ORGANUM
Examination of these provides assessment of the functional integrity of the brainstem and basal ganglia. Many of these stereotyped motor responses are present at birth, symmetrical and disappear at 4 to 6 months - this indicates the normal maturation of descending inhibitory cerebral influences.
Grasp and rooting reflexes are inhibited by maturation of frontal lobes but may reappear later in life with acquired frontal lobes but may reappear later in life with acquired frontal lobe lesions. Asymmetry or persistence of the primitive reflexes may indicate focal brain or peripheral nerve lesions,
Reflex | Description | Age at appearance | Age at disappearance |
|---|---|---|---|
Moro | Light drop of head produces sudden extension followed by flexion of the arms and legs | Birth | 6 months |
Grasp | Placing finger in infant's palm results in flexing of infant's fingers | Birth | 6 months |
Rooting | Tactile stimulus about infant's mouth results in the mouth pursuing the stimulus | Birth | 4-6 months |
Trunk incurvation (Gallant) | Stroking the skin along the edge of vertebrae produces curvature of the spine with concavity on the side of the stroke | Birth | 4 months |
Placing | When dorsum of the foot is brought into contact with the edge of a surface, infant places foot on the surface | Birth | 4-6 months |
Asymmetrical tonic neck | With infant supine, turning of the head results in ipsilateral extension of arm and leg with flexion of opposite extremities in a 'fencing' posture | Birth | 3 months |
Parachute | Stroking lateral aspect of sole from the heel up results in dorsiflexion of the great toe and fanning of the remianing toes | Birth | 12-18 months |