Vascular anatomy and pathology

Question 1

What are the three arterial branches off the aortic arch and their tributaries?

Answer 1

There are three arterial branches off the aortic arch; Brachiocephalic, left common carotid and left subclavian. The brachiocephalic artery branches into the right common carotid and right subclavian.

Question 2

Where do the vertebral arteries originate?

Answer 2

The left and right vertebral arteries branch off the left and right subclavian arteries respectively.

Question 3

Which veins drain the head, neck, upper limbs, upper thorax and mammary glands?

Answer 3

The subclavian and internal jugular veins drain the head, neck upper limbs, mammary glands & superior thorax.
Once they unite, they become the brachiocephalic vein.
Once the brachiocephalic veins unite they become the superior vena cava.

Question 4

Describe the arteries of the upper limb.

Answer 4

The axillary artery is a continuation of the subclavian artery and begins when it passes the first rib. It supplies the lateral thorax, axilla and upper limb. It has three parts based on its location to the pectoralis minor muscle. Medial, behind and lateral.
The brachial artery begins once it passes teres major.
The radial and ulnar arteries arise from the bifurcation of the brachial artery. As the radial artery runs distally it winds around the lateral aspect of the wrist.

Question 5

What is special about deep veins?

Answer 5

Deep veins accompany all major arteries and share the same name. The often occur as pairs (venae comitantes) and are contained in the vascular sheath.

Question 6

Describe superficial veins

Answer 6

Superficial veins are closer to the surface and connect to the deep veins via perforating vessels. Veins drain superficial to deep and valves are often present just below the branch of a perforating vessel.

Question 7

Describe the course of upper limb veins

Answer 7

The radial part proceeds as the cephalic vein while the ulnar part proceeds as the basilic vein.

Most of the course of the basilic vein is superficial. About half way up the arm it travels deep under the muscles.
Around the lower border of teres major the anterior and posterior humeral veins feed into it before it joins the brachial vein to become the axillary vein.
The axillary vein continues as the subclavian vein after the first rib.
The cephalic vein is on the radial side and crosses the snuff box superficial to the radial styloid.
The cephalic vein moves medially as it approaches the cubital fossa where it gives off the medial cubital vein. It then continues along the lateral border of the biceps.
It joins the axillary vein inferior to the clavicle.

Question 8

Describe the course of lower limb arteries

Answer 8

The femoral artery is a continuation of the external iliac artery. It supplies to lower limb.
The profunda femoris is also known as the deep femoral artery. It is the main blood supply to the thigh and terminates in the 4th perforating artery.
The femoral artery itself continues down the thigh and into the popliteal fossa where it becomes the popliteal artery.
At the inferior border of the popliteus muscle the popliteal artery divides into two branches; The anterior and posterior tibial artery.
The posterior tibial artery is larger and more direct. It supplies the posterior compartment of the leg and foot. Its main branch is the fibular or peroneal artery. It passes inferior to the medial malleolus where it divides into the medial and lateral plantar arteries that supply the sole of the foot.
The anterior tibial artery is smaller and passes through the superior gap in the interosseus membrane supplying the anterior compartment of the leg. At the ankle it becomes the dorsalis pedis artery and can be palpated anterior to the ankle joint.

Question 9

Describe the veins of the lower leg

Answer 9

Deep veins in the leg accompany all major arteries and their branches. They often occur as pairs (venae comitantes) and are contained within the vascular sheath Major deep veins in the leg are: Anterior tibial vein, Posterior tibial vein and the Posterior fibular vein. These three veins drain into the popliteal vein posterior to the knee.
The two major superficial veins are the great and small saphenous.
The great saphenous vein forms the dorsal venous network and travels anterior to the medial malleolus.
It passes posterior to the medial femoral condyle, anastomoses with the small saphenous vein and drains into the femoral vein.
The small saphenous vein ascends posterior to lateral malleolus and passes along lateral border of calcaneal tendon, ascends between the heads of gastrocnemius and empties into the popliteal vein in popliteal fossa.

Question 10

List the major superficial veins of the body and their location

Answer 10

Basilic (ulna), cephalic (radial), greater saphenous (medial lower leg) and small saphenous (postero lateral lower leg).

Question 11

List the arteries the thoracic aorta gives rise to

Answer 11

The descending aorta gives rise to the intercostals, superior phrenics, bronchials, subcostals and oesophageals.

Question 12

List the arteries the abdominal aorta gives rise to

Answer 12

The abdominal aorta gives rise to:

• Inferior phrenic artery
• Celiac trunk
• superior mesenteric artery
• Middle suprarenal arteries
• Renal arteries
• Gonadal arteries
• Inferior mesenteric artery
• Lumbar and median sacral arteries

Question 13

What organs does the celiac artery supply?

