Osteology of the thoracic cavity

Question 1

explain the shape and the functions of the thorax.

Answer 1

Has irregular shaped cylinder:
houses the heart
allow structures to pass from the neck to abdomen.
play a vital role in breathing.

Question 2

how many opening does the thorax have? Differentiates the opening of thorax.

Answer 2

2 openings

1. Superior thoracic opening
   narrow and always open and continuity of the neck

2.inferior thoracic aperture/ opening
wide and closed by the diaphram

Question 3

what encloses the thoracic cavity
the content of the the thoracic cavity

Answer 3

Enclosed by thoracic wall and diaphragm
Two Pleural Cavities + Mediastinum

Question 4

The skeletal elements of the thoracic wall

Answer 4

Anterior; sternum
Posterior 12 thoracic vertebrae and intervertebral discs
lateral: 12 ribs and costal cartilages

Question 5

Explain the 3 parts of the sternum

Answer 5

3 Parts
Manubrium (broad and situated superiorly)
Body (narrow and longitudinally orientated)
Xiphoid process (small and situated inferiorly)

Question 6

The content of the sternal angle

Answer 6

Major surface landmark
Used by clinicians when performing examinations of thorax
Used to find 2nd rib (reference when counting ribs)
1st rib not palpable
- Due to overlying clavicle and surrounding tissues

Question 7

explain the facets in the manubrium and which structures articulates with

Answer 7

Superior surface: Jugular (or suprasternal) notch, along the midline

Clavicular notches: Articulate with left and right clavicles

Lateral surfaces: Facets for articulation with 1st costal cartilage

Lower ends of lateral surfaces: Demifacets for articulation with upper half of 2nd costal cartilage

Question 8

The content of the Body ( sternum)

Answer 8

Superior aspects of lateral margins: Demifacets for articulation with lower half of 2nd costal cartilage

Anterior surface: Transverse ridges representing lines of fusion between segmental elements

Lateral surfaces: Four facets for articulation with costal cartilages of ribs 3-6

Inferior aspects of lateral surfaces: Demifacets for articulation with upper half of the 7th costal cartilage

Inferior end: Attached to xiphoid process

Question 9

DEFINE Sternebrae?

Answer 9

Transverse ridges representing lines of fusion between segmental elements known as sternebrae (embryological origin of the sternum)

Question 10

The xiphoid process

Answer 10

Smallest part of sternum

Variable shape: Can be wide, thin, pointed, bifid, curved or even perforated

Superior aspects of lateral margins: Demifacets for articulation with lower half of 7th costal cartilage

Question 11

The structure that contribute to the mobility and elasticity of wall?

Answer 11

The ribs

Question 12

The content of ribs

Answer 12

Typical Ribs:
>Ribs 3-9
>Have a fairly uniform structure with >standard features among them

Atypical Ribs
Ribs 1, 2, 10, 11 and 12
Have unique features not found in all other ribs

Question 13

COntent of a typical rib

Answer 13

> they have curved structure/ shaft with posterior and anterior ends
- Anterior end continuous with its costal cartilage
- Posterior end articulates with vertebral column

head:
> 2 t articulating facet separated by a crest

Smaller superior facet articulates with vertebrae above
Larger inferior facet articulates with own vertebrae

Question 14

typical rib (Tubercle)

Answer 14

Projects posteriorly from junction of neck and shaft
Articular part: Medial and has an oval facet for articulation with a facet on transverse process of own vertebrae
Non-articular part: Raised and roughened by ligament attachments

Question 15

Shaft of the typical rib

Answer 15

shaft> thin and flat on the external and internal surfaces

angle > shaft bends forward

Costal groove> found along inferior margin of shaft internal surface.

Question 16

Differentiates all the Atypical Ribs

Answer 16

Rib 1
Flat in horizontal plane
Broad superior and inferior surfaces
Head
- Only one articular facet
- Articulates with T1 vertebrae
Scalene tubercle: Distinct feature found on superior surface of rib
Grooves formed by subclavian vein (anterior) and subclavian artery (posterior)

Rib 2
Flat like rib 1, but twice as long

Rib 10
Head: Only one facet for articulation with its own vertebrae (T10)

Ribs 11 and 12
Short, have little curvature and are pointed anteriorly
Head: Only one facet for articulation with own vertebrae (T11 and T12, respectively)
No necks or tubercles

Question 17

Explain the thoracic vertebral bodies.

Answer 17

Heart shaped.
2 Demifacets articulating with the ribs.
superior costal facet articulate with inferior facet on the head of own rib

Inferior costal facet articulate with superior facet head of rib below

Question 18

Name the flexible musculoskeletal wall

Answer 18

Thoracic wall

Question 19

Thoracic Vertebrae

Answer 19

Circular Vertebral Foramina

Superior articular processes
- Flat
- Articular facets face posteriorly

Inferior articular processes
- Project from laminae
- Articular facets face anteriorly

Question 20

The shape of the vertebral foramina for thoracic vertebrae

Answer 20

Circular

Question 21

Transverse processes

Answer 21

Projects posterolaterally
transverse facet articulate with the turbecle of its own ribs

Question 22

Explain the superior articular processes

Answer 22

Flat and articular facet faces posteriorly.

Question 23

Explain the inferior articular processes.

Answer 23

Projects from laminae and articular facets face anteriorly

Question 24

Transverse costal facets articulate with what?

Answer 24

Tubercle of own rib

Question 25

True or false
The spinous processes in thoracic vertebrae is short

Answer 25

False
its is long

Question 26

Explain all the exception of the thoracic vertebrae.
T1, T10(T9), T11 AND T12

Answer 26

T1- superior costal facet is complete
articulates with a single facet on the head of the 1st rib
1st rib does not articulate with C7 vertebrae.
T10 (often T9)
Only articulate with own rib
lacks inferior costal facet.
T11 and T12
articulate with their own rib respectively.
lacks the transverse costal facets.

Question 27

Differentiates between manubriosternal joint and Xiphisterna joint.

Answer 27

The manubriosternal joint is the secondary cartilaginous joint between manubrium and the body
The Xiphisterna joint is the primary cartilaginous joint between xiphoid process and the body

Question 28

Thoracic Vertebral 10

Answer 28

only have one facet. Superior facet articulating with its own ribs

Question 28

Thoracic Vertebral 10

Answer 28

only have one facet. Superior facet articulating with its own ribs

Question 29

Explain the sternocostal joints

Answer 29

Between the upper seven costal cartilages and sternum
1st joint is the primary cartilaginous joint
2nd-7th plane type synovial joints
thin capsules reinforced by sternocostal ligaments

Question 30

Differentiates between Joints of the sternum, manubriosternal joint and xiphosternal joint

Answer 30

Manubriosternal joint:
between the body and manubrium
has secondary cartilaginous joint

Xiphoidsternal joint:
between the xiphoid processes and the body and primary cartilaginous joint

Question 31

The interchondral joint

Answer 31

Between the adjacent ribs mainly 7-10
usually plane type synovial joints
Provide indirect connection to sternum
contribute to forming costal margin

Question 32

The costotransverse joint

Answer 32

Plane type synovial joint
Between tubercle of rib and transverse process of own vertebra

Thin joint capsule surrounds joint
Two extracapsular ligament stablise joint:
- Costotransverse ligament (medial): extends
between neck of rib and transverse process
- Lateral costotransverse ligament (lateral): extends
between roughened non-articular part of tubercle
and tip of transverse process