Thorax I: 1.3 & 1.4

1.3 Identify a typical rib

1.3.1 Which ribs are typical?

3rd to 9th rib

1.3.2 What are the characteristic features of a typical rib?

Characteristic features of a typical rib:

Curved shaft with anterior and posterior end.

Head -- articulates with bodies of vertibrae

Neck

Tubercle -- articulates with transverse process

Angle -- a point just lateral to the tubercle where the shaft bends forward

Costal groove -- lodges intercostal vessels & nerve.

1.3.4 What is a 'flail chest'?

Fracture of two or more ribs in two or more places, resulting from trauma. It produces an unstable ''flail'' segment and is often associated with underlying lung trauma or pneumothorax. It leads to asphyxia unless corrected promptly.

1.3.5 What is paradoxical respiration?

In which all part of a lung is deflated during inhalation & inflated during exhalation (as in the case of 'flail chest')

1.4 Identify the 1st rib (an atypical rib).

1.4.1 Locate the important structures related to the 1st rib

Anterior groove -- Subclavian vein

Posterior groove -- subclavian artery

1.4.2 What is 'cervical rib'? Give its incidence and its significance.

'Cervical rib' is an extra rib which arises from the 7th cervical vertebra. Presence can cause a form of thoracic outlet syndrome due to compression of the longer trunk of the brachial plexus (which causes the weakening of the hand muscles) or subclavian artery (which causes Adson's sign).

1.4.3 What are the boundaries of the 'thoracic inlet' (superior thoracic aperture)?

Body of vertebra TI posteriorly, the medial margin of rib I on each side, and the manubrium anteriorly.