Anatomy of the back, nerves and vessels Flashcards
What does the spinal cord lie in?
Vertebral canal/foramen
Where does the spinal cord end?
Ends at conus medullaris at L1/L2 (adult); L3 (child)
What lie in the intervertebral foramen?
Spinal cord nerve roots
What nerves are found in the cauda equina?
`L2-5, S1-5 and Co
Where are lumbar punctures performed?
Lumbar puncture at L3/4 or L4/5 in children
Where are there enlargements in the spinal cord and why?
Cervical and Lumbar enlargements for brachial and lumbar plexus nerves respectively
To which vertebral level does the dura matter and the arachnoid matter descend?
S2
What does the lateral horn contain?
The lateral horn contains the cell bodies of the sympathetic neurons
Where is the lateral horn present?
The lateral horn is present:
o Between levels T1-L2/3 vertebrae (thoracolumbar/sympathetic outflow) – sympathetic
o Between levels S2-S4 vertebrae (sacral/parasympathetic outflow) – parasympathetic
What vertebral levels show sympathetic outflow?
T1-L2/3
What vertebral levels show parasympathetic outflow?
S2-4 plus cervical (facial) nerves
Describe the sympathetic signalling pathway to the spinal cord
- In sympathetic signalling, the signal leaves the lateral horn, through the white myelinated ramus communicans to a sympathetic ganglion in the sympathetic chain where it synapses to receive another NT, before re-entering the ventral rami and dorsal rami after traveling through the grey unmyelinated ramus communicans
- Nerves can exit below and above where it originates by travelling up or down the sympathetic chain
If sympathetic fibres only originate between T1-L2(3), how do parts of the body above and below these levels receive sympathetic innervation?
Can travel up and down the sympathetic chain/trunk to other sites
What are splanchnic nerves?
The splanchnic nerves are paired visceral nerves (nerves that contribute to the innervation of the internal organs), carrying fibers of the autonomic nervous system (visceral efferent fibers) as well as sensory fibers from the organs (visceral afferent fibers).
Describe the autonomic signalling to the thoracic viscera
Sympathetic preganglionic fibres to the thoracic viscera (heart, lungs) also synapse in the chain, then go to the cardiopulmonary plexus to the prevertebral ganglion, and then on to the heart and lungs.
Describe the autonomic signalling to the abdominal viscera
Sympathetic fibres to abdominal viscera do not synapse in the chain – the merely pass through it with out synapsing there and synapse instead on prevertebral/preaortic ganglia in the abdomen and then on to the abdominal viscera.
Define the parasympathetic nerves
Parasympathetic nerve fibres arise from the CNS with the S2, S3, and S4 spinal nerves and from the 3rd, 7th, 9th and 10th (10th = vagus) cranial nerves - craniosacral outflow.
Define the origin of the pelvic parasympathetic splanchnic nerves
- The S2, S3, and S4 spinal nerves are commonly referred to as the pelvic splanchnic nerves – i.e. they supply pelvic organs.
- The pelvic splanchnic nerve cell bodies reside in the lateral grey horn of the spinal cord at the T12-L2(3) vertebral levels (just like the sympathetic nerve cell bodies) and run down the sympathetic chain to S2-4
What is a sentinel lymph node?
The sentinel lymph node is the hypothetical first lymph node or group of nodes draining a cancer. Common ones are the axillary lymph nodes and breast cancer
What does the thoracic duct drain?
Thoracic Duct - drains lymph from whole body except right upper quadrant (3/4 body)
What does the right lymphatic duct drain?
Right Lymphatic Duct - drains only the lymph of the right upper quadrant of the body
Where do the two lymphatic ducts drain into?
These drain into the circulatory system at the left brachiocephalic vein between the left subclavian and left internal jugular veins
What specific name is given to the C1 vertebrae?
Atlas
What specific name is given to the C2 vertebrae?
Axis
What specific name is given to the C7 vertebrae?
Vertebra prominens
Describe some morphological features of cervical vertebrae
Presence of transverse foramen for vertebral arteries
Small wide body
Smaller spinous processes and transverse processes
Large triangular vertebral foramen
Describe some morphological features of thoracic vertebrae
Heart shaped body
Circular vertebral foramen
Long downward facing spinous processes
Describe some morphological features of lumbar vertebrae
Large kidney shaped body
Low smaller triangular vertebral foramen
Long and slender transverse processes
Short spinous processes
What developmental changes occur in the neonate to produce the secondary cervical lordoses?
Becomes apparent when baby begins to hold up its head
What developmental changes occur in the neonate to produce the secondary thoracic/lumbar lordoses?
Becomes apparent when the infant beings to walk upright
In what plane are the articular facets of the cervical vertebrae?
Horizontal/transverse
In what plane are the articular facets of the thoracic vertebrae?
Coronal
In what plane are the articular facets of the lumbar vertebrae?
Sagittal/vertical
What movements are permitted in the cervical region due to the orientation of their articular facets?
Flexion/extension
lateral flexion/extension
Rotation
What movements are permitted in the thoracic region due to the orientation of their articular facets?
Lateral rotation
Axial rotation
Lateral flexion/extension
What movements are permitted in the lumbar region due to the orientation of their articular facets?
Flexion/extension
Lateral flexion/extension
NO ROTATION
What vertebral level is the spine of the scapula?
T3
What vertebral level is the spine of the vertebra prominens?
C7
What vertebral level is the inferior angle of the scapula?
T7
What vertebral level is the summit of the iliac crest?
L4
Whats another name for the synovial plane joint found between two articular processes of two adjacent vertebrae?
Zygopophysial joint (zygopophyseal)
Where are the axillary lymph nodes found?
Armpit
What lymph nodes are found at the bifurcation of the trachea?
Tracheobronchial group
Where is the thoracic duct located?
Between azygos vein and the thoracic aorta
What is the filum terminale?
The filum terminale (“terminal thread”), is a delicate strand of fibrous tissue, about 20 cm in length, proceeding downward from the apex of the conus medullaris. It is one of the modifications of pia mater.
Where does the film terminale attach inferiorly and what is its function?
Coccyx (referred to as the coccygeal ligament)
Provides longitudinal support to the spinal cord
Which nerve cell component makes up the grey matter of the spinal cord?
Nerve cell bodies
Which nerve cell component makes up the white matter of the spinal cord?
Myelinated axons
Between what vertebral levels does the sympathetic chain extend?
C1-Coccyx
What does the white ramus communicans do?
Carries preganglionic autonomic fibres the the sympathetic chain
What does the grey ramus communicans do?
Carries postganglionic autonomic fibres to the ventral rami.
Do parasympathetic nerve fibres enter the sympathetic chain?
No
Which spinal cord segments give rise to the parasympathetic nerves?
S2-4
