Shoulder girdle muscles

Question 1

O and I of pectoralis minor

Answer 1

O = ribs 3-5, I = coracoid process

Question 2

What do the shoulder girdle muscles do

Answer 2

All the shoulder girdle muscles have proximal attachments (origin) on the axial
skeleton, and distal attachments (insertion) on the shoulder girdle (scapula
and/or clavicle).
None of the muscles cross the glenohumeral joint, and thus none directly
cause GH joint motion.

Question 3

What are the shoulder girdle muscles

Answer 3

Two anterior (anterior trunk)
* Pectoralis minor
* Serratus anterior (anterior to the scapula)
Three posterior (Posterior trunk)
* Trapezius
* Rhomboids
* Levator scapulae

Question 4

Concentric actions of the pectoralis minor

Answer 4

Protraction, downward rotation and depression

Question 5

O and I of seratus anterior

Answer 5

O = ribs 1-9, I = anterior surface and medial border of the scapula

Question 6

Concentric actions of the seratus anterior

Answer 6

Protraction and upward rotation

Question 7

Trapezius O and I

Answer 7

O = occipital protuberance, cervical and thoracic vertebrae spinous processes
I = spine of scapula, lateral 1/3 of the clavicle, and acromion process

Question 8

Concentric actions of the trapezius

Answer 8

Upper fibres - elevation
Middle fibres - elevation, retraction, upwards rotation
Lower - depression, retraction and upwards rotation

Question 9

Rhomboids O and I

Answer 9

O= C7-T5 spinous processes
I = medial border of scapula

Question 10

Concentric actions of the rhomboids

Answer 10

Elevation, retraction, downwards rotation

Question 11

Concentric action of the levator scapulae

Answer 11

Elevation