The Spinal Cord:
-Gross and Microscopic Structures
-The spinal pathways
-Spinal reflexes
-Clinical correlates of the spinal cord
Naiphinich Kotchabhakdi Ph.D.
Neuro-Behavioural Biology Center, Institute of Science and Technology,
Mahidol University, Salaya, Nakornpathom 73170 Thailand
Email: scnkc@mahidol.ac.th
Sudarachnoid
space
Epidural
space
Cut edge
of dura
Pia
Spinal
nerve
1
3
5
8. Cut surface of posterior arch of atlas 9. Accessory nerve 10. Cuneate fasciculus
11. Gracile fasciculus 12. Posterior lateral sulcus 13. Denticulate ligament 14. Cut
edge of dura 15. Dorsal rootlets of 5th cervical nerve 16. Pia mater
4
6
7. Sympathetic trunk 8. Dorsal ramus of second thoracic nerve 9. Gray
communicant ramus 10. White communicant ramus
9. Femoral nerve 10. 5th lumbar spinal nerve ganglion 11. Obturator
nerve 12. 1st sacral dorsal foramen 13. Coccygeal nerve 14.Gluteus
maximus muscle 15. Termination of filum terminale
2
1. Vertebral artery 2. Vertebral veins 3. Posterior longitudinal ligament
4. 3rd cervical spinal ganglion 5. Ventral (anterior) median fissure with
anterior spinal artery 6. Subdural space 7. Denticulate ligament 8.
Dorsal rootlets of 3rd cervical nerve 9. Arachnoid trabeculae 10.
Arachnoid mater 11. Dura mater 12. Epidural fat 13. Spinous process of
3rd cervical vertebra
8. Epidural fat with internal vertebral venous plexus 9. Ligamentum flavum
10. 10th thoracic vertebra
7
8
Cauda equina
3
4
Dorsal root
(sensory)
+
Ventral root
(motor)
Spinal nerve
Segmentation of spinal cord
Cross section of C8 segment
DORSAL COLUMNS
DH
Approx. 1 cm
LATERAL
FUNICULUS
VH
VENTRAL
FUNICULUS
Intermediate
horn
DH: Dorsal horn
VH: Ventral horn
(White matter stained purple)
Central
canal
Note that the myelin stain used has made the white matter appear dark gray or black
9
10
1. Dorsal (posterior) median sulcus 2. Dorsal (posterior) intermediate sulcus 3.
Posterior median septum 4. Posterior funiculus 5. Posterior lateral sulcus 6. Sub
stantia gelatinosa 7. Dorsal (posterior) gray horn, nucleus proprius 8. Lateral
funiculus 9. Thoracic nucleus (dorsal nucleus of Clarke) 10. Intermediolateral
gray column 11. Ventral (anterior) gray horn 12. Ventral funiculus 13. Anterior
median fissure 14. Ventral white commissure 15. Intermediate gray substance
16. Medial longitudinal fasciculus 17. Anterior corticospinal tract 18. Tecto
spinal tract 19. Reticulospinal tract 20. Vestibulospinal tract 21. Spinotectal tract
22. Anterior spinocerebellar tract 23. Rubrospinal tract 24. Spinothalamic tract
25. Lateral corticospinal tract 26. Posterior spinocerebellar tract 27. Cuneate
fasciculus 28. Gracile fasciculus
5
Motoneurones in ventral horn
6
Rexed laminae
From Wikipedia, the free encyclopedia
The Rexed laminae comprise a system of ten
layers of grey matter (I-X), identified in the early 1950s
by Bror Rexed to label portions of the spinal cord.
Similar to Brodmann areas, they are defined by their
cellular structure rather than by their location, but
the location still remains reasonably consistent.
1. Rexed B (1952). "The cytoarchitectonic organization of the spinal cord
in the cat.". J Comp Neurol 96 (3): 414–95.
2. Rexed B (1954). "A cytoarchitectonic atlas of the spinal cord in the
cat.". J Comp Neurol 100 (2): 297–379.
