Upper thorax anatomy

Question 1

Define the terms origin and insertion used in describing muscle morphology

Answer 1

Origin is where the muscle starts, usually it does not move when the muscle contracts (eg. the ribs for pectoralis major). Insertion is where the muscle ends, it usually does move when the muscle contracts (eg. humerus for pectoralis major).

Question 2

Where is pectoralis major muscle inserted?

Answer 2

The humerus

Question 3

Which nerve (nerves) supply the pectoralis major muscle?

Answer 3

Medial and lateral pectoral nerves

Question 4

What are the actions of pectoralis major muscle?

Answer 4

adduction of the humerus, medial rotation of the humerus

Question 5

When you examine a patient how do you test to verify whether the pectoralis major is working or not?

Answer 5

Ask the patient to pull the arm tightly against the chest and feel for the contraction of pectoralis. (There are other muscles which pull the arm against the chest so feeling the muscle directly is needed)

Question 6

What are the surface markings of the following

Apex of the lung
Lower border of the lung
Lower border of the pleural cavity
Oblique fissure
Horizontal fissure

Answer 6

Apex of the lung; 2 finger breaths above the anterior end of the clavicle (the patients fingers, think children).

Lower border of the lung; anteriorly 6th rib, midaxillary line 8th rib, posteriorly 10th rib.

Lower border of the pleural cavity; anteriorly 8th rib, midaxillary line 10th rib, posteriorly 12th rib.

Oblique fissure: Along the 5th rib, starting under the 4th rib at the back and finishing at the 6th rib at the front.

Horizontal fissure: Under the 4th right costal cartilage.

Question 7

What are the main braches off the following main arteries and what organs/tissues do these vessels supply:

Answer 7

Left common carotid
Left subclavian Left common carotid; Internal carotid artery - most of the cerebrum (brain), external carotid artery - most of the face and upper part of the neck.

Left subclavian - the arm and some of the lower neck and shoulder

Question 8

What is the distribution of the phrenic nerve?

Answer 8

The diaphragm, sensory and motor

Question 9

Does the phrenic nerve enter the abdomen?

Answer 9

Yes, by piercing the central tendon of the diaphragm, alongside the Inferior vena cava on the right and adjacent to the apex of the heart on the left.

Question 10

Do the vagus nerves enter the abdomen?

Answer 10

If so where? Yes, passing through the oesophageal hiatus in the diaphragm.

Question 11

Note the surface markings of the heart. At what position are the following normally found?

Answer 11

a) right border of the heart
b) the apex of the heart a) right border of the heart - right sternal edge

b) the apex of the heart - 5th intercostal space, mid-clavicular line.

Question 12

What is the thoracic duct? Where does it join the vascular system?

Answer 12

The channel draining all the lymph from below the diapgragm back to the blood stream. The junction of the left subclavian vein and left internal jugular vein.

Question 13

Look at a chest Xray Which chambers and vessels form the right and left heart borders of the cardiac shadow?

Answer 13

Right from the top of the mediastinum down, subclavian vein, brachiocephalic vein, superior vena cava, right atrium, inferior vena cava (only just)
Left from the top down, left subclavian artery, arch of aorta, left pulmonary artery, left auricular appendage, left ventricle

Question 14

If an object is inhaled into the trachea, in which lung would you most expect it to be lodged and why?

Answer 14

Right main bronchus, it lies more vertically and is a more direct continuation of the trachea. (The L is less vertical due to the heart)

Question 15

What are the names of the three splanchnic nerves? What functions do they serve?

Answer 15

Greater, lesser and least splanchnic nerves. They supply the sympathetic nerve supply to the bowel. The bowel is anatomically divided into three parts, fore gut, mid gut and hind gut. The three nerves each supply one of these parts.

Question 16

Why is the blood supply to the thyroid so rich?

Answer 16

To allow rapid washout of thyroxine to control body metabolism; to allow rapid delivery of thyroid stimulating hormone and substrates: If the blood flow was very poor then control of thyroid function would not be as responsive. Iodine is only present in very low concentrations but is essential for the production of thyroxine, so the thyroid also needs a high blood flow to deliver enough iodine.

Question 17

Where do the thyroid arteries arise from?

Answer 17

Superior thyroid artery; external carotid

Inferior thyroid artery; thyrocervical truck, a branch of the subclavian artery.

Question 18

Are there nerves related to the thyroid arteries?

Answer 18

Yes
Inferior thyroid arteries - recurrent laryngeal nerves
Superior thyroid arteries - external laryngeal nerves

Question 19

Where are the parathyroid glands usually located? How many are there? How are they
developed?

Answer 19

On the posterior surface of the thyroid gland
Four
From the pharyngeal pouches

Question 20

Where is the midclavicular line?

Answer 20

Middle of the clavicle

Question 21

Where is the anterior axillary line?

Answer 21

The fold of muscle at the anterior of the axilla

Question 22

Where is the mid-axillary line?

Answer 22

The middle of the axilla

Question 23

What is the lymph drainage from the breast medial to the nipple?

Answer 23

Internal thoracic lymph nodes

Question 24

What is the lymph drainage from the breast lateral to the nipple?

Answer 24

Axillary lymph nodes

Question 25

What is the large muscle covering the shoulder region?

Answer 25

Deltoid

Question 26

What are the nerves supplying the pectoralis major muscle?

Answer 26

Medial and lateral pectoral nerves

Question 27

Where do the intercostal nerves run?

Answer 27

Deep to the internal intercostal muscles in a groove just below the rib

Question 28

What does the internal thoracic (mammary) artery branch into?

Answer 28

Musculphrenic to supply the diaphragm and superior epigastric arteries to supply the front of the abdomen

Question 29

What nerve supplies the diaphragm?

Answer 29

Phrenic nerve (C3,C4,C5-keep the diaphragm alive)

Question 30

Why would a tumour of the left lung cause a horse voice?

Answer 30

Invades the left recurrent laryngeal nerve, supplying the pharynx

Question 31

3 branches of the aorta

Answer 31

Brachiocephalic trunk (divides into right common carotid and subclavian vessels)
Left common carotid
Left subclavian

Question 32

Where does the left recurrent laryngeal nerve run?

Answer 32

Under the arch of the aorta and into the groove between the trachea and oesophagus

Question 33

What does the thoracic duct do?

Answer 33

Drains all the lymph from the lower half of the body and the bowel back into the blood stream

Question 34

Which vagus nerve passes through the diaphragm behind the oesophagus and which in front?

Answer 34

The right vagus behind and the left in front

Question 35

What does the thoracic duct drain into?

Answer 35

Into the confluence of the left subclavian vein and internal jugular vein on the left side of the neck

Question 36

What are the intercostal veins on the right and left side of the vertebral bodies called?

Answer 36

Right side = azygous system

Left side = hemi-azygous system

Question 37

What will you find running across the necks of the ribs?

Answer 37

The sympathetic chain

Question 38

How many sympathetic ganglia are there in the thorax?

Answer 38

12, one per vetebra

Question 39

How many sympathetic ganglia are there in the neck?

Answer 39

3

Question 40

How many sympathetic ganglia are there in the abdomen and pelvis?

Answer 40

One per vertebra

Question 41

From the 5th-12th thoracic ganglia there will be a nerve running forwards over the vertebral body to form the 3 ………. nerves?

Answer 41

Splanchnic nerves - supply the bowel