Workbook - Vertebral column and spinal cord Flashcards
How many vertebrae are there in the vertebral column?
33.
How many cervical vertebrae are there?
Seven.
How many thoracic vertebrae are there?
Twelve.
How many lumbar vertebrae are there?
Five.
How many sacral vertebrae are there?
Five.
How many coccygeal vertebrae are there?
Four.
-fused into one coccyx
What are the main subdivisions of a typical vertebra? (2)
- Body (anteriorly)
- Vertebral arch (posteriorly)
What are the subdivisions of the vertebral arch? (5)
- Pedicle
- Lamina
- Articular processes (sup & inf)
- Spinous processes
- Transverse processes
What is the function of pedicles?
Attach transverse process to the vertebral body.
What is the function of lamina?
Attach tranverse process to spinous process.
Where are articular processes situated?
Protrude posterior to vertebral notches.
What is the function of spinous and transverse processes?
Attachment of muscles and ligaments.
Which vertebrae are the smallest?
Cervical vertebrae.
What is the distinctive feature of cervical vertebrae?
Transverse foramen.
-smaller in C7
What structures pass through transverse foramen? (3)
- Vertebral arteries and veins
- Sympathetic nerve plexus
What are the spinous processes of C3-6 like?
Short and bifid.
What is the spinous process of C7 like?
Vertebra prominens - very long.
-bony landmark
Which 2 cervical vertebra are atypical?
- C1 (atlas)
- C2 (axis)
What are the main features of C1? (3)
- Lacks vertebral body and spinous processes (ant and post tubercles instead)
- Consists of ant and post tubercles (each with tubercle and lat mass)
- Tubercle on med of lat mass (»transverse ligament to secure dens)
What are the main features of C2? (2)
- 2 sup articular facets (large, flat surfaces which atlas rotates on)
- Dens (odontoid process) from sup vertebral body
What holds the dens in position?
Transverse ligament.
What is the function of the dens?
Prevent horizontal dislocation of the atlas (C1).
What are the distinguishing features of the thoracic vertebrae? (4)
- Long spinous processes (»post/inf)
- Heart-shaped body
- Circular vertebral foramen
- Articulate with ribs
What are the types of facets on thoracic vertebrae for articulation with ribs? (2)
- Costal demi-facets on body (sup/inf)
- Costal facet on transverse process
Which part of the rib do the costal demi-facets articulate with?
Head of ribs (own rib and rib below).
Which part of the rib do the costal facets articulate with?
Tubercle of rib.
What are the distinguishing features of the lumbar vertebrae?
- Large body/size
- Long, thin transverse processes (except L5)
- Cylindrical body and triangular foramen
- Short, sturdy spinous processes
How is the transverse process of L5 different?
Cone-shaped for iliolumbar ligaments»_space; pelvic bones.
Which 2 spinal regions consist of fused vertebrae?
- Sacral
- Coccygeal
What structures hold vertebrae together? (3)
- Facet joints
- Intervertebral discs
- Ligaments
What is another name for facet joints?
Zygaphyseal joints.
What do facet joints do?
Connect superior and inferior articular processes of adjacent vertebrae.
What is the function of intervertebral discs?
- Provide flexibility in the spine
- Act as shock absorbers
What are the components of intervertebral discs?
- Annulus fibrosus
- Nucleus pulposus
What is the annulus fibrosus?
Outer fibrocartilaginous ring of intervertebral discs.
- attached to epiphysial rim of vertebral body
- limits rotation between vertebrae
What is the nucleus pulposus?
Gelatinous centre of intervertebral discs.
-acts as a shock absorber
Which ligaments are associated with the vertebral column? (5)
- Anterior longitudinal ligament
- Posterior longitudinal ligament
- Ligamentum flavum
- Ligamentum nuchae
- Interspinous ligaments
What are the attachments of the anterior longitudinal ligament?
SUPERIOR - base of skull and C1
INFERIOR - ant surface of sacrum
What is the function of the anterior longitudinal ligament?
- Limits hyperextension of vertebral column
- Reinforces intervertebral discs
What are the attachments of the posterior longitudinal ligament?
