Neurological examination of the infant
1) Posture and muscle tone
2) Primitive reflexes
3) Age invariable items.
Posture and muscle tone
1) Resting posture -observing the infant undressed. The infant should have flexion of the elbows, hips, and knees (varying with age). Hypertonia in the extremities decreases after 3 months of age, with the upper extremities then the lower extremities. At the same time, tone in the trunk and neck increases.Â
2) Passive tone - determining resistance of passive movements of the joints while the infant is awake and not crying. One can do this by flapping the hands and feet, and by other maneuvers. The scarf sign is where the arm is pulled across the chest and if the elbow passes the midline, then hypotonia is present.Â
3) Active tone - traction response up to 3 months of age. The infant's hands are held with the examiner's thumbs in the infant's palms, and the fingers around the wrists. The infant is slowly pulled to a sitting position. Normally the elbows flex and the neck raises the head. If hypotonia is present, then the head lags backward, then as the erect position is assumed, the head then drops forward. If hypertonia is present, the head is maintained backwards.
Primitive reflexes
-Present from the time of birth
 -Represents spinal reflexes until the infant becomes older and higher cortical functions suppress them.
Vertical suspension
The infant is suspended by holding the chest with both hands and lifting the patient in an upright position, with the legs dangling. Scissoring or hyperextension of the legs is seen spasticity is present; consider cerebral palsy
Segmental medullary reflexes
- Sucking reflex  -Afferent fibers of CN V and IX -efferent fibers of CN VII, IX, and XII.
Moro reflex
Head hyperextended, falling back about 3 centimeters in relation to the trunk. A normal response is seen when the infant opens his hands, extends and abducts the arms, and then brings them together, followed by a cry. It is present in all newborns and disappears before the age of 6 months.
Tonic neck response
This reflex can be elicited when the head is turned to the side while the rest of the body lies flat on the table. A normal response is extension of the arm and leg on the side that the head is turned, and flexion of the arm and leg on the opposite side (similar to a fencing stance). Abnormal responses occur when this response is sustained or if it occurs differently when the head is turned to the right or left (i.e., the response is not the same when tested on both sides). It usually disappears about 6 to 7 months of age.
Palmar and plantar grasp reflexes
They are performed by applying gentle pressure to the palm or sole. An abnormal response occurs when this response is absent before 2 to 3 months of age or asymmetric. The palmar grasp reflex should disappear by 6 months; the plantar by 9 to 10 months.
Parachute response
The infant is suspended horizontally with the face down, and is brought quickly down toward the floor, making sure that the infant is firmly held. A normal response should be seen at 8 to 9 months and consists of arms extended and hands open.
Reflex placing and stepping responses
Reflex placing is seen when the dorsum of the foot is placed against the edge of the examination table. Reflex stepping is seen when the sole of the foot is placed on the table, and the infant appears to be walking. This reflex disappears at about 4 to 5 months of age.