Prep for USMLE

Username: Password:     Forgot Password

New:

Author	7 Posts
mesh Forum Guru Topics: 77 Posts: 401	Jun 05, 2005 - 8:17 PM       #1 why there is reversal of cutaneous reflex(babinski reflex, instead of flexor respose there is extensor respose) in case of UMN lesion. while the other cutaneous reflexes are lost. plz explain thanks.
Prep4USMLE.com Advertisement	Register To Remove Advertisement
Siam Forum Newbie Topics: 1 Posts: 2	Jun 19, 2005 - 8:21 PM       #2 Hmmm...what I got from "First AID" is UMN=everything up (tone,DTR,toes) but for cutaneous reflex...I don't know either
ssrpk Forum Junior Topics: 154 Posts: 2850	Jun 19, 2005 - 9:26 PM       #3 cutaneous reflexes are lost in case of UMN lesion
mesh Forum Guru Topics: 77 Posts: 401	Jun 19, 2005 - 9:50 PM       #4 yeah u r right but y there is an extensor response.if the reflex is lost then there should nt be ne response.( in this particular case we can say that it is altered nt lost).
ssrpk Forum Junior Topics: 154 Posts: 2850	Jun 19, 2005 - 11:24 PM       #5 well it's just the way the builtin inherent neural circuitry is made, which is quite evident in infants in whom the myelination process of the corticospinal spinal tracts are ongoing....therefore they elicit babinski's sign uptill one yr of life ,which becomes -ve thereafter for the rest of the life untill and unless UMN lesion takes place (back to the stone age) more importantly the details are'nt very well known!
alphahmed Forum Junior Topics: 6 Posts: 44	Jun 26, 2005 - 4:05 AM       #6 Well... I will try to guess... it is because of two elements for the Babinski's sign one is through UMN reflex which is normally dominent but when there is UMN leision it weakens leting the LMN reflex to occur... Am I right?
mesh Forum Guru Topics: 77 Posts: 401	Jun 26, 2005 - 11:49 AM       #7 it is nt only with babinski sign it is with all reflexes,that there r two elements one is UMN and other is LMN. UMN has downregulatory control over the reflexes...so when there is UMN lesion down regulation is lost and it leads to hyperreflexia.... and in case of LMN lesion the reflexes are lost .... but here in babinski there is nt hyperreflexia, reflex is present but the response is opposite.... I agree with ssrpk that details are nt very well known....

This thread is closed, so you cannot post a reply.

Similar forum topics Absent Babinski sign -ve ankle jerk and +ve babinski flu's / amide's / pyr's / clo's / phe's ...

Related resources Digitaldoc's blog - USMLEtoMD Pharmacology: Lippincott's Illustrated Reviews Biochemistry: Lippincott's Illustrated Reviews