V.C - K - Blood, Venous, lymphatic drainage of the Vertebral Column (cervical, thoracic, lumbar, sacral)- Pathology&Batson's venous plexus

Question 1

What percentage of the cardiac output does bone receive and what does this allow?

Answer 1

Bone receives up to 10% of cardiac output which allows bone to have a high level of remodelling and repair Therefore a disruption to the blood supply can great impair repair and growth

Question 2

Name one of the largest stores of bone marrow in the body? What are the two types of bone marrow?

Answer 2

The vertebral column is one of the largest stores of bone marrow in the body The two types of bone marrow are red and yellow marrow

Question 3

Bone receives up to 10% of total cardiac output - allows for high level of remodelling and repair Vetebral column is one of the largest stores of bone marrow - red and yellow marrow What is the purpose of red marrow?

Answer 3

The purpose of the red marrow is that it is the primary site for haematopoeisis and therefore need a high vasculature supply

Question 4

What is the name for the vessels lying adjacent to the vertebral column which give branches to supply the vertebral column? (they have specific names depending on the region where they arise)

Answer 4

The vertebral column receives its blood supply segmentally from segmental arteries (specific arteries for each region which will be discussed)

Question 5

What are the arteries supply the cervical region of the vertebral column?

Answer 5

The cervical vertebra are supplied by the vertebral and ascending cervical arteries

Question 6

What passes through the transverse foramen of the cervical vertebrae?

Answer 6

Vertebral artery, along with the vertebral veins and sympathetic nerves pass through the tranverse foramen of C1-C6 vertebrae

The exception is at C7 the vertebral artery passes around the vertebra and not through the transverse foramen

Question 7

Does the vertebral artery always enter through the tranverse foramen of C6? What branches does the vertebral artery give which enter the vertebral canal through the intervertebral foramen?

Answer 7

The vertebral enters through the tranverse foramen of a vertebra other than C6 in 20% of the time The vertebral artery gives spinal branches which enter the vertebral canal through the intervertebral foramen

Question 8

As said, it is the vertebral artery and ascending cervical arteries that are the arterial supply of the cervical region of the vertebral column Whee do both these arteries arise?

Answer 8

The ascending cervical artery is a branch of the inferior thyroid artery of the thyrocervical trunk which is a branch of the subclavian artery The vertebral artery is also a branch of the subclavian artery

Question 9

Where is the ascending cervical artery found running at the level of C4?

Answer 9

At the level of C4 vertebrae, the ascending cervical artery is found to be running along the anterior tubercles of the transverse processes

Question 10

What branches has the ascending cervical artery been shown to give which supply?

Answer 10

The ascending cervical artery is seen to give spinous branches which enter the vertebral canal through the intervertebral foramen Specifically spinal branches to the C4-5 and C3-4 foramen (occasionally C2-3)

Question 11

There is some evidence that C5-6 ad C6-7 are supplied by branches from an artery other than the ascending cervical and vertebral arteries What is the artery?

Answer 11

Some evidence C5-6 and C6-7 are supplied by branches from the deep cervical artery branch of the costocervical trunk

Question 12

What is the arterial supply to the thoracic region?

Answer 12

The thoracic vertebra are supplied by the posterior intercostal arteries and subcostal arteries

Question 13

In most individuals, the arteries supply the thoracic region are symmetrical however some variation can occur Where do the posterior intercostal arteries arise?

Answer 13

First 2 pairs of posterior interocstal arteries arise from the supreme interocstal artery branch of the cosotcervical trunk of the subclavian artery Pair 3-11 and the subcostal artery arise directly formt the thoracic aorta

Question 14

What is the artery typically arising from a left posterior intercostal artery at the level of the 9th to 12th intercostal artery, which branches from the aorta, and supplies the lower two thirds of the spinal cord via the anterior spinal artery?

Answer 14

This would be the Artery of Adamkiewicz - it is the largest anterior segmental medullary artery and connects to the anterior spinal artery to supply the spinal cord

Question 15

The 12th pair of posterior intercostal arteries are termed the subcostal arteries as they arise below the ribs What does the posterior intercostal arteries give to enter the vertebral cnaal?

