Blood & Lymphatic Vessels 1

Learning & Test Objectives

  1. Vascular System:
    1. Microscopic structure of vessel wall.
    2. Types of vessels including capillaries.
    3. Revision of the whole body vessels.
    4. Origin and branching of arteries.
    5. Drainage network of veins.
    6. Topography and course of vessels.
    7. Blood supply distribution.
  2. Lymphatic System:
    1. Structure, function and syntopy of Thymus, Spleen, Lymph node, and Tonsils.
    2. Main lymphatic trunks and ducts.
    3. Regional lymph nodes topography.
    4. Lymphatic drainage of organs.
  3. Blood
    1. Structure of formed blood elements
    2. Development of blood elements - haematopoiesis

 

Description of the test

The test is held by the general rules of written tests (see Continuous Testing – Organisation).

The test on the vessels and lymphatic system is in written format and follows the general rules for written tests (see Continuous testing – organisation). The test is focused on the arteries and vessels of the human body and the lymphatic and immune system. The only vessels of the brain that can be tested are the arteries of the circle of Willis. It is required to know the origin, course, branches and area supplied by each artery. For each vein it is necessary to know its origin, course, tributaries and the region it drains. For the lymphatic and immune systems, it is necessary to know the structure, function and syntopy of the lymphatic organs, the lymphatic ducts and trunks of the trunk and extremities and the groups of lymph nodes in each region of the body. Increased attention should be devoted to the lymphatic drainage of the tongue, stomach, large intestine, lungs, testes, prostate, ovaries, uterus, vagina and mammary glands. For blood elements, it is necessary to know the normal values of the blood count, including the leukogram, the structure of individual types of formed blood elements, the principles of hematopoiesis and the development of individual blood lineages. Part of the test will be based on radiological images. At the end of the tests students will draw and annotate a scheme from the required list of schemes.

 

Clinical correlations

Formation of a blood clot (thrombus) in the arterial or deep venous circulation is a clinically serious state. The thrombus may break off the vessel wall and block a vessel down stream to it. Such a complication is known as a thromboembolism.

Carotid stenosis is caused by an atherosclerotic plaque. A piece of the plaque can break off and travel through the circulation to the blood vessels in the brain. The pieces can lodge in the vessel wall and restrict blood flow, causing a thromboembolic stroke.

The facial artery is palpable where it crosses the margin of the mandible in front of the insertion of the masseter. Applying pressure to this point is used to stop arterial bleeding.

The superficial temporal artery is palpable in front of the auricle and above the temporomandibular joint. The most common disease affecting this artery is a type of arteritis called Horton's disease or temporal arteritis. This disease manifests as a red painful line over the course of the superficial temporal artery.

The sphenopalatine artery is often responsible for nasal bleeding (epistaxis). It can be occluded with electrocautery or embolisation.

The internal thoracic artery can be used as a graft for bypassing a stenotic coronary vessel in cardiosurgery.

Vertebrobasilar insufficiency (beauty parlour syndrome) is a pathological condition caused by decreased blood flow in the posterior part of the brain. It can be caused by congenital arterial stenosis and atherosclerosis and manifests as vertigo, dizziness and even as a stroke. In such patients, hyperextension of the neck, which can occur when having one’s hair washed in a beauty parlour, can compress the vertebral arteries and lead to manifestation of the symptoms.

Subclavian steal syndrome occurs when the subclavian artery is occluded proximally to the origin of the vertebral artery. Blood is redirected from through the common carotid artery, internal carotid artery, and the circle of Willis, where it then passes in a retrograde direction through the vertebral artery to reach the subclavian artery, distal to the occlusion. In this way, circulation to the upper extremity distal to the occlusion is restored. Blood is ‘stolen’ from the circle of Willis in order to supply the upper extremity; this can lead to the development of neurological symptoms resulting from brain ischaemia.

The radial artery serves as an approach for diagnostic and therapeutic coronary catheterisation. The ulnar artery is less commonly used

An aortic aneurysm is most commonly located in the abdominal aorta. Atherosclerosis is one of the major causes of aortic aneurysms.

