Spinal Cord Flashcards
Talk about the spinal cord?
(7)
1- it begins at the foramen magnum
2- it ends at intervertbral disc between L1-2 in adults named conus medullaris within the terminal ventricle
3- 45 cm ( usually vertebral canal -25)
4- it passes inside the vertebral canal ( central )
5- 31 pairs of spinal nerves
(8- cervical
12- thoracic
5- lumbar
5- sacral
1- coccygeal )
6- cylindrical
7- not uniform in diameter as there is
• cervical inlargment where the it gives the origin to brachial plexus
• lumbar enlargent where it gives the origin to lumbosacral plexus
External features of it ?
5 -sulci
1posterior median sulci
2 posterolateral towards the dorsal root
2 anterolateral towards the ventral root
1- fissure
Anterior median fissure
What are the changes of the length of it by age ?
During the fetal life
The spinal cord fills the whole vertebral canal
At birth
It ends at the level of L 3
At adults
Ends at the level of intervertebral disc between L1-2
And this happens Due to the rate of growth of both
What are the meninges ?
Coverings of the cns
1- dura
2- arachnoid
3- pia
Talk about dura mater
(4)
1- it is composed of 2 layers
Outer layer ( periosteal) : attaches the skull lining the cranial cavity
Inner layer ( meningeal) : It is attached to the outer one but separates from it at certain lines to form venous sinuses.
2- the inner layer continous to cover the spinal cord starting from foramen magnum till the 2 sacral and it is continous with the epinurium of the nerve trunks also
3- it is separated from arachnoid by subdural space containg thin film of the serous fluid
4- it is separated from the periosteam of the canal by epidural space containing
* internal vertebral venous plexus
* ct
* fat
Talk about arachnoid mater ?
(6)
1- delicate transparent membrane.
2- It bridges over sulci of
brain.
3-in the brain region, it extends outwards to form arachnoid villi ( ناحية sinus بتاع الديورا )
4- it covers the spinal cord till the 2 sacral vertebrae
5- between arachnoid and pia mater there is subarachnoid space which is filled with CSF
6- it becomes widened at the end forming subarachnoid cistern that contains
1- CSF
2- spinal blood vessels
3- spinal nerve roots ( cauda eqina )
4- filam terminale
Talk about pia mater ?
(4)
1- soft highly vascular
2- firmly adherent to the brain
3- it folds with the sulcus of the brain
4- continue covering the spinal cord till its end and it is thickened at 4 places
1- denticulate ligaments
* each ligament extend along the spinal cord
* 21 pairs of ligaments ( 1 attach to foramen magnum - 7 cervical - 12 thoracic- 1 lumbar)
* each ligament extends laterally one on each side between dorsal and ventral root to attach laterally to dura mater
* has a serrated lateral border ( مسننة )
2- subarachnoid septum : extension arising at the posterior median sulcus to attach to dura mater
3- linea splendens : extension extending along the surface of anter median fissure
4- filum terminale :
*at the tip of conus medullaris the pia is transformed into fibrous filament called filum centring between cauda equina
* at the level of s2 it pierces both arachnoid and dura to pass acquiring a sheath from dura
* silvery appearance
* finally attached to the back of coccyx
Fixation ?
It is due to
1- spinal nerve roots
2- filum terminale
3- denticulate ligaments
4- dura mater attaching to the foramen magnum
Contents of the vertebral canal beliw the conus
Cauda equina
Filum terminale
CSF
Dura
Arachnoid
Blood supply ?
Arterial
1- anterior spinal artery
* arising from 4th part of vertebral artery from subclavian a
* it gives 2 uniting together to give one anterior median a
* it descends along the anterior median fissure supplying ant 2/3 of the spinal
2- posterior spinal artery
* arising from the 4th part of vertebral artery
* gives 2 branches
* it descends along the posterolateral sulcus giving 2 branches one front and one behind the dorsal root
* suply the posterior 1/3
* anatomosis finally with ant, post spinal arteris around the conus medullaris
3- radicular spinal arteries
* arise from vertebral a , posterior intercostal a , lumbar a and lateral sacral
* entering the canal through intervertebral formen
* divides to ant , post which run along ventral and dorsal roots
* anastomosis also with ant , post spinal arteries giving arteria corona
Venous
6
1- anterior median
1- posterior median
2 anterior lateral
2 posterior lateral
Draining to internal vertebral venous plexus in epidural space then to external vertebral venous plexus
Lumbar puncture ?
Introducing a needle into subarachnoid space for
1. Injection of drugs into CSF such as anesthesia
2. Obtaining a sample of CSF
• INTRODUCE THE NEEDLE BETWEEN ( L3-4)
Nucleus found in dorsal horn ?
1- posteromarginal nucleus
2- substantia glatinosa of rolandi
3- nucleus proprius
4 - clarke nucleus
Nucleus found in ventral horn ?
Medial motor nuclei
Ventro-medial and dorso-medial.
• Supply muscles of
the neck and trunk
Lateral motor nuclei
Ventro-lateraland
dorso-lateral nuclei
• In cervical and
lumbosacral region
• Supply muscles of
limbs
Central motor nuclei
• Phrenic nucleus (c3,4&5): supply the diaphragm
• spinal Accessory nucleus from 6 upper cervical segments):
Supply sternomastoid and trapezius
Extra pyramidal tracts طالعين منين ؟
2 from mid brain (crossed): - rubrospinal / tectospinal
• 2 from vestibular nuclei (uncrossed): medial vestibulospinal(medulla)/ lateral vestibulospinal (pons)
• 2 from reticular formation(uncrossed) and some crossed: medial reticulospinal (pons) / lateral reticulospinal(medulla
Lesions of spinal cord ?
