Where does the spinal cord lie?
Lies in vertebral canal (not intervertebral canal)
Where does the spinal cord end?
Ends as conus medullaris at L1 (adult); L3 (child)
What forms the cauda equina?
Lumbar, sacral nerves and the coccygeal nerve
Where does the pia extend and attach to?
coccyx as filum terminale
What is between the Arachnoid and the pia
subarachnoid space, filled with CSF
Where is the lumbar puncture?
Lumbar puncture at L3/4 or L4/5.
Where do the Dural and arachnoid extend to?
S3 vertebra = dural sac
The dural sac is the membranous sheath of dura mater that surrounds the spinal cord and the cauda equina. Contains CSF.
What are Cervical and Lumbar enlargements for?
(for brachial and lumbar, plexus nerves, resp.)
What does the lateral horn contain?
Cell bodies of the sympathetic neurons.
Where is the lateral horn present?
Between levels T1-L2/3 vertebrae (thoracolumbar/sympathetic outflow), and between levels S2-S4 vertebrae (sacral/parasympathetic outflow).
Do sympathetic nerves synapse before reaching the muscle/ tissue?
Is the grey ramus myelinated?
Is the white ramus myelinated?
What is the position of the paravertebral (sympathetic trunk) ganglia?
Lie parallel to the spinal cord
What is the travel of the sympathetic nerve impulses?
They emerge in the ventral root via a white ramus (preganglionic fibres). After synapsing in the sympathetic chain ganglion, they re-enter the spinal nerve via a grey ramus and are distributed in both dorsal and ventral rami of the spinal nerve (postganglionic fibres).
Where do post ganglionic sympathetic nerve impulses travel to?
Skin and body wall structures such as arrector pili muscles, blood vessels and glands
How do parts of the body above and below T1-L2/3 receive sympathetic innervation?
The sympathetic chain - A paired set of paravertebral ganglia stretching from C1 o the end of the coccyx.
What are the three options of travel for the sympathetic fibres leaving the spinal cord?
They can synapse at the level of entry.
They can run up or down the chain and synapse.
They can pass straight through and synapse in a prevertebral/preaortic ganglion.
Where do sympathetic preganglionic fibres to the thoracic viscera (heart and lungs) synapse?
Synapse IN the chain, then go to the cardiopulmonary plexus, and then on to the heart and lungs.
Where do sympathetic preganglionic fibres to the abdominal viscera (heart and lungs) synapse?
They pass THROUGH the chain with out synapsing there and synapse instead on prevertebral/preaortic ganglia in the abdomen and then on to the abdominal viscera.
Where are prevertebral / preaortic ganglia located?
Anterior to abdominal aorta, in plexuses surrounding its major branches
What are splanchnic nerves?
They are sympathetic nerves which:
- Do not re-enter the spinal nerve
- Supply only the viscera
Where do the thoracic splanchnic nerves come from? And where do they synapse?
Come from T1-T4
They synapse in the sympathetic chain before they run to the organ concerned (contained within the thoracic viscera).
Where do the abdominal splanchnic nerves come from? And where do they synapse?
They come from T5-T12 and L1-L2(3)
They synapse outwith the chain in preaortic or prevertebral ganglia and then run to the organ concerned (in the abdominal viscera)
What do the splanchnic nerves T5-T12 have to pass through in order to reach the abdominal organs?
Where does general sensory information from organs run?
With parasympathetic fibres
Where do pain impulses normally run?
Normally run with the sympathetic fibres, (in the pelvis also with parasympathetic fibres)
What is the travel of the sensory afferents from both the sympathetic fibres and the parasympathetic fibres?
Both enter the dorsal root and synapse in the dorsal root ganglion before entering the lateral horn and travelling up the spinal cord to the brain.
Where do parasympathetic nerve fibres arise from?
S2, S3 and S4 spinal nerves
From the 3rd, 7th, 9th and 10th cranial nerves
What name is given to the S2, S3 and S4 nerves?
The pelvic splanchnic nerves- they supply the pelvic organs