Tx Bones

Question 1

What are the 4 bony elements of the thoracic cage?

Answer 1

Ribs (12)
Costal cartilages (12)
Sternum
Thoracic vertebrae (12)

Question 2

What are the 3 types of ribs?

Answer 2

1-7: true ribs (attach directly to sternum)

8-10: false ribs (attach to sternum via costal connection to superior rib)

11-12: floating ribs (no anterior attachment)

Question 3

What are the 3 components of the sternum?

Answer 3

Manubrium (superior)

Body (middle)

Xiphoid process (inferior)

Question 4

Which are the typical and atypical thoracic vertebrae?

Answer 4

T2-9: typical

T1, T10-12: atypical

Question 5

What are the characteristics of a typical thoracic vertebrae?

Answer 5

Body - heart shaped

Foramen - circular

Spinous processes - long and sharp, project inferiorly and overlap inferior vertebrae

Transverse processes - project posteriorly as well as laterally to accomodate ribs; T1-10 have costal facets for articulation with ribs

Articular facets:
- superior facets face posteriorly, inferior facets face anteriorly

Question 6

Describe the costal facets on the typical thoracic vertebrae

Answer 6

On typical vertebrae (T2-9):

Superior demifacet: large semicircle, articulates with same rib (head)

Inferior demifacet: small semicircle, articulates with inferior rib (head)

Transverse costal facet: articulates with tubercle of same rib

Question 7

Describe the costal facets on atypical thoracic vertebrae

Answer 7

T1:

• superior costal facet is circular and receives entire head of rib 1
• inferior costal demifacet articulates with rib 2
• costal facets on TPs

T10:

• single circular facet receives entire head of rib 10
• costal facets on TPs

T11-12:

• single circular facet receives entire head of same rib
• no costal facets on TPs

Question 8

Which vertebrae have a single circular facet to articulate with ribs?

Answer 8

T1, T10-12

Question 9

Which vertebrae have costal facets on the transverse processes to articulate with tubercle of ribs?

Answer 9

T1-10

Question 10

Which are the typical and atypical ribs?

Answer 10

Typical: 3-9
Atypical: 1, 2, 10, 11, 12

Question 11

Describe the atypical ribs:

Answer 11

1:
- shortest, broadest and most sharply curved
- one articular facet on head
- no rib angle
- no costal groove
- grooves for subclavian vessels (V anterior to tubercle, A posterior to tubercle)
- scalene tubercle on superior surface for attachment of anterior scalene

2:
- short and broad, rough superior tuberosity for attachment of serratus anterior

10-12:
- only one articular facet on head

11-12:
- short, no articulation with sternum, no tubercle or neck

Question 12

Describe a typical rib

Answer 12

Ribs 2-9:
- wedge shaped head posteriorly made up of superior and inferior demifacets (articulate with facets of vertebrae) and crest of head for attachment of intra-articular ligament

• neck (lateral to head)
• tubercle (articulates with costal facets on transverse processes)
• angle (where rib slants inferiorly)
• costal groove (internal surface, for passage of neurovascular vessels)
• costal cartilage anteriorly

Question 13

What are the 3 components of the sternum and their features?

Answer 13

Manubrium, body and xiphoid process

Manubrium:

• widest and thickest part
• suprasternal notch
• clavicular notoch
• costal notch for rib 2 at sternal angle

Body:
- costal notches for ribs 3-7

Xiphoid process:

Question 14

At what levels of the Tx spine are the components of the sternum located?

Answer 14

Manubrium: T3-4 level

Body: T5-9 level

Xiphoid: T10 level