Bones - Ribs

Question 1

Anatomy of a typical rib?

Answer 1

1) Head
i) Superior articular facet - articulates with the vertebra above.
ii) Inferior articular facet - articulates with the numerically corresponding vertebra.
2) Neck
i) Tubercle - where the neck meets the body - articulates with the transverse process of the numerically corresponding vertebra.
3) Shaft
i) Costal groove - located on the internal surface of the shaft.

Question 2

How many atypical ribs are there?

Which ones?

Answer 2

1, 2, 10, 11, 12

They all have features not typical of other ribs.

Question 3

Rib 1?

Answer 3

Shorter and wider.

Only one facet on head - articulates with numerically corresponding vertebra.

Marked by two grooves (subclavian artery and vein) and one tubercle that gives attachment to the scalene muscle.

Question 4

Rib 2?

Answer 4

Thinner and longer than rib 1.

Roughened area on external surface of the rib for attachment of the serratus anterior.

Question 5

Rib 10?

Answer 5

Only one facet - articulates with the numerically corresponding vertebrae.

Question 6

Ribs 11 and 12?

Answer 6

No neck

Only one facet - articulate with numerically corresponding vertebra.

Question 7

Articulations?

Answer 7

Posterior

All ribs articulate posteriorly with vertebrae of the spine.

Each rib forms two joints:

1) Costotransverse joint - tubercle (neck) of rib and transverse process of vertebra.
2) Costovertebral joint -

superior costal facet - vertebra above

inferior costal facet - numerically corresponding vertebra

Anterior

Ribs 1-7 - attach independently to the sternum

Ribs 8-10 - attach to the costal cartilages superior to them

Ribs 11-12 - floating ribs

Question 8

Clinical relevance - rib fractures?

Answer 8

Commonly occur in the middle ribs, as a consequence of crushing or direct trauma.

Common complication - soft tissue damage from broken fragments - lung, spleen and diaphragm at risk of damage.

If two or more adjacent ribs are fractured, the affected area is no longer under the control of the thoracic muscles. Displays paradoxical movement during lung inflation and exhalation. This is known as flail chest.

Prevents proper ventilation taking place, placing the patient at risk of hypoxia.

Treatment - fix ribs.