Lines anterior vertebral canal, along posterior of vertebral bodies.
-attached to vertebral bodies and discs
What is the function of the posterior longitudinal ligament?
- Limits flexion of vertebral column
- Prevents posterior herniation of discs
- Reinforces intervertebral discs
What are the attachments of ligamentum flavum?
Pass between laminae (post below»_space; ant above).
-form part of posterior canal
What is the function of ligamentum flavum?
- Resists separation of laminae in flexion
- Assists back extension to anatomical position
What are the attachments of ligamentum nuchae?
BASE - skull (occipital protuberance»_space; foramen magnum)
APEX - C7 spinous process
DEEP SIDE - C1 post tubercle and spinous processes»_space; C7
What is the function of ligamentum nuchae?
- Supports head and returns it to anatomical position
- Resists flexion
- Muscular attachments
What are the attachments of interspinous ligaments?
Pass between adjacent spinous processes from bas to apex.
-blend with supraspinous (post) and ligamentum flava (ant)
What is the function of the interspinous ligaments?
- Limit flexion of vertebral column
- Muscle attachments (dorsal muscles)
What are the contents of the vertbral canal? (3)
- Spinal cord
- Spinal nerve roots
- Meningeal coverings
The vertebral column grows at a faster rate than the spinal cord. What effect does this have?
Spinal cord ends at L1-2.
-lumbar, sacral and coccygeal roots extend further (CAUDA EQUINA)
Where does the spinal cord end in a 2-3 month old foetus?
Near the end of the vertebral canal.
Where does the spinal cord end in a newborn?
~L3.
Where does the spinal cord end in an adult?
L1-2.
Where does filum terminal extend to in newborns and adults?
C1.
Where does the dural sac terminate in adults?
~S1.
What are the meninges surrounding the spinal cord?
- Dura mater
- Arachnoid mater
- Pia mater
What does the subdural space contain?
Potential space - dura mater is tightly adhered to arachnoid mater.
What does the subarachnoid space contain?
- CSF
- Blood vessels
Where is the epidural (extradural space)?
Between the dura and vertebrae.
What does epidural space contain?
Fat and a venous plexus.
What are the main arteries that supply the spinal cord?
Aterior (x1) and posterior (x2) spinal arteries.
-run longitudinally
Where do the anterior and posterior spinal arteries arise?
In the cranial cavity:
- anterior - union of 2 vessels from vertebral arteries.
- posterior - from terminal branch of vertebral arteries.
Where does the anterior spinal artery run, and which area of the spinal cord does it supply?
Parallel to the anterior median fissure.
-supplies anterior spinal cord
Where do the posterior spinal arteries run, and which area of the spinal cord do they supply?
2 branches bracket post/lat sulcus.
-supply posterior spinal cord
Which arteries reinforce the spinal arteries?
Radicular branches of intercostal and lumber arteries.
How do the radicular branches enter the vertebral canal?
Through intervertebral foramina.
What do the radicular branches supply?
- Ventral and dorsal nerve roots
- Peripheral post & ant horns
Describe the main venous drainage of the spinal cord.
- Anterior spinal vein - parallels ant median fissure
- Posterior spinal vein - passes along post median sulcus
> > drain into medullary and radicular veins
join internal plexus in epidural space
drains into SVC
What venous connections are there at each vertebral level?
Connections with intercostal veins and external vertebral venous plexus.
Do spinal veins have valves?
No.
Where do spinal nerves emerge from the vertebral canal?
Intervertebral foramen.
-as ant/post primary rami
In which part of the vertebral column are spinal nerves longer?
In the lower part of the canal.
-spinal cord doesn’t extend the whole canal
Where do spinal nerves C1-7 leave the vertebral column?
Superior to their corresponding vertebrae.
Where do the spinal nerve from C8 downwards leave the spinal column?
C8 leaves above T1, then the rest leave inferior to their corresponding vertebrae.
How many cervical vertebrae and spinal nerves are there?
7 vertebrae, but 8 pairs of spinal nerves.
What is the cauda equina?
Terminal cluster of lumbar, sacral and coccygeal nerves.
-formed from dorsal and ventral spinal nerve roots caudal to cord termination at L1