Which reflex would the nurse observe when a newborn starts to cry and extends the legs arms and fingers when there is a loud noise?

Reflexes are involuntary movements or actions. Some movements are spontaneous, occurring as part of the baby's usual activity. Others are responses to certain actions. Reflexes help identify normal brain and nerve activity. Some reflexes occur only in specific periods of development. The following are some of the normal reflexes seen in newborn babies:

This reflex begins when the corner of the baby's mouth is stroked or touched. The baby will turn his or her head and open his or her mouth to follow and "root" in the direction of the stroking. This helps the baby find the breast or bottle to begin feeding.

Rooting helps the baby become ready to suck. When the roof of the baby's mouth is touched, the baby will begin to suck. This reflex does not begin until about the 32nd week of pregnancy and is not fully developed until about 36 weeks. Premature babies may have a weak or immature sucking ability because of this. Babies also have a hand-to-mouth reflex that goes with rooting and sucking and may suck on fingers or hands.

The Moro reflex is often called a startle reflex because it usually occurs when a baby is startled by a loud sound or movement. In response to the sound, the baby throws back his or her head, extends out the arms and legs, cries, then pulls the arms and legs back in. A baby's own cry can startle him or her and trigger this reflex. This reflex lasts about 5 to 6 months.

When a baby's head is turned to one side, the arm on that side stretches out and the opposite arm bends up at the elbow. This is often called the "fencing" position. The tonic neck reflex lasts about 6 to 7 months.

Stroking the palm of a baby's hand causes the baby to close his or her fingers in a grasp. The grasp reflex lasts until about 5 to 6 months of age.

When the sole of the foot is firmly stroked, the big toe bends back toward the top of the foot and the other toes fan out. This is a normal reflex up to about 2 years of age.

This reflex is also called the walking or dance reflex because a baby appears to take steps or dance when held upright with his or her feet touching a solid surface.

​Many of your baby's movements in their first weeks are done by reflex. This means it is involuntary or happens without your baby trying. If you put your finger in their mouth, they suck reflexively. They shut their eyes tightly to a bright light.

Some reflexes remain with newborns for months, while others go away in weeks. Here are some you can watch for in your baby:

Rooting

In some cases, reflexes change into voluntary behavior. For example, your baby is born with a rooting reflex that prompts him to turn his head toward your hand if you stroke his cheek or mouth. This helps him find the nipple at feeding time. At first, he'll root from side to side, turning his head toward the nipple and then away in decreasing arcs. He'll simply move his head and mouth into position to suck.

Sucking

Sucking is another survival reflex present even before birth. In fact, if you had an ultrasound during pregnancy, you may have seen your baby sucking their thumb.

After birth, when a nipple and areola are placed deeply in your baby's mouth, he automatically begins to suck. This motion actually has two stages. First, he places his lips around the areola with the nipple far back in the mouth, pointed to the junction of the hard and soft palate, and compresses the breast between his tongue and palate (called "expression," this action forces the milk out). In the second phase, or milking action, the tongue moves from the areola to the nipple. This whole process is helped by the suction that secures the breast to the baby's mouth.

Coordinating these rhythmic sucking movements with breathing and swallowing is a relatively complicated task for a newborn. So even though this is a reflexive action, not all babies suck efficiently at first. With practice, however, the reflex becomes a skill that they all manage well.

Rooting, sucking, and bringing his hand to his mouth are considered feeding cues in the first weeks after birth. Later on, after breastfeeding is well established, your baby will start to use these movements to console himself, and may also be comforted by a pacifier or when you help him find his thumb or fingers.

Newborn Reflexes

The following are some normal inborn reflexes you will see during the first weeks. Not all infants acquire and lose these reflexes at exactly the same time, but this table will give you a general idea of what to expect.

Moro or "startle" reflex

A dramatic reflex during these first few weeks is the Moro reflex. If your baby's head shifts position abruptly or falls backward--or if he is startled by something loud or abrupt--he will extend his arms and legs and neck and then rapidly bring his arms together. He may even cry loudly. The Moro reflex, which is present in varying degrees in different babies, usually peaks during the first month and starts to disappear after about two months.

Tonic neck reflex or "fencing" posture

A more interesting automatic response is the tonic neck reflex, or the fencing posture. You may notice that when your baby's head turns to one side, his corresponding arm will straighten, with the opposite arm bent, as if he's fencing. You may not see this response, however, since it is subtle, and if your baby is disturbed or crying, he may not perform it. It disappears at five to seven months of age.

Both the Moro and tonic neck reflexes should be present equally on both sides of the body. If you note that the reflex seems different on one side, or that the baby moves one side of the body better than the other, tell your pediatrician.

Grasping

You'll see still another reflex when you stroke your baby's palm and watch him immediately grip your finger. Or, if you stroke the sole of his foot, you can watch his toes curl tightly. In the first few days after birth, your baby's grasp will be so strong it may seem he can hold his own weight—but don't try it. He has no control over this response and may let go suddenly.

Stepping

Aside from strength, your baby's other special talent is stepping. He can't support his weight, of course, but if you hold him under the arms (being careful to support his head as well) and let his soles touch a flat surface, he'll place one foot in front of the other and "walk."

This reflex will help a newborn crawl to the breast right after delivery when lying on their mother's abdomen. This reflex will disappear after two months, then show up again toward the end of the first year as the learned behavior of walking.

More information

Movement Milestones: Birth to 3 Months

The information contained on this Web site should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.

Which reflex would the nurse observe when a newborn starts to cry and extends the legs?

Which reflex would the nurse observe when a newborn starts to cry?

What are the 4 newborn reflexes?

What is the startle reflex in newborns?