The Thorax Flashcards
Identify which ribs are true ribs, false ribs and floating ribs
Ribs 1-7 are true ribs
Ribs 8-10 are false ribs
Ribs 11 and 12 are floating ribs
What is the structure of the ribs?
There are 3 sections: Head, Neck and Body
Describe the head of a rib
It is wedge shaped, and has 2 articulating facets (except for ribs 1, 10, 11 and 12) to articulate with its corresponding vertebrae and the vertebrae above
Describe the neck of a rib
It has a tubercle which articulates with the transverse process of the vertebrae
Describe the body of a rib
It is flat and curved, its internal side has a groove on its inferior side–> the costal groove
What are the special features of Rib 1
- It has only 1 articulating facet
- It forms a primary cartilaginous joint with the sternum
- It has a groove for the Subclavian vein anterior to the tubercle
- It has a groove for the Subclavian Artery posterior to the tubercle
- The Scalene Tubercle on the upper surface is attached to the scalenus anterior muscle
What kind of joint joins the ribs and the vertebrae?
Synovial joints
What kind of joins are between Costal Cartilages 2-7 and the Sternum?
Synovial Joints
What kind of joins are between Costal Cartilages 8-10 and the Sternum?
They do not articulate directly with the sternum- They have synovial joints with the costal cartilages immediately above them
What are the 3 sections of the Sternum?
Manubrium, Body and Xyphoid Process
Where is the Xyphoid Process?
T9
Where is the Manubriosternal Joint and what is the other name for it?
Level T4, also known as the “Angle of Louis”
What are the parts of Thoracic Vertebrae?
- Spinous Process
- Transverse Processes
- Pedicle (joins body to transverse process)
- Lamina (joins transverse process to the spinous process)
- Superior Articular Process (forms synovial joints with vertebrae above)
What kind of join is between 2 vertebrae?
Secondary Cartilaginous Joint
What is a slipped disc?
When there is a tear in the fibrous ring surrounding the articulating disc, causing the disc to ‘pop out’
What are the movements of the ribs that aid with breathing?
Pump handle movement and Bucket handle movement
Describe Pump Handle movement
In inspiration, the sternum moves outwards and upwards, pulling the ribs with it, increasing the anterior space in the thoracic cavity
Describe Bucket Handle movement
In inspiration, the lower ribs elevate laterally, increasing the transverse space in the thoracic cavity
What are the intercostal muscles?
- External
- Internal
- Innermost
Describe the External Intercostal Muscles (Direction)
Passes downwards diagonally and medially
Describe the internal and innermost intercostal muscles
Passes downwards diagonally and laterally
What are the muscles of respiration?
- Diaphragm
- External Intercostals
- Accessory muscles: Abdominal muscles, sternocleidomastoid and pectoral muscles
What is the neuromuscular supply to the intercostal muscles?
Neurovascular bundles in the costal groove, consisting of Vein, Artery and Nerve
What is the Arterial Supply of the Thorax?
- Posterior Intercostal Arteries
- Internal Thoracic Arteries
- Axillary Artery
What is the venous drainage of the thorax anteriorly?
Anterior Intercostal Veins–> Internal Thoracic Veins–> Subclavian Vein–> Brachiocephalic Vein–> Superior Vena Cava
What is the venous drainage of the thorax posteriorly?
Posterior Intercostal veins–> Azygous system–> Superior Vena Cava
Where does the azygous vein cross into the Superior Vena Cava?
Level T4
Where is the Accessory Hemizygous Vein and where does it cross into the Azygous Vein?
It is on the left side from levels T4-T8 and it join back into the Azygous Vein at T8
Where are the Hemiazygous Veins and where does it cross into the Azygous Vein?
It is on the left side from T9-T12, and it joins back into the Azygous Vein at T9
What is the Nervous Supply of the Thorax?
- Intercostal Nerves
2. Phrenic Nerves
Where does the Phrenic Nerve Originate?
Roots C3,4,5
What are the subdivisions of the mediastinum?
Anterior, Middle, Posterior, Superior and Inferior
What is a Pneumothorax?
When there is air between the visceral and partial pleura of the lung
What is a Pleural Effusion?
When there is fluid in the pleural space
What is a Haemothorax?
When there is blood in the pleural space
Where would you insert a chest drain?
4th/5th intercostal space just anterior to the mid-axillary line or the 2nd intercostal space along the mid-clavicular line
