Muscles Acting on the Scapula

Question 1

Levator Scapulae

Answer 1

Act: Scapular elevation and downward rotation
O: Transverse process of cervical vertebrae C1-C4
I: Superior medial angle of scapula
Innervation: Dorsal Scapular

Question 2

Rhomboid Major

Answer 2

Act: Scapular retraction, elevation, and downward rotation
O: Spinous process of T2-T5
I: Vertebral border of scapula (lower two-thirds)
Innervation: Dorsal Scapular

Question 3

Rhomboid Minor

Answer 3

Act: Scapular retraction and elevation
O: Inferior portion of the ligamentum nuchae
Spinous process of C7 and T1
I: Vertebral border of scapula (near the medial border of the scapular spine)
Innervation: Dorsal Scapular

Question 4

Serratus Anterior

Answer 4

Act: Scapular upward rotation and protraction, scapular depression (lower fibers), scapular elevation (upper fibers), fixation of the scapula to the thorax
O: Anterior portion of 1st - 8th ribs, aponeuroses of the intercostal muscles
I: Costal surfaces of the superior angle of scapula and vertebral border of scapula. Inferior angle of scapula
Innervation: Long thoracic

Question 5

Trapezius (upper one-third)

Answer 5

Act: Scapular elevation and upward rotation, rotation of C spine to the opposite side, extension of C spine.
O: Occipital protuberance, superior nuchal line of the occipital bone, upper portion of the ligamentum nuchae, spinous process of C7.
I: Distal/lateral one-third of clavicle, acromion process, scapular spine.
Innervation: Accessory

Question 6

Trapezius (middle one-third)

Answer 6

Act: scapular retraction and fixation of thoracic spine
O: lower portion of ligamentum nuchae, spinous processes of C7 and T1-T5
I: Distal one-third of clavicle, acromion process, scapular spine.
Innervation: Accessory

Question 7

Trapezius (lower one-third)

Answer 7

Act: Scapular depression, upward rotation and retraction; external rotation and posterior tipping of scapula
O: Spinous processes and supraspinal ligaments of T8-T12
I: Spine of the scapula (medial portion)
Innervation: Accessory

Question 8

Pectoralis Minor

Answer 8

Act: Scapular anterior tilt
O: Costal cartridges of ribs 6-7 and anterior portion of 3rd-5th ribs
I: Coracoid process of scapula
Innervation: Lateral Pectoral