A 2-year-old girl presents to the pediatrician with her mother for a routine well-child visit. Her mother is concerned that the patient is a picky eater and refuses to eat vegetables. She drinks milk with meals and has juice sparingly. She goes to sleep easily at night and usually sleeps for 11-12 hours. The patient has trouble falling asleep for naps but does nap for 1-2 hours a few times per week. She is doing well in daycare and enjoys parallel play with the other children. Her mother reports that she can walk downstairs with both feet on each step. She has a vocabulary of 10-25 words that she uses in the form of 1 word commands. She is in the 42nd percentile for height and 48th percentile for weight, which is consistent with her growth curves. Her temperature is 98.6°F (37°C), blood pressure is 92/56 mmHg, pulse is 106/min, and respirations are 23/min. On physical exam, she appears well nourished. She can copy a line and throw a ball. She can follow the command to “give me the ball and then close the door.” Which of the following is abnormal in this patient?
Fine motor skills
Social and receptive language skills
This child is developmentally normal
Expressive language skills
Expressive language skills
This child is meeting her milestones in every category but expressive language. By 2 years of age, a child should have a vocabulary of over 50 words and be using 2-word phrases.

Assessing whether a child is meeting developmental milestones is important for identifying delays and enabling early intervention. In the gross motor category, a 2-year-old child should be able to jump and walk both up and down stairs with both feet on each step. In the fine motor category, a child should be able to copy a line and build a tower of 6 cubes. In the expressive language category, a child should have a vocabulary of over 50 words and be using 2-word phrases. In the social category, a child should participate in parallel play and be able to follow 2-step commands. Detecting a persistent developmental delay can be important as the first step in identifying a correctable condition such as hearing loss.

Scharf et al. review the evidence regarding the use of developmental milestones in assessing children. They discuss how early identification of delays can allow for referral to required services. They recommend paying special attention to sensory function to avoid missing a correctable hearing deficit.

Incorrect Answers:
Answer B: This child's fine motor skills are appropriate, as she can copy a line. She may also be able to copy a circle and make a tower of 6 cubes at this age.

Answer C: This child's gross motor skills are appropriate because she can walk downstairs with both feet on each step and throw a ball. She should also be able to jump and run at this age.

Answer D: This child's social and receptive language skills are developing appropriately since she can follow 2-step commands and engages in parallel play. She should also be able to point to pictures, body parts, and pieces of clothing when named.

Answer E: This child is not developmentally normal due to her deficits in expressive language. She should be using 2-word sentences and have a vocabulary of over 50 words. Her language should also be intelligible to strangers 50% of the time.

Bullet Summary:
By 2 years of age, a child should be able to walk up and down stairs, copy a line, follow a 2-step command, have a vocabulary of at least 50 words, and use 2-word phrases.