The document describes the anatomy and structures of the spinal cord. It discusses: - The spinal cord's position in the vertebral canal and its extensions above into the medulla oblongata and below into the conus medullaris and filum terminale. - The external features including two enlargements known as the cervical and lumbosacral enlargements. - Internal structures such as the gray matter containing the anterior, posterior and lateral horns, and the white matter containing ascending, descending and proprioceptive tracts that transmit sensory and motor signals. - Ascending tracts that transmit sensory information to the brain and descending tracts that convey motor commands from the brain. -

1. MEDULLA SPINALIS
Muh.Iqbal Basri
Department of Anatomy
Hasanuddin University
1

2. The Spinal Cord
Position
 Lies in vertebral canal
 Continuous above with medulla
oblongata at level of foramen
magnum
 Ends below at lower border of
L1 in adult; at birth at level of
L3
 Ascensus medulla
2

3. External features
 A long cylindrical structure and
slightly flattened anteroposteriorly,
 Conus medullaris
 Filum terminale
 Cauda equina
 Two enlargements (intumescentia)
Cervical enlargement :
corresponds to the C4 to the T1
segments
Lumbosacral enlargement :
corresponds to the L2 to the S3
segments
3

4. 4

5. 5

6. Fissure and sulci
 Anterior median fissure
 Posterior median sulcus
 Anterolateral sulcus － anterior (motor) roots emerge serially
 Posterolateral sulcus － posterior (sensory) roots enter spinal cord,
each bear a spinal ganglion which constitutes the first cell-station of
the sensory nerves
6

7. 7

8. 8

9. 9

10. 10

11. 11

12. 12

13. 13

14. Relationship of segments
of spinal cord to vertebrae
 A portion of the cord that gives
rise to a pair of spinal nerve
constitutes a segment.
 There are 31 segments
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
14

15. Relationship of segments of spinal cord to vertebrae
Spinal segments Vertebral levels (spines)
Upper cervical region (C1~C4) = C1 ~ C4
Lower cervical and upper thoracic
region (C5~T4)
— 1 = C4 ~ T3
Middle thoracic region (T5~T8) — 2 = T3 ~ T6
Lower thoracic region (T9~T12) — 3 = T6 ~ T9
Lumber segments = T10 ~ T12
Sacral and coccygeal segments = L1
15

16. Internal structures
 Central canal
 Gray matter
 Anterior horn (column)
 Posterior horn (column)
 Intermediate zone
 Lateral horn (column)
 Anterior gray commissures
 Posterior gray commissures
 White matter
 Anterior funiculus
 lateral funiculus
 Posterior funiculus
 Anterior white commisure
16

17. Posterior horn (column):
 Marginal layer
 Substantia gelatinosa
 Nucleus proprius
 Nucleus thoraccus
in segments C8~L3
17

18. Intermediate zone
 Intermediolateral nucleus
(lateral horn or column): lies in
segments T1~L3, containing
sympathetic preganglionic
neurons
 Sacral parasympathetic
nucleus: lies in segments S2~S4,
containing parasympathetic
preganglionic neurons
 Intermediomedial nucleus : for
sensation of viscera
18

19. Anterior horn (column): contain motor
neurons
 Three kinds of neuron
 α-motor neuron: larger multipolar
neuron, innervates extrafusal fibers of
skeletal m., producing contraction of m.
 γ-motor neuron: smaller neuron,
innervates intrafusal fibers regulating
muscular tonus
 Renshaw’s cell: negative feedback
mechanism
 Two groups of nuclei
 Medial nuclear group: present in most
segments of spinal cord, innervating axial
muscles
 Lateral nuclear group: present only in
cervical and lumbosacral enlargements,
innervating limb muscles
19

20. Rexed’s lamina
 posterior horn is formed
by lamina toⅠ Ⅵ ；
 Intermediate zone
corresponding to
lamina Ⅶ ；
 Anterior horn is
composed laminae Ⅷ
and Ⅸ ；
 lamina is the grayⅩ
matter surrounding the
central canal.
20

21. Important Subdivision of Spinal Cord Gray Matter
Region Lamina Nucleus
Posterior horn Ⅰ Marginal layer
Ⅱ Substantia gelatinosa
Ⅲ, Ⅳ Nucleus proprius
Intermediate zone Ⅶ Nucleus thoracicus (C8~L3)
Ⅶ Intermediolateral nucleus (T1~L3)
Ⅶ Sacral parasympathetic nucleus (S2~S4)
Ⅶ Intermediomedial nucleus
Anterior horn Ⅸ Motor neuron
21

22. White matter
White matter contains three kinds of fibers:
ascending, descending, and fasciculus proprius
22

23. Ascending tracts
Fasciculus cuneatus
Fasciculus gracilis
Posterior spinocerebellar tract
Anterior spinocerebellar tract
Spinothalamic tract
23

