The Chest Wall #1 Flashcards
List the layers of the chest wall in order
- Skin
- Superficial fascia
- Extrinsic muscle
- Ext. intercostal
- Int. intercostal
- Innermost intercostal
- NVB
- Parietal pleura
- Pleural cavity
- Visceral pleura
- Lung
What is extrinsic muscle?
- Muscle that has attachment outside of the chest
- can move the ribs for breathing
What are intrinsic muscles?
attached entirely within the chest
List the intrinsic muscles
- ext. intercostal
- int. intercostal
- innermost intercostal
Where do intrinsic muscles get their nerve supply from?
get nerve supply from corresponding intercostal nerve of rib above
How do fibres run in ext. + int. intercostal muscle?
- ext.: fibres run from rib above to rib below - forwards and down
- int.: fibres run from rib below to rib above - backwards and up
List the extrinsic muscles
- serratus ant.
- pectoralis major + minor
- abdominal muscles
What is the origin + insertion of pectoralis major?
- arises from chest wall + inserts into upper limb
- causes abduction + int. rotation of humerus
What is endothoracic fascia?
deep fascia inside the intrinsic muscle
What is parietal pleura?
serous mem that covers inside of chest inside endothoracic fascia
What is function of parietal pleura?
- secretes fluid into pleural cavity - lubes + dec friction as lung moves
What is visceral pleura?
covers surface of lung
List the 3 parts of the sternum
- Manubrium sterni
- Body of sternum
- Xiphisternum/Xiphoid process
What is the function of the ribs?
breathing
What is the manubrialsternal joint + what is it also known as?
- Joint between manubrium + body of sternum
- aka sternal angle/angle of Louis
What type of joint is the manubrial sternal joint?
- 2ndary cartilaginous
What type of joint is the xiphisternum and its sig?
- cartilaginous through life and then ossifies at 80/90 to become bone
- no functional sig
What type of joint is the 1st sternocostal joint and the sig of this?
primary cartilaginous therefore doesn’t move as freely
Where is the 1st sternocostal joint attached?
to sternum
List the true, false + free-floating ribs
- true: 1-7
- false: 8-12
- free-floating: 11-12
What is sig about the 2nd sternocostal joint?
has double facet - attached to body + manubrium
What is type of joints are the 8th-10th sternocostal joints?
attach to costal cartilage above it
What is sig about free-floating ribs?
no ant. attachment
What type of joints are the 2nd-7th sternocostal joints and the sig?
synovial so move freely
What type of joints are the chondrochronal joints (8-10) and the sig?
synovial so move freely
How are the ribs angulated and the sig?
- ant. part going up, post. part going down so post. part of rib higher than ant. part
- oblique alignment - ribs face down (post.)
- costal cartilage faces upwards - allows ribs to be horizontal when breathing
Where does SCM attach?
clavicle, sternum + mastoid process
What nerve supplies SCM?
XI
What is function of SCM?
- pulls skull so can look L + R
- pulls skull forward if both used together
- keeps ribcage elevated + prevents it dropping further
What nerve supplies the scalenes?
cervical plexus
What is the function of the scalenes?
- helps to keep the chest wall up
- used in forced breathing
List the scalene muscles
- scalenus ant.
- scalenus medius
- scalenus post.
Where do the scalenes attach?
- scalenus ant. + medius attach to 1st rib
- scalenus post. attaches to 2nd rib
How does a baby’s ribcage compare with an adult’s?
- wider costal margin
- ant. ribs more horizontal
- flatter diaphragm
- ribs more straight
What is the sig of babies having straighter ribs?
- rely on diaphragm for breathing
- can’t do costal breathing
What happens when the diaphragm contracts?
ribs go down which inc chest vol for breathing
Which ribs are typical and why?
3-9
- art with its own vert + 1 above
Where does the head of the rib attach?
to body of vert
What is the costovert joint?
where head of rib joins with body of vert
What is sup. + inf. demi-facet?
- sup: attaches to vert above e.g. 4th thoracic vert
- inf: attaches to its own vert e.g. 5th rib attaches to 5th thoracic vert