Answer 15

The posterior intercostal nerves give spinous branches which pass through the intervertebral foramen to reach the vertebral canal

Question 16

What is the arterial supply to the lumbar region of the vertebral column?

Answer 16

L1-L4 is supplied by the lumbar arteries L5 is supplied by the middle sacral and iliolumbar arteries

Question 17

Where do the lumbar arteries arise? How do they travel along the lumbar vertebrae?

Answer 17

The lumbar arteries arise (usually symmetrically) from the posterior wall of the abdominal aorta They travel laterally alongside the vertebrae until they reach the intervertebral foramen where they give an anterior and posterior continuation as well as a spinal branch

Question 18

The branches coming from the middle sacral artery are much smaller than branches from the lumbar arteries What is the middle sacral artery supplying L5 reinforced with?

Answer 18

The middle sacral artery is reinfroced posteriorly by the iliolumbar artery and a communicating artery from L4

Question 19

What is the arterial supply of the sacrum and coccyx?

Answer 19

The sacrum and coccyx are supplied by the lateral sacral arteries

Question 20

What is the arterial supply to all the regions and where do these arteries arise?

Answer 20

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Question 21

The main segmental arteries supplying each vertebrae give how many periosteal branches? What do these supply? What do these anastamose with?

Answer 21

The mains segmental arteries give 10-20 periosteal arteries for each vertebrae to supply the periosteum of the vertebrae The periosteal arteries of adjacent segmental branches anastomose on anterolateral and posterior surfaces

Question 22

The periosteal branch anastomoses have different names depending on where on the vertebrae the anastamoses occurs WHat are the two names for the different anastamoses region?

Answer 22

Metaphyseal anastamoses - occurs at the anterior and lateral surfaces of the vertebrae Post-central anastamoses - occuring at the posterior surface of the vertebral body

Question 23

As stated, the segmental arteries gives off a spinal artery at the intervertebral foramen and after this gives off an anterior and posterior continuation What branches does the segmental artery give before the spinal artery? What branches does the spinal artery branch of the segmental give off?

Answer 23

The segemental artery gives periosteal and (10-20 per vertebrae) and equatorial artery branches to the vertebral body The anterior vertebral canal artery The segmental (or radicular) medullary artery The posterior vertebral canal artery

Question 24

Three spinal branch of the segmental artery branches * Anterior vertebral canal artery * Segmental (or radicular) medullary artery * Posterior vertebral canal artery What does each supply? How oes the red marrow get its arterial supply?

Answer 24

Anterior vertebral canal body supplies the vertebral body and gives nutrient arteries via nutrient foramen into the vertebral body to supply the red marrow The segmental medullary arterty helps supply the spinal cord (will be discussed later) The posterior vertebral canal artery supplies the vertebral arch

Question 25

What do the anterior and posterior continuations of the segmental arteries supply?

Answer 25

Anterior continuation - supplies other surrounding tissues Posterior continuation - supplies the posterior part of the vertebrae

Question 26

The blood supply to the vertebral body appears to be zonal What are the 3 types of inter-osseus arteries supplying the vertebral body?

Answer 26

• Peripheral branches
• Equatorial branches
• Metaphyseal branches

Question 27

What part of the vertebral body do each of the inter-osseus branches supply? Where do the metaphyseal branches arise?

Answer 27

Peripheral branches - the outer circumference Equatorial branches - supply the central core of the vertebral body along with the nutrient arteries Metapyseal branches - supply an annular zone between and arise from the metaphyseal anastamoses between periosteal branches of the segmental arteries

Question 28

Mature intervertebral discs are largely avascular structures Apart from periphery which receives supply from adjacent vessels How are nutrients supplied to the IV discs?

Answer 28

The IV discs rely on diffusion from the trabecular bone of the adjacent vertebrae for nutrients As each vertebral body has a zonal blood supply, the blood supply to the IV disc will also be zonal

Question 29

Which arteries will form a capillary plexus in the cartilaginous end plate of the IV disc? State where these arteries arise?

