NEWBORN: NORMAL EXAM
Behavior
This 5-day-old infant is in the alert, quiet state. He has spontaneous movements, which have a smooth flowing quality to them and are not excessive, jerky or asymmetric. He seems to be attentive to the environment. He makes attempts to organize and comfort himself by sucking on his fists, which is a favorable behavioral response. When a bright light is directed towards his eyes he has a definite response, which consists of blinking and avoiding the light. With repeated stimulus there is habituation, a diminished response to the stimulus. He responds to sound by quieting and even turning is head and eyes toward the sound. The above observations are the baby equivalent to the adult mental status exam.
Cranial Nerves
Examination of the baby’s cranial nerve function is often accomplished by observing spontaneous activity. During crying, facial movement (Cranial Nerve 7) is observed for fullness or asymmetry. The quality and strength of the cry is a way of looking at Cranial Nerves 9 and 10 function. Sucking and swallowing assesses Cranial Nerves 5, 7, 9, 10, and 12 because all of these cranial nerves are involved in this complex act. Eye movements (Cranial Nerves 3, 4 and 6) can be assessed by using the vestibulo-ocular reflex (doll’s eyes maneuver). When the head is turned, there is conjugate eye movement in the opposite direction. Testing a baby’s behavior response to light (Cranial Nerve 2) and sound (Cranial Nerve 8) also adds to the cranial nerve exam. Pupillary light reflex, corneal reflex, gag reflex and funduscopic exam are done in the same manner as the adult exam.
Tone - Resting Posture
For a term newborn the resting posture is flexion of the extremities with the extremities closely adducted to the trunk. After the first few days of life, the extremities are still predominantly in the flexed position but they are not as tightly adducted as they are in the first 48 hours of life.
Tone - Upper Extremity Tone
Assessing motor function of the upper extremities begins with passive range of motion. This is done by rotating each extremity at the shoulder, elbow and wrist and feeling the resistance and the range of movement. Too little or too much resistance reflects hypotonia or hypertonia. Further testing helps to better define tone and any tone abnormalities.
Tone - Arm Traction
Arm traction is done with the baby in the supine position. The wrist is grasped and the arm is pulled until the shoulder is slightly off the mat. There should be some flexion maintained at the elbow. Full extension at the elbow is seen in hypotonia.
Tone - Arm Recoil
Arm recoil tests tone and action of the biceps. The arms are held in flexion against the chest for a few seconds, then are quickly extended and released. The arms should spring back to the flexed position. The hyotonic infant will have slow incomplete recoil. Asymmetry to this response with lack of recoil would be seen with Erb’s or brachial plexus palsy.
Tone - Hand Position
A newborn baby’s hand is held in a fisted position with the fingers flexed over the thumb. The hand should open intermittently and should not always be held in a tight fisted position. Rubbing the ulnar aspect of the hand or touching the dorsum of the hand will often cause extension of the fingers. Over the first 1 to 2 months of life, the baby’s hand becomes more open. Persistence of a fisted hand is a sign of an upper motor neuron lesion in an infant.
Tone - Lower Extremity Tone
Assessing motor function of the lower extremities begins with passive range of motion. This is done by flexing the hips, then abducting and adducting the hips. Next, flex and extend the hips, the knees and ankles. Further testing helps to better define the tone and any tone abnormalities.
Tone - Leg Traction
Leg traction is done by holding the leg by the ankle. The leg is pulled upward until the buttock starts to be lifted off the mat. The knee should maintain a flexed angle. Full extension of the knee with little resistance to pulling on the leg is a sign of hypotonia.
Tone - Leg Recoil
To test leg recoil, the legs are fully flexed on the abdomen for a few seconds, then the legs are quickly extended and released. The legs should spring back to the flexed position. Legs that remain extended could be due to either hypotonia or abnormal extensor tone.
Tone - Popliteal Angle
The popliteal angle is an assessment of the tone of the hamstring muscles. It is done one leg at a time. The thigh is flexed on the abdomen with one hand and then the other hand straightens the leg by pushing on the back of the ankle until there is firm resistance to the movement. The angle between the thigh and the leg is typically about 90 degrees. Extension of the leg beyond 90 to 120 degrees would be seen in hypotonia.
Tone - Heel to Ear
Holding the baby’s foot in one hand, draw the leg towards the ear to see how much resistance there is to the maneuver. The foot should go to about the level of the chest or shoulder, but not all the way to the ear. If the foot can be drawn to the ear then there is hypotonia.
Tone - Neck Tone
The tone of the neck can be assessed by passively rotating the head towards the shoulder. The chin should be able to rotate to the shoulder but not beyond the shoulder. If the chin goes beyond the shoulder then there is hypotonia of the neck muscles, which is associated with poor head control.
Tone - Head Lag
Starting in the supine position, the baby is pulled by the arms to the sitting position. The head and the arms are observed during the maneuver. The arms should remain partially flexed at the elbow and the head may lag behind the trunk, but should not be fully flexed backwards. When the baby is in the sitting position, the head should be able to come to the upright position for at least a few seconds before dropping forward or backward.
Tone - Head Control
The strength and tone of the neck extensors can be tested by having the baby in sitting position and neck flexed so the baby’s chin is on the chest. The baby should be able to bring the head to the upright position. The neck flexors can be tested by having the head in extension while in the sitting position. The baby should be able to bring the head to the upright position. These tests are an extension of the test for head lag and are done at the same time.
