Thorax Flashcards
What are the two joints connecting the ribs to the vertebral column and what is the overall name
Costovertebral joints: Joints of the heads of the ribs and by the tubercles - the costotransverse joints.
What are the anterior joints of the ribs
Upper 7: articulate with the sternum at the sternocostal joints.
Next 3: articulate with each other
Last 2: Free ribs
Describe the joints of the heads of the ribs
Two articular facets with a ridge in between.
The lower one with its own vertebra, upper one with the vertebra above.
Attached to the ridge between the two and the body of the vertebra above is the intra-articular ligament. The radiate ligament consists of three bands: upper passes across the joint to the body of the vertebra above, the central horizontally and the deep to the anterior longitudinal ligament.
What are the exceptions to the rule for the joints of the heads of the ribs
The first rib articulates with the T1 vertebra only.
the last two ribs only articulate with their own vertebrae. In these instances the radiate ligament consists of two bands (not three).
Describe the costotransverse ligament
3 ligaments: costotransverse, lateral costotransverse, superior costotransverse.
Describe the costochondral joints
Primary cartilaginous joint that each rib makes with its costal cartilage
What type of joint are interchondral joints and which ribs are involved with these
The costal cartilages of 6 and 7, 7 and 8, 8 and 9 are joined to parts of adjacent surfaces of each other by small synovial joints.
Why is the first sternocostal joint different from the others
First costal cartilage articulates with the manubriaum by a primary cartilaginous joint, allowing no movement
What type of joint is the sternocostal joint of ribs 2-7
Synovial joint
Describe the manubriosternal joint
Surfaces are covered by a hyaline cartilage with an intervening disc of fibrocartilage.
How many layers of thoracic muscles are there?
3
- outer
- middle
- inner
What is serratus posterior superior
Outer layer muscle of the thoracic wall. Arises from the spinous processes of the lower two cervical and the upper two thoracic vertebrae. Slopes down and is inserted into the angles of ribs 2-5
What runs on the anterior surface of serratus posterior superior
Dorsal scapular nerve and vessels
What is serratus posterior inferior
Arises from the lower two thoracic and upper two lumbar spinous processes. Inserted just lateral to the angles of the lowest four ribs
What distinguishes the levator costae muscls
They are the only thoracic muscles to be supplied by the posterior rami of spinal nerves (C8-T11). 12 pairs of fan shaped muscles from the tip of a transverse process and inserted into the upper border of the rib below, lateral to its tubercle.
What way do the fibres of the external intercostals go
Obliquely downwards and forwards.
What happens to the fibres of the external intercostals at the costochondral junction.
It is replaced by the anterior intercostal membrane which extends to the side of the sternum.
What is the middle layer of thoracic musculature
Internal intercostal muscles. Fibres run downwards and backwards and extend to the sternum. At the back it is replaced by the posterior intercostal membrane. This extends from the angle of the rib to the superior costotransverse ligament at the posterior limit of the space
How many muscles in the inner layer of thoracic wall
3
- innermost intercostal
- Transversus thoracis: arise from the lower end of the sternum (and are anterior)
- Subcostal muscles: posterior
What is the order of the neuromuscular bundle in the intercostal spaces
Above to downwards: vein, artery , nerve. It runs in the plane between the internal intercostal and innermost intercostal. They are protected by the downward projection of the lower border of the rib.
What artery supplies the upper 2 posterior spaces
Superior intercostal artery - a branch of the costocervical trunk, origin is the second part of the subclavian artery (behind scalenus anterior)
What supplies the remaining 9 posterior intercostal spaces
Posterior intercostals - separate branches fo the descending thoracic aorta.
What vessel supplies the upper 6 spaces anteriorly
The internal thoracic artery
What vessel supplies the lower 7th, 8th and 9th spaces
Musculophrenic artery - gives off two anterior intercostal arteries that pass backwards to make end-to-end anastomosis with the posterior vessels