Answer 29

The metaphyseal arteries (from metaphyseal anastamoses - these are the antero-lateral anastamoses of the periosteal arteries) and nutrient arteries (from the anterior vertebral canal arteries) form capillaries in the cartilaginous end plate of the IV disc from which diffusion will occur

Question 30

Cells within the IV disc require nutrition in order to maintain their integrity, hence a good blood supply is essential As ageing, occurs arteries gradually narrow and deterioate Which arteries are first affected? Consequently, which arteries therefore increase in number supplying the IV disc?

Answer 30

As ageing occurs, arteries gradually narrow and deteriorate with the metaphyseal and nutrient arteries being the first to be affected Consequently, peripheral arteries increase in number meaning the iV disc gains a greater peripheral blood supply

Question 31

Decreased blood supply is linked to disc degeneration Can result in pressure being put on the nerves, resulting in pain and weakness Where does disc degeneration first occur?

Answer 31

It has been shown that disc degeneration first appears at the centre of the disc and the periphery of the disc can be capable of repair long after the centre has degenerated

Question 32

A pathological feature known as Schmorl’s nodes has no definitive cause but it has been strongly correlated with disc degeneration What is a Schmorl’s node?

Answer 32

Schmorl’s node is the herniation of the nucleus pulposus through bony cartilaginous end plate and into the adjacent vertebral body

Question 33

What is the usual symptoms of Schmorl’s nodes? Who are they more common in and where in the spine do they most commonly occur?

Answer 33

Schmorl’s nodes occur frequently and are usually asymptomatic but can be associated with back pain They are more common in males and tend to occur at the thoracolumbar transition (T7-L1)

Question 34

What is the arterial supply to the spinal cord? Where do the arteries arise?

Answer 34

The spinal cord is supplied by three longitudinal arteries The anterior spinal artery arising from the vertebral arteries 2x posterior spinal arteries arising either directly from the vertebral arteries or indirectly form the posterior inferior cerebellar artery

Question 35

Where does the anterior spinal artery run? What branches does it give to supply the spinal cord? What part of the spinal cord does it supply?

Answer 35

Anterior spinal artery runs in the anterior median sulcus It gives sulcal arteries which extend posteriorly to supply the spinal cord The anterior spinal artery supplies the anterior 2/3rds of the spinal cord

Question 36

Where does the posterior spinal arteries run? What branches does it give to supply the spinal cord? What part of the spinal cord does it supply?

Answer 36

Posteiror sinal arteries run in the posterolateral sulcus of the spinal cord And divide into 2 collateral arteries which branch to form the pia plexus Posterior spinal arteries supply the posterior 1/3rd of the spinal cord

Question 37

What are the anterior and posterior spinal arteries backed up by?

Answer 37

They are backed up by the anterior and posterior segmental medullary arteries

Question 38

What are the anterior and posterior segmental medullary arteries also referred to as? What is the difference in size and number between the anterior and posterior segmental medullary arteries?

Answer 38

These are also referred to as radicular feeder arteries as they continue from the radicular arteries which supply the nerve roots Radicular arteries end in the nerve root before reaching the ant. Or post. Spinal arteries, but segmental medullary go on to feed into the spinal arteries. Ant. Seg. Med. as are larger in diameter, but post. Seg. Med. As are more numerous

Question 39

What is the largest anterior segmental medullary artery and where does it arise? What does it assist the anterior spinal arter y in supply?

Answer 39

The largest anterior segmetal medullary artery is the artery of adamkiewicz which arises usually around the 9th-12th (mostly left) posterior intercostal artery It flows into the anterior spinal artery to supply the inferor 2/3rds of the spinal cord

Question 40

Spinal cord infarction (spinal stroke) – death of nervous tissue as a result of interrupted blood supply (21) Relatively rare, accounts for 0.3-1% of strokes Do spinal cord infarctions occur more commonly in the anterior or posterior spinal arteries? What symptoms will arise from the more common infarction site?

