Brachial Plexus Injury: Causes, Symptoms, and Acupuncture Treatment

Brachial plexus injury refers to a series of paralysis symptoms within the area innervated by the brachial plexus, caused by external forces that damage or compress the roots or main trunk of the brachial plexus.

The brachial plexus is formed by the anterior rami of the 5th to 8th cervical nerves and the majority of the anterior ramus of the 1st thoracic nerve. These nerves pass through the interscalene space and the axillary cavity, giving off branches that distribute to the skin and muscles of the upper limb, as well as the muscles of the chest, back, and shoulder girdle.

The main causes include shoulder fractures, dislocations, thoracic surgery, fetal macrosomia, cervical-shoulder strain during delivery, neck trauma, infection, upper arm sprain, and clavicular fractures. In addition, compression from tumors or aneurysms can also induce symptoms of brachial plexus palsy.

【Key Diagnostic Points】

Clinically, it can be divided into two types: upper brachial plexus type and lower brachial plexus type.

1. Upper Brachial Plexus Type

1. Motor impairment: Inability to abduct the upper arm, flex the forearm, externally rotate the arm, or supinate the forearm; the arm is held in a position of straight extension, internal rotation, and adduction.

2. Sensory disturbance: Generally no sensory disturbance, or diminished pinprick sensation at the acromion region.

3. Muscle atrophy: Atrophy or sagging of the muscles in the shoulder and upper arm.

4. Reflex changes: Diminished or absent biceps, triceps, and radial reflexes.

II. Lower Brachial Plexus Type

1. **Motor impairment**: inability to flex the fingers and wrist, hand…

Inability to abduct and adduct the fingers; the thumb cannot flex, adduct, or abduct, and cannot perform opposition with the little finger.

2. Sensory disturbance: hypoesthesia on the ulnar side of the forearm and hand.

3. Muscle atrophy: atrophy of the thenar and hypothenar eminences;

4. Autonomic Nervous System Disorders: Swelling and cyanosis of the hands, thinning and brittleness of the nails, and possible Horner’s syndrome (abnormal sweating on the face and neck), etc.

Treatment

### I. Acupoints and Needling Techniques

1. Brachial Plexus Point (affected side): Located in the depression at the junction of the splenius capitis and sternocleidomastoid muscles in the lower segment of the neck. Use a 30-gauge, 1.5-cun filiform needle. Perform routine local disinfection. Insert the needle obliquely toward the contralateral scapular spine, advancing approximately 1–1.2 cun until reaching the first rib (caution: avoid blood vessels during insertion; do not insert too deeply, as excessive depth may injure the lung apex and cause pneumothorax). Needle sensation: In a normal individual, a spreading numbness, electric shock-like sensation, or radiating sensation down the arm and hand should be elicited.

2. LI15 (Jianyu) (affected side): Located at the midpoint of the upper part of the deltoid muscle, between the acromial extremity of the clavicle and the greater tubercle of the humerus. Use a No. 30 gauge, 2-cun filiform needle. Perform routine local disinfection and insert obliquely downward to a depth of about 1.8 cun. Needling sensation: local distension and pain; in normal individuals, there may be partial radiation toward the elbow.

3. LI13 (Shouwuli) on the affected side: Located on the radial side of the upper arm, on the line connecting LI11 (Quchi) and LI15 (Jianyu), 3 cun superior to LI11 (Quchi). Use a 30-gauge, 2-cun filiform needle. After routine local disinfection, insert perpendicularly to a depth of approximately 1.6 cun. Sensation: local distension and pain; in normal individuals, there is partial radiation toward the radial styloid process.

**4. LI11 (Quchi) (affected side):** With the elbow flexed, the point is located in the depression slightly lateral to the radial end of the cubital crease, approximately at the midpoint of the line connecting LU5 (Chize) and the lateral epicondyle of the humerus. Using a 30-gauge, 2-cun needle, perform routine local disinfection and insert perpendicularly to a depth of approximately 1.8 cun. Needling sensation: local distension and pain.

**5. TE5 (Waiguan) (affected side):** Located on the dorsal aspect of the forearm, on the line connecting TE4 (Yangchi) and the tip of the elbow, 2 cun proximal to TE4. Use a 30-gauge, 1.5 cun filiform needle. After routine local disinfection, insert perpendicularly approximately 1.2 cun toward PC6 (Neiguan). Needle sensation: local distension and pain, or radiation to the dorsum of the hand and the middle finger in healthy individuals.

6. **LI4 (Hegu)** (affected side): Located between the 1st and 2nd metacarpal bones on the dorsum of the hand, near the midpoint of the radial border of the 2nd metacarpal bone. Use a gauge-30, 2-cun filiform needle. After routine local disinfection, insert approximately 1.8 cun in the direction toward SI3 (Houxi). Needle sensation: local distension and pain.

2. Methods

The patient is seated. The aforementioned acupoints are needled according to the standard method and connected to electrical stimulation. The needles are retained for 40 minutes before removal. Treatment is administered once daily, with 10 sessions constituting one course. A rest of 5 days is taken before beginning the next course.

