NeuroTeach 12 - Postural, righting, and primitive reflexes

 Postural, righting, and primitive reflexes

“from 'in utero' fear to ‘released’ inhibition”

American neurologist Abraham Myerson (1881-1948)


2) Posture “antigravity muscles contraction to maintain the erect posture” - lateral vestibular nucleus (Deiters's nucleus)


3) Righting
“Maintaining the orientation of the head to the body and of the head and body in space” - utricle - proprioceptive (tendon) - extereoceptive (surface and visual)



4) Clinical significance “order of myelination is related to the appearance/disappearance of postural and righting reflexes in pediatric patients” - myelination

5) Fear paralysis reflex

- freezing reaction - protective mechanism, response to perceived threat
- US
6) Moro (startle) reflex
- survival system - sudden stimulus - methods: head drop, baby drop, subcutaneous stimulus (epigastric - most sensitive) - auditory, only startle

7) Moro versus startle
Moro Initial – abduction and extension late – adduction and flexion (hands come to front) Startle response is like Moro, but “elbow remain flexed and hands closed”


8) Stepping reflex
“upright sole touch table cause reciprocal flexion and extension of leg simulating walking” - aka walking & dancing


9) Rooting & sucking reflex
“touching mouth cause ipsilateral bottom lip lower, tongue moves, head turn” - to find food - stimulation rooting (corner mouth) & sucking (roof mouth)


10) Babkin (hand-mouth) reflex
“pressure both palms cause mouth open, flex neck, close eyes” - to stimulate the breast - discovered by Russian physiologist Boris Petrovitch Babkin (1877-1950)


11) Palmar (grasp) reflex
“object in open palm cause grasp” - to assist grasp - motor skills, dexterity, handwriting


12) Asymmetrical tonic neck reflex
“turning head toward 1 shoulder ⬆️ ipsi extensor tonus and ⬆️ opposite flexor tonus” - assist birth, cross pattern movements - aka fencing posture - precursor hand/eye coord - press vertebra ➡️relax


13) Lazaru’s sign
“most dramatic tonic neck reflex” - turn, flex, ext of head cause flex arms over the chest & legs in ext - upper brainstem, thalamodiencephalic level - brain death


14) Swimming reflex
“begins to paddle and kick in a swimming motion when face down in a pool of water” - risky procedure, infant swallow water


15) Galant reflex
“swing pelvis towards the side that was stroked (paravertebral) ventral suspension” - spinal Galant, Galant’s infantile - assist birth, crawling, creeping - discovered by Russian neurologist Johann Susman Galant


16) Carbonell-Perez reflex
“stroking along spine cause flexion of arm&legs w/ neck extension” Figure from Carbonell and Perez, 1955


17) Symmetrical tonic neck reflex
- prepare for crawling - if retained: poor posture, W-sitting, impairs vision focus change from far to close


18) Parachute reflex
“baby's body is rotated quickly to face forward (as in falling), he will extend his arms forward” - no vision-dependent


19) Landau reflex
“infants when held horizontally in air in prone position, he will maintain a convex arc” - poor in floppy baby syndrome - hypertonic in opisthotonos


20) Plantar (grasp) reflex
- plantar reflex (normal extension) vs plantar grasp reflex (grasping) - development of corticospinal tract - integrated 9-10 months


21) Tonic labyrinthine reflex
“tilting the head back while lying on the back causes the back to stiffen and even arch backwards” - ‘gravity sense’ - unintegrated: abnormal extension pattern or extensor tone


22) Neck righting reflex
“head is turned toward one side results in rotation toward that side” - variation of tonic neck reflex - integrate, can arise directly w/o first turning on its abdomen


23) Placing reflex
“infant held vertically, touching the dorsum of each foot to the side of the examining table causes placement of the foot on top of the table” - tibial stimulus - integrated: 1 year - assess proprioception


24) Traction response
“grasp at wrist and pull to sit observing head control”


25) Adduction response
“hold leg in extension and sole is stroked cause other leg 1st withdraw&extend toes, after bring towards the side of stimulus” - withdrawal response, in stimulated foot


26) Facial reflexes
- nasal reflex (stimulation of nasal cavity lead to apnea) - blink reflex (bright light close eyes) - doll’s eye reflex (disappear within 2 weeks) - auditory orienting reflex (sudden cause blink, quieter eye&head turning)

27) Oral reflexes
- rooting reflex - sucking reflex - swallowing reflex - gag reflex (developed 19th week in utero) - cry reflex (1st verbal communication)

28) Frontal release signs
- primitive reflexes - area of brain dysfunction - frontal lobe is responsible for some inhibitory effect - condition disrupts inhibitory pathways, reflex is ‘released’ from inhibition

29) Palmar reflex
“stroking the palm of the hand is followed by flexion of fingers or closing of the hand”

- signifies damage to the frontal lobe of the opposite side


30) Palmomental reflex
“stroking on the thenar eminence of the hand causes contraction of mentalis muscles of the chin” - Marinesco-Radovici sign, Kinn reflex, Marinesco Reflex - frontal & temporal lobes - no sided-lesion - AD, PD, ALS


31) Rooting & sucking reflex
“look at tongue” - bulldog or chewing reflex, tongue blade inserted into mouth produces clenching of the jaw that holds the blade


32) Snout reflex
“tapping of closed lips cause pursing of lips” - aka orbicularis oris reflex - diffuse brain damage - exaggerated – ‘wolfing’ reflex


33) Glabellar reflex
“unable to resist blinking when tapped repetitively on the glabella” - aka Myerson's sign, orbicularis oculi - PD and early dementia - discovered by American neurologist Abraham Myerson (1881-1948)


34) Head retraction reflex
“reflex hammer tap below nose with head bent forward cause backward jerk of the head” - bilateral pyramidal lesions, ALS - Niemann-Pick Type C 10.1002/mdc3.12976 via: Mov Disord Clin Pract


35) Corneomandibular reflex
“stimulation of cornea causes contralateral movement of the mandible” - usually associated movement > reflex - supranuclear interruption of ipsilateral corticotrigeminal tract - ALS