The corona mortis of Hesselbach is a term for an aberrant obturator artery arising from the bed of the external iliac artery, usually from the inferior epigastric artery. It crosses the pecten pubis (linea terminalis) and heads to the lesser pelvis and enters the obturator canal. The corona mortis is considered to be an anatomic variant, which is present in 25 % of cases. In 5 % of cases the beds of both arteries are interconnected via an anastomosis (accessory aberrant obturator artery).

The arterial pulse on the lower extremity can be palpated in four places:


  • Femoral artery in the femoral triangle, caudal to the inguinal canal
  • Popliteal artery in the popliteal fossa

  • Posterior tibial artery behind the medial malleolus
  • Dorsal pedis artery on the dorsum of the foot, laterally to the tendon of the extensor hallucis longus
     

The medial circumflex femoral artery is the main artery of the hip joint. Fractures of the femoral neck may lead to compression or disruption of the retinacula of Weibrecht, through which vessels of the femoral head pass, which impairs the healing process.

Central venous catheterisation is the insertion of a catheter into the internal jugular or subclavian vein. It is used for long-term intravenous administration of medication, fluids or nutrition, and for the measurement of central venous pressure (normal value 1–10 mmHg). Potential complications are: pneumothorax caused by puncturing the cervical pleura and injury to the brachial plexus and subclavian artery.

Portal hypertension is a condition of increased pressure in the portal system. It is caused by obstruction to the portal venous blood flow, which may occur in the circulation before the liver (prehepatic portal hypertension – within the portal vein and its tributaries), inside the liver parenchyma (intrahepatic portal hypertension) or after the liver (posthepatic portal hypertension  between the liver and right heart). One of the most common causes of intrahepatic portal hypertension is liver cirrhosis. Increased pressure inside the liver leads to the redistribution of portal blood into the systemic circulation, circumventing the liver. This is achieved through portocaval anastomoses, connections between the portal and the caval systems.

Lymphoedema is swelling due to congestion of lymphatic fluid. It occurs when lymph drainage is insufficient and may progress to elephantiasis, a condition where parts of the skin, subcutaneous tissues or entire regions (scrotum, limbs) swell up to large or even massive proportions.

2-stage rupture of the spleen is a life-threatening situation and a diagnostic challenge in closed abdominal trauma. After injury to the pulp, the splenic parenchyma ruptures and blood accumulates under the capsule. The pressure under the capsule rises and eventually causes the capsule to rupture, which causes blood to spill out into the peritoneal cavity.

Breast cancer most commonly occurs in the upper inner quadrant. Therefore, the cancer commonly spreads to the axillary lymph nodes.

Axillary exenteration is the complete removal of the level I and II axillary nodes (according to Berg) in breast cancer. The level III lymph nodes are inaccessible due to their location behind the brachial plexus and axillary vessels.
 

Curiosities

The thick muscular wall of arteries tends to maintain a circular lumen. Veins have a much thinner muscular wall and so the shape of their lumen often changes due to pressure from surrounding structures.

The carotid sinus (sinus caroticus) is an enlargement located at either the bifurcation of the common carotid artery or at the beginning of the internal carotid artery. Free nerve endings are located in the wall of the carotid sinus, which monitor blood pressure. Compression of the wall can cause a reflex decrease in blood pressure.

The carotid body (glomus caroticum) is located in the carotid bifurcation. It is a chemoreceptor, which detects changes in the internal environment (mainly partial pressure of oxygen, concentration of carbon dioxide and changes in pH).

The anastomosis of Haller / arc of Riolan (anastomosis magna) is an anastomosis between the middle and left colic arteries, located close to the left colic flexure. It interconnects the arterial beds of the superior and inferior mesenteric arteries.

The term perforator is clinically used for both venous and arterial perforators. A venous perforator interconnects the superficial (subcutaneous) and deep venous system. An arterial perforator is an artery, which penetrates through a muscle and fascia into subcutaneous tissue.
 

Required drawings

Schemes of the coronary arteries (not included in the test)
Scheme of the coeliac trunk and its branches
Scheme of the superior and inferior mesenteric artery and their branches
Scheme of the hepatic portal vein and its tributaries
Scheme of the cerebral arterial circle of Willis

Radiological pictures

Heart and vessels

Created: 26. 3. 2017 / Modified: / Responsible person: MUDr. Azzat Al-Redouan