This document describes the different tracts of the spinal cord, dividing them into short tracts within the spinal cord, and long tracts connecting the spinal cord to other parts of the central nervous system. The long tracts are further divided into ascending tracts traveling from spinal cord to brain, and descending tracts traveling from brain to spinal cord. The descending tracts are then described in more detail, including the pyramidal, extrapyramidal, vestibular, reticular, tectospinal, rubrospinal, and olivospinal tracts.

2. By Definition these are
 Bundle or groups of nerve fibers
used for spinal cord connections
 Sub classed as..
 1- Short tracts.
 2-Long Tracts.

4. Short Tracts are just within the
spinal cord for its connections
with itself.
Subclassed as :
1- associative (Connects
adjecent parts of same side
spinal cord)

5. 2- Commissural connects
opposite halves of spinal cord.

6. LONG TRACTS connects spinal
cord to other parts of CNS .
Subdivided as
1- Ascending tracts (Ascend
fronm spinal cord to brain)
2-Decending tracts(Decends
from brain to spinal cord)

7. THE DESCENDING TRACTS
OF SPINAL CORD
 These tracts descends from brain to spinal
cord and carry motor information.
 These are further divided as
 1- Pyramidal tracts.
 2- Extrapyramidal tracts.

8. PYRAMIDAL TRACTS
 Pyramidal tracts or corticospinal tracts originate from
motor area of cerebral cortex and extend to the
thoracic region of spinal cord. Just a little of them
goes to sacral region.
 Further divided as
 1- Anterior
 2- Lateral

9.  Diameter of each nerve fiber is 4-22 microns
 They are presnt since birth but later in old age they
may dissapear causing automatic shivering
movements.
 ORIGIN : ; these originate from motor area of cerebral
cortex from following cells
 Betz Cells – Area 4 (30%)
 Premotor area 6 (30%)
 Somatosensory area of parietal lobe (39%)
 Other parts of frontal lobe. (1%)


10.  Course :
 Crona radiata (Fan like apparatus)
 Internal Capsul (passage bw thalamus andcaudate
nucleus)
 Pons
 M.O
 Spinal cord

17.  Termination :
 Motor neurons of gray horn. Upto mid thoracic level and
least to sacral region.
 Function :
 voluntary movements
 Fine and skilled movements of body.
 Effect of Lesions :
 Voluntary movements
 Muscle tone
 Reflexes
 Weakened muscles
 One body side paralysis
 Four limbs paralysis

18.  EXTRAPYRAMIDAL TRACTS :
 Other than pyramidal tracts.
 Medial longitudinal Fasciculus :
 Descends through posterior part of anterior white column.
 Origin : Takes origin from 4 different sites.
1. Vestibular nuclei (Present in medulla – cranial nuceli for
vestibular nerve)
2. Reticular Formation ( Region of pons involved in sleep wake
cycle)
3. Superior Colliculus (Area below thalamus – surrounds pineal
gland )
4. Internal cells of Cajal (pace maker cells of GIT that produce
Basal electrical rythem)

19.  Course : Directly enters the spinal cord from brain
stem and are well defined at cervical region only .
 Termination : they terminates on anterior motor
neurons either directly or indirectly via internuncial
neurons.
 Function : helps in reflex ocular movements and
movement of neck.
 Effect of lesion : Reflex ocular and neck movements
are effected.

20.  Anterior Vestibulospinal Tracts
 Situated in anterior white column along its periphery.
 Origin: Arise from medial vestibular nuclei of M.O .
and extend upto thoracic region.
 Termination : anterior motor neurons directly or
indirectly.
 Function : Concerned with adjustment of position of
head and body during angular and linear motion.

21. Lateral vestibulospinal tracts
 Situated in anterior part of lateral white matter.
 Origin : Lateral vestibular nuclei of Medulla – Dieter’s
nucleus.
 Extent : present throughout the spinal cord.
 Course : Descends from Dieter’s nucleus directly in the
spinal cord to its lateral white column with few being
crossed before reaching spinal cord.
 Termination : Anterior Motor neurons directly or
indirectly.
 Function : tht of previous one.
 Effect of lesion : adjustment of head and body remains no
more coordinated during acceleration.

22.  4-Reticulospinal Tracts :

 Situated in anterior white column , posterior to anterior
vestibulospinal tracts .
 Origin : Reticular formation of pons and medulla.
 Course : . pontine are uncrossed and descends in medial part of
anterior column.

 From medulla are crossed and uncrossed (mixed) and descends
to anterior parts of anterior and lateral column.

 Extention : upto thoracic segments.
 Termination : Gamma motor neurons of anterior gray horn.
 Function : Controls diameter of blood vessels , breathing ,
movementn maintenance .
 Effect of lesions : disturbed movement, breathing and b.p.

23.  Tectospinal tract :
 Situated in anterior white column of spinal tract .
 Origin : superior colliculous of mid brain.
 Extention : lower cervical segments.
 Course : after taking origin, it cross the mid line and
at decussation level and then descends directly in to
spinal cord.
 Termination : Anterior motor neurons , directly or
indirectly.
 Function : movement of head in response to audio and
video stimuli.
 Effect of Lesion : function is disturbed.

24.  Rubrospinal tract :
 Present in lateral white column of spinal cord.
 Origin : Red nucleus of mid brain (Larg cell area –
controls crawling of babies)
 Extent : upto thoracic level of spinal cord .
 Course : after taking origin, it cross the mid line and at
decussation level and then descends directly in to
spinal cord through reticular formation of midbrain .
 Termination : terminates at anterior motor neurons
only indirectly.
 Function: Facilitates the function of flexor joints.

25.  Olivospinal tract :
 Situated in lateral white column of spinal cord .
 Origin : Medulla oblongata – inferior olivary nucleus.
 Course : Descends directly to spinal cord from M.O .
 Termination : Anterior motor neurons.
 Function : Reflex movements of joints.
 Effect of lesion : Reflex movement of joints is lost .
