Term
Basic info on Meninges:
-What are they
-What are the laters (and in between spaces)
-Spinal Tap How to/what layers pass through |
|
Definition
Meninges are a specialized series of protective coverings of connective tissue that surround and protect the spinal cord
The three laters are separated from the vertebral canal and from one and other by the:
Epidural Space- space between the bony vertebral canal and the dura
Subdural Space- space between dura and arachnoid
Subarachnoid Space- space between arachnoid and pia, contains cerebrospinal fluid (CSF)
This information is relevant if need to know how to do a spinal tap- will pass through the:
skin, superficial fascia, supraspinous ligament, interspinous ligament, ligamentum flavum, epidural space, dura mater, subdural space, and arachnoid (end up in the subarachnoid space to get CSF)
To do a Spinal Tap should look for the Iliac Crests (at plevis area- approximate level of L4 is at the peak of the crests) this will show you that you are at the area of the back between L2-S2 called the lumbar cistern ( should perform spinal tap between L3-L4 or L4-L5 for a child). Should be performed at this area, because this is the area of the Cauda Equina (see separate card) so the needle will not puncture the spinal cord. |
|
|
Term
Dura Mater
-What is it
-Where does it end
-What is the area around it and whats in that area |
|
Definition
Tough outermost connective tissue covering of the spinal cord.
It extends to the level of the second sacral vertebra where it ends by forming a sheath around the filum terminale.
The space just outside the dura mater between the vertebral column is called the epidural space, within this space is the internal vertebral venous plexus. |
|
|
Term
Arachnoid Mater
-What is it?
-Where is it?
-Spaces deep it ot-what's in it?
-Why clinically significant? |
|
Definition
The outer surface of the arachnoid is smooth, numerous fine strands of delicate connective tissue project from its inner surface to become continuous with the pia mater
It ensheathes the cauda equina and terminates with dura at S2.
Deep to the Arachnoid layer is the subarachnoid space, CSF is located here. The goal of a spinal tap is to reach this region and withdraw CSF.
to do a spinal tap- will pass through the:
skin, superficial fascia, supraspinous ligament, interspinous ligament, ligamentum flavum, epidural space, dura mater, subdural space, and arachnoid (end up in the subarachnoid space to get CSF)
To do a Spinal Tap should look for the Iliac Crests (at plevis area- approximate level of L4 is at the peak of the crests) this will show you that you are at the area of the back between L2-S2 called the lumbar cistern ( should perform spinal tap between L3-L4 or L4-L5 for a child). Should be performed at this area, because this is the area of the Cauda Equina (see separate card) so the needle will not puncture the spinal cord. |
|
|
Term
Pia Mater
-What is it, what is made of it |
|
Definition
Pia adheres closely to the spinal cord and nerve rootlets (it cannot be "peeled off")
It forms the filum terminale and the denticulate ligaments |
|
|
Term
|
Definition
Spinal Cord (including Cauda Equina) is composed of Dorsal and Ventral Roots (in the white matter), both leave the spinal cord gray matter, where sensory neurons (will be in dorsal root) synapse with motor neuron cell bodies (their processes will become the ventral root), and join together as a spinal nerve (contains somatic sensory, somatic motor, and postganglionic sympathetic neurons as well as visceral afferent neurons in the T1-L2 region of the spinal cord) for a brief moment before splitting into Dorsal and Ventral Rami (both containing al the same constituents as the spinal nerves they came from)
The White Mater where the processes of the motor and sensory neurons are located was the Marginal Layer Embryologically, formed from the processes of Neuroblast cells (which were derived from neuroepithelial cells)
The gray matter embryologically is the Mantle Layer, formed from the Neuroblast cell bodies. Within the mantle layer there is the Alar Plate (becomes the dorsal gray matter-where dorsal roots enter), and the Basal Plate(where the cell bodies of the somatic motor neurons are located, this is also the region that will form the intermediolateral cell column where the cell bodies of the sympathetic motor neurons between T1 and L2 are found)
Dorsal Roots may be confused with ventral roots, but looking down onto the cadaver from the "prone" position, the dorsal roots will be more superior (dorsally located) and the ventral roots will be more inferior/deep (more ventrally located). Another way to tell the apart is to look for a denticulate ligament: the dorsal root will be above the ligament and the ventral root will be below.
