Diaphragm

Question 1

How much of the diaphragm is composed of the strong central tendinous section?

Answer 1

21%

Question 2

From what vertebrae are the diaphragmatic crus arising?

Answer 2

L3 and L4 bodies

Question 3

Where do the costal muscles of the diaphragm arise?

Answer 3

Medial proximal portion 13th rib, distal 12th, costochondral jxn 11th, all of 10th and 9th and 8th costal cartilages

Question 4

where does the pars sternalis originate?

Answer 4

base xiphoid cartilage, adjacent transverse fascia, 8th costal cartilages

Question 5

What goes through the caval foramen?

Answer 5

adventia of the caudal vena cava+ caudal VC

Question 6

what goes through esophageal hiatus?

Answer 6

esophagus, blood supply to esophagus, dorsal and ventral vagal trunks

Question 7

what passes through aortic hiatus?

Answer 7

aorta, azygous, hemiazygous veins and lumbar cistern of the thoracic duct

Question 8

What passes through the paired minor foramina of Morgagni?

Answer 8

aka sternocostal triangles

egress cranial epigastric arteries (terminations of internal thoracic arteries)

Question 9

Describe embryologic development of diaphragm?

Answer 9

transverse septum from cervical vertebrae region –> caudal migration to central tendon
dorsal mesentery of esophagus –> median portion–> crura
Lateral pleuroperitoneal folds–> migrate medially and complete partition
myoblasts from body wall invade to form costal muscles

Question 10

What muscles contribute to inspiration?

Answer 10

parasternal intercostal muscles –>dorsal displacement of sternum
Intercostals –> chest wall expansion