shoulder+arm muscles

posterior back muscles (6)

1. trapezius

2. latissimus dorsi

3. levator scapulae

4. rhomboid major

5. rhomboid minor

6. teres major

trapezius (o/i)

origin: occipital bone, spinous processes of thoracic vertebrae

insertion: acromion and spine (of scapula)

trapezius (shape/architecture)

shape: trapezoid

architecture: convergent

levator scapulae (o/i)

origin: transverse process of C1-C4

insertion: superior angle (of scapula) + medial border

levator scapulae (shape/architecture)

shape: strap

architecture: parallel

rhomboid minor (o/i)

origin: spinous processes of C7-T1

insertion: medial border (of scapula)

rhomboid minor (shape/architecture)

shape: rhomboid

architecture: parallel

rhomboid major (o/i)

origin: spinous processes of T2-T5

insertion: medial border (of scapula)

rhomboid major (shape/architecture)

shape: rhomboid

architecture: parallel

anterolateral muscles (4)

1. pectoralis major

2. pectoralis minor

3. serratus anterior

4. deltoid

pectoralis major (o/i)

origin: body of sternum, rib cartilages, clavicle

insertion: greater tubercle of humerus

pectoralis major (shape/architecture)

shape: triangular

architecture: convergent

pectoralis minor (o/i)

origin: ribs 3-5

insertion: coracoid process (of scapula)

serratus anterior (o/i)

origin: ribs 1-9

insertion: medial border (of scapula)

serratus anterior (shape/architecture)

shape: serrated

architecture: parallel (convergent overall)

deltoid (o/i)

origin: lateral clavicle, acromion and spine (of scapula)

insertion: deltoid tuberosity of humerus

deltoid (shape/architecture)

shape: triangular

architecture: multipennate

deep (rotator cuff) (4)

1. subscapularis

2. supraspinatus

3. infraspinatus

4. teres minor

subscapularis (o/i)

origin: subscapularis fossa

insertion: lesser tubercle (of humerus)

supraspinatus (o/i)

origin: supraspinous fossa (of scapula)

insertion: greater tubercle of humerus

infraspinatus (o/i)

origin: infraspinous fossa

insertion: greater tubercle of humerus

teres minor (o/i)

origin: inferior lateral border (of scapula)

insertion: greater tubercle (of humerus)

function of rotator cuff muscles

stabilise and move the shoulder at glenohumeral joint

muscle/s that medially rotate humerus at GHJ

1. subscapularis

muscle/s that laterally rotate humerus at GHJ

1. infraspinatus

2. teres minor

muscle/s that abduct humerus at GHJ

1. supraspinatus

anterior (flexor) arm muscles (4)

1. biceps brachii

2. coracobrachialis

3. brachialis

4. brachioradialis

biceps brachii (o/i)

origin:

• short head: coracoid process

• long head: supraglenoid tubercle

insertion: radial tuberosity (of radius)

biceps brachii (shape/architecture)

shape: bicipital, fusiform

architecture: parallel

coracobrachialis (o/i)

origin: coracoid process of scapula

insertion: medial humeral shaft

coracobrachialis (shape/architecture)

shape: round (cylindrical)

architecture: parallel

brachialis (o/i)

origin: anterior, distal humeral shaft

insertion: coronoid process of ulna

brachialis (shape/architecture)

shape: quasi-fusiform

architecture: parallel

brachioradialis (o/i)

origin: lateral supracondylar ridge (of humerus)

insertion: styloid process (of radius)

brachioradialis (shape/architecture)

shape: quasi-fusiform

architecture: parallel

ARCHITECTURE OF ALL ANTERIOR ARM MUSCLES = PARALLEL

posterior (extensor) arm muscles (1)

triceps brachii

triceps brachii (o/i)

origin:

• lateral: superior, lateral margin of humerus

• long: infraglenoid tubercle (of scapula)

• medial: posterior humeral surface inferior to radial groove

insertion: olecranon process of ulna

triceps brachii (shape/architecture)

shape: tricipital, fusiform

architecture parallel