Both dorsal and ventral roots exit the vertebral column through the intervertebral foramina. The dorsal root ganglion where the cell bodies of the sensory neurons are also found here. |
|
|
Term
|
Definition
Spinal Cord (including Cauda Equina) is composed of Dorsal and Ventral Roots (in the white matter), both leave the spinal cord gray matter, where sensory neurons (will be in dorsal root) synapse with motor neuron cell bodies (their processes will become the ventral root), and join together as a spinal nerve (contains somatic sensory, somatic motor, and postganglionic sympathetic neurons as well as visceral afferent neurons in the T1-L2 region of the spinal cord) for a brief moment before splitting into Dorsal and Ventral Rami (both containing al the same constituents as the spinal nerves they came from)
The White Mater where the processes of the motor and sensory neurons are located was the Marginal Layer Embryologically, formed from the processes of Neuroblast cells (which were derived from neuroepithelial cells)
The gray matter embryologically is the Mantle Layer, formed from the Neuroblast cell bodies. Within the mantle layer there is the Alar Plate (becomes the dorsal gray matter-where dorsal roots enter), and the Basal Plate(where the cell bodies of the somatic motor neurons are located, this is also the region that will form the intermediolateral cell column where the cell bodies of the sympathetic motor neurons between T1 and L2 are found)
Ventral Roots may be confused with dorsal roots, but looking down onto the cadaver from the "prone" position, the ventral roots will be more inferior/deep (ventrally located) and the ventral roots will be more superior (more dorsally located). Another way to tell the apart is to look for a denticulate ligament: the dorsal root will be above the ligament and the ventral root will be below.
Both dorsal and ventral roots exit the vertebral column through the intervertebral foramina. The dorsal root ganglion where the cell bodies of the sensory neurons are also found here. |
|
|
Term
|
Definition
| It is made of pia matter and is a small triangular extension the projects laterally between the dorsal and ventral roots. They are attached to the dura and the pia of the spinal cord. They play a role in stabilizing the position of the spinal cord. It can usually be seen next to a white clear-like shark tooth looking projection (though the ligament is made of pia) |
|
|
Term
|
Definition
| The pointed terminus where spinal cord ends at approximately L2. At the tip a slender filament of pia called the filum terminale (looks to be a darker color and is on top of the rest of the Cauda Equina) extends from the tip of the conus medullaris and eventually attaches to the coccyx anchoring the rest of the cord. |
|
|
Term
|
Definition
| The filum terminale (looks to be a darker color and is on top of the rest of the Cauda Equina) extends from the tip of the conus medullaris (L2) and eventually attaches to the coccyx anchoring the rest of the cord. |
|
|
Term
|
Definition
A collection of dorsal and ventral roots, these select groups exit consecutively at the apropriate levels to make up the lower lumbar, sacral, and coccygeal spinal nerves. It begins at around L2, L3 in children.
This is the area that you will want to perform a spinal tap (L3-L4, L4-L5 in children) since the needle will not puncture the spinal cord.
In the embryo the spinal cord and the vertebrae are at the same level, however the vertebrae begin to grow at a much faster rate than the cord can. Since the spinal nerves were already formed the dorsal and ventral roots from the regions of the spine L2 and below are forced to grow in order to reach their respective vertebrae- thus the cauda equina is formed.
If an individual is born with Spina Bifida (defect of the vertebral arch, usually the lamina) a menigocele can form. Potentially the cauda equina can be displaced into the menigocele sac making it a meningomyelocele. This may cause hydrocephaly (CSF to go into the meningocele which is very painful and can happen even in a regular meningocele) by the medulla to be displaced caudally. More importantly the meningomyelocele can be accompanied with neurological symptoms such as the pelvic organs and legs being dysfunctional. |
|
|
Term
| Ventral Ramus/Intercostal Nerve |
|
Definition
Also referred to as Intercostal Nerves. They are regular and segmental and contain somatic sensory, somatic motor, and postganglionic sympathetic neurons.
The sympathetic motor neurons will exit the gray matter with the ventral roots (embryologically gray matter is mantle layer, ventral/intermediolateral cell columns are from the basal plate part of the mantle layer. The white matter embryologically is the marginal layer) into the sympathetic chain ganglia via white ramus communicans. Some of these will synapse in the chain and travel via gray ramus communicans to the dorsal or ventral rami.
These postganglionic motor fibers will act on: the smooth muscles that make up the walls of blood vessels as vasoconstrictors (vasomotor-end in smooth muscle of peripheral blood vessels), the smooth muscle that is associated with hair shafts in the skin (pilomotor), and stimulate the sweat glands to secrete (sudomotor).
