Erb's palsy often becomes noticeable shortly after birth because the baby has difficulty moving one shoulder or arm. The affected limb may rest in an unusual position, while hand movement remains relatively normal. Recognizing these symptoms helps families obtain timely medical evaluation and appropriate follow-up.
Why Erb's palsy changes arm movement
The brachial plexus is responsible for carrying nerve signals from the spinal cord to the arm.
Its upper nerve roots help control shoulder movement and elbow bending.
When these nerves are injured, the muscles may not receive normal signals.
A newborn may therefore struggle to lift the arm or bend the elbow.
The weakness often affects one side more than the other.
Parents may first notice the difference when the baby stretches, cries, or responds to handling.
The absence of obvious pain does not rule out a neurological injury.
Understanding the waiter's tip position
One classic sign of Erb's palsy is the waiter's tip posture.
The affected arm may rest beside the baby's body.
The shoulder turns inward, and the elbow remains relatively straight.
The forearm may rotate so that the palm faces backward.
This position results from weakness in muscles supplied by the injured upper brachial plexus nerves.
Not every affected baby displays the complete posture.
The appearance depends on which nerves and muscles are involved.
Reduced shoulder and elbow movement
A baby with Erb's palsy may have difficulty raising the arm outward.
Elbow bending can also be limited.
Parents may notice that the affected arm moves less during normal newborn activity.
The baby may still move the fingers and grasp objects.
This pattern occurs because the lower nerve roots that control many hand functions may remain intact.
However, more extensive brachial plexus injuries can also affect the wrist and hand.
The pattern of weakness helps clinicians identify the likely nerve involvement.
The Moro reflex and newborn examination
The Moro reflex is a normal newborn response to sudden changes in position or sensation.
Typically, both arms move outward before returning inward.
A baby with Erb's palsy may show reduced movement on the affected side.
Doctors describe this as an asymmetric Moro reflex.
However, a broken collarbone can produce a similar finding because shoulder movement is painful.
A neurological examination is needed to distinguish these conditions.
Clinicians evaluate movement, reflexes, muscle tone, and associated injuries.
When symptoms require specialist attention
Any newborn with unexplained arm weakness should be evaluated promptly.
Persistent inability to bend the elbow or lift the shoulder deserves particular attention.
Doctors may arrange follow-up to assess whether movement improves over the first weeks.
If recovery is limited, referral to a pediatric brachial plexus specialist may be appropriate.
Early assessment is important because treatment decisions for severe injuries can be time-sensitive.
Can symptoms improve naturally?
Yes.
Some babies experience temporary nerve dysfunction caused by stretching.
As nerve function returns, movement may improve.
Other injuries involve more extensive damage and require longer treatment.
Parents should not assume that preserved finger movement means the entire injury is mild.
Recovery must be assessed through repeated examinations.
Common questions around Erb's palsy symptoms
What is the first sign of Erb's palsy?
Reduced movement of one shoulder or arm is a common early sign.
Can a baby move their fingers with Erb's palsy?
Yes. Hand movement is often preserved in classic C5-C6 injuries.
Does a limp arm always mean Erb's palsy?
No. Fractures and other neurological conditions can also cause reduced movement.
To learn more, visit: https://birthinjuryadvocate.com/birth-injuries/erbs-palsy/
