Week 1 - Thoracic Osteology Flashcards
Identify the main features & functions of the thoracic cavity - A typical rib - First rib - Sternum - Thoracic vertebrae (alongside cervical & lumbar) Describe how the ribs articulate with the vertebrae and the sternum, and understand the movement the movements which occur at these joints
What are the defining characteristics of Thoracic Vertebrae?
- Vertebral Body - Heart shaped
- Demi Facets - articulate with heads of ribs
- Costal Facets - articulate with tubercles of ribs
- Spinous processes - long & point inferiorly
What are the 3 types of ribs?
- True
- False
- Floating
Describe the Typical Ribs
- Head has 2 articular facets
- Neck
- Body is thin flattened and curved
which ribs are atypical ribs?
Ribs 1, 2, 10, 11, & 12
Why is Rib 1 atypical?
- Shorter & wider
- Only 1 facet for articulation with its corresponding vertebrae
- Superior surface is marked by two grooves for the subclavian vessels
Why is Rib 2 atypical?
- Longer and thinner than rib 1
- Two articular facets on the head as “normal”
- Roughened area on its upper surface for Serratus ant.
Why is Rib 10 atypical?
Only has one facet for articulation with its numerically corresponding vertebrae
Why is Rib 11 & 12 atypical?
- No neck
- Only contain one facet
What are the muscles located within the intercostal space?
- External intercostal muscles
- Internal intercostal muscles
- Innermost intercostal muscles
What does the term ‘intercostal’ mean?
Between ribs
What is the function of the external intercostal muscles?
Lifts the rib to increase lung volume
What are the characteristics of the external intercostal muscle?
- Most superficial muscle
- Fibers directed downward & forward
- Extends from rib tubercle to costochondral junction
What is the origin and insertion of the internal intercostal muscle?
- Origin: Inferior margin of costal cartilage and inner lip of costal groove
- Insertion: Superior border of the rib below
What is the role of the interchondral internal intercostal muscles?
Elevates the ribs
The interchondral part of the internal intercostal muscles is situated between the cartilaginous attachments of the ribs to the sternum
Where does the internal thoracic artery arise from?
Arises from the first part of the subclavian artery
At which intercostal space does the internal thoracic artery divide?
Sixth intercostal space
What are the main branches of the internal thoracic artery?
- Superior epigastric artery
- Musculophrenic artery
What is the significance of intercostal nerves?
Supply:
- Intercostal muscles
- Skin of the anterolateral chest
- Abdominal wall
True or False: The intercostal nerves arise from the anterior rami of thoracic spinal nerves T1 to T11.
True
What is the function of the collateral branch of the intercostal nerve?
Motor:
- innervates the intercostal muscles (play a role in breathing by helping to raise or depress the ribs)
Sensory:
- sensory innervation to the parietal pleura (lining the chest cavity) and the periosteum (lining the bones) of the ribs
- contributes to the overall sensation of the chest wall
Cutaneous:
- branches to the skin in the midaxillary line
- contributing to the sensation of the chest wall
Runs parallel to the main nerve on the upper border of the rib below
What is the purpose of an intercostal nerve block?
Deliver anesthetic agent to the nerve
Fill in the blank: The _______ and _______ supply the upper six intercostal spaces.
- Anterior intercostal arteries
- Internal thoracic artery
What do posterior intercostal veins drain into?
- Brachiocephalic vein
- Superior intercostal vein
- Azygos vein
- Hemiazygos vein
What is the thoracic inlet?
The superior opening of the thoracic cage
