Spinal Cord and Spinal Nerves Flashcards
How many vertebrae are in each compartment of the vertebral column?
- 7 Cervical
- 12 Thoracic
- 5 Lumbar
- 5 Sacral
- 1 Coccygeal
How many spinal cord segments are there?
- 31
- 8 Cervical
- 12 thoracic
- 5 Lumbar
- 5 Sacral
- 1 Coccygeal
Where does the C1 nerve emerge?
between base of skull and C1 vertebra
Where do nerves C2-C7 emerge?
Superior to their numbered pedicles
Where does C8 emerge from?
Inferior to pedicle of Cervical vertebra 7
Where to nerve T1-Co1 emerge?
Inferior to their numbered pedicles
What are the names of the 2 enlargements of the spinal cord?
- Cervical enlargement (for brachial plexus)
- Lumbar enlargement (Sciatic nerve)
What are the 2 structures formed by extensions of the pia matter?
- Denticulate ligaments
- Filum Terminale
What is the Dura and bone separated by?
Fat filled epidural space
How does the dura surrounding the cord differ from that surrounding the brain?
One one layer thick (meningeal) as periosteal layer surrounding brain becomes periosteum of the skull
How are the dura and arachnoid matter separated?
Subdural space (potential space)
What is the termination of the spinal cord known as?
Conus Medullaris
What makes up the Cauda Equina?
Dorsal & ventral roots of lower lumbar, sacral & coccygeal segmental spinal nerves
How does the spinal cord change in length with age?
- Foetus= Spinal cord & dura terminate at end of vertebral column
- Birth= Filum terminale extends to Co1, spinal cord terminates at L3
- Adult=Spinal cord terminates at L1, Dural sac subarachnoid space termination S2
Describe the arterial supply of the spinal cord
-Arterial blood via unpaired anterior & paired posterior spinal arteries
What do spinal arteries arise from?
Vertebral arteries
What are the vertebral arteries supported by in the spinal cord?
Segmental medullary & radicular arteries along the length of the cord
Where do the spinal branches arise in different levels of the body?
- Vertebral= neck
- Posterior intercostal= thorax
- Lumbar= abdomen
- Lateral sacral= pelvis
What type of nerve fibres are carried in the dorsal grey horn of the spinal cord?
-Somatic & visceral sensory
What is contained within the dorsal root of the spinal cord?
- Dorsal root ganglion
- Somatic & visceral sensory fibres
What type of nerve fibres are carried in the ventral grey horn of the spinal cord?
- Somatic motor
- Visceral motor
What nerve fibres are contained within the spinal nerve?
Mixed: Somatic & visceral motor and Somatic & visceral sensory
What does each spinal nerve take as it leaves the vertebral canal? What does this become?
- Meningeal coverings
- Form the Epineurium (protective outer sheath of connective tissue)
What is the variation in white matter?
-White matter inc as ascend cord
Where does the ventral grey horn enlarge?
Where motor fibres to limbs arise (cervical & lumbar enlargements)
What are the 2 columns of each side of the midline of the cord? Where are they located?
- Gracile fascicle medially
- Cuneate fascicle laterally
- Above segment T6
Where are the following located and what are there functions:
- Dorsal column
- Lateral corticospinal tract
- Ventral corticospinal tract
- Spinothalamic tract
- DC: right, ipsilateral joint position sense & vibration sense
- LCT: Voluntary movement on right (located on right of spinal cord)
- VCT: Voluntary movement on right (located on left of spinal cord)
- ST: Contralateral pain, light touch & temp (located on left of spinal cord)
What is the functional difference between dorsal &ventral nerve roots?
Dorsal = Sensory Ventral = Motor
What conditions would you obtain a sample of CSF for?
- Meningitis
- Subarachnoid haemorrhage
- Guillain-Barré Syndrome
Starting from the skin list the layers pierced when doing a lumbar puncture
- Skin
- Fat
- Supraspinous ligament
- Interspinous ligament
- Dura mater
- Arachnoid mater
Which spinal cord segment has the most white matter? Why?
- Cervical segment
- All fibres from the whole body travel in the cervical spinal cord
What information is carried in the sections of the dorsal white matter?
- (medial) fasciculus gracilis= fibres from lower limb
- (lateral) fasciculus cuneatus= fibres from upper limb
What are the inferior & superior boundaries of the epidural space?
Superiorly=Foramen Magnum
Inferiorly= Tip of sacrum at sacrococcygeal membrane
What are the clinical presentations of a nerve compression between L5 & the sacrum?
- Sciatica
- Weakness in dorsiflexion= foot drop
