Sun10October1036AM 4

Regarding the diaphragm, which of the following is correct?

(Please select 1 option)

Is partly derived from the pleuroperitoneal membranes This is the correct answer

Has an origin from the body of the sternum

Has the aorta passing behind it at T10 Incorrect answer selected

Has the left phrenic nerve passing through its central tendon

Has primary accessory motor innervation from the intercostal nerves

Explanation

The diaphragm is partly derived from the pleuroperitoneal membranes and mesoderm. The primary motor innervation is from C345 via the phrenic nerve. The peripheral portions of the diaphragm send sensory afferents via the intercostal (T5-T11) and subcostal nerves (T12). It consists of a central tendon and a muscular margin.

The fleshy fibres rise in front from the back of the xiphoid cartilage of the sternum, laterally by six serrations from the inner surfaces of the lower six ribs interdigitating with the transversalis, posteriorly from the arcuate ligaments, of which there are five, a pair of external, a pair of internal, and a single median one.

The external arcuate ligament stretches from the tip of the twelfth rib to the costal process of the first lumbar vertebra in front of the quadratus lumborum muscle, the internal and middle are continuations of the crura which rise from the ventro-lateral aspects of the bodies of the lumbar vertebrae, the right coming from three, the left from two.

On reaching the level of the twelfth thoracic vertebra each crus spreads out into a fan-shaped mass of fibres, of which the innermost join their fellows from the opposite crus in front of the aortic opening to form the middle arcuale ligament; the outer ones arch in front of the psoas muscle to the tip of the costal process of the first lumbar vertebra to form the internal arcuate ligament, while the intermediate ones pass to the central tendon.

The aorta crosses the diaphragm at T12.

Answer Statistics

1

45%

2

8%

3

24%

4

20%

5

6%

Times answered: 229