The thorax

Question 1

List the boundaries of the thoracic cage:

Answer 1

Posteriorly: the thoracic vertebrae
Laterally: All 12 pairs of ribs (along with fascia/muscles, VAN, skin)
Anteriorly: The manubrium, sternum, and costal cartilages of ribs 7-10 and the xiphisternal joint
Inferior: This space is closed off by the diaphragm in the living.

Question 2

What are the boundaries of the superior thoracic aperture?

Answer 2

T1- posteriorly
First pair of ribs and their costal cartilages- laterally
Manubrium and medial end of clavicle- anteriorly

Question 3

What are the boundaries of the inferior thoracic aperture?

Answer 3

• 12th thoracic vertebra posteriorly
• 11th & 12th pairs of ribs laterally
• Costal cartilage of ribs 7-10 anteriorly
• Xiphisternal joint anteriorly

Question 4

Which ribs are considered “true ribs” and why?

Answer 4

The first 7 pairs of ribs, because they have a direct attachment to the sternum. (Also called “vertebrosternal ribs”)

Question 5

Which ribs are considered “false ribs?”

Answer 5

Ribs 8, 9, and 10 are considered false ribs because they are attached to the sternum via COSTAL CARTILAGE

Question 6

Which ribs are considered “floating ribs?”

Answer 6

11th and 12th ribs are considered floating because they only have a vertebral attachment. They are not attached to the sternum, or to other ribs via cartilage.

Question 7

Which ribs are considered “vetebrosternal?”

Answer 7

Ribs 1-7

Question 8

How many spaces are there in the thoracic cage?

Answer 8

11

Question 9

Name three structures that pass through the superior thoracic aperture

Answer 9

The trachea, the oesophagus, and the LCC

Question 10

What is the relation of the suprasternal notch with the trachea?

Answer 10

The trachea lies posterior to the suprasternal notch

Question 11

Which rib forms a joint with the sternum at the level of the manubriosternal joint?

Answer 11

2nd pair of ribs

Question 12

What is the structural and functional significance of the manubriosternal joint?

Answer 12

Located between the manubrium and body of the sternum. The movement between the two bones increases the anterioposterior diameter of the thoracic cage, thus facilitating inspiration

Question 13

What is the functional significance of the sternoclaviclar joint?

Answer 13

This is the only connection between the axial and appendicular parts of the skeleton. The weight of the limb cannot be supported unless this joint is intact. Arm must be supported in a sling if the clavicle is fractured, or the joint is dislocated.

Question 14

Which ribs form costal-sternal joints?

Answer 14

Ribs 1-7

Question 15

What is the functional sigificance of the sternocostal joints?

Answer 15

Assist in respiration

Question 16

Name the ribs that form the costal margin

Answer 16

The cartilage of ribs 7, 8, 9, and 10, along with the 11th and 12th ribs

Question 17

Ribs 3-9 are “typical” as they have the following major landmarks:

Answer 17

Head, neck, body, tubercle

Question 18

Which ribs are considered atypical?

Answer 18

1st, 2nd, 10th, 11th, and 12th ribs are atypical

Question 19

What makes the first pair of ribs atypical?

Answer 19

Wide and flat, has superior and inferior surface. Has only one articulatory surface where it connects with T1

Question 20

What do the 10th, 11th, and 12th ribs have in common?

Answer 20

They all only have one facet on their heads, and as such only articulate with a single vertebra

Question 21

What features are lacking in ribs 11 and 12?

Answer 21

A second facet, as well as the neck and tubercles

Question 22

How many floating ribs do we have?

Answer 22

Four- two pairs of floating ribs

Question 23

What are the names of the intercostal muscles?

Answer 23

Innermost, interior intercostals and exterior intercostals

Question 24

The articulation of the rib tubercles with the transverse process of the vertebrae are called the

Answer 24

Costotransverse joints

Question 25

What is an accessory rib, and where might they be found?

Answer 25

Accessory ribs are an additional pair of ribs attached to the vertebra of C7