24. 24

25. 25

26. Ascending tracts
Tract Site of origin Funiculus Termination Function
Fasciculus
gracilis
Spinal ganglia
below segment
T5
Posterior Gracile
nucleus
Convey
proprioceptive
and fine touch
sensation of
trunk and limbsFasciculus
cuneatus
Spinal ganglia
above segment
T4
Cuneate
nucleus
Posterior
spinocerebellar
Homolateral
nucleus
thoracicus
Lateral Cerebellum Unconscious
proprioception
from lower limb
and lower
portion of trunkAnterior
spinocerebellar
Contralateral
Laminae
Ⅴ~Ⅶ
Spinothalamic Laminae ,Ⅰ
Ⅳ~Ⅶ
Lateral
and
anterior
Dorsal
thalamus
Pain,
temperature and
simple touch
sensation of
trunk and limbs
26

27. Descending tracts
Lateral corticospinal tract
Anterior corticospinal tract
Rubrospinal tract
Vestibulospinal tract
Reticulospinal tract
Medial longitudinal fasciculusTectospinal tract
Fasciculus proprius
27

28. 28

29. Descending tracts
Tract Site of origin Funiculus Termination Function
Lateral
corticospinal
Cerebral cortex Lateral Laminae
Ⅳ~Ⅸ
anterior
horn
Voluntary movement
Anterior
corticospinal
Cerebral cortex Anterior
Rubrospinal Red nucleus Lateral Laminae
Ⅶ~Ⅶ
Excitatory of flexors
Vestibulospinal Homolateral
vestibular
nuclei
Anterior Laminae
Ⅶ~Ⅷ
Excitatory of extensors
Reticulospinal Reticular
formation
Anterior
and lateral
Laminae
Ⅶ~Ⅷ
Voluntary movement
Medial
longitudinal
fasciculus
Vestibular
nuclei
Anterior Laminae
Ⅶ~Ⅷ
Coordinate neck with eye
movement
Tectospinal Superior
colliculus
Anterior Laminae
Ⅵ~Ⅷ
Fasciculus
proprius
Spinal cord Anterior,
lateral and
posterior
Spinal cord Intrinsic reflex
mechanism of spinal cord
29

30. 30

31. Main functions of spinal cord
 Conduction of excitations
 Reflex activity
31

32. 32

33. TABLE : TRACTUS ASCENDENS, DESCENDENS and
ASCENDENS+DESCENDENS
FUNICULUS ASCENDENS DESCENDENS ASCENDENS+DE
SCENDENS
ANTERIOR
1. Tractus
Spinothalamicus
Anterior
1. Tractus
Corticospinalis
Anterior
2. Tractus
Vestibulospinalis
3. Tractus
Reticulospinalis
4. Tractus
Tectospinalis
1. Fasciculus
Proprius Anterior
2. Fasciculus
Septomarginalis
Anterior
33

34. TABLE : TRACTUS ASCENDENS, DESCENDENS and
ASCENDENS+DESCENDENS
FUNICULUS ASCENDENS DESCENDENS ASCENDENS+DE
SCENDENS
LATERALIS
1. Tractus
Spinocerebellari
s Ventralis
2. Tractus
Spinocerebellari
s Dorsalis
3. Tractus
Spinothalamicus
Lateralis
4. Tractus
Spinotectalis
1. Tractus
Corticospinalis
Lateralis
2. Tractus
Olivospinalis
1. Fasciculus
Propius Lateralis
34

35. TABLE : TRACTUS ASCENDENS, DESCENDENS dan
ASCENDENS+DESCENDENS
FUNICULUS ASCENDENS DESCENDENS ASCENDENS+DE
SCENDENS
POSTERIOR
1. Fasciculus
Gracilis
2. Fasciculus
Cuneatus
1. Fasciculus
Propius
Posterior
2. Fasciculus
Interfascicularis
Propius (a,b,c,d)
35
Keterangan :
A = Coma Schultze
B = Tractus Septomarginalis (T bawah)
C = Area Ovalis Flechsig (L)
D = Trigonum Philipe Gombault (S)

36. 36

37.  TRACTUS/FASCICULUS
1. Tractus Spinothalamicus Anterior (touch + press)
2. Tractus Spinothalamicus Lateralis (pain + thermal)
3. Tractus Spinocerebellaris Ant/Ventral (muscle
tones+ tendo)
4. Tractus Spinocerebellaris Post/Dorsal (muscle
tones+ tendo)
5. Tractus Corticospinalis Ant/Lat (motoric)
6. Fasciculus Cuneatus
7. Fasciculus Gracilis
37
(position, movement,
discrimination,vibration)

38. 38

39. 39