Actions of Back Muscles

Question 1

Trapezius

Answer 1

Elevation, retraction, depression of scapula; rotation of glenoid fossa superiorly

Question 2

Latissimus Dorsi

Answer 2

Extension, adduction, medial/internal rotation of humerus; lifts body toward arm in climbing

Question 3

Levator Scapulae

Answer 3

Elevates scapula medially, rotates glenoid fossa inferiorly

Question 4

Rhomboid Major

Answer 4

Retracts and rotates scapula to depress glenoid cavity; attaches scapula to thoracic wall.

Question 5

Rhomboid Minor

Answer 5

Retracts and rotates scapula to depress glenoid cavity; attaches scapula to thoracic wall

Question 6

Serratus posterior superior

Answer 6

Elevates ribs during respiration

Question 7

Serratus posterior inferior

Answer 7

Depresses ribs during respiration

Question 8

Splenius Capitus

Answer 8

unilateral contraction yields lateral flexion of neck and rotation of head to one side. Bilateral contraction yields head and neck extension.

Question 9

Splenius Cervicis

Answer 9

unilateral contraction yields lateral flexion of neck and rotation of head to one side. Bilateral contraction yields head and neck extension.

Question 10

Iliocostalis

Answer 10

Unilateral contraction yields lateral flexion, bilateral contraction yields extension.

Question 11

Longissimus

Answer 11

Unilateral contraction yields flexion, bilateral contraction yields extension

Question 12

Spinalis

Answer 12

Unilateral contraction yields flexion, bilateral contraction yields extension.

Question 13

Semispinalis Capitus

Answer 13

Extension of head

Question 14

Semispinalis Cervicis

Answer 14

Extension of vertebral column

Question 15

Multifidus

Answer 15

Unilateral contraction rotates to contralateral side; stabilizes vertebrae

Question 16

Rotators

Answer 16

Extension and rotation of vertebral column