Answer 40

95% of spinal cord infarctions occur anteriorly If there is damage to the anterior spinal artery - the corticospinal and spinothalamic tract will be affected meaning the patient will lose motor functions as well as the sensory functions of crude touch/presure, pain and temperature

Question 41

Posteiror spinal cord infarctions are far less common than anterior Remember anterior accounts for 95% of spinal cord infarctions What symptoms will arise from the posterior spinal artery infarctions?

Answer 41

If there is damage to the posteiror spinal arteries, the dorsal columns will be affected meaning the patient will lose the sensory functions of fine touch, proprioception and vibration

Question 42

There is less blood supply to the spinal cord in the mid- thoracic region compared cervical and thoracolumbar regions Where are spinal cord infarctions most common?

Answer 42

Spinal cord infarctions are most common in the thoracic region due to the lower blood supply Patients present with sudden onset of symptoms with rapid progression However, due to it’s rarity the exact course isn’t well documented and symptoms and progression can vary

Question 43

What are some of the possible causes of spinal cord infarcitons?

Answer 43

Vertebral fractures Dislocations Vasculitis External compression due to eg abdominal tumours

Question 44

The venous drainage of the spinal cord is distrubuted similarly to the arteries but much more variable What is the drainage?

Answer 44

The spinal cord is drained by the sulcal veins draining neural tissue into 6 longitudinal veins that run down the length of the spinal cord including : 3 anterior and 3 posterior spinal veins

Question 45

What is the difference in the number of spinal veins in different regions of the vertebral column?

Answer 45

In the lumbar region, the anteromedial vein is a single vessel as is the midline posteromedian vein However in the cervical and throacic regions, they are accompanied by anterolateral x2 and posterolateral x2 veins

Question 46

Once blood is drained into the 3 anterior and 3 posterior spinal veins via the sulcal veins, where does this blood drain?

Answer 46

The blood drains via radicular and spinal medullary veins into the internal vertebral venous plexus found in the epidural space

Question 47

Where does the internal vertebral venous plexus drain to?

Answer 47

The ianterior and posterior internal vertebral venous plexus drain into the anterior and posterior external vertebral venous plexuses and these drain into segmentally arranged veins

Question 48

What are the segmentally arranged systemic veins which the external vertebral venous plexuses drain into? Do the venous plexuses have valves?

Answer 48

The vertebral veins mainly in the cevical region draining into the subclavian then brachiocephalic (innominate) veins The azygous vein in the thoracic region via posterior intercostal veins The ascending lumbar veins in the lumbar region The internal and external vertebral venous plexuses are valveless

Question 49

What are the internal vertebral venous plexuses also known as? Where are the anterior and posterior internal vertebral venous plexuses found?

Answer 49

Also known as the anterior and posterior epidural venous plexus Anterior internal vertebral venous plexuses are 2 longitduinal channels along the anterior apsect of the canal on either side of the posterior longitudinal ligament Posterior internal vertebral venous plexuses are 2 longitudinal channels along the posterior aspect of the canal on inner surfaces of the laminae and ligamentum flavum

Question 50

How do the longitduinal channels of the anterior internal vertebral plexus anastamose? How do the longituindal channels of the posterior internal vertebral plexus anastamose?

Answer 50

The anterior anastomose across the midline behind the posterior longitduinal ligament The posterior anastamose across the midline with some vessels emerging to join the posterior external vertebral venous plexus by passing between the free medial edges of the ligamentum flavum

Question 51

The anterior and posterior plexuses communicate freely with one another through a series of venous rings What do the internal vertebral venous plexuses form at the foramen magnum? What veins join the internal vertebral venous plexuses drianing the vertebral column?

Answer 51

At the foramen magnum, the plexuses form an intricate net-work which open into the vertebral vein The radicular veins and basivertebral veins all join the internal vertebral venous plexuses draining the vertebral column

Question 52

External vertebral venous plexuses are a network of veins surrounding the external aspect of the vertebral column Where do these plexuses lie around the vertebral column?

