Thorax

Question 1

What structures are found in the superior mediastinum?

Answer 1

From anterior to posterior the superior mediastinum contains the thymus, the great veins, the great arteries, the trachea and the oesophagus.

Question 2

What features does a typical rib possess?

Answer 2

1. Head with 2 demifacets for articulation with the numerically corresponding vertebra and the vertebra above
2. Tubercle which articulates with the transverse process of the corresponding vertebra
3. Subcostal groove, containing the intercostal neurovascular bundle.

Question 3

Which ribs are considered atypical?

Answer 3

Ribs 1, 2, 10 11 and 12 – they have features that are not common to all the ribs.

Rib 1 is shorter and wider than the other ribs. It only has one facet on its head for articulation with its corresponding vertebrae (there isn’t a thoracic vertebrae above it). The superior surface is marked by two grooves, which make way for the subclavian vessels.

Rib 2 is thinner and longer than rib 1, and has two articular facets on the head as normal. It has a roughened area on its upper surface, where the serratus anterior muscle attaches.

Rib 10 only has one facet – for articulation with its numerically corresponding vertebrae.

Ribs 11 and 12 have no neck, and only contain one facet, which is for articulation with their corresponding vertebrae.