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By Definition these are Bundle or groups of nerve fibers used for spinal cord connections Sub classed as.. 1- Short tra...
Short Tracts are just within the spinal cord for its connections with itself.Subclassed as :1- associative (Connects ad...
2- Commissural connects opposite halves of spinal cord.
LONG TRACTS connects spinal cord to other parts of CNS .Subdivided as1- Ascending tracts (Ascend fronm spinal cord to b...
THE DESCENDING TRACTS     OF SPINAL CORD These tracts descends from brain to spinal  cord and carry motor information. T...
PYRAMIDAL TRACTS Pyramidal tracts or corticospinal tracts originate from  motor area of cerebral cortex and extend to the...
 Diameter of each nerve fiber is 4-22 microns They are presnt since birth but later in old age they    may dissapear cau...
 Course : Crona radiata (Fan like apparatus) Internal Capsul (passage bw thalamus andcaudate  nucleus) Pons M.O Spin...
 Termination : Motor neurons of gray horn. Upto mid thoracic level and    least to sacral region.   Function :   volun...
 EXTRAPYRAMIDAL TRACTS :                    Other than pyramidal tracts.                 Medial longitudinal Fasciculus...
 Course : Directly enters the spinal cord from brain  stem and are well defined at cervical region only . Termination : ...
 Anterior Vestibulospinal Tracts Situated in anterior white column along its periphery. Origin: Arise from medial vesti...
Lateral vestibulospinal tracts    Situated in anterior part of lateral white matter.   Origin : Lateral vestibular nucle...
 4-Reticulospinal Tracts : Situated in anterior white column , posterior to anterior  vestibulospinal tracts . Origin ...
 Tectospinal tract : Situated in anterior white column of spinal tract .  Origin : superior colliculous of mid brain. ...
 Rubrospinal tract : Present in lateral white column of spinal cord. Origin : Red nucleus of mid brain (Larg cell area ...
 Olivospinal tract : Situated in lateral white column of spinal cord . Origin : Medulla oblongata – inferior olivary nu...
Tracts of spinal cord (1)
Tracts of spinal cord (1)
Tracts of spinal cord (1)
Tracts of spinal cord (1)
Tracts of spinal cord (1)
Tracts of spinal cord (1)
Tracts of spinal cord (1)
Tracts of spinal cord (1)
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Tracts of spinal cord (1)

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Tracts of spinal cord (1)

  1. 1. By Definition these are Bundle or groups of nerve fibers used for spinal cord connections Sub classed as.. 1- Short tracts. 2-Long Tracts.
  2. 2. 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)
  3. 3. 2- Commissural connects opposite halves of spinal cord.
  4. 4. 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)
  5. 5. 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.
  6. 6. 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
  7. 7.  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%)
  8. 8.  Course : Crona radiata (Fan like apparatus) Internal Capsul (passage bw thalamus andcaudate nucleus) Pons M.O Spinal cord
  9. 9.  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
  10. 10.  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)
  11. 11.  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.
  12. 12.  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.
  13. 13. 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.
  14. 14.  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.
  15. 15.  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.
  16. 16.  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.
  17. 17.  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 .

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