Diaphragm

Question 1

What is the origin of the diaphragm?

Answer 1

Sternal origin: Attached by 2 slips from the back of the xiphoid process
Costal origin: Attached by slips from the inner surfaces of the lower 6 costal cartilages of both sides
Vertebral origin: Attached by two muscular bands (called right & left crura) and five arcuate ligaments (one median, 2 medial & 2 lateral)

Question 2

Origin of the right and left crura

Vertebral origin

Answer 2

Right crura: Arises from the bodies of the upper four lumbar vertebrae
Left crura: Arises from the bodies of the upper three lumbar vertebrae

Question 3

What structure connects the 2 crura together?

Vertebral origin

Answer 3

Median arcuate ligament

Question 4

What are the attachment points of the median arcuate ligament?

Vertebral origin

Answer 4

Tendinous arch which connecting the crura together
Each medial arcuate ligament (right and left) is a tendinous arch that connects the crus with the tip of the transverse process of the 1st lumbar vertebra

Question 5

What are the attachment points of the lateral arcuate ligament?

Vertebral origin

Answer 5

Tendinous arch which connects the tip of the transverse process of 1st vertebra to the last rib

Question 6

Insertion of the diaphragm

Answer 6

Fibers of the sternal, costal & vertebral parts converge to be inserted into a central tendon which is more anterior than posterior in position

Question 7

Nerve supply of the diaphragm

Answer 7

Motor Branch: Phrenic nerve (C 3,4,5)
Sensory Branches: Lower 6 intercostal nerves

Question 8

Action of the diaphragm

Answer 8

The diaphragm contracts and flattens during inspiration to increase the volume of the chest cavity.

Question 9

Relations of the upper surface of the diaphragm

Answer 9

Its central tendon is related to the pericardium & heart
Right cupola is related to right pleura & base of right lung
Left cupola is related to left pleura & base of left lung

Question 10

Relations of the lower surface of the diaphragm

Answer 10

Right cupola is related to right lobe of liver
Left cupola is related to left lobe of liver and stomach

Question 11

What are the openings of the diaphragm?

Answer 11

Aortic opening
Esophageal opening
Venacaval opening

Question 12

Location of the aortic opening of the diaphragm

Answer 12

At the level of the lower border of 12th thoracic vertebra
Lies in the median plane behind the median arcuate ligament

Question 13

Contents of the aortic opening

Answer 13

Vena azygos
Aorta
Thoracic duct

Question 14

Location of the esophageal opening

Answer 14

At the level of the 10th thoracic vertebra

Question 15

Contents of the esophageal opening

Answer 15

Esophagus
Anterior & posterior gastric nerves
Esophageal branches of the left gastric vessels

Question 16

Location of the venacaval opening

Answer 16

At the level of the 8th thoracic vertebra

Question 17

Contents of the venacaval opening

Answer 17

Inferior vena cava
Right phrenic nerve

Question 18

How does the diaphragm affect a tension pneumothorax?

Answer 18

Contraction of the diaphragm draws more free air into the pleural space, reducing the size of the lung and inhibiting appropriate ventilation

Question 19

What are the effects of a tension pneumothorax?

Answer 19

Hypoxia and reduced venous return to the heart, leading to cardiovascular collapse