M6 SPINAL CORD Flashcards
Connects the brain with most of the body
Spinal cord
Occupies the upper 2/3 of the adult spinal canal within the vertebral column
Spinal cord
Normally 42 to 45 cm long
Spinal cord
Is the conical distal (inferior) end of the spinal cord
Conus medullaris
In adults, the conus ends at what level of the vertebral column?
L1 OR L2
What nuerons do the lateral enlargements at the cervical and lumbosacral levels accomodate?
Upper and lower limb innervation
It is inferior to the end of the spinal cord.
Filum terminale
It is a bundle of connective tissue and glia that connects the end of the cord to the coccyx.
Filum terminale
Filum terminale is a bundle of ______________ and ____ that connects the end of the cord to coccyx?
Connective tissue and glia
Long roots are required for axons from the termination of the cord to exit the lumbosacral vertebral column.
Cauda equina
Is lined with ependymal cells and filled with csf.
Central canal
Central canal is lined with what? And filled with what?
Ependymal cells and CSF
Opens upward into the inferior portion of the fourth ventricle
Central Canal
Spinal Cord Segments (adults)
C8, T1, T12, L5, S
Vertebral Bodies of C8
C6-7
Vertebral Bodies of T1
C7-T1
Vertebral Bodies of T12
T10-T11
Vertebral Bodies of L5
T12-L1
Vertebral Bodies of S
L1-2
Bony spinous processes (adults)
C6, T3, T8, T10, and T12,L1
Anatomy of spinal cord, superior to inferior.
Conus medullaris, cauda equina, and filum terminale
Cross section of the spinal cord
Deep median fissure and shallow posterior median sulcus
Divides the cord into symmetric right and left halves joined in the central midportion
Deep median fissure
Contains a fold of pia and blood vessels
Anterior median fissure
Floor of anterior median fissure
Anterior white commissure
Attached to the spinal cord along a shallow vertical groove
Dorsal nerve roots
Lies at a short distance anterior to the posterior median sulcus
Posterolsteral sulcus
Where do ventral nerve roots exit?
Anterolateral sulcus
True or false:
Each segment of the spinal cord gives rise to four roots.
True
How many pairs of spinal nerves has a ventral root and a dorsal root?
31 pairs
Each root is made up of how many rootlets?
1 to 8 rootlets
Axons sending information to the periphery leave the anterolateral cord in small groups
Rootlets
Dorsal root of a typical spinal nerve, close to the junction with the ventral root
Dorsal root ganglion
A swelling that contains nerve cell bodies that give rise to sensory axons
Dorsal root ganglion
Portion of a spinal nerve outside the vertebral column
Peripheral nerve
Surrounds and protects the spinal cord
Vertebral column
Vertebraes
7 cervical
12 thoracic
5 lumbar
1 sacrum
1 coccyx
Exit of nerve roots from the vertebral column
Intervertebral foramina
Form from the ventral rootlets from a single segment coalesce
Ventral roots
Contains sensory axons that bring information into the spinal cord and enter the posterolateral spinal cord via rootlets
Dorsal root
Has a dorsal root ganglion located outside the spinal cord
Dorsal root
Contains the cell bodies of sensory neurons
Dorsal root ganglion
Sensory axons enter the spinal cord, the large-diameter fibers, transmitting proprioceptive and touch information, are located medially: small-diameter fibers, transmitting pain and temparature information are located laterally
Dorsal root ganglion
Sensory axons that transmit proprioceptive and touch information that are located medially.
Large diameter fibers
Sensory axons that transmit pain and temperature information that are located laterally.
Small diamete fibers
What roots join briefly to form a spinal nerve?
Dorsal and ventral
Smaller gamma motor neuron axons supply?
Intrafusal muscle of the muscle spindles
Preganglionic autonomic fibers:
Thoracic, upper lumbar, and midsacral levels
Largely sensory
Dorsal root
Contains afferent fibers from the nerve cells in its ganglion
Dorsal nerve root
*contains fibers from cutaneous and deep structures
Dorsal root
Largest fibers come from muscle spindles and participate in spinal cord reflexes
Dorsal root
Impulses from mechanoreceptors in skin and joints
Dorsal root
Nerve roots are small and carry
Dorsal root
Branches of typical spinal nerves
Posterior primary division, anterior primary division, and Rami communicantes
Medial branch, largely sensory and lateral brach, mainly motor
Posterior primary division
Larger than the posterior primary division
Anterior primary division
Forms the cervical, brachial, and lumbosacral plexus
Anterior primary division
Thoracic region, it remains segmental as intercostal nerves
Anterior primary division
Join the spinal nerves to the sympathetic trunk
Rami communicantes
Only the thoracic and upper lumber nerves with white ramus communicans, but the gray ramus is present in all spinal nerves
Rami communicantes
Made up of two symmetric portions joined across the midline
Gray matter: Columns
Cross section of the spinal cord shows an H shaped internal mass of gray matter surrounded by white matter
Columns
Extends the entire length of the spinal cord and is considered to consist of columns
Gray matter
Column in front of the central canal
Ventral gray column
It contains the cells of origin of the fibers of the ventral roots, incl. Alpha and gamma motor neurons
Ventral gray column
Lies between the dorsal and ventral gray columns
Intermediolateral gray column
Columns is also called?
Horn
Prominent lateral triangular projection in the thoracic and upper lumber regions but not in the midsacral joint
Intermediolateral gray column
Give rise to sympathetic axons that leave the spinal cord within the ventral roots
Lateral horn
Gives rise to preganglionic parasympathetic axons that leave the spinal cord within the sacral ventral roots
Sacral parasympathetic neurons
Reaches almost to the posterolateral sulcus
Dorsal gray column