Osteology of the thoracic cavity Flashcards
explain the shape and the functions of the thorax.
Has irregular shaped cylinder:
houses the heart
allow structures to pass from the neck to abdomen.
play a vital role in breathing.
how many opening does the thorax have? Differentiates the opening of thorax.
2 openings
- Superior thoracic opening
narrow and always open and continuity of the neck
2.inferior thoracic aperture/ opening
wide and closed by the diaphram
what encloses the thoracic cavity
the content of the the thoracic cavity
Enclosed by thoracic wall and diaphragm
Two Pleural Cavities + Mediastinum
The skeletal elements of the thoracic wall
Anterior; sternum
Posterior 12 thoracic vertebrae and intervertebral discs
lateral: 12 ribs and costal cartilages
Explain the 3 parts of the sternum
3 Parts
Manubrium (broad and situated superiorly)
Body (narrow and longitudinally orientated)
Xiphoid process (small and situated inferiorly)
The content of the sternal angle
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
explain the facets in the manubrium and which structures articulates with
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
The content of the Body ( sternum)
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
DEFINE Sternebrae?
Transverse ridges representing lines of fusion between segmental elements known as sternebrae (embryological origin of the sternum)
The xiphoid process
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
The structure that contribute to the mobility and elasticity of wall?
The ribs
The content of ribs
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
COntent of a typical rib
> 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
typical rib (Tubercle)
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
Shaft of the typical rib
shaft> thin and flat on the external and internal surfaces
angle > shaft bends forward
Costal groove> found along inferior margin of shaft internal surface.
Differentiates all the Atypical Ribs
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
Explain the thoracic vertebral bodies.
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
Name the flexible musculoskeletal wall
Thoracic wall
Thoracic Vertebrae
Circular Vertebral Foramina
Superior articular processes
- Flat
- Articular facets face posteriorly
Inferior articular processes
- Project from laminae
- Articular facets face anteriorly
The shape of the vertebral foramina for thoracic vertebrae
Circular
Transverse processes
Projects posterolaterally
transverse facet articulate with the turbecle of its own ribs
Explain the superior articular processes
Flat and articular facet faces posteriorly.
Explain the inferior articular processes.
Projects from laminae and articular facets face anteriorly
Transverse costal facets articulate with what?
Tubercle of own rib
True or false
The spinous processes in thoracic vertebrae is short
False
its is long
Explain all the exception of the thoracic vertebrae.
T1, T10(T9), T11 AND T12
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.
Differentiates between manubriosternal joint and Xiphisterna joint.
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
Thoracic Vertebral 10
only have one facet. Superior facet articulating with its own ribs
Thoracic Vertebral 10
only have one facet. Superior facet articulating with its own ribs
Explain the sternocostal joints
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
Differentiates between Joints of the sternum, manubriosternal joint and xiphosternal joint
Manubriosternal joint:
between the body and manubrium
has secondary cartilaginous joint
Xiphoidsternal joint:
between the xiphoid processes and the body and primary cartilaginous joint
The interchondral joint
Between the adjacent ribs mainly 7-10
usually plane type synovial joints
Provide indirect connection to sternum
contribute to forming costal margin
The costotransverse joint
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
