ANATOMY OF THE SPINAL CORD Flashcards
The_______________ is a long cylindrical structure, covered by meninges, flattened anteroposteriorly & occupies most of the cranial 2/3rd of the vertebral canal.
spinal cord
The extent of the spinal cord from the medulla oblongata at the foramen magnum to terminate caudally (distally) as the ____________ in the adult at L1 level
conus medullaris
In a 3 month-old fetus, it extends the whole length of the vertebral canal at level of __ vertebra
S2
In a 3 month-old fetus, it extends the whole length of the vertebral canal at level of S2 vertebra, but because of greater growth in length of the vertebral column than in the spinal cord, the ___________ lies at the level of L2 vertebra at birth & at lower limit of L1 or upper limit of __ at the age of 20.
conus medullaris, L2
Beyond the conus medullaris, a prolongation of pia mater extends as a thin cord- ___________
Filum terminale
The Filum terminale is attached to the posterior aspect of the _st coccygeal segment.
1st coccygeal segment.
In adults, the spinal cord measures __ - __ cm long (from foramen magnum to level of L1/L2 vertebra).
42-45 cm
FUNCTIONS
- The spinal cord is the major _________ & ____________ between the body & the brain.
- The spinal cord carries messages between the CNS and the rest of the body, and mediates numerous spinal reflexes such as the _________
- reflex center & conduction pathway
2. knee-jerk reflex.
_______ ligaments are 2 flattened bands of pial tissue that attach to the spinal dura with about 21 teeth
Dentate ligaments
_________ is a pial filament extending from the conus medullaris to the end of the dural sac , with which it fuses
Filum terminale
_________ provide the strongest anchorage & fixation of the spinal cord to the vertebral canal
Spinal nerve roots
There are 31 pairs of spinal nerves which arise from each side of the spinal cord namely:
_ cervical
__ thoracic
_ lumbar
_ sacral
_ coccygeal
The spinal nerves contain both motor & sensory fibres
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
The part of the spinal cord from which a pair of spinal nerves arises is called a _____ segment
spinal segment
Dorsal root contain _______ nerve fibers with a Dorsal root ganglion
Sensory
Ventral root contain ______ and Autonomic nerves fibers
Motor
The Dorsal & Ventral roots unite at the _________ foramen to form the spinal nerve
Next, Having left the vertebral canal,
spinal nerves divide into _____ & _____ rami, each of which carry motor & sensory nerves.
Intervertebral foramen,
Dorsal & Ventral rami,
- Spinal nerves C1 to C7 exit _____ the pedicle of the corresponding vertebrae
- ALL other spinal nerves exit _____ the pedicles of the corresponding vertebrae
- the C8 nerve passes _____ the pedicle of C7 (there is noC8 vertebra)
- L5 nerve passes under the pedicle of the L5 vertebra.
- above
- below
- under
- L5
The lumbar, sacral & coccygeal roots that exit below the conus at L1/L2 are contained within the dura as far as its lower limit at S2 & are called the ____________
Cauda Equina
The lumbar & sacral roots below the end (termination) of the cord at vertebral level L2, continue as a leash of nerve roots termed the _____________
Cauda equina
The cross section of the spinal cord include:
- the Central canal
- H-shaped Grey matter
- white matter
The cross section of the spinal cord include:
- the C___ral canal
- H-shaped Gr_y matter
- wh_te matter
- Central
- Grey
- white
The _________ which is the center ( also contains csf) is surrounded by a H-shaped _________, which is in-turn surrounded by the ________ which is made up of the long ascending and descending fibers
- Central canal
- grey matter
- white matter
THE ASCENDING TRACTS: include the following:
- the Posterior & Anterior Spinocerebellar tracts.
- the Lateral & Anterior Spinothalamic tracts.
- the Posterior Columns comprise a medial & lateral tracts , termed respectively:
- the Fasciculus Gracilis (of Goll) &
- the Fasciculus Cuneatus (of Burdch).
THE ASCENDING TRACTS: include the following:
1. the Anterior & Posterior__________ tracts.
- the Lateral & Anterior ________ tracts.
- the Posterior Columns comprise a medial & lateral tracts , termed respectively:
- the Fasciculus _______ (of Goll)
&
-the Fasciculus _______ (of Burdch).
Spinocerebellar,
Spinothalamic
Gracilis and Cuneatus
The Fasiculus Gracilis abd Cuneatus are concerened with ______ touch and pro____eption
Fine touch, propioception
the Anterior & Posterior Spinocerebellar tracts ascends on the same side of the cord & enter the _________ through the inferior & superior cerebellar peduncles respectively
cerebellum
THE LATERAL & ANTERIOR SPINOTHALAMIC TRACTS is concerned with P_in and Tem_erature
Pain and Temperature
The descending Tracts include the following:
- the Pyramidal (Lateral Cerebrospinal or Crossed motor ) tract.
