2-3 respiratory muscles

Question 1

external oblique

Answer 1

origin = iliac crest
insertion = ribs 5-12

pulls ribs toward iliac crest, compressing ribs

expiration

Question 2

internal oblique

Answer 2

origin = iliac crest
insertion = ribs 9-12 (false ribs) & rectus abdominis

lowers ribs & rectus abdominis

expiration

Question 3

rectus abdominis

Answer 3

origin = pubis
insertion = ribs 5-7 & xiphoid process

compresses abdomen, lowers ribs & sternum to shrink the thoracic cavity

expiration

Question 4

quadratus lumborum

Answer 4

origin = iliac crest
insertion = lumbar vertebrae 1-4 & rib 12

pulls rib 12 down to ilium & decreases the size of the thorax

expiration

Question 5

diaphragm

Answer 5

origin = lower ribs, sternum, vertebrae
insertion = central tendon

contraction of the diaphragm results in pulling it downward & subsequently expanding the lungs vertically

inspiration - primary muscles

innervated by cervical nerves

Question 6

internal (interossus) intercostals

Answer 6

origin = superior part of lower rib
insertion = inferior part of upper rib

when contracted, upper rib moves towards lower rib shrinking the thoracic cavity

expiration

innervated thoracic nerves

Question 7

interchondral internal intercostals

Answer 7

origin = inferior side of upper rib
insertion = superior side of lower rib

they act to raise the rib below

inspiration

innervates thoracic nerves

Question 8

external intercostals

Answer 8

origin = inferior side of upper rib (except 12)
insertion = superior side of lower rib

elevate the lower rib towards the upper rib

inspiration

innervate thoracic nerves

Question 9

transversus thoracis

Answer 9

origin = (posterior surface) sternum
insertion = ribs (inner surfaces of costal cartilage in ribs 2-6)

contraction lowers the ribs

expiration

innervated by thoracic nerves

Question 10

levatores costarum

Answer 10

origin = spine (transverse process)
insertion = ribs (external surface, below origin)

elevates ribs toward the attachment point on the spine

inspiration

innervated cervical & thoracic

Question 11

serratus posterior inferior

Answer 11

origin = spine (lower thoracic / upper lumbar)
insertion = inferior side of lower ribs (~9-12)

movement of ribs toward the spine

expiration

innervates thoracic

Question 12

serratus posterior superior

Answer 12

origin = spine (thoracic vertebrae)
insertion = superior side of upper ribs

expands thoracic cavity

inspiration

innervates thoracic

Question 13

serratus anterior

Answer 13

origin = scapula
insertion = ribs 1-8/9

elevated the ribs to increase area of thorax

inspiration

innervates cervical & 1st thoracic

Question 14

sternocleidomastoid

Answer 14

origin = sternum & clavicle
insertion = skull

sternum is elevated, pulling the rib cage & expanding the thoracic cavity

inspiration - accessory muscle

innervates cervical

Question 15

scalene muscles

Answer 15

origin = (transverse process from the cervical) spine
insertion = ribs 1-2

elevated ribs toward the point of attachment on spine

inspiration

innervates cervical

Question 16

pectoralis major

Answer 16

origin = humerus bone
insertion = clavicle & sternum
elevates sternum to increase area of rib cage

inspiration

innervates cervical & 1st thoracic

Question 17

pectoralis minor

Answer 17

origin = scapula
insertion = ribs 2-5

ribs elevate to scapula, expanding the rib cage

inspiration

innervates cervical & 1st thoracic

Question 18

subclaviculus

Answer 18

origin = clavicle
insertion = 1st rib

1st rib elevates, expanding ribs

inspiration

innervates cervical & 1st thoracic