Erb’s palsy (or obstetric brachial plexus palsy) results from damage to a baby’s brachial plexus during delivery. The brachial plexus is a complex network of nerves emerging from the spinal cord and the symptoms of Erb’s palsy concern control, movement and feeling in the arm.
These nerves are made up of thousands of fibres responsible for carrying electrical messages between the brain and the different muscles that work the arm and hand. When the fibres are damaged, the flow of messages from the brain are weakened or disrupted, and this can stop the corresponding muscles from working properly.
Symptoms of Erb’s palsy therefore include weakness, paralysis and lack of sensation in the shoulder, elbow, wrist and hand, depending on which nerves were damaged and the extent of that damage. See Grades of Erb’s palsy and Understanding brachial plexus injury.
Symptoms of Erb’s palsy can be seen immediately or soon after birth. The classic sign of a baby with Erb’s palsy is the affected arm hanging down and rotated medially (turned in) with the hand flexed back and palm facing up (often referred to as the ‘waiter’s tip’ position).
Symptoms of Erb’s palsy
If damage is primarily to the upper trunk of the brachial plexus (the C5, C6 nerve roots), symptoms of Erb’s palsy could include:
- Partial or complete paralysis of the arm depending on the extent of damage
- A limp, pronated arm (turned in) with wrist flexed back in the ‘waiter’s tip’ position
- Weak shoulder abduction (difficulty lifting the arm from the shoulder)
- Difficulty rotating the arm away from the shoulder (as if to put your arm in a sleeve)
- Weak elbow flexion (difficulty bending the arm at the elbow)
- Pronated arm with palm facing down or back (no forearm supination enabling the palm to face up or out)
- Inability to regulate the temperature of the arm due poor circulatory system
- Numbness / loss of sensation in areas of the affected arm
90 per cent of people with this type of injury will return to having normal function with the correct treatment.
If there is also damage to the C7 nerve root, symptoms will include the above and also:
- Difficulty extending the wrist (straightening the wrist or bending it away from the body)
72 per cent of people with damage affecting the C5, C6 and C7 nerve roots will return to having normal function with the right treatment.
If there is injury to the nerves of the upper, middle and lower trunk of the brachial plexus (C5, C6, C7, C8 and T1), symptoms will include:
- Complete paralysis of the shoulder, arm and hand
- Horner’s syndrome, characterised by a constricted pupil and droopy eyelid due to damage to a bundle of nerves responsible for controlling some of the muscles of the eye. This can happen when the lower trunk of the brachial plexus is avulsed (torn right away) from the spinal cord.
In these cases, surgery is required, but few children will gain full functional recovery if all five nerve roots are damaged.
Associated symptoms of Erb’s palsy
Children showing the symptoms of Erb’s palsy may also experience associated weakness, paralysis and loss of sensation in their arm, including:
- Decreased grip in their hand due to weakness in the arm
- Associated torticollis – characterised by the baby’s head being held tilted to one side and the face turned to the look towards the other side. It is due to tightness of the muscle on one side of the neck.
- Trouble controlling movement in the arm, wrist and hand due to paralysis or muscle weakness
- A bent elbow because the joint is very tight (contracture of the elbow)
- Atrophy (deterioration) of the affected muscles in the arm
- Stunted growth in the affected shoulder, arm and hand
- Cramping, pain and discomfort (although not everyone with Erb’s palsy experiences this)
- Problems with their shoulder and shoulder pain due to weak muscles
- Loss of sensation, circulatory problems and the loss of the skin’s ability to heal means infections are common.
Can symptoms of Erb’s palsy get better?
Damage to brachial plexus nerves is usually caused by an excessive pull on the baby’s head after its descended, but when its shoulders are still in the uterus and stuck against the mother’s pelvic bone. This can cause the nerves to stretch or tear.
If the injury to the brachial plexus nerves is mild and primarily affects the upper and middle nerve trunks (C5, C6 and C7 roots) then it’s very possible for the damaged nerves to repair themselves shortly after birth. Healing can take up to three months and your paediatrician will perform regular tests to monitor any improvement.
If the injury is more severe and the nerve has been torn (ruptured) or, at worst, completely severed (avulsed) from the spinal cord, surgery will be required to recover any movement and sensation in the arm. The injury may be permanent. See also Erb’s palsy legal issues: Theories of material propulsion versus excessive traction causing injury.
It’s important to start physiotherapy for your baby as soon as Erb’s palsy has been identified and he/she has recovered from a traumatic birth. Physiotherapy cannot heal the nerves, but performing passive exercises on your baby can prevent muscles from deteriorating as the nerves begin to heal. It is also recommended before and after surgery if no self-healing occurs.
See also Treatment for Erb’s palsy.