Brachial Plexus Injury: Symptoms, Causes, and What You Need to Know

Brachial plexus injury occurs when the network of nerves responsible for controlling movement and sensation in the shoulder, arm, and hand becomes damaged—often due to trauma such as car accidents, sports injuries, or difficult childbirth. These nerves originate from the spinal cord in the neck and extend through the armpit region into the arm. When disrupted, they can lead to a range of physical impairments that significantly impact daily function.

Common Signs and Symptoms of Brachial Plexus Damage

One of the most noticeable effects of brachial plexus injury is motor dysfunction. This typically presents as partial or complete paralysis affecting the muscles of the upper arm, forearm, and hand. Depending on the severity and location of the nerve damage, individuals may struggle with lifting their arm, gripping objects, or even moving their fingers. In more severe cases, total muscle weakness throughout the entire arm can occur, making everyday tasks like dressing or eating extremely challenging.

Sensory disturbances are also prevalent. Patients often report numbness, tingling, or a complete loss of sensation in parts of the arm, hand, or shoulder. This lack of feeling not only increases the risk of accidental burns or cuts but can also contribute to long-term complications if left untreated.

Different Types of Brachial Plexus Injuries and Their Specific Symptoms

Upper Brachial Plexus Injury (Erb's Palsy)

This type of injury usually affects the nerves C5 and C6 and commonly results from forceful separation of the shoulder from the head—such as during a fall or traumatic birth. The hallmark symptoms include paralysis of key muscles like the deltoid, supraspinatus, infraspinatus, teres minor, and the clavicular head of the pectoralis major.

As a result, the affected arm tends to hang limp, rotated inward due to the unopposed action of the latissimus dorsi and sternal portion of the pectoralis major. This posture is sometimes referred to as "waiter's tip" position, where the arm is adducted and internally rotated with the elbow extended and forearm pronated.

Lower Brachial Plexus Injury (Klumpke's Paralysis)

In contrast, lower brachial plexus injuries involve the C8 and T1 nerve roots and primarily affect the intrinsic muscles of the hand. This leads to significant weakness or paralysis in fine motor control, resulting in a condition known as claw hand deformity—where the ring and little fingers remain flexed due to unbalanced muscle pull.

Patients may also experience Horner's syndrome in some cases, characterized by drooping eyelid, constricted pupil, and reduced sweating on one side of the face, indicating possible involvement of the sympathetic nervous system.

Why Early Diagnosis Matters

Timely evaluation by a neurologist or orthopedic specialist is crucial. Diagnostic tools such as electromyography (EMG), nerve conduction studies, and MRI scans help determine the extent and location of nerve damage. Early intervention—including physical therapy, occupational rehabilitation, or surgical repair—can dramatically improve outcomes and prevent permanent disability.

Understanding the signs of brachial plexus injury empowers patients to seek prompt medical attention. Whether recovering from an accident or managing a congenital condition, recognizing symptoms like muscle weakness, sensory loss, or abnormal limb positioning is the first step toward effective treatment and long-term recovery.