Lecture 4: Diaphragm; Mechanisms of Breathing (& Breast)

Question 1

What is the median arcuate ligament?

Answer 1

Formed by crus over descending aorta - attach to lumbar vertebrae

Question 2

What are the lengths of the crura?

Answer 2

Right L1-3/4

Left L1-2/3

Question 3

What is the medial arcuate ligament?

Answer 3

Reflection of diaphragm over psoas major

Question 4

What is the lateral arcuate ligament?

Answer 4

Reflection of the diaphragm over quadratus lumborum

Question 5

What level does the IVC pierce the diaphragm and what is the function of this?

Answer 5

T8, when the diaphragm contracts it opens up orifice and promotes blood return to heart

Question 6

What level does the oesophagus pierce the diaphragm and what is the function of this?

Answer 6

T10, when the diaphragm is expanding for breathing this orifice acts as a sphincter and closes off the stomach so that reflux of acidic stomach contents doesn’t occur when intra-abdominal pressures increase

Question 7

What level does the aorta pierce the diaphragm?

Answer 7

T12

Question 8

Where does the azygous vein move through the diaphragm?

Answer 8

Slings of crura

Question 9

Where does the sympathetic trunk move through the diaphragm?

Answer 9

Enters under the median arcuate ligament

Question 10

What nerve innervates the diaphragm and what spinal segments is it from?

Answer 10

Phrenic, C3,4,5

Question 11

What does the phrenic nerve supply for the diaphragm?

Answer 11

Sensory to central tendon and pericardium, motor to all of diaphragm

Question 12

What nerve provides sensory supply to the periphery of the diaphragm?

Answer 12

Intercostals

Question 13

How do the lungs inflate?

Answer 13

Parietal pleura is attaches to the thoracic cage, due to surface tension, when the parietal pleura moves the visceral pleura moves. The visceral pleura is attached to the lungs so when it moves the lungs move - when the thoracic cage opens the lungs expand

Question 14

What are rhythmic contractions controlled by?

Answer 14

Resp centre in brainstem

Question 15

Where does pump handle occur?

Answer 15

Ribs 2-5 - sternum moves up and outward and expands thoracic cavity in anteroposterior direction

Question 16

Where does bucket handle occur?

Answer 16

Ribs 7-10 - ribs move outwards - increase transverse diameter of thoracic cage

Question 17

What muscles assist with expansion in respiration?

Answer 17

Scalene, external intercostals, medial internal intercostals

Question 18

What muscles assist with collapse in respiration?

Answer 18

Lateral internal intercostals, abdominal muscles (increase pressure)

Question 19

What are hiccups?

Answer 19

Quick inspirations due to spasmodic contractions of the diaphragm

Question 20

What are hiccups caused by?

Answer 20

Irritation of the phrenic nerve, diaphragm or resp centre

Question 21

What muscle does the mammary gland sit anterior to?

Answer 21

Pec Major

Question 22

How many lobules are in each breast and where do they drain?

Answer 22

15-20 - lactiferous duct

Question 23

How is the mammary gland attached?

Answer 23

Via suspensory ligament to skin and fascia

Question 24

What fraction of the breast sits over what muscle?

Answer 24

2/3 pec major, 1/3 serratus anterior

Question 25

What is the position of the nipple?

Answer 25

4th intercostal space

Question 26

What is unique about the areola?

Answer 26

Sebaceous glands for lubrication

Question 27

What is the difference between young and old breast tissue?

Answer 27

Young is dense, old is fatty

Question 28

What is the blood supply to the mammary gland?

Answer 28

Internal thoracic, intercostals, subclavian

Question 29

What are the lymphatics for the breast?

Answer 29

Sub alveolar plexus

Question 30

Where is breast cancer usually derived from?

Answer 30

Glandular epithelium in lobules

Question 31

What part of the breast can be confused with a swollen lymph node?

Answer 31

Axillary tail

Question 32

Where is milk stored in the breast?

Answer 32

Lactiferous sinus