l9/10 myology of upper limb

components of pectoral girdle

• clavicle

• scapula

function of pectoral girdle

stabilizes, positions and move the scapula and clavicle

⤷ anchors upper limb to the axial skeleton

muscles that move the pectoral girdle (6)

1. trapezium

2. levator scapulae

3. rhomboid major

4. rhomboid minor

5. serratus anterior

6. pectoralis major

pectoral girdle (posterior muscles) (4)

1. trapezius

2. levator scapulae

3. rhomboid major

4. rhomboid minor

trapezius (o/i)

origin: skull + thoracic vertebrae

• occipital bone, spinous processes

insertion: clavicle (acromion) and scapula (spine)

trapezius (shape, architecture)

shape: trapezoid

architecture: convergent

levator scapulae (o/i)

origin: cervical vertebrae

⤷ posterior tubercle of transverse processes of C1-C4

insertion: superior scapula

⤷ superior angle and medial border

levator scapulae (shape/architecture)

shape: strap

architecture: parallel

rhomboid minor (o/i)

origin: cervical + thoracic vertebrae

⤷ spinous processes of C7-T1, nuchal ligament

insertion: medial border of scapula

rhomboid major

origin: cervical + thoracic vertebrae

⤷ spinous processes of T2-T5

insertion: medial border of scapula

rhomboid minor/major (shape/architecture)

shape: flat, rhomboid

architecture: parallel

pectoral girdle (anterolateral muscles) (4)

1. pectoralis major

2. pectoralis minor

3. serratus anterior

4. deltoid

pectoralis major (o/i)

origin: sternum, rib cartilages + clavicle

⤷ body of sternum, costocartilages 2-6, inferomedial portion of clavicle

insertion: greater tubercle of humerus

pectoralis major (shape/architecture)

shape: fan, triangular

architecture: convergent

pectoralis minor (o/i)

origin: 3 ribs

⤷ anterosuperior surfaces of ribs 3-5

insertion: coracoid process of scapula

pectoralis minor (shape/architecture)

shape: fan

architecture: convergent

serratus anterior (o/i)

origin: ribs

⤷ anterosuperior margins of ribs 1-8/9

insertion: medial border of scapula

serratus anterior (shape/architecture)

shape: serrated

architecture: parallel (partly convergent overall)

deltoid (o/i)

origin: lateral clavicle, acromion, spine of scapula

insertion: deltoid tuberosity of humerus

deltoid (shape/archiecture)

shape: triangular

architecture: parallel (A), multipennate (B)

rotator cuff (deep muscles) (4)

1. subscapularis

2. supraspinatus

3. infraspinatus

4. teres minor

function of rotator cuff muscles

stabilize and move the glenohumeral joint

subscapularis (o/i)

origin: subscapular fossa of scapula

insertion: lesser tubercle of humerus

subscapularis function

medial rotation of arm at shoulder joint

supraspinatus (o/i)

origin: supraspinous fossa of scapula

insertion: greater tubercle of humerus

supraspinatus function

abduction of arm at shoulder joint

infraspinatus (o/i)

origin: infraspinous fossa of scapula

insertion: greater tubercle of humerus

infraspinatus function

lateral rotation of arm at shoulder joint

teres minor

origin: inferior angle of scapula

insertion: greater tubercle of humerus

teres minor function

lateral rotation and extension of arm at shoulder joint

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 (radius) and bicipital aponeurosis

biceps brachii (shape/architecture)

shape: bicipital, fusiform

architecture: parallel

coracobrachialis (o/i)

origin: coracoid process of scapula

insertion: shaft of humerus

coracobrachialis (shape/architecture)

shape: round, cylindrical

architecture: parallel

brachialis (o/i)

origin: shaft of humerus

insertion: coronoid process of ulna

brachialis (shape/architecture)

shape: quasi-fusiform)

architecture: parallel

brachioradilalis (o/i)

origin: lateral supracondylar ridge of distal humerus

insertion: base of styloid process of radius

brachioradialis (shape/architecture)

shape: quasi-fusiform

architecture: parallel

posterior/extensor arm muscles (1)

triceps brachii

triceps brachii (o/i)

origin:

• long head: infraglenoid tubercle of scapula

• medial head: posterior surface of radial groove of humerus

• lateral: shaft of humerus

insertion: olecranon process of ulna

triceps brachii (shape/architecture)

shape: tricipital. fusiform

architecture: parallel

forearm flexors

• biceps brachii

• brachialis

• brachioradialis

ALL FLEX FOREARM AT ELBOW JOINT

biceps brachii (movements)

• supinates forearm at radioulnar joints

• flexes arm at shoulder joint

forearm extensors

triceps brachii

triceps brachii (movements)

• extends forearm at elbow joint

• extends arm at shoulder joint

muscles that elevate scapula.. (4)

1. upper trapezius

2. levator scapulae

3. rhomboid minor

4. rhomboid major

muscles that depress the scapula.. (4)

• pectoralis minor

• pectoralis major (lower fibers)

• trapezius (lower fibers)

• serratus anterior (lower fibers)

• latissimus dorsi (lower fibers)

muscles that protract scapula.. (3)

• pectoralis minor

• pectoralis major

• serratus anterior

muscles that retract scapula.. (4)

• rhomboid minor

• trapezius (middle fibers)

• rhomboid major

• latissimus dorsi (upper fibers)

medial (downward) rotator muscles.. (4)

• levator scapulae

• rhomboid minor

• rhomboid major

• pectoralis minor

lateral (upwward) rotator muscles.. (3)

• trapezius (upper part)

• trapezius (lower part)

• serratus anterior

abductors of UL (2)

• deltoid

• supraspinatus

• deltoid (lateral)

abductors of UL

• deltoid (anterior, posterior)

• triceps (long head)

• teres major

• latissimus dorsi

• pectoralis major

• coracobrachialis

shoulder flexors (4)

• deltoid (anterior)

• pectoralis major (clavicular head)

• coracobrachialis

• biceps brachii

shoulder extensors (4)

• deltoid (posterior)

• teres major

• latissimus dorsi

• triceps (long head)

medial rotator muscles (5)

• pectoralis major

• deltoid (anterior)

• subscapularis

• latissimus dorsi

• teres major

lateral rotator muscles (3)

• teres minor

• deltoid (posterior)

• infraspinatus

elbow flexors (5)

• biceps brachii

• brachialis

• pronator teres

• brachioradialis

• extensor carpi radialis longus

elbow extensors

• triceps brachii (all heads)