These nerves are part of the "VAN" (Vein-Artery-Nerve that are found just inferior to costal grooves) the somatic sensory and motor neurons are used for motion and feelin in the dermatomes in the thoracic region.
Referred pain occurs because the Visceral Afferent Pain Fibers have their cell bodies located in the dorsal root ganglia at T1-L2 however they don't join the ventral rami they enter the sympathetic chain ganglia via white ramus communicans and exit the chain with other post synaptic sympathetic fibers that go to the viscera. When there is an injury like myocardial infarction the visceral afferent pain fibers send a signal that eventually reaches the brain. Since these fibers rarely (potentially never) send signals and are in the same dorsal root ganglia as somatic sensory neurons in a specific dermatome the brain interprets the signal as from the respective dermatome. |
|
|
Term
|
Definition
Contain somatic sensory, somatic motor, and postganglionic sympathetic neurons.
The sympathetic motor neurons will exit the gray matter with the ventral roots (embryologically gray matter is mantle layer, ventral/intermediolateral cell columns are from the basal plate part of the mantle layer. The white matter embryologically is the marginal layer) into the sympathetic chain ganglia via white ramus communicans. Some of these will synapse in the chain and travel via gray ramus communicans to the dorsal or ventral rami.
The dorsal rami go to the skin and muscle of the back (somatic sensory and motor neurons
These nerves are part of the "VAN" (Vein-Artery-Nerve that are found just inferior to costal grooves) the somatic sensory and motor neurons are used for motion and feel in in the dermatomes in the thoracic region.
Referred pain occurs because the Visceral Afferent Pain Fibers have their cell bodies located in the dorsal root ganglia at T1-L2 however they don't join the ventral rami they enter the sympathetic chain ganglia via white ramus communicans and exit the chain with other post synaptic sympathetic fibers that go to the viscera. When there is an injury like myocardial infarction the visceral afferent pain fibers send a signal that eventually reaches the brain. Since these fibers rarely (potentially never) send signals and are in the same dorsal root ganglia as somatic sensory neurons in a specific dermatome the brain interprets the signal as from the respective dermatome. |
|
|
Term
|
Definition
| Left Brachiocephalic Vein |
|
|
Term
|
Definition
Inferior Thyroid Vein
- functions to carry deoxygenated blood from the thyroid gland, where it is transported back to the heart |
|
|
Term
|
Definition
Right Brachiocephalic Vein
- a vein that returns deoxygenated blood from the upper limbs, neck and head to the heart
- approximately two centimeters long
- The two brachiocephalic veins (right and left) merge together with the azygous vein
|
|
|
Term
|
Definition
|
|
Term
|
Definition
| Right and Left Internal Jugular Veins |
|
|
Term
|
Definition
| Right and Left Subclavian Veins |
|
|
Term
|
Definition
| Right and Left Phrenic Nerves |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| Left Common Carotid Artery |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| Recurrent Branch of the Left Vagus Nerve |
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| Right Recurrent Branch of the Right Vagus Nerve |
|
Definition
|
|
Term
|
Definition
Embryologically is the ductus arteriosus which connects the aorta and the pulmonary trunk
If there is an incomplete division of the aorta and pulmonary trunk-interventricular septal defect- a congenital malformation called persistent tuncus arteriosus will occur.
In the adult it connects the inferior region of the aorta and the superior region of the pulmonary trunk |
|
|
Term
| Right Recurrent Laryngeal |
|
Definition
Branch of the vagus nerve (tenth cranial nerve) that supplies somatic motor function and sensation to the larynx. If a patient has cancer it may cause the lymph nodes surrounding the recurrent to become enlarged. If this happens it may press on the nerve causing hoarseness and weakness of the voice- may be diagnostic tool for detecting cancer.
The Right recurrent laryngeal wraps around the right subclavian artery and travels up to the larynx |
|
|
Term
|
Definition
Branch of the vagus nerve (tenth cranial nerve) that supplies somatic motor function and sensation to the larynx. If a patient has cancer it may cause the lymph nodes surrounding the recurrent to become enlarged. If this happens it may press on the nerve causing hoarseness and weakness of the voice- may be diagnostic tool for detecting cancer.
The left recurrent laryngeal maintains an association with the ligamentum artiosum and wraps around the arch of the aorta in order to travel back up to the larynx |
|
|
