Overview
A brachial plexus injury is damage or irritation to the network of nerves that carries signals from the neck to the shoulder, arm, and hand. The brachial plexus controls strength, feeling, and fine movement, so injury can cause pain, numbness or tingling, and weakness in specific parts of the arm. Symptoms can range from mild nerve irritation to significant loss of motion depending on which nerve roots or branches are involved and how severely they are affected. Many cases improve with time and targeted nonsurgical care, but early evaluation helps guide the right rehabilitation plan.
Symptoms
Patients often notice pain in the shoulder, upper arm, or neck, followed by numbness, tingling, or burning sensations. Weakness may make it hard to lift the arm, reach overhead, rotate the shoulder, or control the hand, depending on the specific pattern of nerves involved. In some cases, reflexes can be reduced and muscle bulk may gradually decrease over weeks to months. Symptoms are commonly worse after a traction or impact injury, and they may also worsen when the neck or shoulder positions aggravate the irritated nerves.
Causes
Brachial plexus injury most commonly occurs after trauma, such as shoulder dislocation, falls, or traction injuries from motorcycle or sports accidents. It can also happen during childbirth when newborn shoulders are stretched during delivery, leading to obstetric brachial plexus palsy. Less commonly, compression or scarring from tumors, cysts, or inflammation can irritate the plexus, causing similar neurologic symptoms.
Risk Factors
Risk increases after high-energy accidents, falls, or contact sports where the shoulder or neck can be pulled or impacted. People with prior shoulder dislocations or significant trauma to the collarbone or upper chest may be at higher risk for nerve stretch injury. For obstetric brachial plexus palsy, larger birth size, difficult delivery, or prolonged shoulder delivery can raise risk, even with appropriate care.
Prevention
Seatbelts and appropriate protective gear during sports can reduce the chance of traction or impact injuries to the upper body. Practicing safe lifting and avoiding sudden pulling on the arm can lower risk, especially in activities with children or during moving assistance. For childbirth-related risk, following obstetric protocols and timely intervention during difficult shoulder delivery can help reduce the likelihood of nerve stretch.
How the Diagnosis Is Evaluated
Clinicians start with a detailed history of how symptoms began, including any trauma, traction, or delivery circumstances, and when strength or sensation changed. A focused neurologic examination checks muscle strength in specific nerve distributions, sensation patterns, and reflexes, along with a shoulder and neck exam to look for alternative causes. Depending on severity and timing, tests such as electromyography and nerve conduction studies (EMG/NCS), MRI of the brachial plexus or cervical spine, and sometimes ultrasound may be ordered; not every patient needs every test.
Nonsurgical Treatment Options
Nonsurgical treatment focuses on pain control, protecting the arm from further injury, and restoring function through targeted rehabilitation. Physical therapy and occupational therapy are central and usually include range-of-motion work to prevent stiffness, nerve gliding or mobility techniques when appropriate, and progressive strengthening as nerve function returns. Splinting or bracing may be used to support weak joints and improve hand position during daily activities. Medication such as short-term anti-inflammatories or neuropathic pain agents may be recommended to reduce discomfort and help you participate in therapy. In selected cases, clinicians may use image-guided corticosteroid injections or diagnostic nerve blocks to calm inflammation or reduce pain while rehabilitation progresses.
When to Seek Medical Attention
Seek prompt medical evaluation if you have new or worsening weakness, numbness, or loss of arm function, especially after an accident, fall, or traction injury. Get urgent care or emergency evaluation if symptoms are rapidly progressing, pain is severe and uncontrolled, or you have marked trouble using the hand or holding objects. For newborns or infants with suspected obstetric brachial plexus palsy, contact a pediatric clinician promptly rather than waiting. Also seek urgent care for fever, increasing swelling, or neurologic changes that extend beyond the arm and could indicate a more serious problem.
Frequently Asked Questions
It commonly causes shoulder or arm pain along with numbness, tingling, or burning, followed by weakness in parts of the arm or hand.
Yes, therapy can reduce stiffness, maintain motion, protect weak muscles, and support functional return as nerve signals recover.
Next Steps
If you suspect a brachial plexus injury, arrange an evaluation with a clinician familiar with nerve and shoulder disorders so the correct nerve pattern and severity can be assessed. Early therapy can help protect range of motion and improve outcomes, so ask about a rehabilitation plan even while diagnostic testing is being considered. Seek medical attention promptly if weakness or sensation is worsening or if you cannot use the arm normally.