ANAT Thorax Flashcards
- Name the 3 parts of the sternum and the joints (and joint type) between them.
Manubrium
Body
Xiphoid Process (or Xiphisternum)
-
Manubrosternal Joint - between the manubrium and the body
- fibrocartilaginous - forms the manubrosternal angle through which passes the manubrosternal plane
-
Xiphisternal Joint - between the body and the xiphisternum
- fibrocartilagenous - xiphisternal plane
- Out of the 12 pairs of ribs, which is correct?
a) R11 & R12 are flattened superior-inferior in cross section and more curved
b) R1-7 are continued anteriorly by the costal cartilages
c) R1-7 attach posteriorly to the sternum and are called true ribs, R8-12 do not attach directly to the sternum and are called false ribs
d) Pairs 3-10 are typical, pairs 1, 2, 11 & 12 are different. Most are part bone, part cartilage.
Correct: d) Pairs 3-10 are typical, pairs 1, 2, 11 & 12 are different. Most are part bone, part cartilage.
Incorrect:
a) R1 & R2 are flattened superior-inferior in cross-section and more curved (not R11 & R12)
b) R1-10 are continued anteriorly by the costal cartilages (not just R1-7)
c) R1-7 attach anteriorly (not posteriorly) to the sternum and are called true ribs, R8-12 do not attach directly to the sternum and are called false ribs
- Describe which rib pairs possess which joints (and joint type):
i) costocorporeal
ii) costotransverse
iii) costochondral
iv) sternocostal
v) interchondral
i) costocorporeal - R1-12, head of rib with vertebral body; synovial
ii) costotransverse - R1-10, articular tubercle of rib with transverse process of vertebra, synovial
iii) costochondral - R1-10, chondral end of rib with costal cartilage (hence R11-12 are ‘floating’; no sternal attachment); cartilagenous
iv) sternocostal - R1-7 , costal cartilage directly with sternum, true ribs; synovial (except R1; fibrous)
v) interchondral - R8-10 costal cartilage with costal cartilage of R7, false ribs; synovial
- What is the difference between the fibres of the intercostal muscles?
The intercostal muscles are lcoated between the ribs, in 11 paired sets.
The external intercostal muscles’ fibres are directed downward and forward
The internal and innermost intercostal muscles are directed downward but backward (as opposed to forward)
- Regarding the intercostal muscles:
- What is their function?
- What is their innervation?
The intercostal muscles act to move the ribs.
They are innervated segmentally by the intercostal nerves (11 pairs), which form as a direct continuation of the anterior primary rami without an associated plexus.
- Describe the typical layers of the chest wall, superficial to deep.
Skin,
subcutaneous,
rib / intercostal muscles & intercostal space (containing VAN),
endothoracic fascia,
parietal pleura,
pleural space (potential)/fluid,
visceral pleura,
lung
- Describe what lies in the intercostal spaces.
There are 11 pairs of spaces, between the ribs.
They contain the 3 layers of intercostal muscles. Between layers 2 & 3, in the costal groove are the intercostal vein, artery and nerve (in that order; VAN) from superior to inferior.
The external intercostal muscles’ fibres align downwards and forwards, whilst the internal & innermost intercostal muscles’ fibres align downwards and backwards.
- Which rib joints and the ribs they involve, are not synovial joints?
a) costocorporeal (R1-12), costotransverse (R1-10) and sternocostal (R1-7, except R1 which is synovial)
b) costochondral (R1-12), interchondral (R8-10)
c) sternocostal (R1), costochondral (R1-10)
d) none of the above are correct
Correct: c) sternocostal (R1 - fibrous - whereas the rest (R2-7) are synovial), costochondral (R1-10) - cartilaginous
Incorrect:
a) Listed joints and associated ribs were of synovial classification, where R1 was the sternocostal exception, which is fibrous.
b) costochondral joints are cartilaginous (and also do not exist in R11&12, only R1-10) but interchondral joints (R8-10) that connect with the cartilage of R7 are synovial.
d) (c) was correct