- the Direct Pyramidal (Anterior Cerebrospinal or Uncrossed motor) tract.
The descending Tracts include the following:
- the P__amidal (Lateral Cerebrospinal or Crossed motor ) tract.
- the Di_ect Pyramidal (Anterior Cerebrospinal or Uncrossed motor) tract.
- Pyramidal
2. Direct
THE PYRAMIDAL (LATERAL CEREBROSPINAL or CROSSED MOTOR TRACT
The motor pathway starts at the ____________________, crosses (decussates) in the medulla, then descends in the pyramidal tract on the contralateral (opposite) side of the cord
Pyramidal cells of the motor cortex
. THE DIRECT PYRAMIDAL (ANTERIOR CEREBROSPINAL or UNCROSSED MOTOR) TRACT
Is a small motor tract descending without c___sing at the medulla (no medullary decussation).
crossing
The pyramidal tract __________in the medulla while the
Direct tract does not _____ at the medulla
crosses
cross
ARTERIES OF SPINAL CORD AND NERVE ROOTS
The arteries supplying the spinal cord are branches of the:
1. ve__bral
- asc_nding and d_ep cervical
- i_tercostal
- lu_bar &
- lateral sa_ral arteries.
- vertebral
- ascending and deep cervical
- intercostal
- lumbar &
- lateral sacral arteries
ARTERIES OF SPINAL CORD AND NERVE ROOTS
The arteries supplying the spinal cord are branches of the:
.
- vertebral
- ascending and deep cervical
- intercostal
- lumbar &
- lateral sacral arteries
The arteries of the spinal cord are the:
- __________________ (ASA)
- _________________
(PSA)
The veins of the spinal cord are the:
- Anterior ____ vein
- Paired ______ spinal vein
- Anterior spinal artery
- Paired Posterior spinal arteries
- Anterior spinal vein (three)
- Posterior spinal vein (three)
The anterior & posterior spinal arteries can supply only the short superior part of the spinal cord, by themselves.
The circulation to much of the spinal cord is from the _____________ & ________ arteries
segmental medullary & radicular
the great ________ segmental artery (of Adamkiewicz), which is on the left side in about 65% of people, reinforces the circulation to 2/3rd of the spinal cord, + the lumbosacral enlargement.
anterior
___________ reflex Is a monosynaptic & ipsilateral muscle stretch reflex.
Is incorrectly called a deep tendon reflex.
Has an Afferent & an Efferent limb, like all reflexes
MYOTACTIC REFLEX
SPINAL CORD INJURY
- Complete transection:
- _____ of movement (muscle paralysis) & all sensation below the level of the injured segment.
the paralysis is at 1st flaccid, then becomes spastic after a few weeks & bladder & rectal sphincter control is lost,
loss
what is Complete transection?
loss of movement (muscle paralysis) & all sensation below the level of the injured segment
. Hemisection (Brown-Sequard syndrome): there is
-paralysis & loss of touch & ki__esthetic sense below the level of the lesion on the same side
loss of pain & temperature sensation on the opposite side (because of interruption of the crossed anterolateral tract
kinaesthetic
What is Hemisection (Brown-Sequard syndrome?
paralysis & loss of touch & kinaesthetic sense below the level of the lesion on the same side
loss of pain & temperature sensation on the opposite side (because of interruption of the crossed anterolateral tract
Central cord syndrome, commonly due to _____injury (without transection) following a sudden hyper-extension of the cervical spine
crush
What is Central cord syndrome
it is commonly due to crush injury (without transection) following a sudden hyper-extension of the cervical spine
in Central cord syndrome there is:
- flaccid paralysis (lower motor neurone) &
- loss of pain & temperature sensation in the upper limbs (due to anterior horn damage and interruption of the more deeply placed cervical fibres of the anterolateral tracts).
- The lower limbs may show spasticity if the lumbar fibres of the lateral corticospinal tract are involved (sacral fibres are more superficial).
- flaccid paralysis (lower motor neurone) &
- loss of pain & temperature sensation in the upper limbs (due to anterior horn damage and interruption of the more deeply placed cervical fibres of the anterolateral tracts).
- The lower limbs may show spasticity if the lumbar fibres of the lateral corticospinal tract are involved (sacral fibres are more superficial).
Anterior spinal artery syndrome:
The posterior ______columns (and therefore touch sensation) remain intact, but most of the rest of the cord below the level of the lesion is affected with loss of all motor & sensory functions, except perhaps for the “sacral sparing”.
white
Anterior spinal artery syndrome:
The posterior white columns (and therefore touch sensation) remain intact, but most of the rest of the cord below the level of the lesion is affected with loss of all motor & sensory functions, except perhaps for the “sacral sparing”.
The spinal cord is derived from the caudal part of the ______ tube.
neural
The spinal cord weighs about __ grams, making up _% of the adult brain weight.
30grams , 2%
