Muscles of Respiration

Question 1

How many layers of intercostals are there? Where are they located? What are they called (sup to deep?)

Answer 1

3 layers in the spaces between the adjacent ribs (intercostal space)
External intercostals, internal and innermost

Question 2

How many pairs of muscles do each layer of intercostals have?

Answer 2

11 pairs

Question 3

What are the attachments of the external intercostals?

actions?

Answer 3

superior attach: ribs 1 - 11 (fixed)
inferior attach: ribs 2-12

action: quiet and forced inspiration (through elevation of the ribs)
action: keep the intercostal spaces rigid

Question 4

What are the attachments of the internal intercostals?
actions?
fibre direction?

Answer 4

superior attach: ribs 1 - 11 (fixed)
inferior attach: ribs 2-12

action: forced expiration
action: keep the intercostal spaces rigid

fibre direction: right angles (90 degrees) to external intercostals

Question 5

What are the attachments of the innermost intercostals

actions?

Answer 5

superior attach: ribs 1 - 11 (fixed)
inferior attach: ribs 2-12
separated from the internal intercostals by the nerovascular bundle

action: forced expiration
action: keep the intercostal spaces rigid

Question 6

Levator costarum

Answer 6

12 pairs
superior attachment: TVPs of C7-T11
inferior attachment: ribs (immediately inferior) 
action: elevate the ribs 
accessory muscles to respiration

Question 7

Subclavius

Answer 7

Medial attachment: 1st rib and its costal cartilage
lateral attachment: middle 1/3rd of the inferior surface of the clavicle
action: anchors, depresses and draws the clavicle medially
action: serves as cushion between fractured clavicle

Question 8

What is the principle muscle of respiration?

Answer 8

The diaphragm

Question 9

The diaphragm is what shape muscle? What does it divide?

Answer 9

It is a a dome shaped muscle. It divides the thoracic cavity and abdominal cavity

Question 10

Where does the top of the diaphragm sit during inspiration?

expiration?

Answer 10

approximately 6th intercostal space during inspiration

4th intercostal space during exhalation

Question 11

The diaphragm is divided into two components?

Answer 11

Muscular component and tendinous component

Question 12

What are the attachments to the muscular component of the diaphragm?

Answer 12

Attaches inferiorly onto the:
posterior surface of the xiphoid process,
internal surfaces of lower 6 ribs (and their costal cartilages),
upper lumbar vertebrae via 2 muscular crura
medial arcuate ligaments (upper lumbar vertebral bodies to TVPs - travels over psoas)
lateral arcuate ligaments (L1 TVP to 12th rib - travels over QL)

Question 13

The diaphragm Central Tendon

Answer 13

the muscular fibres converge radially into a strong aponeurotic tendon called the Central Tendon
Has a C-shaped appearance with a central, left and right ‘leaflet’

Question 14

What is the action of the diaphragm?

Answer 14

with contraction, the diaphragm moves inferiorly so that it is flattened

Question 15

What is the innervation of the diaphram?

Answer 15

phrenic nerve (C3,4,5) - C345 keeps the diaphragm alive

Question 16

Contraction of the diaphragm causes _____ movements of the central tendon

Answer 16

inferior

Question 17

as the diaphragm contracts it _____ and increases what?

Answer 17

flattens, increases the vertical imension of the thoracic cavity (increases thoracic volume

Question 18

During inspiration the ribs are raised and move laterally which increases the transverse dimension of the thorax which called _____

Answer 18

the bucket-handle movement

Question 19

As the ribs raise the anterior parts of the ribs and the sternum move anteriorly which increases the anteroposterior dimension of the thorax which is called ______

Answer 19

the pump-handle movement

Question 20

What is the bucket handle movement?

Answer 20

During inspiration the ribs are raised and move laterally which increases the transverse dimension of the thorax

Question 21

What is the pump-handle movement?

Answer 21

As the ribs raise the anterior parts of the ribs and the sternum move anteriorly which increases the anteroposterior dimension of the thorax (sternal angle increases)

Question 22

What causes air to come in during inspiration?

Answer 22

the increases in vertical, transverse and AP dimensions create a negative pressure in the lungs which results in air being drawn in

Question 23

During inspiration the thoracic volume _____ which _______ thoracic pressure AND the abdominal volume _____ which ____ abdominal pressure

Answer 23

increases, decreases

decreases, increases

Question 24

During expiration the diaphragm ______ and moves _____

Answer 24

Relaxes (or eccentrically contracts)

Superiorly

Question 25

During expiration the thoracic volume _____

and the thoracic pressure _____

Answer 25

decreases,

increases

Question 26

normally expiration is an active process T/F?

Answer 26

False - passive, forced expiration requires accessory muscles

Question 27

What is the name for breathing where the diaphragm stays relatively relaxed, and the accessory muscles of respiration lift the chest up and out?

Answer 27

apical breathing

Question 28

What is the name for a hiccup?

Answer 28

Singultus (spasm of diaphragm, epiglottis closes quickly over trachea as air is getting in