**【Commentary】**

Electroacupuncture is quite effective in treating nerve paralysis resulting from brachial plexus nerve injury. It is particularly beneficial for brachial plexus nerve paralysis caused by compression from hematoma in the neck and brachial plexus region following trauma, as well as after the hematoma is absorbed. It also yields good therapeutic results in the early stage of brachial plexus nerve injury after manual or surgical reduction of clavicle fractures, reduction of scapular fractures, or surgical removal of tumors or hemangiomas. However, for infants with birth injuries, it is often difficult to detect the condition early; once identified, the child may already be 1–2 years old, and acupuncture in young children is challenging. By the time the child is 4–5 years old and can tolerate acupuncture, the neuromuscular function has already been paralyzed for too long. Even with meticulous treatment, only muscle position and tone can be restored, and while prolonged treatment may partially revive nerve activity, a complete cure is very difficult. In summary, electroacupuncture is a highly effective therapeutic method for treating brachial plexus nerve injury.

Clinical Presentation and Diagnostic Indicators

Brachial plexus injury symptoms vary widely depending on the severity and location of the nerve damage. Patients typically present with motor deficits, sensory loss, and autonomic dysfunction in the upper limb. Common manifestations include flaccid paralysis of the shoulder and arm, diminished or absent deep tendon reflexes, and muscle atrophy over time. In upper trunk injuries (Erb-Duchenne palsy), the deltoid, biceps, and brachioradialis are affected, resulting in the classic “waiter’s tip” posture with adduction and internal rotation of the shoulder, extension of the elbow, and pronation of the forearm. Lower trunk injuries (Klumpke palsy) involve the intrinsic hand muscles, causing clawing of the fingers and Horner syndrome if the T1 sympathetic fibers are compromised. Complete avulsion of the roots can produce total anesthesia and paralysis from the shoulder distally. Pain, often neuropathic in nature, may accompany these deficits. Electrophysiological studies, such as electromyography and nerve conduction velocity tests, are essential to localize and quantify the injury. Imaging modalities like high-resolution MRI or CT myelography further delineate the structural damage, including root avulsions or neuromas. Accurate assessment of brachial plexus injury symptoms is critical for guiding subsequent management decisions and predicting functional recovery.

Etiological Mechanisms and Risk Factors

The brachial plexus injury causes are predominantly traumatic, but iatrogenic and compressive mechanisms also contribute. High-energy trauma, such as motorcycle accidents, falls from height, or sports collisions, often produces traction or avulsion forces that stretch the plexus beyond its elastic limit. In penetrating injuries, lacerations from knives or glass can transect nerve fibers directly. Radiation therapy to the supraclavicular region may induce progressive fibrosis and ischemic damage, leading to delayed plexopathy. Tumors, particularly Pancoast tumors of the lung apex or metastases from breast cancer, can infiltrate or compress the brachial plexus. Inflammatory conditions like brachial neuritis (Parsonage-Turner syndrome) cause acute-onset pain and weakness without external trauma. Additionally, prolonged improper positioning during surgery or anesthesia—for example, with arm abduction or shoulder depression—can cause compression neuropathy. Understanding these diverse brachial plexus injury causes is essential for prevention, early recognition, and appropriate medicolegal documentation.

Obstetric Considerations and Neonatal Implications

Brachial plexus birth injury represents a distinct subcategory occurring during vaginal delivery, particularly when shoulder dystocia complicates the second stage. Excessive lateral traction on the fetal head and neck stretches the upper roots, most commonly C5–C6. Risk factors include fetal macrosomia, maternal obesity, prolonged labor, and instrumental delivery using forceps or vacuum. The incidence ranges from 1 to 3 per 1000 live births. Fortunately, the majority of these injuries are neuropraxic and recover spontaneously within the first few months. However, more severe cases may involve root avulsion or neuroma formation, leading to persistent deficits such as impaired shoulder abduction, external rotation, and elbow flexion (Erb’s palsy). Brachial plexus birth injury often causes parental distress and necessitates close follow-up by a multidisciplinary team including neonatologists, physiatrists, and pediatric orthopedists. Early initiation of passive range-of-motion exercises can prevent joint contractures. Surgical intervention is reserved for cases lacking biceps function by 3–6 months of age, typically involving nerve grafting or transfer to reinnervate the affected muscles.

Therapeutic Strategies and Rehabilitation Approaches

Optimal brachial plexus injury treatment requires a tailored, staged approach based on injury type, severity, and time since onset. Conservative management is appropriate for neuropraxic injuries and involves physiotherapy to maintain joint mobility, prevent contractures, and strengthen intact muscles. Neuromodulatory agents like gabapentin may alleviate neuropathic pain. For complete avulsions or ruptures that do not show spontaneous recovery by 3–6 months, microsurgical reconstruction is indicated. Common techniques include nerve grafting using sural nerve autografts, nerve transfer (e.g., spinal accessory to suprascapular nerve, intercostal to musculocutaneous nerve), and in chronic cases, tendon transfers or free-functioning muscle transplantation. Postoperative rehabilitation is intensive and protracted, often spanning 12–24 months. Occupational therapy focuses on functional tasks, while electrical stimulation may enhance reinnervation. Psychological support is crucial given the profound impact on daily life and vocational capacity. Multidisciplinary collaboration among neurosurgeons, hand surgeons, physiatrists, and therapists maximizes outcomes. Emerging strategies, such as neurotrophic factor delivery and bioengineered nerve conduits, hold promise for improving brachial plexus injury treatment in the future.