TRANSECTION OF THE SPINAL CORD 1 FINAL BY DR K AMBAREESHA

Spinal cord transection, a complete or partial severing of the spinal cord, results in a loss of motor and sensory function below the level of injury, often caused by significant trauma.

1. TRANSECTION OF SPINAL CORD Dr. K. Ambareesha ,. PhD Associate professor Physiology

2. Complete transection of spinal cord Spinal cord is completely separated from the higher centers Cause : Gunshot wounds, occlusion of blood vessel due to thrombosis

3. Effects of complete transection of spinal cord are described in following three stages: Stage of spinal shock Stage of reflex activity Stage of reflex failure

4. Transection 3 types: complete, incomplete and hemisection . A. Complete Transection of Spinal Cord immediate effects 1. Stage of spinal shock (or stage of flaccidity): Features Portion above the cut-unaffected; below the section: deprived of all activities. Duration of shock: 3 weeks Cause: Stoppage of tonic bombardment of spinal motor neurons by excitatory impulses in the descending pathway. Flaccid paralysis

5. Subnormal body temperature. Muscle tone: completely lost. All reflexes (superficial and deep): +++ ↓ or lost. All sensations below transection : lost. Urinary bladder and rectum: paralysed Penis: flaccid, erection impossible. BP ↓ s

6. Later effects (after 1 wk) 2. Stage of reflex activity Autonomic reflexes recover within days or weeks retention of urine (sphincter vesical recover very soon than detrusor muscle) paralysed blood vessel tone returns Muscle tone returns slowly, reflex in character → paraplegia in flexion (limbs adopt a position of flexion) spinal man cannot stand unsupported . No muscle wasting.

7. Paraplegia in flexion (A) and extension (B)

8. 3. Reflex (Failure) movements: return in approx. 2 weeks. Cause ( i ) Denervation hypersensitivity to the mediators; (ii) growing of collateral Features Abnormal Babinski response Mass reflex - advantage Deep (or tendon) reflexes: sluggish After 6 months, marked activity ↑ extensor reflexes. Coitus (sexual) reflex: absent.

9. B. Incomplete or Irregular Transection of the Spinal Cord Stage of spinal shock: As above Stage of reflex activity: → paraplegia in extension . Features All features of UMNL Involuntary movement: infrequent. Reflex movements ( i ) extensor thrust reflex: positive; (ii) Crossed extensor reflex: positive.

10. C. Hemi section of the spinal cord: Brown Sequard Syndrome (ANS functions remain normal) On the same side On the opposite side Below the level of hemisection Extensive motor loss of UMNL type Little sensory loss Below the level of hemisection Either no paralysis or paralysis of few muscles of UMNL type. Extensive sensory loss At the level of hemisection Sensory changes LMNL type Motor changes At the level of hemisection Sensory changes: Some loss of pain Motor changes : Nil 3. Above the level of hemisection A band of hyperaesthesia 3. Above the level of hemisection Hyperaesthesia may be referred .

11. Hemisection of the spinal cord

12. Brown sequard syndrome i.e. motor & sensory changes below the level of hemisection

13. Sensory Disturbances A. Syringomyelia ( Syrinx = cavity; myelia = S. cord) Cause: Extensive growth of neuroglial tissue round the central canal of the spinal cord with cavity formation. Common site: Cervical region

14. Tabes dorsalis (A) Pale dorsal columns; (B) Characteristic features of tabes dorsalis

15. Features Lightning pain (a) perforating ulcers at pressure points. anaesthesia round the anus, over legs, upper chest and hands. Charcot joint . Loss of position sense and vibration sense. Deep (or tendon) reflexes: lost. Marked disturbance of voluntary movements.

16. C. Disseminated (multiple) sclerosis Cause: Patchy widespread destruction of myelin in the CNS. Sign and symptoms manifest according to the ascending and descending pathways involved. (It is a crippling disease ).