Bror Rexed (June 19, 1914 - August 21, 2002) was a Swedish neuroscientist and
professor at Uppsala University. Internationally, he is best known today for his
development of the system now known as Rexed laminae
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REXED Laminae:
I-VI: Posterior/dorsal horn
Lamina I: posteromarginal nucleus
Laminae II/III: substantia gelatinosa
Laminae III/IV/V: nucleus proprius
Lamina VI: nucleus dorsalis
VII-IX: Anterior/ventral horn
Lamina VII: intermediolateral nucleus
Lamina VIII: motor interneurons
Lamina IX: motor neurons which also contain
the in the sacral region
Lamina X: neurons bordering Central canal
8
The Spinal pathways:
9
Dorsal Column System
(Fasiculus Gracilis and Cuneatus)
P o s t c e n tr a l
gyrus
T H A LA M U S
M ID
B R A IN
G r a c ile
fu n ic u l u s
PO NS
T o M a in S e n s o r y N u c le u s
o f T r i ge m in a l
M E D IA L
L E M N IS C U S
C un eate
f u n ic u l u s
M E D ULLA
C U N E A TE
NUC LEUS
G R A L IL E
N U C L EU S
lo w e r T
L
S
upper T
C
CUNEATE
F U N IC U L U S
( T6 -C 2 )
C E R V IC A L
G r a c il e
fu n i c u lu s
S
G R AC IL E
FU N IC U L U S
( S a c r a l- T 7 )
SACRAL
D O R S A L C O L U M N -M E D IA L L E M N IS C A L S Y S T E M
( F in e T o u c h , V ib r a tio n a n d J o in t P o s it io n )
10
Anterolateral System (ALS)
11
SpinoSpino-cerebellar
pathways
Dorsal Spinocerebellar Tract
12
Lateral
Corticospinal
Tract
13
14
Ventral Horn
15
Lateral (Intermediolateral) Horn
(preganglionic autonomics)
16
Sir Charles Scott Sherrington
Nobel Prize Winner in 1932
17
18
19
20
Myotactic reflex
21
Clinical correlates of the Spinal Cord:
Dermatomes
Spinal segments
22
Lesion of the Spinal Cord at T1
23
SPINAL CORD DISORDERS
SPINAL CORD
DISEASE
Vascular
Infectious
B12 , Biotin & Nutrition
Radiation
Tumor, Trauma & Toxic
Developmental & Hereditary
24
Poliomyelitis
25
SPINAL CORD DISORDERS
Spinal bifida
Spondylosis
Paraneoplastic
Arachnoiditis
Syringomyelia
Multiple Sclerosis & Myelitis
Systemmic disorders
Amyotrophic Lateral Sclerosis
Neural tube defects:
(Folic acid deficiency)
Spinal bifida
Meningocele
Meningo-myeolocele
Syringo-myelocele
Myeocele
Arnold-Chiari
Malformation
26
Syringomyelia
27
Amyotrophic
Lateral Sclerosis
(ALS)
Motor neurone
Disease
28
NeuroNeuro-syphilis
Tabes dorsalis
Syphilitic
Meningoencephalitis
29
30
Development of a Central Cord
Lesion
These pictures would be seen in syringomyelia, ependymoma, and intrinsic glioma
or astrocytorna.
The progress of the signs relates directly to
degree of involvement shown in the cord
sections
31
32
33
UMN Lesions (Pyramidal
Syndrome)
A. Paralyze movements in hemiplegic,
quadriplegic, or paraplegic distribution,
not individual muscles
B. Atrophy of disuse only (late and slight)
C. Hyperactive MSRs Clonus
D. Clasp-knife spasticity
E. Absent abdominal and cremasteric
reflexes
F. Extensor toe sign (Babinski sign)
34
Plantar Flexion
Dorsi- Flexion
LMN Lesions
A. Paralyze individual muscles or sets of
muscles in root or peripheral nerve
distribution
B. Atrophy of denervation (early and severe
C. Fasciculations and fibrillations
D. Hypoactive or absent MSRs Hypotonia
UMN = upper motoneuron; LMN = lower
motoneuron; MSRs = muscle stretch
reflexes
35