The thoracic wall, diaphragm, and mechanics of breathing

Question 1

what structures are superficial to the thorax?

Answer 1

Skin and superficial fascia
- includes breast tissue
Bones
-Clavicle
-Scapula
Muscles and deep fascia
-Pectoralis major
Serratus anterior
Rectus abdominis

Question 2

where does pectoralis major attach?

Answer 2

At the clavicle, sternum, costal cartilages
humerua

Question 3

what innervates the pectoralis major?

Answer 3

medial and lateral pectoral nerves

Question 4

where does serratus anterior attach?

Answer 4

ribs 1-9, intercostal fascia
- medial border of the scapula

Question 5

what innervates the serratus anterior?

Answer 5

long thoracic nerve

Question 6

where does the rectus abdominis attach?

Answer 6

Costal cartilages of ribs 5-7, xiphoid process
Pubic bones and joint

Question 7

what innervates the rectus abdominis?

Answer 7

Anterior rami of T7-T12 spinal nerves

Question 8

where is the sternocostal joint?

Answer 8

Between the sternum and the cartilage of the ribs

Question 9

what type of joints are the sternocostal joints?

Answer 9

synovial
except between the sternum and R1, this is a cartilaginous joint

Question 10

what is the sternocostal joint between the sternum and cartilage of R1 cartilaginous?

Answer 10

It does not support movement as important structures move through the anterior apature of the thoracix cage

Question 11

where are the costochondral joints?

Answer 11

Between the ribs and cartilage

Question 12

what type of joint are the costochondral joints?

Answer 12

cartilaginous

Question 13

what are interchondral joints?

Answer 13

Joints between rib 6-9 costal cartilages

Question 14

what type of joints are interchondral joints?

Answer 14

synovial

Question 15

what are the anterior thoacic age joints?

Answer 15

Sternocostal
Costochondral
Interchondral

Question 16

what are the posteruor thoracic cage joints?

Answer 16

Costovertebral
Costotransverse

Question 17

what type of joints are costovertebral and costotransverse joints?

Answer 17

synovial

Question 18

what is a costovertebral joint between?

Answer 18

Head of the rib and vertebral body

Question 19

what is the costotransverse joint between?

Answer 19

Tubercle of the rib
Transverse process of the vertebra

Question 20

what is the function of synovial joints in the thoracic cage?

Answer 20

They allow movement of the rib cage during respiration

Question 21

what are the muscles of the thoracic wall intercostal space?

Answer 21

External, internal and innermost

Question 22

what are the nerve of the thoracic intercostal space?

Answer 22

Intercostal nerves

Question 23

what are the blood vessels of the thoracic intercostal space?

Answer 23

Anterior/posterior intercostal arteries and veins

Question 24

where are the blood vessels and nerves in the thoracic intercostal space?

Answer 24

Between the internal and innermost intercostal muscle layers

Question 25

what is the endothoracic fascia?

Answer 25

Connective tissue layer

Question 26

where is the endothoracic fascia?

Answer 26

deep to the innermost intercostal muscle

Question 27

what are the features of the external intercostal muscles?

Answer 27

fiber direction- anteriorly, inferiorly Contract to life the thoracic cage during inspiration

Question 28

what are the features of the internal and innermost intercostal muscles?

Answer 28

Fiber direction - posteriorly, inferiorly Contract to lower the thoracic cage during forced expiration

Question 29

what are the arteries of the intercostal space?

Answer 29

Anterior intercostal artery Blood flows down to the subclavian artery, then the internal thoracic artery, then the anterior intercostal artery The posterior intercostal artery, Blood flows into the thoracic aorta, then the posterior intercostal artery.

Question 30

what are the veins of the intercostal space?

Answer 30

Anterior intercostal veins Internal thoracic vein flows into the subclavian vein Posterior intercostal vein Azygos system - drain into hemiazygouse vein or accessory hemiazoygous vein depending on the location

Question 31

what is the Azygos system?

Answer 31

Anastomotic pathway to drain blood from body wall to superior vena cava Azygos vein - main drainage on the right Hemiazygos vein Accessory hemiazygos vein - main drainage on left -drain into azygos vein

Question 32

what are the features of the intercostal nerves?

Answer 32

Accompany blood vessles Ventral ramus of spinal nerves Supply intercostal muscles, skin and parietal pleura

Question 33

what makes up the floor of the thoracic cavity?

Answer 33

the diaphragm

Question 34

what features of the thoracic floor?

Answer 34

fills inferior thoracic aperture Separates thoracic from abdominopelvic cavity Radiating muscle fibres Central tendon

Question 35

what are the features of the diaphragm shape?

Answer 35

Dome-shaped with relaxed Flat when contracted

Question 36

what innervated the diaphragm?

Answer 36

Phrenic nerve

Question 37

what is the blood supply to the diaphragm?

Answer 37

the internal thoracic artery

Question 38

what are the apertures within the diaphragm?

Answer 38

Aortic hiatus Vena caval foramen Oesophageal hiatus

Question 39

what is the function of the aortic hiatus?

Answer 39

T12 level Descending aorta, thoracic duct, azygous vein run through

Question 40

what is the function of the vena caval foramen?

Answer 40

T8 level Inferior vena cava runs through

Question 41

what is the Oesophageal hiatus?

Answer 41

T10 level Oesophagus, vagus nerves

Question 42

what happens in the thoracic cavity during inspiration?

Answer 42

External intercostal muscles contract - the rib cage rises and expands - diaphragm contracts to become flattened This increases the thoracic cavity volume Lungs stretch Lung volume increases Intrapulmonary pressure goes down Air flows down the pressure gradient, moving into the lungs

Question 43

what happens in the thoracic cavity during expiration?

Answer 43

External intercostal muscle relax The rib cage descends and reduces Diaphragm relaxes and rises, becomes dome shaped Lungs recoil and the thoracic cavity volume decreases Lung volume goes down and intrapulmonary pressure goes up Air flows down the pressure gradient, which is now higher inside than out, so air moves out of the lungs