Objective 10 - Muscles of Respiration

Question 1

Primary muscles of respiration

Answer 1

Diaphragm
Intercostals (external, internal, innermost, subcostal)

Question 2

Secondary muscles of respiration

Answer 2

Scalenes
Pectoralis minor
Serratus anterior
Serratus posterior
Quadratus lumborum
Latissimus dorsi

Question 3

What nerve innervates the diaphragm?

Answer 3

C3-C5

Question 4

What is the action of the intercostals?

Answer 4

external: quiet and forced inhalation
internal: forced expiration

Question 5

What is the action of anterior and middle scalenes?

Answer 5

Sidebend the neck to the same side with unilateral contraction

Question 6

What is the innervation of the anterior and middle scalenes?

Answer 6

C3-C6

Question 7

What is the action of pectoralis minor?

Answer 7

Stabilizes the scapula by drawing inferiorly and anteriorly against the thoracic wall

Question 8

What is the innervation of the pectoralis minor?

Answer 8

medial pectoral nerve (C8, T1)

Question 9

What syndrome is associated with pectoralis minor?

Answer 9

thoracic outlet syndrome

Question 10

What is the action of the serratus anterior?

Answer 10

protracts scapula and holds against thoracic wall; rotates scapula

Question 11

What is the innervation of the serratus anterior?

Answer 11

long thoracic n. (C5-7)

Question 12

What is the action of serratus posterior superior?

Answer 12

Elevates ribs

Question 13

What is the action of the serratus posterior inferior?

Answer 13

Depresses ribs

Question 14

What is the action of the quadratus lumborum?

Answer 14

Extends and laterally flexes the vertebral column; fixes 12th rib during inspiration

Question 15

What is the innervation of the latissimus dorsi?

Answer 15

Thoracodorsal (C6-8)