Spinal Cord, Spinal Nerves, and Reflexes I & II Flashcards
What are the anterior, posterior, and lateral boundaries of the vertebral canal?
anterior: vertebral bodies, intervertebral discs, and posterior longitudinal ligament
posterior: vertebral laminae and the ligament flavum
lateral: vertebral pedicles and the intervertebral foramina
What are the six contents of the vertebral canal?
- spinal cord
- spinal nerve rootlets/roots
- spinal meninges - pia, arachnoid, and dura
- epidural fat
- CSF
- blood vessels
What opening is at the superior end of the spinal cord?
foramen magnum
What structure is at the inferior end of the spinal cord and at what vertebrae?
conus medullaris at L1/L2 (adults); L3/L4 (newborns)
The spinal cord is __ inches long
18
The spinal cord has a cervical enlargement that supplies upper limbs. The enlargement occurs at what segment?
C5-T1
The spinal cord as a lumbosacral enlargement that supplies the lower limbs. This enlargement occurs at what segment?
L1-S3
The ventral lateral selves and dorsal lateral sulcus are lateral grooves at the site of respective rootlet attachments. Which one is more prominent?
dorsal
The following structures are in the correct order, true or false?
spinal cord - rootlet - root - spinal nerve - rami
true
True or false?
The white matter is deeper, while the gray matter is found more superficial.
false; white matter is superficial, gray matter is deeper, forming an H-like shape
The central canal is the most central within the middle of the gray matter and contains what?
CSF
White matter is primarily found where?
neural fiber processes (axons), with minimal cell bodies
Axons bundle to form ___, which relay information to the brain (ascending) or inferiorly/peripherally (descending)
tracts
____ columns are formed by primary ascending fibers (central processes of sensory fibers)
dorsal
primary sensory neurons start at the receptor and synapse with secondary sensory neurons either in the ___ ___ or ___, leading to tertiary sensory neurons which end in the cerebral cortex
spinal cord, medulla
dorsal columns transmit what?
ipsilateral fine touch and proprioception
This is a subset of dorsal column, which carries lower body information
fasciculus gracilis
What is fasciculus cuneatus?
subset of dorsal column, carries upper body info (only found in spinal cord)
What is the name of the pathway that sensory neurons carrying fine touch and proprioception take as they ascend to the thalamus and eventually terminate in the contralateral brain?
medial lemniscal
True or false?
The spinothalamic tract is found in both the lateral and ventral columns of white matter
true
The spinothalamic tract is formed by ___ ascending fibers
secondary
The lateral spinothalamic tract transmits what?
contralateral pain and temperature
The anterior spinothalamic tract transmits what?
crude touch and pressure
The spinothalamic tract passes through the medulla without crossing, then secondary fibers terminate in the ___ before continuing to the ___
thalamus; cortex
The lateral corticospinaltract is found where?
in the lateral column of white matter
The lateral corticospinal tract is formed by descending ___ ___ ___, which originate in motor cortices of the cerebrum
upper motor neurons (UMN)
In regards to the lateral corticospinal tract, UMN fibers cross the midline (decussate) in the medulla at the ____, thus run contralaterally in the spinal cord
pyramids
note: the left side of the brain controls the right side of the body. this is why
The lateral corticospinal tract synapses with lower motor neurons in the ventral gray horn for eventual distribution to skeletal muscle for voluntary ___ ____
motor control
Lesions in what tract lead to paralysis below the level of the damage?
lateral corticospinal tract
____ matter is primarily formed by neural cell bodies, axon terminal branches and dendrites. It is shaped like an “H”.
gray
Ventral horns are found at all levels of the spinal cord. True or false?
true
Ventral horns contain somatic motor neuron cell bodies which innervate what?
skeletal muscle
Dorsal horns are found only in the thoracic and cerebral segments of the spinal cord. True or false?
false; all levels
Dorsal horns contain what?
central process of sensory neuron axons and interneurons
What do interneurons do?
integrate various sensory and motor neurons
Lateral horns are found only at spinal cord segments ___ to ___
T1 - L2
Lateral horns contain what?
parasympathetic neuron cell bodies
This part of gray matter is found at all levels of the spinal cord, is the deepest/central region of spinal cord, contains central canal, and connects the left and right gray columns
gray commissure
The central canal is continuous with the ___ ventricle of the brain, found through entire length of the spinal cord
4th
A ventral rootlet is formed along the ___ ____ sulcus and is a collection of axons from motor neurons in the lateral and ventral gray horns
ventral lateral
Ventral nerve roots contain ___ fibers only
motor
A single dorsal nerve root is a collection of central axonal processes from pseudo unipolar neuron cell bodies located in the what?
dorsal root ganglion
The spinal ganglion is found near the ___ foramina. It is important to note that all spinal nerve sensory neuron cell bodies are found within this ganglia.
intervertebral
A single dorsal root splits into a series of dorsal rootlets which enter the spinal cord at the ____ ____ sulcus
dorsal lateral
Dorsal nerve roots contain only ___ fibers
sensory
A spinal nerve is formed near the ____ foramen
intervertebral