Spinal Cord and Meninges Flashcards
Where do spinal nerves pass out of the Vertebral Canal?
Intervertebral Foramina (formed by Superior and Inferior Vertebral Notches on Adjacent Vertebrae)
How many cervical vertebrae/spinal nerves
7 Cervical Vertebrae
8 Pairs Spinal Nerves
How many thoracic vertebrae/spinal nerves
12 Thoracic Vertebrae
12 Pairs Thoracic Spinal Nerves
How many Lumbar vertebrae/spinal nerves
5 Lumbar Vertebrae
5 Pairs Lumbar Spinal Nerves
How many Sacral vertebrae/spinal nerves
5 Sacral Vertebrae
5 Pairs Sacral Spinal Nerves
How many Coccygeal vertebrae/spinal nerves
1 Coccygeal bone (multiple fused)
1 Nerve
Where do C1-C7 spinal nerves pass out?
Above their corresponding vertebrae
Where does C8 spinal nerve pass out?
Below C7 Vertebrae
Where do T1 and below Spinal nerves pass out?
Below their corresponding vertebrae
What is the Cervical Enlargement
Enlargement of the VGH as motor fibres to Brachial Plexus arise
What is the Lumbar/Sacral Enlargement
Enlarged VGH as motor fibres to the Lumbosacral plexus arise
Conus Medullaris
Tapered end of the SC within the SC
Level of Conus Medullaris in adults
L1-L2
Due to SC regression during growth
Level of Conus Medullaris in neonates
L3-L4
Filum Terminale
Modification of Pia Mater from Conus Medullaris to Co1
Gives Longitudinal support to SC
Approximate length of Filum Terminale
20cm
Lumbar Cistern
Enlargement of Subarachnoid Space beneath level of the CM
Contents of the Lumbar Cistern
CSF
Filum Terminale
Cauda Equina
Clinical significance of Lumbar Cistern
Site of Lumbar Puncture (L4-L5) as less chance of damaging nerves
Surface landmark: Posterior Iliac Crest
Cauda Equina
Bundle of nerves associated with vertebrae below level of CM. Nerves descend in bundle to appropriate IVF
Sx of Cauda Equina Syndrome
Micturition Difficulties
Loss of Anal Sphincter Tone (Incontinence)
Saddle Anaesthesia
Lower Back/Leg Pain
Blood Supply to the Spinal Cord
2 Posterior Spinal As
1 Anterior Spinal As
8-10 Segmental Medullary As/Radicular As (arising from Posterior Intercostal As)
Venous Drainage of SC
Anterior/Posterior Spinal Veins
Drain into Internal Vertebral Plexus in Epidural Fat
Drains into large systemic veins and Azygous system
At which levels is the Lateral Grey Horn present, and why?
T1-L2
S2-S4
Sympathetic chain/splanchnic nerves arise at these levels
Dura mater in the SC?
Only one layer (meningeal)
Periosteal layer reflects and adheres to external bone of skull
Denticulate Ligaments
Modifications of Pia mater that project to lateral walls of Vertebral Canal
Stabilise the SC
Types of fibres in Dorsal Root
Sensory (somatic and visceral)
Cell bodies in DRG
Types of fibres in Ventral Root
Somatic Motor
Visceral Motor
(separate to one another. Cell body in VGH)
Superior and Inferior limits of Epidural/Extradural Space?
Foramen Magnum
Sacrococcygeal Membrane @ tip of sacrum
Superior and Inferior limits of Subarachnoid Space?
Cerebral Cortex
S2
