Case 2 anatomy

Question 1

what forms the intervertebral foramen?

Answer 1

the superior notch on the pedicle of one vertebra and the inferior notch on the pedicle of an adjacent vertebra

Question 2

which curvature develops first - cervical or lumbar?

Answer 2

cervical

Question 3

what is kyphosis?

Answer 3

exaggerated sagittal curvature in the thoracic region

Question 4

what is lordosis?

Answer 4

abnormal inward lordotic curvature of the lumbar and cervical regions of the spine

Question 5

what is scoliosis?

Answer 5

where the spine twists and curves to the side

Question 6

what movements are possible in the vertebral column?

Answer 6

flexion, extension, lateral flexion, rotation and circumduction

Question 7

describe the cervical vertebrae

Answer 7

• Spinous process is small and bifid
• The inferior articular facets face anteriorly and inferiorly
• The superior articular facets face posteriorly and superiorly
• The transverse process possesses a foramen transversarium
• It has a large and triangular vertebral foramen (cervical spine enlargements)
• The small body is broad from side to side
• Upper surface of vertebral body shaped as a concave, lower surface concave in sagittal cut +

Question 8

describe the thoracic vertebrae

Answer 8

• The inferior articular facets face anteriorly and medially
• The superior articular facets face posteriorly and laterally
• Costal facets are present on the bodies and transverse processes
• It has a small, circular vertebral foramen
• The spinous process is long and downward pointing
• The body is medium-sized and heart shaped

Question 9

describe the lumbar vertebrae

Answer 9

• The inferior articular facets face laterally
• The superior articular facets face medially
• The vertebral foramen is triangular
• The spinous processes are short, flat and quadrangular
• The pedicles are strong and directed backwards
• The body is large and kidney shaped

Question 10

which vertebrae are atypical?

Answer 10

1, 2, 7

Question 11

describe the atlas

Answer 11

• Doesn’t possess a body or spinous process
• Has anterior & posterior arches and two lateral masses
• The lateral mass on each side articulates superiorly with the occipital condyles and with the axis inferiorly

Question 12

describe the axis

Answer 12

• Posses an odontoid process (dens) that projects superiorly from the body

Question 13

describe the vertebra prominens

Answer 13

• Possesses a long, non-bifid spinous process that is easily palpable
• Foramen transversarium is small and transmits only the vertebral vein (not the vertebral artery)

Question 14

what are the sacral cornua?

Answer 14

• most caudal parts of the intermediate sacral crest
• on each side, they form the lateral margin of the sacral hiatus
• articulate with the coccygeal cornua

Question 15

what type of joint is the atlanto-occipital joint? what movement does it allow?

Answer 15

• condyloid synovial joint

- flexion, extension and lateral flexion

Question 16

what supports the atlanto-occipital joint?

Answer 16

• Supported by the anterior and posterior atlanto-occipital membranes
• The anterior atlanto-occipital membrane is a continuation of the anterior longitudinal ligament
• Anterior atlanto-occipital membrane connects the anterior arch of the atlas to the anterior margin of the foramen magnum
• The posterior atlanto-occipital membrane connects the posterior arch of the atlas to the posterior margin of the foramen magnum

Question 17

what type of joints are the atlanto-axial joints?

Answer 17

• Three atlanto-axial joints; two lateral and one medial
• Lateral joints are located between the inferior facets of the atlas and the superior facets of the axis
• Lateral joints are synovial plane joints
• The medial atlanto-axial joint is located between the anterior arch of the atlas and the odontoid process of the axis
• Medial atlanto-axial joint is a pivot synovial joint

Question 18

what connects the odontoid process to the anterior margin of foramen magnum?

Answer 18

apical ligament

Question 19

what does the alar ligament do?

Answer 19

connects the odontoid process to the medial side of the occipital condyles

Question 20

what does each cruciate ligament do?

Answer 20

• Transverse part of the cruciate ligament – attached to the inner aspect of each lateral mass, holds the odontoid process against the anterior arch of atlas
• Vertical part of the cruciate ligament – extends between the posterior surface of the body of the axis to the anterior border of the foramen magnum

Question 21

what is the membrane tectoria?

Answer 21

an extension of the posterior longitudinal ligament, it attaches to the occipital bone and covers the odontoid process and other ligaments

Question 22

what are zygapophyseal joints (facet joints)? what type of joint?

Answer 22

• Located between adjacent vertebral arches
• Formed by the articular surfaces of adjacent superior and inferior articular facets
• Synovial plane joints

Question 23

what are the ligaments of the zygapophyseal joint/vertebral arch?

