Muscles of the Shoulder Girdle

Synergists of lower trap

upper and middle traps

Nerves that innervate the rhomboids

dorsal scapular, C4, C5

Action of serratus anterior

protracts and upwardly rotates scapula; stabilizes vertebral border to thoracic cage (with rhomboids and middle trap)

Action of the middle trap

retracts and aids in scapular elevation

Action of the rhomboid minor

retracts and elevates scapula, assists in downward rotation of scapula

Action of rhomboid major

retracts and elevates scapula; inferior fibers aid in downward rotation of glenoid cavity

Synergists of the levator scapulae

rhomboids and trapezius

Nerve supply of the subclavius

subclavian branch of the brachial plexus, C5, C6

Origin of the Levator Scapulae

transverse processes of the first four cervical vertebrae

Synergists of rhomboid minor

trapezius, levator scapulae, latissimus dorsi and rhomboid major

Insertion of levator scapulae

vertebral border of scapula between superior angle and scapular spine

Reversed origin-insertion action of the pec minor

when scapula is fixed, aids in rib elevation during forced inspiration

Insertion of the pec minor

coracoid process of the scapula

Origin of the upper trapezuis

external occipital protuberance, medial 1/3 of the superior nuchal line, ligamentum nuchae and spinous process of the 7th cervical vertebrae

Insertion of the subclavius

groove on the inferior surface of the clavicle, between the costo-clavicular

Reversed origin-insertion action levator scapulae

laterally fixes and slightly rotates cervical spine when scapula is fixed

Reversed origin-insertion action of upper trapezius

laterally flexes head and neck; rotates head and neck away from side of contraction; bilateral contraction extends head and neck

Nerves innervating the serratus anterior

long thoracic, C5, C6, C7

Origin of rhomboid minor

lower part of ligamentum nuchae, spinous processes of C7 and T1

Nerves supplying the pec minor

medial pectoral nerve from brachial plexus, C6, C7, C8

Origin of middle trapezius

spinous processes of T-1 to T-5

Synergists of the middle trap

rhomboids, levator scapulae, upper/lower traps

Origin of the lower trap

spinous processes of T-6 to T-12

Origin of the subclavius

1st rib at the junction of the costal cartilage

Origin of the pec minor

anterior surfaces of 3rd, 4th and 5th ribs near the costal cartilage

Insertion of serratus anterior

costal surface of vertebral border along the inferior angle of scapula

Action of the pec minor

depresses and downwardly rotates scapula, shoulder stabilizer

Action of the subclavius

depresses clavicle, pulls inferiorly and anteriorly

Nerves supplying the levator scapulae

dorsal scapular C5, ventral rami of C3 and C4

Insertion of the upper trapezius

lateral 1/3 of the clavicle and acromion process

Synergists of the upper trapezius

levator scapulae, clavicular head of sternocleidomastoid, middle/lower traps

Insertion of lower trap

medial 1/3 of scapular spine

Insertion of rhomboid minor

medial border of scapula at root of the spine

Insertion of the rhomboid major

medial border of scapula from spine to inferior angle

Synergists of the pec minor

pec major, serratus anterior

Synergist of serratus anterior

pec minor

Action of the lower trap

scapular depression, protraction, upward rotation, and stabilization; aids with maintaining spinal extension

Action of upper trapezius

scapular elevation and upward rotation; when acting with other trap sections retracts the scapula

Action of levator scapulae

scapular elevation, downward rotation and retraction (with upper trap)

What innervates the trapezius

spinal accessory and ventral rami of C3 and C4

Origin of rhomboid major

spinous processes of T2 to T5

Insertion of middle trap

superior border of scapular spine

Origin of serratus anterior

superior lateral surfaces of the upper 8 or 9 ribs at the side of the chest

Synergists of rhomboid major

trapezius, levator scapulae, latissimus dorsi, rhomboid minor