Hypertonicity in newborns

From birth to about 5–6 months, children often display a posture indicative of hypertonicity: fists are clenched; arms are bent at the elbows and held close to the body; legs are slightly spread and bent at the hips and knees; and the bent legs are drawn up towards the belly. This condition is known as physiological hypertonicity. It gradually decreases from top to bottom: trunk muscles around 2.5 months; upper limb muscles by 3 months; and lower limb muscles by 4 months. By 6 months, the tone in the antagonist muscles becomes balanced. Some infants may have higher muscle tone from birth, while others may have lower. Every child has some muscle tone. The most important factor to consider when assessing motor functions is the range of voluntary movements, meaning those that the child performs independently.