Answer 23

• Intertransverse ligament – extends between adjacent transverse processes
• Ligamentum flavum – extends between the lamina of adjacent vertebrae
• Supraspinous – runs between the tips of adjacent spinous processes
- interspinous

Question 24

what forms the ligamentum nuchae?

Answer 24

In the neck the supraspinous and interspinous ligaments are thickened to form a strong ligament that extends from C7 to the external occipital protuberance

Question 25

what type of joints are those between adjacent vertebral bodies? describe it

Answer 25

- Joints are cartilaginous - The articulating surface of each body is covered by cartilage - Hyaline cartilage covers the articulating surfaces of the vertebral bodies - Intervertebral discs are sandwiched between each body – the discs are pads of fibrocartilage which bind the bodies together thereby making the vertebral column a semi-rigid structure – the discs make up a quarter of the length of the vertebral column - The IV discs consist of the annulus fibrosus and the nucleus pulposus

Question 26

describe the IV discs - what do they consist of

Answer 26

Annulus fibrosus: • Inserts into the epiphyseal rim of the vertebral body • Made of concentric layers of fibrocartilage • Binds to the anterior and posterior longitudinal ligaments • Forms the peripheral part of the disc Nucleus pulposis: • Composed of a semi-liquid gelatinous substance • Contains approx. 90% water at birth and 70% water in old age • An avascular structure • Forms the central core of the disc

Question 27

what is broader the anterior or posterior longitudinal ligament?

Answer 27

anterior

Question 28

how many vertebra do we have?

Answer 28

33

Question 29

what arises from the conus medullaris?

Answer 29

first lumbar nerve roots arise from the distal end of the cord and the remaining lumbar, sacral and coccygeal nerve roots arise from the conus medullaris

Question 30

what happens once the spinal nerves exit the vertebral canal through the intervertebral foramen?

Answer 30

they divide into dorsal and ventral rami

Question 31

where does cervical nerve 8 exit the vertebral canal?

Answer 31

through the IV foramen between C7 and T1

Question 32

how do the spinal nerves exit in the sacral region?

Answer 32

the ventral rami exit the vertebral column through the anterior sacral foramina and the dorsal rami exit via the posterior sacral foramina

Question 33

what is epineurium?

Answer 33

connective tissue that surrounds the spinal nerve - merges with dural mater of dural sac at nerve roots

Question 34

describe the arterial supply of the spinal cord

Answer 34

- The anterior spinal artery runs down the anterior median fissure to supply the anterior aspect of the spinal cord - The anterior spinal artery arises from the vertebral artery - The two posterior spinal arteries arise from either the vertebral or posterior inferior cerebellar arteries - This blood supply is supplemented by a number of radicular arteries – these are branches of the ascending cervical, deep cervical, vertebral, posterior intercostal and lumbar arteries - The radicular vessels enter the vertebral canal via the intervertebral foramen

Question 35

describe the arterial supply and venous drainage of the vertebrae

Answer 35

* The vertebrae receive a rich blood supply from nutrient and equatorial branches of the vertebral, ascending cervical, posterior intercostal, subcostal, lumbar, iliolumbar and lateral and medial sacral arteries * Venous blood from the vertebrae drains into the internal venous plexus

Question 36

describe the venous drainage of the spinal cord - what happens to the blood after?

Answer 36

- Venous blood from the spinal cord drains into the internal vertebral venous plexus - In turn, the internal venous plexus drains into the external vertebral venous plexus - Blood from here drains into regional vessels (vertebral, posterior intercostals, lumbar and lateral sacral veins), which subsequently drain into the brachiocephalic veins, superior vena cava or internal iliac veins as appropriate - The internal venous plexus is located in the epidural space

Question 37

what are the different plexuses? what are their roots?

Answer 37

* Cervical plexus – C1-C5 * Brachial plexus – C5-T1 * Lumbar plexus – L1-L4 * Sacral plexus – L4-S4 - cervical and branchial both have 5 roots - lumbar has 4 - sacral has 6 - start with C1 and go to T1, then there's a break, then start with L1

Question 38

the sciatic nerve is formed from the ventral rami of which spinal nerves?

Answer 38

L4 - S3 bascially the sacral plexus, but without S4

Question 39

describe the route of the sciatic nerve

Answer 39

* Formed from the ventral rami of L4-S3 * Emerges from the greater sciatic foramen * Enters buttock from under piriformis muscle * Lies deep to gluteus maximus * Crosses ischial tuberosity, descends on obturator internus, gemelli and quadriceps femoris * Lies deep to hamstrings and is crossed by long head of biceps * Bifurcates into tibial and common peroneal nerves