Spinal Cord Flashcards
Medulla spinalis
Tail of the brain
2%
Spinal cord
Anterior Longitudinal Ligament
Vertebral body
Intervertebral disks (in between each vertebral
body) § Posterior Longitudinal Ligament
Anterior to the Spinal Cord
Skin
§ Subcutaneous tissue
§ Supraspinous ligament
§ Interspinous ligament
§ Ligamentum Flavum
Posterior to the Spinal cord
Secures the Spinal Cord in the vertebral canal
Composed of fibrous, collagenous fibers that is
attached to the dura of the spinal cord
Denticulate Ligament
TOPOGRAPHIC ORGANIZATION
Lower cervical to T1
Spinal nerves for Brachial plexus
Sensory nerves from upper limbs enter in this
enlargement
Cervical Enlargement
§ Sensory nerves from lower limbs enters the spinal
cord from this area
§ Spinal nerves for lumbosacral plexus
Lumbar Enlargement
Emerge through the intervertebral foramen, which are
located between each vertebra.
Spinal nerve
Pairs of spinal nerve
31 pairs
§ Cervical: 8
§ Thoracic:12
§ Lumbar: 5
§ Sacral: 5
§ Coccygeal:1
Emerge from the spinal cord to exit the spine
above their corresponding vertebra.
Spinal nerve c1 to c7
Conical Termination of the Spinal Cord
Ø Spinal cord is present up until L1 or L2 of the vertebra
Conus Medullaris
§ Cutaneous innervation for saddle area
§ Motor innervation for sphincters
§ Parasympathetic innervation for bladder
Functions of Conus medullaris
Ø Condensed pia that extends caudally from conus
medullaris
Ø The pia is invested with dura at S2 to become coccygeal
ligament
Ø Surrounded by cauda equina, the long roots from the
lumbar and sacral regions (Lumbo-Sacral roots)
Filum Terminale
Notes
Posterior horn sends axons to terminate directly at anterior horn cells or are directed to the white mater
Notes
White matter-dendrites and axons
Gray matter- soma of nucleus
conducting cord composed of white matter
Funiculi
Afferent fibers
enter the dorsal horn
Posterior/dorsal funiculus
Efferent fibers exit through
the anterior horn
Anterior funiculus
enclosed by posterior and
anterior funiculus
Lateral funiculus
Contains Dorsal column pathway
Dorsal intermediate septum
Carries light touch, vibratory, and joint
position senses
§ Ascending tract
§ Divided into 2 fasciculi:
o Fasciculus Gracilis
o Fasciculus Cuneatus
Dorsal column pathway
Carry pain, temperature, and light touch
sensation.
§ Includes a larger lateral tract and a smaller
anterior tract
§ Ascending tract- extremities going to the
spinal cord to the thalamus
Spinothalamic Tract
carries motor signals. § comprises two tracts, with the lateral tract
being the predominant one.
§ Descending tract- Cortex to the spine
Corticospinal tract
Lateral spinothalamic tract
Pain and Temp
Lateral spinothalamic tract
1st order neuron
Dorsal Root Ganglion
(Spinal ganglion)
Lateral spinothalamic tract
2nd order neuron
Gray matter (lamina I,IV,V)
Axons of the 2nd order neurons decussate at the?
Anterior white commissure
3rd order neuron
Thalamus
Axons of the third order neurons pass through the?
Internal capsule
Termination?
Primary Somesthetic Area
(Brodmann 1,2,3)
surrounds the central canal
§ lined by ependymal cells similar to the
ventricles
Substantia Gliosa
Low neural density
Dorsal part of dorsal horn
Neurons at this area are non myelinated or thinly myelinated.
LAMINA 1
Covering of Lamina I (Tip of the dorsal horn)
Most numerous in Lumbosacral region
Posteromarginal nucleus
Corresponds to substantia gelatinosa
Cells (tightly packed)
LAMINA II
motor neurons, General somatic efferent neurons
nerve cells that carry signals from the brain to the skeletal muscles to initiate voluntary muscles to initiate voluntary movmt
Somatic Efferent Neuron
Receives collateral or direct termination of dorsal root fibers
Intermediate Gray Zone
“Posterior Thoracic Nucleus” or
“Nucleus Dorsalis”
Dorsal nucleus of Clarke
