Final answer:
The most suitable approach for a 12-month-old's physical examination is to have the infant sit in the parent's lap, which provides comfort and security. Developmental milestones at this age include beginning to stand and possibly walk, as well as showing cognitive development through interaction with the environment and people.
Step-by-step explanation:
The best approach to the physical examination for Keith, a 12-month-old infant, during his well-infant examination would be to have the infant sit in the parent's lap to complete as much of the examination as possible. This approach is generally preferred because it helps to keep the infant calm and secure, as the presence and proximity of the parent can provide comfort during the examination. Additionally, it allows the healthcare provider to assess the involvement and interaction between the child and parent, which is an important part of a well-infant examination.
With regard to specific developmental milestones, by the age of 12 months, infants often begin to stand while holding onto furniture or someone's hand, and some may start walking. At this age, infants typically demonstrate cognitive development by watching where toys go when dropped, and they may cooperate with dressing and communicate through babbling or simple gestures like waving.
It is important for healthcare professionals to be attentive to the infant's sensory abilities, reflexes, and overall growth during infancy, as these can provide critical insights into the child's developmental progress.