anatomy and blood supply of spinal cord
TRANSCRIPT
Dr. Nishtha Jain
Senior Resident
Department of Neurology
GMC, Kota
Part of the central nervous system (CNS)
Extends caudally
Protected by the bony structures of the vertebral column.
Covered by the three membranes of the CNS, i.e., the
dura mater, arachnoid and the innermost pia mater.
Occupies only the upper 2/3 of the vertebral canal.
By age 2 months, it reaches the adult L1-L2 level.
The average length- 45 cm(adult male) and 42 to 43
cm(adult female).
The corresponding average length of the spinal column
is 70 cm.
If the level of the tip of the conus is below the mid-L2
vertebral body, the conus is considered low-lying.
According to its rostrocaudal location the spinal cord can
be divided into four parts:
-cervical,
-thoracic,
-lumbar and
-sacral.
The number of spinal
nerves and spinal
segments:
-8 cervical,
-12 thoracic,
-5 lumbar,
-5 sacral and
-one coccygeal spinal
segment
SPINAL CORD LEVELS RELATIVE TO
THE VERTEBRAL BODIESSPINAL CORD LEVEL CORRESPONDING
VERTEBRAL BODY
Upper cervical Same as cord level
Lower cervical +1
Upper thoracic +2
Lower thoracic + 2 to 3 levels
Lumbar T 10 – T 12
Sacral T 12 – L1
ENLARGEMENTS ENLARGEMENTS :
contains more motor neurons to supply the limbs
• Cervical: Extends from C5 to T1 segments to form brachial plexus
widest circumferance-38mm at C6
Lumbosacral: Extends from L2toS3 to form lumbosacralplexus.
Widest circumferance -35mm at S1
LAMINA
I Nucleus posteromarginalis
II Substantia gelatinosa
III and IV Nucleus proprius dorsalis
V Zone anterior to lamina IV
VI Zone at the base of dorsal horn
VII Intermediate zone
VIII Zone in the ventral horn (restricted to medial aspect
in cervical and lumbar enlargements)
IX Medial and lateral anterior horn cell columns.
X cells surrounding the central canal
PATHWAYS IN THE SPINAL CORDAscending (afferent) pathways Descending (efferent)
pathways
Descending tracts Five descending systems exert tonic effects on the motor
neurons.
The vestibulospinal tract and The medial reticulospinal
tract tend to facilitate the motor neurons of antigravity
muscles.
The corticospinal tract, The corticorubrospinal tract, and
The lateral reticulospinal tract inhibit the antigravity
muscles and facilitate the antagonists.
VESTIBULOSPINAL TRACT
RETICULOSPINAL TRACT
RUBROSPINAL TRACT TECTOSPINAL TRACT
LATERAL SPINOTHALAMIC TRACT
ANTERIOR SPINOTHALAMIC TRACT
SPINOCEREBELLAR TRACT
HEMISECTION OF SPINAL CORD
(BROWN-SEQUARD SYNDROME)
Central cord syndrome
Seen in syringomyelia
Interrupt fibres of lateral
spinothalamic tract that
passes in front of the
central canal.
sensory dissociation
Arterial Supply to the Spinal Cord
Anterior spinal artery:
ORIGIN: Branches of right and left vertebral arteries in
the upper cervical canal.
COURSE: runs caudally in the anterior median fissure.
TERMINATION: filum terminale
SUPPLIES: Anterior two third of the cord
Two posterior spinal arteries:
ORIGIN : Branched from either 1. Vertebral 2.Posterior inferior cerebellar arteries.
COURSE: Runs down in the posterolateral sulcus divides into two collateral arteries medial and lateral along the posterior nerve roots.
These communicate around the cord forming pial plexus arterial vaso corona/arteriae coronae.
SUPPLIES :Posterior one third of the cord
Segmental arteries:
Branches of Deep cervical, Ascending cervical, Intercostal and Lumbar
Segmental arterial feeders reach the cord as anterior and posterior radicular arteries.
ANTERIOR RADICULAR ARTERIES: Larger and less in number.
POSTERIOR RADICULAR ARTERIES: Smaller and more in number.
Great anterior medullary artery of Adamkiewicz-arises from aorta at T12 or L1 vertebral level unilateral left side
Anterior Spinal Artery Syndrome
-Back or neck pain of sudden onset
-Rapidly progressive flaccid and areflexic paraplegia
-Loss of pain and temperature to a sensory level
-Preservation of proprioception and vibration sensation
-Urinary incontinence
Posterior spinal artery syndrome
-Loss of proprioception and vibratory sense
-Preserved pain and temperature sensation
-Loss of myotatic and cutaneous reflexes below involved
segment
-Absence of motor deficits
VENOUS DRAINAGE
Two median longitudinal
Two anterolaterlal
Two posterolateral
Drain below through internal vertebral venous plexus into
the vertebral posterior intercostal, lumbar, and lateral
sacral veins.
And drain above into the basilar venous plexus.
THANK YOU
Referrences Localization in clinical neurology by Paul W. Brazis 6th
edition
Bradley’s Neurolgy in clinical practice 6th edition
DeJong's The Neurologic Examination, 6th Edition
Textbook of Human Neuroanatomy by Inderbir Singh 9th
edition
Anatomy and Physiology of the Spinal Cord. Madame
Curie Bioscience Database