Infant Reflexes and Muscle Tone Overview

Oct 23, 2024

Reflexes and Muscle Tone in Infants

Importance

  • Assessing neuromuscular status in infants is crucial.

Top Infant Reflexes to Know

1. Babinski Reflex

  • Age Range: 0 to 12 months
  • Description: Toes fan out when the sole or bottom of the foot is stroked.

2. Rooting or Sucking Reflex

  • Age Range: 0 to 4 months
  • Description: Sucking motion occurs when the side of the cheek or mouth is stroked.

3. Tonic Neck Reflex

  • Age Range: 0 to 4 months
  • Description: When placed on the back, the infant turns their head to one side, flexes the arm on the opposite side, and extends the arm the same direction they are facing.
  • Clinical Examples:
    • A 9-month-old is expected to still show the Babinski reflex.
    • Reflex assessed by stroking the outer sole of the foot: Babinski.
    • Rooting reflex assessed by stroking the cheeks of the newborn.
    • The tonic neck reflex involves an infant flexing the arm on the opposite side to which the head is turned.

Additional Reflexes

4. Moro Reflex (Startle Reflex)

  • Age Range: 0 to 4 months
  • Description: In response to a loud noise or sudden movement, the infant stretches out their arms and legs, then pulls them back.

5. Stepping Reflex (Walking/Dancing Reflex)

  • Age Range: 1 month+
  • Description: Seen when the baby is held upright or lightly touches the ground, resembling a walking or dancing motion.

6. Palmer Grasp

  • Age Range: 0 to 3 months
  • Description: Infants grasp any object placed in their palm.

7. Plantar Grasp

  • Age Range: 0 to 8 months
  • Description: Similar to the palmer grasp but involves curling toes around an object placed under them.

Muscle Tone

  • Normal Muscle Tone: Healthy muscles are never fully relaxed; infants typically have increased muscle tone and resist extremity movement.
  • Abnormal Muscle Tone:
    • Hypotonia: Decreased muscle tone that must be reported to the healthcare provider.
    • Head Lag: May indicate neurological abnormalities such as Down syndrome or spinal injury.

Study Tips

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