Lecture 8.3: Thoracic walls and diaphragm Flashcards
What are breasts?
They are a collection of mammary glands, located on the thoracic wall of females; they are part of us
What does the bony framework of our thorax consist of?
Sternum, 12 thoracic vertebrae and 12 ribs
Name the parts of the sternum and what they do
- Manubrium: articulates with the clavicle
- Body: most ribs attach here
- Xiphoid process: cartilaginous
What kind of bones are ribs?
They are flat bones
Describe the ribs: group names, numbers, where they attach
First we have the ‘true’ ribs; 1-7 because they attach directly to the sternum. Then we have the ‘false’ ribs; 8-10 because they do not attach directly, rather, they attach to the superior rib. Lastly, we have the ‘floating’ ribs; 11-12, the don’t articulate with the sternum at all.
What is the main difference between ribs 1-10 and 11-12?
1-10 have their own costal hyaline cartilage whereas 11-12 do not.
Describe the structure of a typical rib; which number ribs have this similar layout?
Ribs 3-9
- HEAD of the rib; articulates with the vertebrae at two small impressions called the superior and inferior facets
- NECK of the rib
- TUBERCLE; with a smooth facet attaching nothing and a rough bump that attaches muscles/ligaments
- BODY; curved and vertically orientated, has a superior and an inferior border; also has the COSTAL GROOVE on the inferior border, where the “VAN” will lay!
What are some features of the THORACIC vertebra?
- Longer and more verticle spinous process
- Since the T vertebra articulate with the ribs, it must have inferior and superior costal facets at the posterior end of the body
- Also articulates with the ribs at the transverse processes
What are the joints in the thorax called? (2) Describe them.
- Costovertebral: between the head of the rib and the vertebrae
- Costotransverse: between the transverse process of the vertebra and the smooth part of the rib
Describe the costovertebral joint in detail
So the head of the rib articulates with the inferior costal facet of the vertebra above, the IV disc, and also the superior costal facet of the vertebra below. WE NUMBER THE RIB BY THE VERTEBRA BELOW
What ligament is associated with the costovertebral joint? describe it
The RADIATE ligament; ‘radiating’ around all the articulating points of the costovertebral joint
What ligament is associated with the costotransverse joint? describe it
There are 3 but we are focusing only on the lateral costotransverse ligament; it joins the transverse process and the rough part of the rib tubercle
What are apertures?
An opening, hole, or gap
Name and describe the thoracic apertures we have
- Superior aperture; hole is formed by the superior part of the manubrium, the inferior walls of the first pair ribs, and the superior part of the T1 vertebra
- Inferior aperture: larger hole formed by the xiphoid process of the sternum, the costal margin, the inferior border of the 12th rib and the T12 vertebra.
Describe the closing off/opening of the superior and inferior aperture.
Superior: partially closed by the suprapleural membrane
Inferior: completely closed off by a muscle called the DIAPHRAGM
What is the costal margin?
It’s the upside down shape V when you look at the rib cage
Describe the peripheral attachments of the diaphragm
- The xiphoid process
- Costal margin
- 11th and 12th ribs
- The arcuate ligaments
- The lumbar vertebral body via left an right vrus
Describe how the diaphragm sits in the body
It has two domes; the right side (on your own body) is higher than the left due to placement of the liver. These domes attach to the LUMBAR vertebra via CRURA, which are ligaments.
Describe the ligaments of the disphragm.
The right crus is longer as the right dome sits higher; this crus attaches to L1-L3.
The left crus attaches L1-L2
What is the central tendon?
In the middle of the diaphragm, is a sheet of pearly white fibrous tissue… does not have any bony attachments
How does the diaphragm help with breathing?
Its contraction increases the volume of the thorax and so inflates the lungs.
What are hiatuses?
Name the ones we have
They are three large holes found in the diaphragm that provides a pathway for structures running through the thorax
- IVC: inferior vena caval
- Oesophagus
- Aortic
Describe the nervous innervation of the diaphragm
Motor: supplied by the phernic nerves, left and right
Sensory: supplied by intercostal and subcostal nerves
Describe and name the intercostal space
The space between the ribs. 3 layers.
- External
- Internal
- Innermost
Describe the external intercostal space
Outermost layer, fibres in a ‘pocket’ direction, when they contract they pull the ribs up and out
Describe the internal intercostal space
fibres run opposite to pocket, don’t really help with anything
Describe the innermost intercostal space
patchy and have altering fibre directionality
What is the neuromuscular bundle?
Found in the COSTAL GROOVE of the ribs; VEINS, ARTERY, NERVES; V.A.N
If you hear the word “intercostal”, what should you automatically think of?
Atomical features between the space of the ribs
Describe the intercostal nerves/arteries/veins
Nerves: originate from anterior rami of spinal nerves
T1-T11. Runs between the middle and deepest layer; also branches
Artery/veins: arises both anterior and posterior. provides blood to intercostal muscles and thoracic walls. Each artery is paired with a vein
Describe the movements of the thorax
Can be changed by muscle:
- Vertically; up/down by diaphragm
- Front/back (AP); contraction of 1-7 rib because they push the sternum outwars
- Lateral (Left/right); external intercostal muscles of ribs 8-10; since they don’t directly articulate with the sternum, it pushes laterally.