Answer 13

The celiac trunk is the artery of the foregut. It supplies all organs of the foregut that arose during development. Distal oesophagus, stomach, liver, gall bladder, pancreas, spleen, duodenum.

Question 14

What organs does the superior mesenteric artery supply?

Answer 14

The superior mesenteric artery supplies the midgut. From the proximal duodenum to the transverse colon. This includes the caecum, appendix and ascending colon.

Question 15

What organs does the inferior mesenteric artery supply?

Answer 15

The inferior mesenteric artery supplies the hindgut. This stretches from the splenic flexure up to and including the rectum.

Question 16

Why is the transverse colon more prone to ischaemia?

Answer 16

Prox 2/3 of transverse colon is supplied by SMA while later 1/3 by IMA –watershed area between these 2 areas-sensitive to ischaemia)

Question 17

Describe the azygous system

Answer 17

Most thoracic structures are drained by a network of veins called the azygous system. This is a network of veins on each side of the vertebral column
- Azygous
- Hemiazygous
- Accessory Hemiazygous
They show considerable variation. The azygous has small connections with the IVC and may serve also as bypass for the IVC
It receives deoxygenated blood from the posterior thorax and abdomen

Question 18

What are the three layers of blood vessels?

Answer 18

Blood vessels have three layers; Tunica intima, tunica media and tunica externa.

Question 19

Describe the cellular make up of the vessel layers

Answer 19

Tunica intima is made up of squamous epithelial cells.
Tunica media consists of smooth muscle and elastic connective tissue.
Tunica externa (adventitia) consists of loosely arranged connective tissue.

Question 20

Explain how arteries are different to veins

Answer 20

Arteries carry blood away from the heart and veins carry blood toward the heart.
The tunica media is thicker in an artery (which also has a smaller lumen)
Some major arteries such as the aorta have a large elastic connective tissue component in the tunica media to cope with the systolic blood pressure.
Veins have a thinner tunica media and a larger lumen and also may contain valves to prevent backflow.

Question 21

What is the difference between superficial and deep veins?

Answer 21

Deep Veins accompany all major arteries and their branches and share the same name. They often occur as pairs (venae comitantes) and are contained within the vascular sheath. Venae comitantes are usually found with certain smaller arteries, especially those in the extremities. Larger arteries, on the other hand, generally do not have venae comitantes. They usually have a single, similarly sized vein which is not as intimately associated with the artery.
Superficial veins are closer to the surface & connect to the deep veins by perforating vessels. Venous blood moves from the superficial to the deep. Venous valves & skeletal muscle contraction help move the venous blood towards the heart.

Question 22

List the venae comitantes in the body

Answer 22

Examples of arteries and their venae comitantes:
• Radial artery and radial veins
• Ulnar artery and ulnar veins
• Brachial artery and brachial veins
• Anterior tibial artery and anterior tibial veins
• Posterior tibial artery and Posterior tibial veins
• Fibular artery and Fibular veins

Question 23

What are some examples of arteries without venae comitantes

Answer 23

Examples of arteries that do not have venae comitantes (i.e. those that have “regular” veins):
• Axillary artery and the axillary vein
• Subclavian artery and the subclavian vein

Question 24

Briefly describe atheroscleorsis and list the vessels it affects

Answer 24

Atherosclerosis is a common degenerative disorder affecting walls of medium to large arteries - (the aorta, coronary vessels, and carotid vessels but also large arteries to the lower limb & the renal artery). The pathological process involves chronic inflammation and deposition of lipids and cellular debris within the walls

Question 25

Describe stage one of atherosclerosis

Answer 25

Stage one: The inner lining of the artery (endothelium) can be damaged due to high cholesterol and triglyceride levels, toxic substances of cigarette smoke, high sugar levels and other factors in blood. High blood pressure can also cause damage to the inner lining.
The first signs are fatty streaks. Once the vessel is damaged atherosclerosis begins and plaques begin to form.

Question 26

Describe stage two of atherosclerosis

Answer 26

Stage two: because of the damage fats, cholesterol, platelets, cellular debris and calcium begin to deposit in the walls of the vessel. This may stimulate the cells of the artery wall to produce more material and so more cells accumulate in the innermost layer of the artery wall where the atherosclerotic lesions form.
As cells accumulate and divide fat builds up around them and connective tissue forms. This build-up is called plaque. It usually affects large and medium-sized arteries.
This thickens the endothelium significantly, the diameter shrinks and blood flow decreases, reducing oxygen supply.

Question 27

List the risk factors for atherosclerosis

Answer 27

• genetic predisposition,
• increasing age,
• diabetes,
• high LDL cholesterol levels,
• high blood pressure
• life-style choices such as smoking, an unhealthy diet, being overweight and a lack of physical activity

Question 28

List arteries that are more susceptible to atherosclerosis

Answer 28

Medium to large arteries – in descending order the lower abdominal aorta, coronary arteries, popliteal arteries, internal carotid arteries and the vessels of the circle of willis

Question 29

How does atherosclerosis cause long term damage?