17. Disseminated (multiple) sclerosis

18. 2. CEREBELLUM

19. Anatomical lobes:

20. Functional parts of the cerebellum

21. Intro Cerebellum is the largest part of the hindbrain and lies behind the pons and medulla oblongata separated by the IV ventricle. It consists of a narrow, worm like central body vermis , and two lateral lobes, the right and left cerebellar hemisphere. The cerebellum is connected with the brain stem by three peduncles: i . Inferior cerebellar peduncles—Between Cerebellum and medulla oblongata. ii. Middle cerebellar peduncles—Between Cerebellum and pons iii. Superior cerebellar peduncles—Between Cerebellum and midbrain

22. Phylogentic classification of cerebellum:  Archicerebellum  Paleocerebellum  Neo cerebellum Anatomical division of cerebellum:  Anterior lobe  Posterior lobe  Flocculonodular lobe Functional division of cerebellum:  Vestibulocerebellum  Spinocerebellum  Cerebrocerebellum

23. Functional divisions:  Vestibulocerebellum ( Flocculonodular lobe)  Spinocerebellum ( Vermis & intermediate zone)  Neocerebellum ( cerebrocerebellum )

24. Vestibulo cerebellum:  Connected to vestibular apparatus  Role in control of body posture, equilibrium & visual fixation Spinocerebellum :  Mainly connected to spinal cord Vermis : Controls muscle movements of axial body, neck, shoulder, hips  Maintains posture via vestibulospinal & reticulospinal pathways Intermediate zone: Control of muscular contraction of upper & lower limbs via corticospinal tract

25. Cerebrocerebellum :  Connected with pons and cerebral cortex  Concerned with overall planning and programming of sequential motor movements  Coordinates the timing and duration of contraction of different groups of muscles

26. Cerebellar cortex: It is arranged in three uniform layers. a . Outer molecular layer- consists of dendrites of purkinje cells b. Intermediate purkinje layer- consists of cell bodies of purkinje cells c . Inner granular layer- consists of granular and golgi cells

27. Functional unit of cerebellum. PF = Parallel fi bres , P = Purkinje cell, Gr = Granule cell, Go = Golgi cell, CF = Climbing fi bre .

28. Afferent input to cerebellar cortex: Climbing fibers – arises from inferior olivary nucleus and conveys proprioceptive impulses from different parts of the body to cerebellar cortex Mossy fibers- main afferent fibers to cerebellar cortex and deep cerebellar nuclei

29. Cerebellar nuclei: These are masses of grey matter scattered in white matter of cerebellum and has four nuclei on each side. a. Fastigial Nucleus: It is placed near the midline on the roof of IV ventricle. b. Emboliform nucleus: Lies below the above nuclei. c. Dentate nucleus: This crenated nuclei situated lateral to all other nuclei and is the largest of all

30. Cerebellar nuclei.

31. Afferents to cerebellum  Cortico - ponto cerebellar fibers  Dorsal spinocerebellar tract  Ventral spinocerebellar tract  Cuneo cerebellar fibers  Vestibule cerebellar fibers  Tecto cerebellar fibers

32. Afferent tracts to the cerebellum

33. Efferents from cerebellum:  Cerebello dentato rubro thalmocortical tract  Cerebello olivary tract  Cerebello rubr spinal tract  Fastigo bulbar tract

34. Connections

35. Functions

36. Pathways for cerebellar control of voluntary movements

37. Pathways of cerebellar error control of voluntary movements

38. Applied aspects: Cerebellar disorder: the characteristic symtoms are seen. No sensory loss or paralysis is seen 1. Ataxia 2. Scanning of speech 3. Intention tremor 4. Nystagmus 5. Asthenia 6. Atonia 7. Dysmetria 8. Decomposition 9. Drunken gait 10. Dysdiadochokinesia

39. CEREBELLAR LESION

40. Name the features of cerebellar lesion

41. Thank you