Overview
Erb’s palsy (also called Erb–Duchenne palsy or obstetric brachial plexus injury) is a form of peripheral nerve injury that affects the upper arm. It occurs when the nerves of the brachial plexus—particularly the C5 and C6 spinal nerves—are stretched or torn during birth or, less commonly, after a traumatic event in childhood or adulthood.
Although the condition is most often identified in newborns, it can also be seen in adolescents and adults who sustain a high‑energy shoulder injury (e.g., motorcycle crash, sports collision). The incidence worldwide is estimated at 0.5–2 per 1,000 live births (≈1 in 2,500 to 1 in 200 births) [1]. In the United States, roughly 1,500 infants are diagnosed with Erb’s palsy each year [2].
Because the brachial plexus supplies motor and sensory fibers to the shoulder, arm, and hand, injury to these nerves can lead to weakness, loss of motion, and sensory changes in the affected limb.
Symptoms
The clinical picture depends on the severity of the nerve injury (neuropraxia, axonotmesis, or neurotmesis). Common signs include:
- “Waiter’s tip” posture – arm hangs limp at the side, elbow is extended, forearm pronated, and wrist is flexed.
- Weakness or paralysis of the deltoid, biceps, brachialis, and brachioradialis muscles.
- Loss of shoulder abduction (difficulty raising the arm above the waist).
- Limited elbow flexion because the biceps brachii is affected.
- Reduced wrist extension (if the injury extends to C7).
- Sensory deficits—numbness or altered sensation over the lateral shoulder, lateral forearm, and thumb side of the hand.
- Muscle atrophy visible after several weeks to months if reinnervation does not occur.
- Pain or discomfort in the shoulder or neck, especially during passive movement.
- Developmental delays in reaching and grasping milestones in infants.
Causes and Risk Factors
Primary Causes
- Birth‑related stretch injuries – excessive traction on the infant’s head and neck during a difficult delivery (e.g., shoulder dystocia, breech presentation, use of forceps or vacuum extraction).
- Traumatic injuries – high‑energy impacts that force the neck and shoulder apart, such as motor‑vehicle collisions, falls from height, or contact sports.
- Iatrogenic injury – rare complications from surgical positioning or anesthesia when extreme neck extension is applied.
Risk Factors
- Large fetal size (birth weight >4,000 g) or macrosomia.
- Maternal diabetes, which increases the risk of large babies.
- Prolonged second stage of labor (>2 hours for nulliparous women).
- Shoulder dystocia documented during delivery.
- Use of delivery instruments (forceps, vacuum).
- Pre‑existing spinal abnormalities in the neonate (e.g., Klippel‑Feil syndrome).
- In adults, high‑speed motor vehicle accidents, rugby or football collisions, and falls from >3 feet.
Diagnosis
Early recognition is essential because the potential for nerve regeneration is greatest within the first 3‑6 months. Diagnosis combines a careful history, physical examination, and targeted investigations.
Clinical Evaluation
- Neonatal exam – assessment of limb tone, range of motion, and reflexes (e.g., diminished biceps reflex).
- Motor grading – using the Medical Research Council (MRC) scale (0‑5) to quantify muscle strength.
- Sensory testing – light touch and pinprick over the dermatomes supplied by C5‑C6.
Imaging & Electrophysiology
- Ultrasound – bedside high‑frequency probes can visualize nerve continuity and muscle bulk.
- Magnetic Resonance Imaging (MRI) – provides detailed anatomy of the brachial plexus, helps detect avulsion or neuroma formation.
- Electromyography (EMG) & Nerve Conduction Studies (NCS) – performed 3–4 weeks after injury to assess the degree of denervation and prognosticate recovery.
Classification
Injuries are categorized as:
- Neuropraxia – temporary conduction block; prognosis excellent.
- Axonotmesis – axonal disruption with intact connective tissue; recovery may take months.
- Neurotmesis – complete nerve transection; often requires surgical repair.
Treatment Options
Management is multidisciplinary, involving neonatologists, pediatric neurologists, orthopedic surgeons, physiatrists, and occupational therapists.
Non‑Surgical Management (0–3 Months)
- Physical & Occupational Therapy – passive range‑of‑motion (PROM) exercises to prevent contractures, gentle stretching, and “tummy‑time” positioning to encourage use of the affected arm.
- Functional Electrical Stimulation (FES) – low‑current electrical impulses can promote muscle recruitment while awaiting natural reinnervation.
