Neuroanatomy (revision) Flashcards
Describe the horns of the grey matter and what is contained within them?
H-shaped, contains neuron cell bodies within ‘horns’
- Dorsal/posterior horns -> cells bodies of interneurons
- Lateral horns -> visceral (autonomic) motor cell bodies (T1-L2 segments)
- Ventral/anterior horns -> somatic motor cell bodies
What is contained in white matter?
Columns containing a number of ascending and descending tracts (axons). All tracts are paired and some decussate
- Ventral (ant) columns
- Lateral columns
- Dorsal (posterior) columns
What nuclei are located in the dorsal root ganglion?
Sensory afferent fibre’s nuclei
Where is the DRG found?
Posterior to the dorsal spinal nerve
What is the spinal nerve?
- Mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body
- Located in intervertebral foramen
What kind of fibres are located in the ventral/anterior root?
Motor
What fibres do anterior and posterior branches of the spinal nerve carry?
Motor and sensory
How do nerve fibres exit from the cervical vertebrae?
- Above their respective vertebrae
- 1st spinal nerve passes above C1
- C8 nerve passes below C7 and above T1 as their is no 8th cervical vertebra
What bone can be considered C0?
Occipital bone
What fibres are carried by C1 nerve?
Motor only (supply neck muscles)
Where does the spinal cord end?
L1/2 (females thought to be body of L2)
In what region do spinal nerves not form plexuses?
Thoracic region (not T1)
Where are the sympathetic cell bodieslocated?
- Lateral horn of T1-L2 segments
- Postganglionic cell bodies lie in paravertebral sympathetic ganglia
- Ganglia interconnected -> sympathetic chain
Where are parasympathetic cell bodies found?
Midbrain and S2-4 segments
What is the ganglion impar?
Where LandR sympathetic chains join, just anterior to coccyx
WHat is there more of; sympathetic ganglion or vertebrae?
More vertebrae as some sympathetic ganglions merge
What is the superior cervical ganglion composed of?
C1-4 sympathetic ganglia
What is the middle cervical ganglion composed of?
C5-6
What is the inferior cervical ganglion composed of?
C7-8
What is the stellate ganglion?
- C7-T1 (inf cervical + T1)
- AKA Cervicothoracic ganglion
What do sympathetics enter the sympathetic chain via?
The white ramus communicantes (WRC)
What do sympathetics leave the sympathetic chain via?
Grey ramus communicantes (GRC)
Where does the heart receive its sympathetics from?
Cervical ganglia (as heart develops in neck)
In what region are there no WRC?
Cervical (as the fibres need to travel up)
What does cholonergic mean?
capable of producing, altering, or releasing acetylcholine, or butyrylcholine (“indirect-acting”), or mimicking their behaviours at one or more of the body’s acetylcholine receptor (“direct-acting”) or butyrylcholine receptor types (“direct-acting”)
In what direction does grey matter “open up”?
Dorsally
Where are the somatic neurone located?
The ends (between the 2 are the visceral)
If a patient has a problem with their motor system but not their sensory where would you think the lesion/problem took place?
Near midline
Where do peripheral nerves exit the spine?
Through intervertebral foramen
What is the segment for the knee reflex?
L3/4
What is the segment for ankle reflex?
S1
How do you test L5
Ask the patient to extent their big toe against resistance
What are the three layers of the meninges?
Dura, arachnoid, pia
Where is CSF found between the meninges?
Arachnoid and pia (subarachnoid space)
What is the space called between arachnoid and dura?
Subdural space
What is the space called outside the dura?
Epidural space
What is the arterial supply of the spinal cord?
- 2 post spinal arteries
- 1 ant spinal artery
- Radicular arteries reinforce these (come from spinal arteries and therefore intercostal)
- Great anterior medullary artery of Adamkiewicz arises from aorta in lower thoracic or upper lumbar vertebral levels (major source of blood for lower 2/3s of spinal cord)
Where does the internal vertebral venous plexus (ant and post.) lie?
In the epidural/extradural space (between dura and vertebrae)
What does the internal vertebral venous plexus communicate with?
Cranial dural venous sinuses and pelvic veins -> spread of infection and metastasis
- Also do not have valves and pressure gradients permit blood flow
In what direction does the nucleus pulposus herniate?
Posterolaterally
What is another type of injury to the spinal nerve?
Bone spurs (cracking back)
What is included in the dorsal column?
- Fasiculus gracilis
- Fasiculus cuneatus
WHITE MATTER TRACTS
LEARN
What do sensory temperature fibres move up the spinal cord via
Lateral spinothalamic tract
What sense goes to the cortex first then the thalamus?
Smell (all others go thalamus first)
WHere are LMN bodies found?
Anterior horn
Where do the UMN descend?
Lateral corticospinal tract
Where is CSF absorbed?
Araqchnoid granulations to dural sinuses
Where are dural sinuses located in meninges?
Between meningeal and periosteal lyers of dura. Then internal jugular and heart
What are the 4 vessels which supply the brain?
- Internal carotid arteries (anterior)
- Vertebral arteries (posterior part)