Answer 52

The anterior external vertebral venous plexus surrounds the anterior aspect of the vertebral bodies is found along the posterior surfaces of the vertebral arches and the spinous process of the vertebrae The posterior external vertebral venous plexus

Question 53

The internal plexus drains into the external plexus, which in turn drains into the vertebral veins of the neck and segmental (posterior intercostal , ascending lumbar, and sacral) veins of the trunk * How do the internal and external vertebral venous plexuses communicate? * Where is the posterior external vertebral venous plexus best developed?

Answer 53

The internal and external vertebral venous plexuses communicate via the intervertebral foramen The posterior external vertebral venous plexuses are best developed in the cervical regio

Question 54

What is the name of the veins draining the internal and external venous plexuses? Where do the basivertebral veins drain?

Answer 54

The intervertebral veins pass through the intervertebral foramina with the spinal nerves and drain the internal and external venous plexuses into the segmental veins The basivertebral veins run through the vertebral body communicating anteriorly with the anterior external plexus and posteriorly with the anterior internal venous plexus

Question 55

Do the basivertebral and intervertebral veins have valves? Remember internal and external vertebral venous plexuses are valveless

Answer 55

It is unkown whether basivertebral and intervertebral veins have valves however there is evidence to suggest that bloodflow can be reversed - thi would make sense for how pelvic neoplms appear in vertebral bodies

Question 56

Little is known in great detail about the lymphatic drainage of the vertebral column Deep lymphatic vessels commonly follow the arteries Where does lymph drain at each level of the vertebral column?

Answer 56

Cervical vertebral column - deep cervical nodes Thoracic vertebral column - posterior intercostal nodes Lumbar vertebral column - lateral aortic and retro-aortic nodes Sacral vertebral column - lateral sacral and internal iliac nodes

Question 57

The lymphatic system can frequently act as a pathway for the spread of disease, such as cancer metastasis and various inflammatory disorders Why do up to 70% of breast cancer patients also develop bone cancer?

Answer 57

This is due to the extensive lymphatic network around the vertebral column

Question 58

What is a metastatic tumour?

Answer 58

The spread of cancer from one part of the body to another is known as metastasis A metastatic tumour is a tumour that is formed by cells that has spread

Question 59

Cells can break off the primary tumour and therefore travel to other parts of the body through the bloodstream or lymphatic system This can result in them settling in a different area and ending up in any organ or tissue What is the most common site of metastasis?

Answer 59

The most common site of metastasis is the vertebral column

Question 60

Spinal column metastases is commonly secondary to malignant neoplasm of what primary neoplasms? What is the most common presenting symptoms?

Answer 60

Spinal column metastases is commonly secondary to malignant neoplasms of the breast, lung and prostate In 90% of patients, pain is the initial symptom

Question 61

Fracturing or collapsing of the vertebral body, pressure on the periosteum from within the vertebra, or nerve root and spinal cord compression are common with metastatic spinal tumours What is the principal process of spinal metastasis and when was it disovered?

Answer 61

The principal process of spinal metastasis is via Batson’s venous plexus and was discovered in 1940 by Oscar Vivian Batson

Question 62

What is the Batson venous plexus? What is it believed to provide a route for?

Answer 62

Batson’s venous plexus is a network of valveless veins tat connect the deep pelvic veins and thoracic veins to the internal vertebral venous plexus It is believed to provide a route for pelvic cancer metastases/infections to the spine due to reversed blood flow

Question 63

Posterior intercostal veins – azygos/hemiazygos veins – Batson vertebral venous plexus – internal vertebral venous plexus In 1940, Batson injected contrast into the vein of the penis in males and veins of the breast in women Results showed that tumor cells spread in the blood into the spinal veins. What was this proven to be a result of?

Answer 63

This was proven to be a result of a venous reflux that resulted from an increased intra-thoracic and/or intra-abdominal pressure

Question 64

What is it likely that the bone mets are cause here?

Answer 64

* Spinal cord compression * Fracture/collapse of the vertebral body * Back pain * Neurological symptoms due to cord compression