Thoracic wall Flashcards
What are the components of the thoracic cage?
1) Sternum
2) 12 pairs of ribs
3) Costal cartilages (Hyaline cartilage)
4) 12 thoracic vertebrae and intervertebral discs
How many ribs are there, and what are its classifications?
12 pairs of ribs,
1) True ribs: 1-7
2) False ribs: 8-10
3) Floating ribs: 11-12
What are the typical ribs?
3-9
What are the components of the typical rib?
1) Posterior head:
- Two facets in the HEAD
- Neck
- Tubercle
2) Shaft”
- Twisted shaft
- Outer surface
- Inner surface
- Upper border
- Lower border
3) The anterior end (cup-shaped articulates with the cartilage
Describe the structure of the posterior end of the typical ribs
1) Head:
- Wedge-shaped, contains two articular facets with a crest in between
2) Neck:
- Extends between the head and tubercle
- Provides an attachment for the costotransverse ligament
3) Tubercle:
- Smooth articular facet for the transverse process of the numerically corresponding vertebrae
- Rough part for the attachment of the lateral costotransverse ligament
Describe the structure of the shaft of the typical ribs
1) Angle:
- It is the point of maximum convexity of the rib, and its weakest point
2) Costal groove:
- Found in the middle of the inner surface, near the lower margin where it protects the nerves and vessels (vein, then artery then nerve “in this order”)
What are the articulations of the typical ribs?
1) Three articulations with the vertebrae, 2 with the head one with the tubercle
2) With the costal cartilage (hyaline cartilage)
Which ribs are considered the Atypical ribs?
Ribs:
1, 2, 10, 11, & 12
Describe the characteristics of the first rib
1) Shortest, Broadest, and most curved rib
2) Its head has one complete facet (unlike the typical with 2-facets)
3) Its tubercle corresponds to the angle
4) It has a (rough “due to muscle attachment”) upper and (smooth) lower surface and outer and inner borders
5) It has a scalene tubercle on the inner border and a scalene ridge on the upper surface (for the attachment of the scalene muscle)
6) It has grooves on the superior surface for the subclavian vessels
What are the different structures in the first rib?
1) Posterior end Head with one facet
2) Neck
3) Tubercle where the angulation starts
4) Body
5) Outer and inner border
6) Upper and lower surfaces
7) Anterior end head
8) Groove for subclavian vessels
9) Tubercle in the inner border for the scalene muscle
10) Ridge on the upper surface for the scalene muscle
Which rib is rarely fractured?
Rib number 1 as the clavicle protects it
Which fascial modification is attached to the inner border of rib 1?
Suprapleural membrane
Describe the characteristics of the second rib
- It is a transition between the first and 3rd typical rib
1) It has a head with 2 facets
2) Its tubercle has a facet
3) It is not twisted so there is not an upper and lower border
4) It has a tuberosity for serratus anterior
Which rib is most easy to fracture?
Rib number 2
What are the different structures in the second rib?
1) Head
2) Neck
3) Tubercle
4) Body
5) Costal end
6) Tuberosity for serratus anterior first and second digitations attachment
7) Scalene posterior muscle attachment
Describe the characteristics of the 10th rib
other than the normal what makes it atypical is that it has a single facet on the head
What makes rib 11 and 12 atypical?
- They are short
1) They have a single large facet on the head
2) They do not have a neck nor a tubercle
3) They have a pointed anterior end
4) Rib 11 has a slight angle and a shallow costal groove
5) Rib 12 is straight and has no costal groove
Which ribs have no neck and tubercle?
ribs 11 and 12
What are examples of abnormal ribs?
Sometimes a person might have an extra rib or a missing rib
1) Cervical rib (Articulates with the transverse process fo C7)
2) Lumbar rib where a person might have and extra rib 13
Describe the sternum bone
Otherwise named as the breast bone:
- Composed of three bony parts:
1) Manubrium
2) Body
3) Xiphoid process
What are the different joints found in the Ribcage anterior
- Sternum:
1) Sternoclavicular joint (synovial joint “features of ball & socket”)
2) First Sterno-chondral joint” (primary cartilage joint/synchondrosis “not movable”)
3) 2-7th rib “Sterno-chondral joints” (synovial plane joint)
4) Manubrio-sternal joint (secondary cartilaginous joint)
5) Xiphisternal joint (secondary cartilaginous, initially it is a symphysis joint, at 40 it becomes a synostosis joint)
- Costochondral joints (Primary cartilaginous)
- Interchondral joints (synovial)
Which structures articulates with the manubrium?
1) Clavicle (synovial joint)
2) First rib via the cartilage (primary cartilage joint)
3) Part of the second rib via the cartilage (synovial joint)
Which structure articulates with the body of the sternum?
Half of rib 2 till Half of rib 7
Which structures articulates with the xiphoid process?
Half of rib 7
What are the corresponding vertebral segments in regard to the jugular/clavicular notch?
The inferior border of T2
What is the vertebral segment that corresponds to the sternal angle?
The lower border of T4
What is the vertebral segment that corresponds to the Xiphoid process?
T10 calcifies after the age of 40
How is the body of the sternum formed?
It is formed by the fusion of four segments (sternebrae) where the transverse ridges indicate the lines of fusion, incomplete ossification will result in a foramen
What are the structures that correlate anatomically with the xiphisternal joint?
1) Central tendon of the diaphragm
2) Inferior border of the heart
3) Superior limit of the liver
What are the different costal cartilages found in the rib cage?
1) Sterno-chondral joints
2) Costal margin (inferior edges of the 7th-10th costal cartilages)
- They are made of hyaline cartilage and calcified with old age reducing their elasticity
What are the different ways to count ribs?
1) Anteriorly: Via the sternal angle which corresponds to rib number 2
2)Posteriorly: Inferior angle of the scapula corresponds to rib 7
Can you collect bone marrow samples from the sternum?
Yes and it is easily accessible due to its subcutaneous position
What are the relations and attachments of the left first rib?
1) Subclavian vein
2) Subclavian artery
3) T1 nerve root
4) Subclavius muscle attachment
5) Scalenus medius attachment
When does the different segments of the sternum ossified?
1) Manubrium: 5-months intrauterine
2) 1st sternebra: 6-month intrauterine
3) 2nd sternebra: 7-month intrauterine
4) 3rd sternebra: 8-month intrauterine
5) 4th sternebra: 9-month intrauterine
6) Xiphod: 4th year