One of the most fascinating reflexes is the Babinski reflex, or plantar reflex, which is stimulated when the bottom of your baby’s foot is touched. If you gently stroke the sole of your newborn’s foot, you’ll probably notice that their big toe extends upward and the rest of their toes flare out.
What Is the Babinski Reflex?
The Babinski reflex is named after neurologist Joseph Babinski, who first described the reflex in 1896. The Babinski reflex is sometimes also referred to as the plantar reflex, extensor plantar reflex, or the Babinski sign. Since its discovery, testing the Babinski reflex has become a common part of newborn and infant examinations throughout the world. It can easily be tested in a newborn simply by stimulating the bottom of the foot. A positive Babinski sign in a newborn is where the big toe extends upward and the rest of the toes flare out.
Signs of a Healthy Babinski Reflex
Your doctor will test your baby’s Babinski reflex when your baby is first born and at some or all of their well check-ups. They will be testing the Babinski reflex along with several other normal newborn reflexes. Some of the other newborn reflexes your doctor will test include:
Rooting Reflex
This is one of the reflexes that has to do with feeding. When your baby’s cheek or the corner of their mouth is stroked or touched, your baby will move their head toward the stimulus and then begin to root. The rooting reflex helps your baby latch onto the breast or bottle, and is usually outgrown by four months.
Moro Reflex
The Moro reflex is also often referred to as the “startle reflex.” Any sudden or loud sound can trigger this reflex in your baby. Your baby will respond by startling, extending their head backwards, raising their arms and legs up into the air, crying, and then folding their arms and legs back in. The Moro reflex is usually outgrown by four months.
Stepping Reflex
If you hold your baby upright on a solid surface, you may notice that your baby begins to take a few steps. It’s pretty amazing, but doesn’t mean that your newborn is ready to walk. It’s just a reflex, but some experts believe it prepares your little one for their future adventures in walking. This reflex is usually outgrown at two months.
Tonic Neck Reflex
Often referred to as the “fencing reflex,” the tonic neck reflex is stimulated when your baby turns their head to one side. The arm on the side they turned their head to will stretch out, and the arm on the opposite side will bend up at the elbow. This reflex usually diminishes by 5 to 7 months.
Sucking Reflex
Another reflex that aids in feeding, the sucking reflex is stimulated anytime you place an object in your baby’s mouth. Whether it’s a breast, bottle, pacifier, or even your finger, your baby will begin to suck. Babies are also known to suck on their own fingers—really anything they can get into their mouth is fair game. The suck reflex begins to form even before your baby is born—at about 32 weeks gestation—which is why babies will often suck on their fingers in utero.
Palmar Grasp Reflex
Your baby’s feet aren’t the only extremities that respond to stimuli with a reflexive reaction. Your baby’s hands do, too. Referred to as the “grasping reflex,” if you touch the palm of your newborn’s hand, you’ll notice that their fingers will grasp your hand. This reflex is usually outgrown by 5 or 6 months.
How to Test for It
To test your baby’s Babinski reflex, your doctor will stroke the bottom of your baby’s foot. They will either use their finger or a gentle tool such as a reflex hammer. They will usually start at the heel of your baby’s foot and work their way upward. Once the foot is stimulated:
The baby’s big toe will extend upward, away from the footThe rest of your baby’s toes will flare, or fan out
When Does It Disappear?
Your baby’s Babinski reflex is strongest in their first nine months, and will usually diminish by 12 months. It’s normal for your baby to have a positive Babinski reflex up to two years old.
When to Be Concerned
The Babinski reflex only a concern after a child is two years old, when it is not displayed in infancy, or when it appears differently on each foot. In rare cases, your baby or older child may have an abnormal Babinski reflex; adults may have issues with their Babinski reflex as well.
Signs of Abnormal Babinski Reflex
In children older than two years old and in adults, there should be no signs of the Babinski reflex upon stimulation of the sole of the foot. When the bottom of the foot in stimulated in an older child or adult, the toes should curl downward. If the big toe extends upward and the toes flare out as they do for infants and children under two, this may indicate a concerning medical condition.
What Causes Abnormal Babinski Reflex?
Older children or adults who have a present Babinski reflex may have an underlying disorder of their central nervous systems. Some of the possible disorders indicated by a persistent Babinski reflex include:
Brain injuryBrain tumorLou Gehrig’s disease (amyotrophic lateral sclerosis)MeningitisMultiple sclerosisSpinal cord defectSpinal cord injurySpinal cord tumorStroke
Should You Be Concerned?
It is always wise to contact your doctor with any concerns you may have about your child’s development. If there is anything wrong, your doctor will help you take the proactive steps needed to diagnose and treat any issues your child may have.
A Word from Verywell
When you first meet your new baby, you may be unprepared for some of the strange little reflexes they are born with, such as the Babinski reflex. In fact, some parents even think that some of the jerky movements their babies are prone to are indications of an issue. Remember, too, that you shouldn’t sort this all out alone. If you feel confused about any aspect of your baby’s behavior, or would like to know where to find more information about what to expect, your baby’s pediatrician is an excellent resource. They want to answer all of your questions—big and small—and you shouldn’t hesitate to bring up any concerns you may have about your baby’s health or well being.