Answer 29

Most of the damage occurs when plaques become fragile and rupture. Plaques generally continue to change and progressively enlarge through cell death and degeneration, remodelling of the extracellular matrix and organisation of superimposed thrombus. Atherosclerotic plaques are susceptible to rupture ulceration and erosion, haemorrhage into the plaque, atheroembolism and aneurysm formation.

Question 30

What are some long term effects of atheroscleosis?

Answer 30

thrombus formation, emboli & aneurysms . Plaques that rupture cause the formation of thrombi that can block blood flow or break off and travel to another part of the body.
The weakened vessel wall may form an aneurysm which has the potential to burst or be a site for thrombus accumulation.
The serious long-term effects of atherosclerosis cause lack of blood supply to various tissues and Peripheral Vascular Disease. (PVD)

Question 31

Describe a fusiform aneurysm and how it is formed

Answer 31

Fusiform aneurysms are also known as atherosclerotic aneurysms.
These lesions occur because of a severe form of atherosclerosis. Damage to the media results in arterial stretching & elongation that may extend over a considerable length. These vessels may have more focal areas of fusiform or even saccular enlargement, the vertebrobasilar system is commonly affected. Intraluminal clots are common
An aneurysm is an abnormal focal dilation of an artery. The main complication is that they may rupture causing local bleeding and have a predisposition to accumulation of thrombus.

Question 32

Discuss how atherosclerosis may cause stroke

Answer 32

Stroke can be a serious long-term complication of atherosclerosis.
Major causes of stroke involve ischaemia or haemorrhage of cerebral arteries. Ischaemia often results from severe, flow-limiting stenosis caused by atherosclerotic disease usually in the internal carotid artery and thromboembolism from carotid plaque. Some of the causes of haemorrhage include cerebral aneurysms, the main cause of which is chronic high blood pressure and atheromatous change.

Question 33

Define neovascularisation

Answer 33

The formation of new blood vessels, usually in the form of functional microvascular networks, capable of perfusion by red blood cells, that form to serve as collateral circulation in response to local poor perfusion or ischemia.

Question 34

What is deep vein thrombosis?

Answer 34

An abnormal clot that forms in the deep veins often in the leg or thigh.

Question 35

What are the three predispoitions to DVT?

Answer 35

• Immobility; orthopedic surgery, long aeroplane flights, pregnancy ,being bedridden
• Hypercoagulability; estrogens; OCP, HRT, genetics; Factor V Leiden, polycythemia, malignant neoplasia, smoking
• Trauma to the vein; fracture, bruising.

Question 36

What are some symptoms of DVT?

Answer 36

• pain or swelling in the calf, thigh, or both.
• warmth or discoloration at the site.
• half of the time asymptomatic

Question 37

What is a potential serious complication of DVT?

Answer 37

PE

Question 38

How is a DVT treated?

Answer 38

Treatment; anticoagulants (heparin warfarin, aspirin) and preventative compression stockings.

Question 39

What is PVD?

Answer 39

Lack of blood supply to major peripheral arteries such as the femoral and popliteal arteries results in peripheral vascular disease (PVD).
There may be no symptoms until the condition is advanced and severe.
Signs and symptoms may include;
- Intermittent claudication – leg pain and cramps that develop during walking and disappear after rest due to ischaemia of the leg muscles caused by narrowing or occlusion of the leg arteries.
- Coldness
- Numbness
- Pins and needles
- Muscular weakness
- Blue or purple tinge to the skin
- Wounds that won’t heal (vascular ulcers)
- Blackened areas of skin or skin loss (gangrene)

Question 40

Define Stenosis and explain how it affects the blood vessels

Answer 40

The abnormal narrowing of a passage in the body.
Atherosclerosis is a common cause of vessel stenosis. Plaque formation thickens the endothelium significantly, the diameter shrinks and blood flow decreases, reducing oxygen supply

Question 41

Define plaque and explain how it affects the blood vessels

Answer 41

Build-up of fat, connective tissue, cellular debris and calcium due to vessel damage. It usually affects large to medium sized arteries. Plaques can cause both stenosis, emboli and other pathology due to limited blood supply.

Question 42

Define emboli and explain how it affects the blood vessels

Answer 42

The obstruction of a blood vessel by a foreign substance or a blood clot that travels through the bloodstream, lodging in a blood vessel, plugging the vessel
Causes;
- Pathology of vessel wall (Atheroma)
- Pathology within blood (Bacterial infection (eg heart valves), Coagulation disorders, Fat embolism, Tumour embolism)