Muscles Of The Shoulder And Arm

Front 1

Trapezius (upper)

Back 1

O= External occipital protuberance, medial third of superior nuchal line of occipital bone, ligamentum. nuchae, spinous processes of C6-T12

I= Lateral third of clavicle, acromion process, and spine of the scapula.

A= Scapular elevation and upward rotation, assist in retraction of scapula.

N= Spinal accessory (cranial nerve [CN] XI) C2,C3,C4 sensory component.

Hint 1

Function: Raises and lowers the shoulders and shrug them (more vertical line of pull)

Front 2

Trapezius (middle)

Back 2

O= Spinous processes of C7-T3

I= Scapular spine

A= Scapular retraction (adduct)

N= Spinal accessory (CN XI) C3, C4 sensory component

Hint 2

Function: Squeeze shoulder blades together and stabilize scapula; (horizontal line of pull makes it very effective at scapular retraction)

Front 3

Trapezius (lower)

Back 3

O= Spinous processes of middle and lower thoracic vertebrae T4-T12.

I= Base of scapular spine

A= Scapular depression and upward rotation; assist in retraction.

N= Spinal accessory (CN XI) C3, C4 sensory component.

Hint 3

Function: It's diagonal line of pull is more downward(vertical), depress and upward rotate scapula.

Front 4

Levator Scapulae

Back 4

O= Transverse processes of first four cervical vertebrae.

I= Vertebral border of scapula (between the superior angle and spine).

A= Scapular elevation and downward rotation.

N= Third and Fourth cervical nerves and dorsal scapular nerve (C5).

Hint 4

Function: Elevates and retracts the scapula and abduct the neck (diagonal line of pull is mostly vertical)

Front 5

Rhomboid minor

Back 5

O= Spinous processes of C7-T1 vertebrae.

I= Medial border of scapula near the level of the spine, superior to rhomboid major.

A= Retracts the scapula and rotates it to depress the glenoid cavity; fixes scapula to thoracic wall (scapulothoracic articulation).

N= Dorsal scapular nerve(C4, C5).

Hint 5

Function: Retracts, rotates, and fixes the scapula.

Front 6

Rhomboid major

Back 6

O= Spinous processes of T2-T5 vertebrae.

I= Medial border of scapula near the level of the spine to the inferior angle.

A= Retracts the scapula and rotates it to depress the glenoid cavity; fixes scapula to thoracic wall (scapulothoracic articulation ).

N= Dorsal scapular nerve (C4, C5).

Hint 6

Function: Retracts, rotates, and fixes the scapula.

Front 7

Latisimus Dorsi

Back 7

O= Spinous process T7-L5 (via dorsolumbar fascia); posterior surface of sacrum, iliac crest and lower 3 ribs.

I= Bicipital (intertubercular) groove of humerus (medial floor)

A= Extension, hyperextension, adduction, and medial (internal) rotation.

N= Thoracodorsal nerve (C6,C7,C8).

Front 8

Teres Major

Back 8

O= Axillary border (scapula) near the inferior angle.

I= Crest below the lesser tubercle.

A= Shoulder extension, medial rotation, and adduction.

N= Lower scapular nerve (C5, C6, C7)

Front 9

Back 9

O= Subscapular fossa(scapula).

I= Lesser tubercle (humerus)

A= Shoulder medial rotation; and adduct the arm to help hold the humerus head in glenoid cavity.

N= Upper & lower subscapular nerves (C4, C6)

Front 10

Back 10

O= Axillary border (scapula).

I= Greater tubercle (humerus).

A= Shoulder lateral rotation and horizontal abduction.

N= Axillary nerve (C5, C6).

Front 11

Back 11

O= Infraspinous fossa (scapula).

I= Greater tuburcle (humerus).

A= Shoulder lateral rotation and horizontal abduction.

N= Suprascapular nerve (C5, C6).

Front 12

Supraspinatus

Back 12

O= Supraspinous fossa (scapula).

I= Greater tubercle(humerus).

A= Shoulder abduction.

N= Suprascapular nerve (C5, C6).

Front 13

Rotator Cuff Muscles

Back 13

•Supraspinatus

•Infraspinatus

•Teres Minor

•Sunscapularis

Front 14

Middle (Lateral)Deltoid

Back 14

O= Acromion Process.

I= Deltoid tuberosity.

A= Shoulder abduction.

N= Axillary nerve (C5, C6).

Front 15

Posterior Deltoid

Back 15

O= Spine of scapula.

I= Deltoid tuberosity.

A= Shoulder extension, hyperextension, abduction, horizontal abduction, lateral (external) rotation.

N= Axillary nerve (C5, C6 ).

Front 16

Anterior Deltoid

Back 16

O= Lateral third of clavicle.

I= Deltoid tuberosity.

A= Shoulder flexion, abduction, horizontal adduction, and medial rotation.

N= Axillary nerve (C5, C6)

Front 17

Back 17

O= Sternal costal cartilage of first six ribs.

I= Lateral lip of bicipital groove of humerus.

A= Shoulder extension (1st 60°) from 180° to 120°.

N= Lateral & medial pectoral nerve (C5, C6, C7, C8, T1).

Front 18

Pectoralis Major (clavicular & sternal portions)

Back 18

A= Shoulder adduction, horizontal adduction, medial rotation.

N= Lateral & Medial pectoral nerve (C5, C6, C7, C8, T1).

Front 19

Pectoralis Major (clavicular portion)

Back 19

O= Medial third of clavicle.

I= Lateral lip of bicipital groove of humerus.

A= Shoulder flexion (1st 60°).

N= Lateral & medial pectoral nerve (C5, C6, C7, C8, T1).

Front 20

Pectoralis Minor

Back 20

O= Anterior surface of ribs 3-5.

I= Coracoid process of scapula.

A= Scapular depression, protraction, downward rotation and tilt.

N= Medial pectoral nerve (C8, T1)

Hint 20

Function: pulls the shoulder girdle down and forward; elevate the thorax during forced inhalation. The muscle is on the anterior surface while the scapula moves on the posterior surface.

Front 21

Serratus Anterior

Back 21

O= Lateral surface of the upper 8 ribs (1-8).

I= Vertebral (medial) border of the scapula anterior surface.

A= Scapular protraction, upward rotation.

N= Long thoracic nerve (C5, C6, C7)

Hint 21

Function: allows forward rotation of the arm and to pull scapula around the rib cage; upward rotation allowing abduction of the arm.

Front 22

Coracobrachialis

Back 22

O= Coracoid process(scapula).

I= Medial surface of humerus (midpoint).

A= Stabilize the shoulder joint; Assist in shoulder flexion and medial rotation.

N= Musculocutaneous nerve (C6, C7).

Hint 22

Lies deep to the biceps brachii.