Lecture 4 RH

Question 1

What are the basic components of the diaphragm?

Answer 1

diaphragm contains a central tendon with muscle fibers around it attach to.

Question 2

How many domes does the diaphragm contain?

Answer 2

diaphragm is made up of 3 domes; the left dome which projects lower than the right dome due to the heart’s positiion in the thorax.

Question 3

Where does the diaphragm attach to the rest of the body?

Answer 3

xiphoid process

Costal margin at the inferior 6 ribs. at the back end it only gets a few attachments to ribs. This is due to other muscles that attach at that location. For this reason, the diaphragm also attaches to continuous connective tissue posteriorly. These tissue are the arcuate ligaments

2 attachments to the lumbar spine at the crura.

Question 4

What are the 3 types of arcuate ligaments present in the thorax?

Answer 4

Median arcuate ligament (arches over descending aorta)

Medial arcuate ligament (over psoas major)

Lateral arcuate ligament (over quadratus lumborum)

Question 5

Where do the crura attach?

Answer 5

right crus at L1-3/4

Left crus at L1-2.3

Question 6

Where does the IVC penetrate the diaphragm?

Answer 6

T8 slightly to the right

Question 7

Where does the oesophagus penetrate the diaphragm?

Answer 7

T10 (posteriorly in the muscular part of the diaphragm)

Question 8

Where does the aorta pass through the diaphragm?

Answer 8

T12 and passes behind the median arcuate ligament between the crura

Question 9

How does the diaphragm assist IVC in venous return?

Answer 9

IVC uses contraction of the diaphragm to move blood towards the heart. The diaphragm’s contraction widens IVC and simultaneously causes lower pressure in the abdomen forcing blood upwards.

Question 10

What is the functional significance of the oesophagus’s position?

Answer 10

Diaphragm forms a functional sphincter around the oesophagus. When the diaphragm contracts the oesophagus is closed up to prevent stomach content reflux.

Question 11

Where does the right phrenic nerve penetrate the diaphragm?

Answer 11

Right phrenic nerve penetrates the right side of the diaphragm at the central tendon.

Question 12

Where does the left phrenic nerve penetrate the diaphragm?

Answer 12

Left phrenic nerve penetrates diaphragm at the muscular part of the diaphragm.

Question 13

How do the azygous veins enter the diaphragm from the thorax?

Answer 13

azygous system of veins penetrates diaphragm through slings of the crura.

Question 14

How does the sympathetic trunk penetrate the diaphragm to go from the thorax to the lower abdomen?

Answer 14

sympathetic trunk enters the abdomen under medial arcuate ligament

Question 15

What nerves innervate the diaphragm?

Answer 15

mostly the phrenic nerve which supplies motor innervation to the whole diaphragm. Also some sensory innervation to central diaphragm and pericardium.

Lower intercostal nerves are sensory to the periphery of the diaphragm.

Question 16

Where is pain referred to from the diaphragm?

Answer 16

C3, 4, 5 roots cause pain to be referred to the upper limb and neck.

Question 17

How do the lungs expand during inspiration?

Answer 17

parietal pleura is attached to the thoracic walls and visceral pleura to the viscera directly. when thoracic cage expands the lungs expand allowing inspiration.

Question 18

What is the main respiratory muscle involved in quiet respiration?

Answer 18

The diaphragm.

Question 19

How does expiration take place?

Answer 19

relaxation of muscle and elasticity of lung allow expiration to take place.

Question 20

What is the mechanism of pump handle action?

Answer 20

When intercostal muscles contract the rib is raised upwards and for this reason the antero-posterior dimensions of the rib cage are increased.

Question 21

What is the mechanism of bucket-handle action?

Answer 21

bucket handle action causes an increase in the inferior dimensions and as a result expands the rib cage inferiorly.

Question 22

What causes the different movements observed in the rib cage during breathing?

Answer 22

The shape of the ribs and how they are influenced by being pulled upwards.

Question 23

Which intercostal muscles assist in inspiration?

Answer 23

External intercostals elevate the ribs and assist in inspiration

Question 24

Which intercostal muscles assist in expiration?

Answer 24

Internal intercostal muscles help collapse the rib cage (assist in expiration)

Question 25

What is the function of the scalenes?

Answer 25

Scalene muscles attach to first and second ribs and act as accessory respiratory muscles.

Question 26

How do abdominal muscles assist respiration?

Answer 26

abdominal muscles assist forced expiration.

Question 27

How do pec major and minor influence respiration?

Answer 27

pec major and pec minor assist inspiration. This is because when they attach to a fixed humurous causing the thoracic cage to open

Question 28

What are hiccups and what causes it?

Answer 28

hiccups are caused by spasmodic contractions of the diaphragm. It is hypothesized to be initiated by neurons in phrenic nerve, daphragm muscle itself, and respiratory centers in the brainstem.

Question 29

What is the location of the mammary gland relative to internal structures?

Answer 29

mammary glands sit on fascia superficial to the pectoralis major. And space known as retromammary space.

Question 30

What is the structure found directly posterior to the nipple?

Answer 30

just before the nipple is the lactiforous sinus which stores milk.

Question 31

What does the mammary gland contain within it?

Answer 31

mammary glands contain areoli, fat lobules, and suspensory ligaments

Question 32

What structures hold mammary glands together?

Answer 32

suspensory ligaments hold the mammary gland in place.

Question 33

Where is the mammary gland located relative to the serratus muscle? What is the axillary tail?

Answer 33

1/3rd of the breast sits anteriorly over serratus anterior and an axillary tail which can be confused with swollen lymph nodes or cancer.

Question 34

What level does the nipple lie relative to ribs?

Answer 34

nipple lies in 4th intercostal space

Question 35

What is the areola and what does it do?

Answer 35

pigmented area around nipple is known as areola. It contains sebaceous gland which are important for lubrication

Question 36

What is the difference between the breast of old and young women?

Answer 36

young women have dense breasts. (more connective tissue and less fat)

Old women have less dense breasts. (more fatty less connective tissue)

Question 37

What arteries supply mammary glands?

Answer 37

internal thoracic artery. Medially (aka mammary artery)

branches of axillary artery.

branches of subclavian artery. lateral mammary branches for example

posterior intercostal artery branches

Question 38

What veins drain the mammary glands?

Answer 38

veins follow similar pattern to the arteries.

Question 39

What path does lymphatic drainage of the breast follow?

Answer 39

lymphatics form a subareolar plexus right under the areola. This then connects to a number of lymph nodes to the right lymphatic duct on the right and left thoracic duct on the left.

Question 40

Why is cancer often tested for in lymph nodes of the abdomen?

Answer 40

some lymphatics go from the breast to the abdomen.