L24 Flashcards
what superficial structure isn’t part of the thoracic wall but is integral to its function?
skin and superficial fascia including breast tissue
what bones aren’t part of the thoracic wall but are integral to the thorax’s function?
clavicle and scapula
what muscles aren’t part of the thoracic wall but are integral to the thorax’s function?
pectoralis major, serratus anterior, rectus abdominis
what bones is pectoralis major attached to? 4
clavicle, sternum, costal cartilages, humerus
what innervates the pectoralis major? 2
medial and lateral pectoral nerves
what bones and tissues does the serratus anterior attach to? 3
ribs 1-9, intercostal fascia, medial border of scapula
what innervates the serratus anterior?
long thoracic nerve
what bones and tissues does rectus abdominis attach to? 3
costal cartilages of ribs 5-7, xiphoid process, pubic bones
what innervates rectus abdominis? 1
anterior rami of T7-T12 spinal nerves
what are the 3 kinds of anterior thoracic cage joints?
sternocostal/sternochondral, costochondral, interchondral
what are the sternocostal/sternochondral joints in the anterior thoracic cage? and what kind of joint is it?
sternum to cartilages, synovial
what is the exception to the sternocostal joints?
joint between sternum and R1 = cartilaginous
what are the costochondral joints and what kind of joint is this?
ribs 1 - 10 to cartilages, cartilaginous
what are the interchondral joints and what kind of joint is this?
ribs 6 - 9 to costal cartilages, synovial
what are the 2 kinds of posterior thoracic cage joints?
costovertebral and costotransverse
what does the costovertebral joint articulate?
head of rib and vertebral body
what does the costotransverse joint articulate?
tubercle of rib and transverse process of vertebra
what do the synovial joints allow the rib cage to do during respiration?
movement
when the thoracic joints are damaged this?
reduces the movement of the thorax
if there is reduced movement of the thorax due to injury what affects does this have on respiration?
respiration becomes diaphragmatic breathing
what are the three layers of intercostal muscle called?
external, internal and innermost
what are the nerves and blood vessels of the intercostal space?
intercostal nerves, anterior/posterior intercostal arteries and veins
where do the intercostal nerves and blood vessels lie within the intercostal space?
between the inner and innermost layers
what layer of connective tissue lies deep to the innermost intercostal muscle?
endothoracic fascia
what direction do the fibres of the external intercostal muscle travel and work in?
anterior inferiorly
what action does the external intercostal muscle cause?
contracts to lift the thoracic cage in inspiration
what direction do the fibres of the internal and innermost intercostal muscles travel and work in?
posterior inferiorly
what action do the inner and innermost intercostal muscles cause?
contracts to lower the thoracic cage in forced expiration
how do the intercostal veins and arteries interact?
anastomose laterally
what arteries is the anterior intercostal artery derived from?
subclavian –> internal thoracic –> anterior intercostal
what artery is the posterior intercostal artery derived from?
thoracic aorta –> posterior intercostal artery
what does the anterior intercostal vein drain into?
internal thoracic vein
what does the posterior intercostal vein drain into?
azygos system (depending on location)
what leads the blood drain from the body wall to superior vena cava?
anastomotic pathway of azygos system
what vein is the main drainage on the right?
azygos vein
what vein is the main drainage on the left?
accessory hemiazygos vein
what other vein allows drainage on the left?
hemiazygos vein
what does the accessory hemiazygos vein drain into?
azygos vein
what do the intercostal nerves accompany?
blood vessels
intercostal nerves are what in relation to the spinal nerves?
ventral ramus of spinal nerves
what do the intercostal nerves innervate?
intercostal muscles, skin and parietal pleura
what are the three main surgical approaches to the thoracic cavity?
intercostal space, rib bed, sternum
what fills in the inferior thoracic aperture?
diaphragm
what separates the thoracic from the abdominopelvic cavity?
diaphragm
what muscle of the thoracic cavity has fibres in all directions?
diaphragm
what attachments does the central tendon of the diaphragm have? 3
sternal, costal and lumbar
what shape is the diaphragm when relaxed?
dome-shaped
what shape is the diaphragm when contracted?
flat
what is the diaphragm innervated by?
phrenic nerve
what supplies the diaphragm?
internal thoracic artery
what are the 3 apertures in the diaphragm?
aortic hiatus, vena cava foramen, oesophageal hiatus
what travels through the aortic hiatus?
descending aorta, thoracic duct, azygos vein
what travels through the vena cava foramen?
inferior vena cava
what travels through the oesophageal hiatus?
oesophagus and vagus nerves
at what level is the aortic hiatus?
T12
at what level is the vena cava foramen?
T8
at what level is the oesophageal hiatus?
T10
what happens first in inspiration?
external intercostal muscles contract
what happens second in inspiration?
rib cage rises and expands
what happens to the diaphragm during inspiration?
contracts to become flattened
what happens to the thoracic cavity volume during inspiration?
increases
what happens to intrapulmonary volume during inspiration?
increases
what happens to intrapulmonary pressure during inspiration?
decreases
how does air move into the lungs?
by flowing down the pressure gradient
what happens first in expiration?
external intercostal muscles relax
what happens second in expiration?
rib cage descends and reduces
what happens to the diaphragm in expiration?
diaphragm relaxes and rises becoming dome-shaped
what do the lungs do during expiration?
recoil
what happens to the thoracic cavity volume during expiration?
decreases
what happens to intrapulmonary volume during expiration?
decreases
what happens to intrapulmonary pressure during expiration?
increases
how does the air get expired?
flows down the pressure gradient which is now lower outside