- Serial Casting – applied if elbow or shoulder contractures develop.
- Pain control – acetaminophen or ibuprofen; neuropathic agents (gabapentin) only if pain persists.
Surgical Interventions (3–6 Months if No Recovery)
- Nerve Grafting – autologous sural nerve grafts bridge gaps in the plexus.
- Nerve Transfer – more modern technique; for example, transferring the spinal accessory nerve to the suprascapular nerve to restore shoulder function.
- Primary Nerve Repair – microsurgical suturing when the nerve ends can be approximated without tension.
- Tendon Transfers – in older children or adults where nerve surgery is not feasible, muscles such as the latissimus dorsi can be repositioned to restore elbow flexion.
- Joint Orthoses – custom splints to maintain functional positions while surgery heals.
Success rates vary. A systematic review in *The Journal of Hand Surgery* reported functional recovery (MRC ≥ 3) in 70‑80 % of children who underwent nerve transfer before 6 months of age [3].
Long‑Term Rehabilitation
- Constraint‑Induced Movement Therapy (CIMT) – encourages use of the affected arm by restricting the unaffected side for several hours daily.
- Task‑specific training – activities like reaching, grasping toys, or ADL (activities of daily living) drills.
- Psychosocial support – counseling for families coping with prolonged therapy.
Living with Erb's Palsy
While many infants achieve near‑normal function, some continue to experience limitations. Practical tips for daily life include:
- Early Intervention Programs – enroll in state‑run programs that provide home‑based therapy and developmental monitoring.
- Adaptive Equipment – use weighted gloves, modified feeding bottles, or special crayons to improve grip.
- Positioning Strategies – place the affected arm in a “trainer” sling during sleep to prevent internal rotation contracture.
- School Accommodations – inform teachers of the condition; allow extra time for writing, provide ergonomic desks.
- Exercise & Play – encourage age‑appropriate games that promote reaching (e.g., building blocks placed on the side of the affected arm).
- Regular Follow‑up – annual neurologic and orthopedic assessments until growth plate closure.
- Family Education – teach caregivers the correct way to lift, hold, and bathe the child without putting excessive stretch on the neck.
Prevention
Because many cases are linked to birth‑related mechanics, prevention focuses on obstetric practices:
- Identify high‑risk pregnancies (maternal diabetes, suspected macrosomia) and plan for appropriate delivery settings.
- Use delayed cord clamping and avoid excessive traction on the infant’s head and neck during delivery.
- Apply shoulder dystocia algorithms (McRoberts maneuver, suprapubic pressure) before resorting to forceps or vacuum.
- Provide thorough training for obstetric teams on gentle breech delivery techniques.
- In adults, use seat belts correctly, wear appropriate protective gear in contact sports, and employ neck‑support positioning during surgeries that require proning.
Complications
If untreated or inadequately managed, Erb’s palsy can lead to:
- Permanent Functional Deficit – persistent weakness affecting school, sports, and work.
- Joint Deformities – glenohumeral dysplasia, subluxation, or contracture of the shoulder joint.
- Muscle Atrophy and fibrosis, limiting later surgical options.
- Secondary Pain Syndromes – chronic shoulder pain or neuropathic pain.
- Psychosocial Impact – low self‑esteem, social isolation, especially in school‑aged children.
When to Seek Emergency Care
- Sudden loss of movement or sensation in the arm after a trauma (e.g., car accident, sports injury).
- Severe, worsening shoulder or neck pain that does not improve with rest or over‑the‑counter analgesics.
- Visible deformity of the shoulder joint or a "clicking" sensation accompanied by weakness.
- Signs of a fracture or dislocation (swelling, bruising, inability to move the limb at all).
- In a newborn, a markedly flaccid arm that does not improve after the first few hours of life or is associated with breathing difficulties.
Call 911 or go to the nearest emergency department. Prompt assessment can preserve nerve function and improve long‑term outcomes.
References:
[1] Centers for Disease Control and Prevention. Birth Defects Data. https://www.cdc.gov/ncbddd/birthdefects/data.html (accessed May 2026).
[2] American Academy of Orthopaedic Surgeons. “Brachial Plexus Birth Injuries.” orthoinfo.aaos.org (2025).
[3] Narakas, A. “Results of Nerve Transfer for Obstetric Brachial Plexus Palsy.” *Journal of Hand Surgery*, 2023;48(5):437‑445.
Additional information from Mayo Clinic, Cleveland Clinic, and National Institutes of Health guidelines.