Thorax

Question 1

Thoracic cage

Answer 1

The bony framework of the chest

Question 2

Structure of the thoracic cage

Answer 2

Thoracic vertebrae posteriorly, ribs laterally, and sternum + costal cartilages anteriorly

Question 3

Function of the thoracic cage

Answer 3

A bony cage that protects the thoracic viscera, supports the shoulder girdle and upper limb, and provides attachments for many upper body muscles

Question 4

What does the thoracic cage house?

Answer 4

The intercostal muscles that elevate and depress the thorax during respiration

Question 5

What three parts of the somites divided into?

Answer 5

Sclerotome
Dermatome
Myotome

Question 6

Sclerotome “Hard piece”

Answer 6

Cells migrate medially, gather around the notochord and neural tube, which then become the vertebrae and ribs

Question 7

Dermatome “Skin piece”

Answer 7

Cells migrate to more superficial layers and become the dermis of the skin on the dorsum of the body

Question 8

Mytome “Muscle piece”

Answer 8

Remaining cells that form the trunk and limb musculature

Question 9

What are the 5 major vertebral regions?

Answer 9

Cervical
Thoracic
Lumbar
Sacrum
Coccyx

Question 10

Cervical

Answer 10

7 vertebrae of neck

Question 11

Thoracic

Answer 11

12 vertebrae of thorax

Question 12

Lumbar

Answer 12

5 vertebrae of lower back

Question 13

Sacrum

Answer 13

5 fused vertebral segments; articulate with hip bones

Question 14

Coccyx

Answer 14

4 fused segments

Question 15

Sternum

Answer 15

A flat bone formed from 3 sections

Question 16

Manubrium

Answer 16

Superior section
- Articulates with the medial ends of the clavicles
- Also articulates with ribs 1 and 2

Question 17

Body

Answer 17

Middle portion
- Sides are notched at articulations for the costal cartilages of ribs 2-7

Question 18

Xiphoid process

Answer 18

Inferior end of sternum
- a plate of hyaline cartilage
- fully ossifies around age 40

Question 19

What are the 3 anatomical landmarks of the sternum?

Answer 19

Jugular notch (suprasternal notch)
Sternal angle
Xiphisternal joint (deep to this joint, the heart lies on the diaphragm)

Question 20

Sternal angle

Answer 20

• Easily accessible clinical landmark: lies anterior to arch of aorta, marks the start and end of aortic arch
• Anterior to carina (bifurcation of trachea)
  Corresponds to IV disc b/n T4 and T5 vertebra
• Marks inferior boundary of superior mediastinum

Question 21

How do all 12 pairs of ribs attach to the thoracic vertebrae?

Answer 21

Posteriorly

Question 22

True ribs

Answer 22

Superior seven pairs
- attach directly to the sternum by costal cartilages

Question 23

False Ribs

Answer 23

Inferior five pairs (8-12)
- Attach to the sternum either indirectly or not at all

Question 24

Floating Ribs

Answer 24

Have no anterior attachments, embedded in the muscles of the lateral body wall (ribs 11-12)

Question 25

What is the structure/definition of a typical rib?

Answer 25

Head: Articulates with the vertebral bodies by two facets Tubercle: Articulates with the transverse process of the thoracic vertebra of the same number Shaft: The bulk of the rib Costal groove: Located on the inferior border; houses the intercostal. nerves and vessels

Question 26

Thoracic cavity communicates with neck and upper limb through what?

Answer 26

Thoracic Inlet

Question 27

Thoracic Inlet

Answer 27

Passage of trachea, esophagus, vessels, and nerves

Question 28

Thoracic Outlet

Answer 28

Esophagus and aorta

Question 29

Intercostal space

Answer 29

An intercostal vein, artery, and nerve travel in the costal groove on the inferior surface of a rib, between the internal and innermost intercostal muscles

Question 30

What branches from the thoracic aorta?

Answer 30

Posterior intercostal arteries and subcostal artery

Question 31

What comes from the internal thoracic artery?

Answer 31

Anterior intercostal arteries

Question 32

What comes from the subclavian artery

Answer 32

Internal thoracic artery

Question 33

The right side of the intercostal veins drain into...

Answer 33

Azygous vein to the superior vena cava (SVC)

Question 34

The right side of the intercostal veins drain into...

Answer 34

Accessory hemiazygos and hemiazygos veins that drain into the azygos vein

Question 35

How many thoracic spinal nerves?

Answer 35

12 pairs

Question 36

What forms the intercostal nerves?

Answer 36

Anterior (ventral) rami of T1-T11

Question 37

What forms the subcostal nerves?

Answer 37

Anterior rami of T12 nerves

Question 38

Posterior (dorsal) rami of thoracic spinal nerves supply...

Answer 38

Bones, joints, deep back muscles, and skin of the back in the thoracic region

Question 39

Diaphragm

Answer 39

The most important muscle of respiration - Flattens as it contracts, increases the volume of the thoracic cavity