Postural Reflexes

Overview

• Automatic movements controlling equilibration.
• Combat gravity effects during upright posture and movement.
• Origin: Higher centers including Midbrain, Basal Ganglia, and Cortex.
• Pattern: Appear during infancy; persist throughout life.
• Differentiates from primitive reflexes (present at birth, disappear over time).
• Function: Provide basis for voluntary movement, posture, and balance.

Classification and Timeline

Broadly classified into three groups based on function and chronological appearance.

Reflex Type	Function	Appearance	Clinical Significance
Righting Reflexes	Orient head in space; align body with head	Birth – 6 months	Pre-requisite for head control and rolling.
Protective (Propping)	Protect body from injury during falls	6 – 9 months	Essential for independent sitting.
Equilibrium Reactions	Maintain balance when center of gravity shifts	6 months onwards	Essential for standing and walking.

Foundational Assessment: Postural Tone

Postural tone creates the required resistance to passive movement, serving as the prerequisite for postural reflexes.

• Traction Response: Pull infant to sitting position. Normal term infant shows slight head lag, then head falls forward. Severe lag indicates hypotonia.
• Vertical Suspension: Hold infant by axillae. Normal infant remains suspended with flexed lower extremities. Hypotonic infant slips through hands.
• Horizontal (Ventral) Suspension: Hold infant prone over hand. Normal infant raises head and flexes limbs. Hypotonic infant drapes over hand forming an inverted “U” shape.

Righting Reflexes

• Level of Control: Midbrain.
• Role: Maintain head in vertical position; align body segments.

Labyrinthine and Optical Righting

• Test: Blindfold child (Labyrinthine) or keep eyes open (Optical); suspend vertically and tilt.
• Response: Head orients to vertical axis.
• Timeline: Emerges 2–4 months.
• Significance:
  • Correlates directly with acquisition of head control.
  • Delay indicates general developmental delay or marked hypotonia.

Landau Reflex

• Test: Suspend infant horizontally in prone position.
• Response: Extension of head, trunk, and hips (“Airplane posture”).
• Timeline: Appears 3 months; peaks 6–8 months; disappears 12–24 months.
• Diagnostic Significance:
  • Hypotonia: Infant collapses into inverted “U” shape (Classic Approach to a floppy infant sign).
  • Hypertonia/Spasticity: Excessive extension or lower extremity scissoring.
  • Absence: Strong indicator of motor dysfunction (e.g., Cerebral Palsy).
  • Prognostication: Favorable prognostic sign for eventual standing.

Body-on-Body (BOB) and Neck-on-Body (NOB)

• Test: Rotate head to one side (NOB) or rotate hips (BOB).
• Response by Age:
  • Immature (0–4 months): Log rolling (body turns as a solid block).
  • Mature (6+ months): Segmental rolling (shoulders rotate, then pelvis follows).
• Significance: Segmental rolling indicates cortical maturation and ability to dissociate body parts. Essential prerequisite for crawling and walking.

Protective / Parachute Reactions

• Level of Control: Cortical.
• Trigger: Body displacement shifting center of gravity outside base of support.

Anterior Parachute

• Test: Suddenly thrust infant downwards towards surface while holding waist.
• Response: Extension of arms and opening of hands to break the fall.
• Timeline: Appears 6–8 months; fully developed 10–11 months; persists throughout life.
• Diagnostic Significance:
  • Asymmetry: Most sensitive sign for mild Hemiplegia. Affected arm extends slowly, fails to extend, or extends with fisted hand.
  • Absence: Indicates severe quadriparesis or severe cognitive delay. Also signals delayed walking.

Lateral and Posterior Propping

• Test: Displace body to shift center of gravity outside base of support.
• Response: Observe for spontaneous arm extension and propping to prevent falling.
• Timeline: Lateral appears 7 months; Posterior appears 9 months.
• Diagnostic Significance:
  • Determines readiness for independent sitting.
  • Child cannot sit safely unassisted until lateral propping is established (Tripod sitting).
  • Posterior propping allows child to pivot safely while sitting.

Equilibrium Reactions

• Level of Control: Cortical.
• Trigger: Subtle adjustments of trunk tone to maintain balance during supporting surface tilt.
• Test: Tilt child on rocker board or bed.
• Response: Curving of trunk against the tilt; extension of extremities on the uphill side to shift center of gravity back.
• Diagnostic Significance:
  • Absolute prerequisite for standing and walking.
  • Motor Discrepancy: Child exhibiting righting and protective reflexes but lacking equilibrium reactions may stand but will suffer frequent falls.

Clinical Utility and Diagnostics

Early Diagnosis of Cerebral Palsy (CP)

• Diagnosis relies heavily on the “Motor Quotient” (interplay of primitive vs. postural reflexes).
• Classic CP Pattern: Retention of Primitive Reflexes (e.g., ATNR, Moro) combined with Delayed or Absent Postural Reflexes.
• Clinical Example: 9-month-old infant with persistent Moro reflex and absent Parachute reflex possesses high probability of CP.

Localization of Neurological Lesions

• Hemiparesis: Asymmetry in Parachute or Placing reactions.
• Midbrain Damage: Absent Righting Reflexes.
• Cortical/Basal Ganglia Damage: Absent Equilibrium Reactions.

Neuromotor Prognostication

• Timely appearance of postural reflexes serves as a superior predictor of eventual ambulation compared to the mere disappearance of primitive reflexes.
• Presence of Landau reflex acts as a strong positive predictor for eventual standing capability.