Case 2 anatomy Flashcards
what forms the intervertebral foramen?
the superior notch on the pedicle of one vertebra and the inferior notch on the pedicle of an adjacent vertebra
which curvature develops first - cervical or lumbar?
cervical
what is kyphosis?
exaggerated sagittal curvature in the thoracic region
what is lordosis?
abnormal inward lordotic curvature of the lumbar and cervical regions of the spine
what is scoliosis?
where the spine twists and curves to the side
what movements are possible in the vertebral column?
flexion, extension, lateral flexion, rotation and circumduction
describe the cervical vertebrae
- 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 +
describe the thoracic vertebrae
- 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
describe the lumbar vertebrae
- 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
which vertebrae are atypical?
1, 2, 7
describe the atlas
- 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
describe the axis
- Posses an odontoid process (dens) that projects superiorly from the body
describe the vertebra prominens
- 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)
what are the sacral cornua?
- 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
what type of joint is the atlanto-occipital joint? what movement does it allow?
- condyloid synovial joint
- flexion, extension and lateral flexion
what supports the atlanto-occipital joint?
- 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
what type of joints are the atlanto-axial joints?
- 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
what connects the odontoid process to the anterior margin of foramen magnum?
apical ligament
what does the alar ligament do?
connects the odontoid process to the medial side of the occipital condyles
what does each cruciate ligament do?
- 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
what is the membrane tectoria?
an extension of the posterior longitudinal ligament, it attaches to the occipital bone and covers the odontoid process and other ligaments
what are zygapophyseal joints (facet joints)? what type of joint?
- Located between adjacent vertebral arches
- Formed by the articular surfaces of adjacent superior and inferior articular facets
- Synovial plane joints
what are the ligaments of the zygapophyseal joint/vertebral arch?
• 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
what forms the ligamentum nuchae?
In the neck the supraspinous and interspinous ligaments are thickened to form a strong ligament that extends from C7 to the external occipital protuberance
what type of joints are those between adjacent vertebral bodies? describe it
- 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
describe the IV discs - what do they consist of
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
what is broader the anterior or posterior longitudinal ligament?
anterior
how many vertebra do we have?
33
what arises from the conus medullaris?
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
what happens once the spinal nerves exit the vertebral canal through the intervertebral foramen?
they divide into dorsal and ventral rami
where does cervical nerve 8 exit the vertebral canal?
through the IV foramen between C7 and T1
how do the spinal nerves exit in the sacral region?
the ventral rami exit the vertebral column through the anterior sacral foramina and the dorsal rami exit via the posterior sacral foramina
what is epineurium?
connective tissue that surrounds the spinal nerve - merges with dural mater of dural sac at nerve roots
describe the arterial supply of the spinal cord
- 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
describe the arterial supply and venous drainage of the vertebrae
- 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
describe the venous drainage of the spinal cord - what happens to the blood after?
- 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
what are the different plexuses? what are their roots?
- 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
the sciatic nerve is formed from the ventral rami of which spinal nerves?
L4 - S3
bascially the sacral plexus, but without S4
describe the route of the sciatic nerve
- 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
