Final answer:
The statement that the first part of the Moro reflex is characterized by extension and abduction rather than adduction is true. The Moro reflex is a neonatal reflex which shows an infant spreading out the arms (abduction) and then bringing them back in (adduction).
Step-by-step explanation:
The statement that extension and abduction, not adduction, is the first part of the Moro reflex is true. The Moro reflex is an automatic reaction in infants and is characterized by three distinct components:
- The infant suddenly spreads out the arms (abduction), moving them laterally away from the midline of the body.
- The arms are then brought back in (adduction) toward the body.
- This is often accompanied by crying.
Therefore, the initial movement in the Moro reflex is abduction, not adduction. This reflex is part of the infant's instinctive behaviors and is present from birth until about three to four months of age.
The Moro reflex, observed in infants, unfolds in three sequential stages. First, the infant instinctively extends and abducts their arms, moving them outward from the body's midline. Subsequently, the arms undergo adduction, returning towards the body. This reflex is often accompanied by crying, emphasizing its involuntary nature.
This automatic response is integral to an infant's instinctive behaviors and typically persists from birth until approximately three to four months of age. Crucially, the initial phase of the Moro reflex involves abduction, underscoring the orchestrated and innate nature of this early developmental response.