A brachial plexus birth injury affects the network of nerves responsible for movement and sensation in a baby's shoulder, arm, and hand. The injury can range from temporary nerve stretching to severe tearing. Some infants recover naturally, while others require therapy, surgery, or long-term rehabilitation.
What is a brachial plexus birth injury?
The brachial plexus is a network of nerves connecting the spinal cord to the upper limb.
It begins in the neck and travels through the shoulder toward the arm and hand.
These nerves transmit signals that allow muscles to move and the skin to sense touch.
A birth-related brachial plexus injury occurs when one or more nerves become stretched, compressed, or torn.
The resulting weakness depends on which nerves are affected.
Some babies have difficulty moving the shoulder or bending the elbow.
Others experience weakness throughout the arm, including the wrist and fingers.
Brachial plexus injuries are estimated to affect approximately one to two newborns per 1,000 live births, although reported rates vary.
Understanding the five nerve roots
The brachial plexus develops from five nerve roots: C5, C6, C7, C8, and T1.
The upper roots contribute heavily to shoulder and elbow movement.
The middle roots help control additional arm and wrist functions.
The lower roots supply many muscles involved in hand movement.
The location of nerve damage helps explain the baby's symptoms.
An upper-root injury may leave the hand relatively strong.
A lower-root injury may cause pronounced hand weakness.
Damage across all five roots can affect the entire arm.
What causes brachial plexus damage during delivery?
Shoulder dystocia is an important risk factor.
This complication occurs when the baby's shoulder becomes obstructed after the head has emerged.
Mechanical forces during difficult delivery may stretch the nerves between the neck and shoulder.
Other associated circumstances include larger birth weight, maternal diabetes, breech presentation, and instrument-assisted delivery.
However, brachial plexus injuries can occur without recognized shoulder dystocia.
Some cases arise from forces that are not related to improper delivery management.
An injury diagnosis alone does not prove medical negligence.
Recognizing the symptoms
A baby may move one arm less than the other.
The shoulder may appear weak, or the elbow may remain unusually straight.
Some newborns cannot lift the affected arm.
Others have reduced hand movement or grip.
An asymmetric Moro reflex may provide another clinical clue.
Doctors should also consider an associated collarbone fracture, which can cause pain-related movement restriction.
Treatment and recovery
Treatment depends on the severity and location of the nerve damage.
Mild stretching injuries often improve during the first months of life.
Physical and occupational therapy can help preserve joint movement.
More severe injuries may require evaluation for nerve grafting or nerve transfer surgery.
Early specialist assessment is important when meaningful recovery is limited.
Common questions around brachial plexus birth injuries
Can a newborn brachial plexus injury heal completely?
Yes. Many mild injuries recover substantially or completely.
Does every brachial plexus injury require surgery?
No. Surgery is generally considered for selected severe injuries or limited spontaneous recovery.
Can brachial plexus injuries affect the hand?
Yes. Lower-root or extensive injuries may reduce hand movement and grip.
