Monday, June 16, 2008

Spinal Cord

Elongated and cylindrical part of the central nervous system which is contained in the upper two-third of the vertebral canal.

Integration and association of sensory modalities.

Extent :

Begin as continuation of the medulla oblongata at the level of the upper border of posterior arch of Atlas above (rostral) to first pair of cervical nerve , cuts middle of dens Axis vertebrae and end as a pointed end -conus medularis at the level of L1.

Dimension :
Length - 45cm in male and 42 cm in female
Weight- 30 gm

Enlargements :
Cervical C4-T2
Lumbosacral L1-S3

Part of the spinal cord where a pair of spinal nerves is attached.

Duramater (endosteal + meningeal)
Acachnoid mater

Contents of epidural space
connective tissue
internal vertebral venous plexus

Filum terminale:
Continuation of piamater .
starts from the lower end of spinal cord at level of L1.
Has 2 parts : Filum terminale internum-15cm and filum terminale externum-5cm

Best site for lumbar puncture :
Adult : between L3-L4
Infant: between L4-L5

Protection of spinal cord
Vertebral canal
Hydrostatic pressure of CSF
Filum terminale
Ligamentum denticulatum

Arterial supply of spinal cord.

2 sources
1. Longitudinally oriented vessels
anterior spinal artery
posterior spinal artery

2. segmental spinal arteries derived from:
verterbral artery
deep cervical arteries
posterior intercostal arteries
lumbar arteries

Structure of spinal cord :

Inner core of the Grey matter and outer white matter

Nerve cell groups in :

Anterior grey column
alpha efferent
gamma efferent

Posterior grey column
substantia Gelatinosa
Nucleus proprius
Nucleus dorsalis
Visceral affarent nucleus

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