Spinal Cord Flashcards
What is the annulus fibrosus?
The outer layer of a intervertebral disc made up of dense collagen that has nerve and blood supply
What is the nucleus pulposus?
The inner layer of an intervertebral disc that has no nerve or blood supply
Water covers what percentage of the nucleus pulposus?
80%
What is the nucleus pulposus degenerated from?
The notochord
Is it easy for the nucleus pulposus to heal after injury?
No
What is the ligamenta flava?
A pair of small ligaments that connect the laminae of adjacent vertebrae
What is the relation between ligamenta flava and spinal stenosis?
As we age or due to certain degenerative conditions, the ligamentum flavum can thicken or hypertrophy. This thickening can contribute to the narrowing of the spinal canal, which is known as spinal stenosis. This can compress the spinal cord or spinal nerves, leading to symptoms such as pain, numbness, or weakness in the limbs.
What movement can decrease the compression from spinal stenosis?
Flexion
Facet joint hypertrophy is often caused by what?
Degenerative changes
Facet joint hypertrophy causes what issue?
Nerve root impingement
What is the difference between a central (spinal stenosis) disc herniation and a paracentral (root impingement) disc herniation)
A central disc herniation occurs when the disc material protrudes directly backward into the spinal canal. This can put pressure on the spinal cord itself, potentially leading to symptoms like numbness, weakness, or even loss of bowel or bladder control if severe.
A paracentral disc herniation, is when the disc material protrudes off to one side of the midline. This generally affects one or more nerve roots, rather than the spinal cord itself. Symptoms typically include radicular pain (pain that radiates along the course of a nerve), numbness, and weakness in the distribution of the affected nerve.
What are the different types and grades of a disc herniation?
- Buldge: (Least severe) you can preform traction on this/ McKenzie extension
- Protrusion: The annulus fibrosus remains intact, but bulges outward, causing the disc to be asymmetrical. You can preform traction on this/ McKenzie extension
- Extrusion: The annulus fibrosus is disrupted and disc material bulges out further, but it remains connected to the disc.
- Sequestration: (Most severe) Disc material breaks through the annulus fibrosus and moves away from the disc into the spinal canal.
The nervous system has two main branches. What are they?
- Central Nervous System (CNS)
- Peripheral Nervous System (PNS)
*Both have afferent and efferent components
What does afferent mean?
Information is flowing in
What does efferent mean?
information is being issued out
In the peripheral nervous system there is an afferent branch and an efferent branch, what are they each responsible for?
Afferent: Sensory
Efferent: Motor
Sensory (afferent) nerves transmit impulses where?
From sensory receptors towards the CNS
Motor (efferent) nerves transmit impulses where?
Away from the CNS towards the rest of the body
Efferent nerves break into two categories, what are they and what do they support?
- Somatic (voluntary): skeletal muscles
- Visceral (involuntary): cardiac and smooth muscle
Visceral motor nerves can be further split into two final categories, what are they and what do they do?
- Sympathetic: mobilizes body into action (fight/flight)
- Parasympathetic: relaxes body (rest/digest)
What are the functional units of the nervous system in the CNS? (5)
- Neuron: cell body, axon, dendrites
- Astrocyte: support, regulate ions, exchange of material between neurons and capillaries
- Microglia: defend, immune defense against invading microorganisms
- Oligodendrocyte: Myelin Sheath: wrap and insulate, form myelin sheath
- Ependymal Cells: line cavities, create, secrete, and circulate cerebrospinal fluid
What are the functional units of the nervous system in the PNS? (3)
- Neuron
- Satellite Cell: surround neuron cell bodies
- Schwann Cell: insulate, help form myelin sheath
The spinal cord is developed from what?
the neural tube
Is the dorsal horn responsible for sensory or motor responses?
Sensory
Is the ventral horn responsible for sensory or motor responses?
Motor
Is the gray matter myelinated?
No
What makes up the intermedial lateral horn?
T1-L2: Sympathetic
Sacral S2-S4: Parasympathetic
Is white matter myelinated?
Yes
What flows through the central canal of the spinal cord?
Cerebrospinal fluid (CSF) - nutrition and protection
Where does the spinal cord initiate?
The Foramen magnum
Where does the spinal cord end?
T12-L2
What does conus medullaris mean?
cone shape at the end of spinal cord
What does cauda equina mean?
horse tail
List the protective structures of the spinal cord in order from most superficial to deepest.
- Dura Mater: (Superficial) thick and strong
- Arachnoid Mater: (Middle) spider web like
- Pia Mater: (Deepest) directly around the spinal cord
What specialized ligament is associated with the dura mater?
Filum terminale externum
What specialized ligaments are associated with the pia mater? (2)
- Denticulate ligament
- Filum terminale internum
Where is the epidural space?
Between the dura and vertebral bony wall
Where is the subdural space?
Between the dura and arachnoid mater, potential space
Where is the subarachnoid space?
Cerebrospinal fluid
In the spinal cord there are two enlargements. What are they and what do they contain?
- Cervical enlargement: cervical plexus and brachial plexus
- Lumbosacral enlargement: lumbar plexus and sacral plexus