Positions - Prone
In the prone position, the baby should be able to extend the neck to the point where the head can be turned side to side. When the arms are extended by the side of the trunk, the baby should be able to bring them forward into a flexed position. The buttock should be somewhat elevated because the hips are flexed and adducted. A baby that is flat on the mat and can’t turn the head back and forth has low tone and weakness.
Positions - Ventral Suspension
The baby is placed in the prone position, suspended in the air by the hand placed under the chest. The baby’s head position, back and extremities are observed. The head should stay in the same plane as the back. The back should show some resistance to gravity and not be simply draped over the hand on the chest. The extremities should maintain some flexion tone and not dangle in extension. Ventral suspension is a very good way to assess a baby’s neck and trunk tone.
Positions - Vertical Suspension
The examiner holds the baby in the upright position with feet off the ground by placing the hands under the arms and around the chest. The baby should be suspended in this position without slipping through the hands of the examiner. If there is shoulder girdle weakness the arms will extend upwards and the examiner will have to reposition their grasp of the baby to avoid the baby slipping through their hands. It feels like trying to hold on to a slippery fish.
Reflexes - Deep Tendon Reflexes
Testing deep tendon reflexes is an important part of the newborn neurological exam. They can be technically difficult to do. The first thing is to use a reflex hammer, not a finger or a stethoscope. Ideally, the baby is in a quiet alert state with the head in the midline. The head turned to one side can reinforce the tone and reflexes on that side. I usually start with the knee jerk because is the easiest to obtain. Take control of the leg with the hand under the knee and the leg at about a 90 degree angle at the knee. Then strike the patellar tendon with the reflex hammer using a pendular action rather a chopping action.
Reposition the leg and try several times if you have trouble getting a knee jerk. Next, I go to the ankle jerk. If I can’t get an ankle jerk in the conventional fashion, I place my fingertips on the plantar aspect of the foot, flex the foot slightly, then strike the back of my fingers. For the bicep jerk, have the arm flexed at the elbow, thumb over the bicep tendon, then strike the thumb with a pendular action. Because of the predominantly flexor tone of the newborn, it is rare to obtain a triceps jerk.
Absence of deep tendon reflexes is a much more important finding than hyperreflexia in the newborn. A normal newborn can have hyperreflexia and still be normal, if the tone is normal, but absent reflexes associated with low tone and weakness is consistent with a lower motor neuron disorder. Preserved or exaggerated reflexes associated with low tone is the hallmark of what is called central or cerebral hypotonia and the cause is an upper motor neuron lesion.
Reflexes - Plantar Reflex
The normal response to stroking the lateral aspect of the plantar surface of the foot is extension of the great toe and fanning of the other toes. If the stimulus is brought across the ball of the foot then a grasp reflex will be elicited and the toes will plantar flex. The up going toes or “Babinski sign” is normal in the infant and may be present for the first year of life because of the incomplete myelination of the corticospinal tracts.
Primitive Reflexes - Suck, Root
The baby should have a strong coordinated suck reflex with good stripping action of the tongue. There should be resistance to pulling out the pacifier. A root reflex is obtained by gently stroking the cheek towards the lips. The baby should open the mouth towards the stimulus and turn the head to latch on to the object.
Primitive Reflexes - Moro
The Moro reflex is obtained by holding the baby’s head and shoulders off of the mat with the arms held in flexion on the chest. The examiner suddenly lets the head and shoulders drop back a few inches while releasing the arms. The arms should fully abduct and extend, then return towards the midline with the hand open and the thumb and the index finger forming a “C” shape. An absent or incomplete Moro is seen in upper motor neuron lesions. An asymmetric Moro is most often seen with a brachial plexus lesion. The brachial plexus palsy is on the side of the poorly abducted arm.
Primitive Reflexes - Galant
The Galant reflex (trunk incurvation) is obtained by placing the baby in ventral suspension, then stroking the skin on one side of the back. The baby’s trunk and hips should swing towards the side of the stimulus.
Primitive Reflexes - Stepping
The Galant reflex (trunk incurvation) is obtained by placing the baby in ventral suspension, then stroking the skin on one side of the back. The baby’s trunk and hips should swing towards the side of the stimulus.
Primitive Reflexes - Grasp
Placement of the examiner’s finger in the palm of the hand or on the sole of the foot will cause flexion and grasping of the fingers or toes. One should avoid touching the dorsum of the hand while eliciting the grasp reflex because stimulating the back of the hand causes a hand opening reflex to occur. With the two competing reflexes, the grasp response will be incomplete or inconsistent. You can actually see this happen with the baby that is being examined. The grasp reflex can be reinforced by applying traction on the arm.
Head Shape and Sutures
The head should be closely inspected as part of the neurological examination. There can be molding of the head, which is an expected finding in a newborn. Palpate the sutures and outline the anterior and posterior fontanelles.
Head Circumference
It is very important to measure the head circumference, which sometimes is referred to as the OFC (occipital-frontal circumference) because the measurement is obtained by placing the measuring tape around the most prominent aspect of the frontal and occipital bones. The most accurate measurements are obtained with a plastic tape measure rather than a paper tape measure because the paper can stretch. The head circumference measurement should be plotted on a standardized head growth chart for the appropriate sex.