LMNL AND UMNL

Question 1

بسم الله الرحمن الرحيم وبه نستعين
Mention casuses of LMNL AND EX

Answer 1

Causes:
Damage to Alpha motor neurons in AHCs and their axons supplying muscles
Damage to Cranial nerve nuceli and their axons supplying muscles
Ex:
Poliomyelitis
DM ,Alcoholism and Berberi thiamin def
?Myathenia gravis NMJ

Question 2

illustrate the effects of LMNL

Answer 2

PRA Paralysis + reflexes+atrophy
-Paralysis : Localized Ipsilateral Paralysis of muscle or group of muscles supplied by this nerve !
Regenration may occur if distance between 2 ends is below 2mm
_________________________
Reflexes loss of all reflexes related to muscles due to interrupted reflex arc :
1-muscle tone = flaccid paralysis
2-dEEp reflexes = areflexia
3-superficial reflexes lost
___________________________________________
Atrophy of the muscle due to
No Voluntary of Reflex movments
The degenrated nerve no longer produces trophic factor for metabolism in muscles
____________________________________________
May occur:
Fasficulations : felt + seen ! due to pathological discharge of Ach from degenrated nerve and the muscle is not yet atrphied
Fibrillation felt not seen due to Denervation hypersneistivity and contraction of Indivudal fibers that hasn’t yet been atrophied
____________________________________

Question 3

Most common reason for UMNL ?

Answer 3

Hemmorhage or thrombosis in the internal capsule

Question 4

Mentio Causes of the UMNL

Answer 4

1-Damage to motor cortec neurons
2-damage to pyramidal and extrapyramidal tracts

Question 5

Mention effects of UMNL

Answer 5

Paralysis :
Contralateral hemiplegia Improved by ability to do gross movments but lost fine movement of fingers Due to
Ipsilateral Corticospinal tracts - ExtraPyramidal tracts
If cut was in the pyramidal tract after meduaal after crossing it is called ipislateral paralysis the patient can move with gait called circumduction
___________________________________________
Reflexes :
SR and Muscles tone : There is Hypertonia and hyperreflexia why? becasuse of the supraspinal centers controlling y motor neurons affected so no discharge from inhibitory reticular formation but the pacemaker Facilitatory reticular formation activate y motor neruon more and more casuing increasing sensitivity of the muscle spindle to strech and incrasing a neurons dischargre so the tone ;; muscle enter what is called spasiticity and it is called Clasp Knife spasticity why ?
due to Alternative Stretch-incerse stretchr reflexes as a cycle as Relaxation or release followed the intial resistance
-Tendo jerks deep reflexs: hyper reflexia due to hypertonia becasue of strong y neurons discharge and so stertch activates afferetns more and alpha motor neurons more and more
Clonus : Oscillitatory jerks due to Stretch - inverse stretch reflexes cycles repeated in patella and ankle
appears when hypertonic muscles subjected to Sustained Stretch

-superficial reflexes :-Loss of abdominal and cremastric reflexes
Plantar reflex + babinski sign
____________________________-
Muscle state :
Minimal dissuse atrophy
as Reflexes are intact
and The LMN contiune dischargin Trophic factorss for Muscle metabolism

Question 6

First 2 week of UMNL
Acute UMNL decribe?

Answer 6

-Contralateral flaccid paralysis
loss of all reflexes
-so it is similar to LMNL except
Wide spread
+Babinski

Question 7

Spasiticity is called

Answer 7

Gamma rigidity

Question 8

الحمدلله رب العالمين