Osteology of the Thoracic cavity

Question 1

State the basics of the Thorax

Answer 1

It is an irregularly shaped cylinder that houses the hear and lungs. It allows structure to pass between the neck and abdomen while also playing a vital role in breathing.

Question 2

What are the two openings of the Thorax?

Answer 2

Superior thoracic aperture.
-It is narrower and always open
-It is for continuity with neck
Inferior thoracic aperture.
-It is wider and closed by the diaphragm

Question 3

What is the thoracic cavity and what are its traits?

Answer 3

It is a space in your chest region and it is enclosed by the thoracic wall and diaphragm. It contains two pleural cavities and the mediastinum.

Question 4

What is the thoracic wall?

Answer 4

It is a flexible musculoskeletal wall (made of muscles and skeletal elements) that shelters the heart and lungs.

Question 5

What are the skeletal elements of the thoracic wall?

Answer 5

Anterior: There is the sternum
Posterior: Twelve thoracic vertebrae with there intervertebral discs
Lateral: Twelve pairs of ribs and their costal cartilages

Question 6

Parts of the sternum.

Answer 6

Manubrium (broad and most superior)
Body (narrow and longitudinally oriented)
Xiphoid process (small and inferiorly situated)

Question 7

What is the sternal angle of the sternum?

Answer 7

The sternal angle is a major surface landmark
It is used to find the 2nd rib
Due to the clavicle and surrounding tissue, 1st rib is not palpable.

Question 8

State traits of the manubrium (superior region of the sternum).

Answer 8

Superior surface: Jugular notch, situated along the midline.
Clavicular notches: Articulates with the left and right clavicles.
Lateral surfaces: Facets for articulation with the 1st costal cartilages.
Lower ends of lateral surfaces: Act as demi-facets for articulation with upper half of 2nd costal cartilage

Question 9

State traits of the body (longitudinal oriented part of the sternum)

Answer 9

Superior aspect of lateral margin: Act as a demi-facet for articulation with lower half of the 2nd costal cartilage.
Anterior surface: there are transverse bridges that represent lines of fusion between segmental elements known as sternebrae (embryological origin of sternum).
Lateral surfaces: There are 4 facets of articulation with costal cartilages of ribs 3-6
Inferior aspect of lateral margin: Act as demi-facet for articulation with upper half of the 7th costal cartilage.
Inferior end: Attached to the xiphoid process.

Question 10

State traits of the xiphoid process (smallest and inferior region of the sternum)

Answer 10

-They have a variable shape.
superior aspect of lateral margin: Act as demi-facet for articulation with lower half of the 7th costal cartilage.

Question 11

State the traits about ribs

Answer 11

-Each rib terminates anteriorly with a costal cartilage.
-All 12 pairs of ribs articulate with the vertebral column posteriorly.
-Ribs 1-7 are true ribs, articulate directly with sternum
-Ribs 8-12 are false, don’t directly articulate with sternum
-Ribs 11 and 12 are floating ribs, have no anterior articulation.

Question 12

What is the costal margin?

Answer 12

Unity of costal cartilage of ribs 7-10.

Question 13

What are false ribs?

Answer 13

Ribs 8-10 as their connection to the sternum is via the costal cartilage of ribs 1-7.

Question 14

What are true ribs?

Answer 14

Ribs 1-7, because their costal cartilage connects directly with the sternum.

Question 15

What are floating ribs?

Answer 15

Ribs 11 and 12, they have no anterior articulation.

Question 16

Which ribs are typical ribs?

Answer 16

Ribs 3-9 are considered typical ribs, du to their somewhat uniform shape and standard features.

Question 17

Which are atypical ribs?

Answer 17

Ribs that aren’t 3-9, therefore 1,2,10,11 and 12 are atypical ribs.

Question 18

How many ribs are there?

Answer 18

There are 12 ribs in total with costal cartilage that allows for mobility and flexibility to facilitate respiration among other factors.

Question 19

What are the traits of typical ribs?

Answer 19

Their anterior is continuous with the costal margin while their posterior end articulates with the vertebral column.