerve

Pectoralis Minor — Action

Protraction and depression of scapula

muscles of the anterior compartment of the arm (3)

biceps brachii

coracobrachialis

brachialis

Biceps Brachii — Origin

Long head: supraglenoid tubercle of scapula

Short head: coracoid process of scapula

Biceps Brachii — Insertion

Radial tuberosity; deep fascia of forearm via bicipital aponeurosis

Biceps Brachii — Innervation

Musculocutaneous nerve (C5-C7).

Biceps Brachii — Primary and Secondary Actions

Primary: supinates forearm.

Secondary: flexes forearm at elbow (while supinated)

Secondary: flexes shoulder (weak)

Coracobrachialis — Origin

Coracoid process of scapula

*Shared with short head of biceps brachii

Coracobrachialis — Insertion

Medial aspect of humerus at midshaft.

Coracobrachialis — Innervation

Musculocutaneous nerve (C5-C7).

Coracobrachialis — Action

Adducts and flexes the arm at glenohumeral joint.

Brachialis — Origin

Distal half of anterior humerus.

Brachialis — Insertion

Coronoid process and tuberosity of ulna.

Brachialis — Innervation

Musculocutaneous nerve (C5-C7)

Brachialis — Action

ONLY pure flexor of forearm

muscles of the posterior compartment of the arm (2)

triceps brachii

anconeus

triceps brachii origin (long head)

infraglenoid tubercle

triceps brachii origin (lateral head)

posterior humerus lateral to radial groove

triceps brachii origin (medial head)

shaft of humerus medial to radial groove

Triceps Brachii — Insertion

Olecranon process of ulna

Triceps Brachii — Innervation

Radial nerve

Triceps Brachii — Action

Extends forearm (especially medial head)

Extends arm (long head only; only long head crosses glenohumeral joint)

Adducts arm

Anconeus — Origin

Posterior humerus, just superior to capitulum

Anconeus — Insertion

Lateral surface of proximal ulna

Anconeus — Innervation

Radial nerve

Anconeus — Action

Synergist of triceps brachii in elbow extension

muscles of the anterior compartment of the forearm (8)

pronator teres - superficial layer

flexor carpi radialis - superficial layer

palmaris longus - superficial layer

flexor carpi ulnaris - superficial layer

flexor digitorum superficialis - middle layer

flexor digitorum profundus - deep layer

flexor pollicis longus - deep layer

pronator quadratus - deep layer

Pronator Teres — Origin

Superficial head: medial supracondylar ridge of humerus

Deep head: coronoid process of ulna

Pronator Teres — Insertion

Radial shaft

Pronator Teres — Innervation

Median nerve

Pronator Teres — Action

Flexion and pronation of forearm

Flexor Carpi Radialis — Origin

Common flexor tendon

Flexor Carpi Radialis — Insertion

Radial side of wrist

Flexor Carpi Radialis — Innervation

Median nerve

Flexor Carpi Radialis — Action

Flexion and abduction of hand

Palmaris Longus — Origin

Common flexor tendon

Palmaris Longus — Insertion

Palmar aponeurosis

Palmaris Longus — Innervation

Median nerve

Palmaris Longus — Action

Flexion of hand

Flexor Carpi Ulnaris — Origin

Common flexor tendon and ulnar shaft

Flexor Carpi Ulnaris — Insertion

Pisiform at ulnar side of wrist

Flexor Carpi Ulnaris — Innervation

Ulnar nerve

Flexor Carpi Ulnaris — Action

Flexion and adduction of hand

Flexor Digitorum Superficialis — Origin

Common flexor tendon, coronoid process, and radial shaft

Flexor Digitorum Superficialis — Insertion

Middle phalanges II-V

Flexor Digitorum Superficialis — Innervation

Median nerve

Flexor Digitorum Superficialis — Action

Flexion of hand and digits II-V (at MCP/PIP joints only)

Flexor Digitorum Profundus — Origin

Radius, ulna, and adjacent interosseous membrane