Median Nerve Palsy: Causes, Symptoms, and Acupuncture Treatment

Median nerve palsy is a condition caused by injury or compression of the median nerve due to various reasons, leading to motor and sensory dysfunction within the area innervated by the median nerve.

The median nerve contains motor, sensory, and autonomic nerve fibers. It originates from the spinal cord at cervical levels 6 to 8 and thoracic level 1, and occasionally from cervical level 5. It primarily has the following four branches:

1. Muscular Branch

The pronator teres muscle is innervated. It is located on the radial side of the palmar aspect below the elbow joint. When this muscle contracts, it causes the forearm to pronate.

With the arm pronated and the forearm flexed, the flexor carpi radialis produces wrist flexion and abduction; the palmaris longus tenses the palmar fascia and flexes the wrist; the flexor digitorum superficialis flexes the middle phalanges of the 2nd to 5th fingers.

2. Anterior Interosseous Nerve (of the forearm)

It innervates the flexor pollicis longus, which flexes the distal phalanx of the thumb; the flexor digitorum profundus, which flexes the distal and middle phalanges of the 2nd to 5th digits and flexes the wrist; and the pronator quadratus, which pronates the forearm.

**Common Palmar Digital Nerve**

It innervates the abductor pollicis brevis, causing flexion of the first phalanx of the thumb, and the third and fourth lumbricals, causing flexion of the metacarpophalangeal joints.

4. Palmar Branch

It belongs to the cutaneous nerve, distributing to the skin of the thenar eminence and the flexor side of the wrist joint.

The common primary causes include post-fracture injury or compression, direct traumatic compression of the median nerve, accidental stimulation or injury of the median nerve during surgery, median nerve fibroma, systemic metabolic diseases (e.g., diabetes mellitus), or poisoning (e.g., lead poisoning). Additionally, certain occupations involving repetitive wrist use, inflammation of the carpal tunnel, and other factors can all lead to median nerve palsy.

【Diagnostic Key Points】

Depending on the specific location of median nerve damage, the number and degree of affected muscle paralysis vary, but can generally be classified into two major categories: motor impairment and sensory impairment.

I. Motor Disorders (Yundong Zhang’ai)

For example, when the median nerve is damaged proximal to its branch to the forearm muscles, paralysis may occur in all the aforementioned muscles, though to varying degrees. Since the median nerve plays a crucial role in maintaining thumb function, complete median nerve paralysis results in the inability to flex the thumb and oppose it to the little finger. Opposition between the thumb and other fingers also becomes difficult, making it impossible to grasp objects. Under normal conditions, when the thumb opposes the little finger, the entire pads of both fingers come into contact. In median nerve paralysis, a false opposition position appears. This occurs because the deep head of the flexor pollicis brevis and the adductor pollicis are innervated by the ulnar nerve; these two muscles cause thumb adduction and flexion of the first phalanx, leading to the false opposition position. The thumb shifts to the same plane as the other fingers, the thenar eminence atrophies, and the palm flattens into an “ape-hand” deformity. Due to the action of antagonistic muscles, the second and third fingers assume a slightly extended position. If the only manifestation is the inability to oppose the thumb and little finger, this indicates that the median nerve lesion is located in the middle or lower third of the forearm.

Forearm pronation is limited, but with the upper limb in a flexed position, the brachioradialis (innervated by the radial nerve) allows slight pronation. In median nerve paralysis, wrist flexion is weakened; however, the flexor carpi radialis (innervated by the radial nerve) and the palmaris longus (innervated by the ulnar nerve) also contribute to wrist flexion, so some flexion function is preserved. When flexing the wrist, ulnar deviation occurs due to traction from the flexor carpi ulnaris (innervated by the ulnar nerve).

II. Sensory Disturbances

The sensory distribution is mainly located on the radial half of the palm and the dorsal aspects of the distal phalanges of the index and middle fingers (2nd and 3rd digits), with the most pronounced changes in the distal segments of the thumb, index, and middle fingers. Because the median nerve is rich in sympathetic nerve fibers, damage to it often causes burning pain (causalgia). When sympathetic nerve impairment is prolonged, significant trophic disturbances and vasomotor dysfunctions are frequently observed in the skin and nails: on the lateral half of the palmar surface of the hand, the skin appears pale or flushed, with hyperhidrosis or anhidrosis—most evident in the middle and index fingers. Occasionally, the skin becomes dry with hyperkeratosis or thinning, and the nails become brittle and lose their normal luster.

Treatment

I. Acupoints and Needling Methods

1. **PC2 (Tianquan)** (affected side): Located 2 *cun* below the anterior axillary fold, between the short and long heads of the biceps brachii muscle. To locate, extend the arm with the palm facing upward. Use a 30-gauge, 2 *cun* filiform needle. Perform routine local disinfection. Insert the needle along the medial border of the humerus to a depth of approximately 1.8 *cun*. Needling sensation: local distension and pain, or radiation toward the wrist.

2. LI11 (Quchi) on the affected side: Located on the elbow, with the elbow flexed and the hand held as if offering a salute, in the depression at the radial end of the cubital crease. Using a 30-gauge, 2-cun filiform needle, perform routine local disinfection, then insert perpendicularly toward HT3 (Shaohai) to a depth of approximately 1.8 cun. Needling sensation: local distension and pain.

3. PC6 (Neiguan) on the affected side: Located 2 cun proximal to the palmar wrist crease, between the tendons of palmaris longus and flexor carpi radialis. Use a 30-gauge, 1.5 cun filiform needle. After routine local disinfection, insert perpendicularly toward TE5 (Waiguan) to a depth of approximately 1.3 cun. Needling sensation: local distension and pain, or radiation toward the dorsum of the hand and the middle finger.

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

2. Methods

The patient assumes a sitting position. The above acupoints are needled according to the standard method, with electroacupuncture applied. The needles are retained for 40 minutes and then removed.

Once daily, with 10 sessions constituting one course of treatment. Rest for 5 days before resuming acupuncture.

[Commentary]

For patients with median nerve palsy, electroacupuncture treatment, though requiring a relatively longer duration (generally showing effect after about three courses of treatment), yields quite satisfactory results. For temporary palsy caused by inflammation or hematoma compression, the therapeutic outcome is even more favorable (often showing improvement within about ten sessions). In cases of muscle atrophy due to median nerve rupture from various causes, the aforementioned method can often restore atrophied muscles and partially recover nerve function. However, such patients are generally difficult to cure completely; if no effect is observed after three courses of treatment, acupuncture should be discontinued and surgical intervention should be considered.

Clinical Manifestations of Median Nerve Dysfunction

Median nerve palsy symptoms hand dysfunction is often the most conspicuous aspect of this condition. The median nerve provides motor innervation to the thenar muscles (abductor pollicis brevis, opponens pollicis, and superficial head of flexor pollicis brevis) as well as the first and second lumbricals. Sensory innervation covers the palmar aspect of the thumb, index, middle, and radial half of the ring finger. Consequently, patients typically present with impaired thumb opposition and abduction, leading to a characteristic “ape hand” deformity in chronic cases. Fine motor tasks, such as pinching or gripping small objects, become markedly difficult. Sensory loss in the aforementioned digits can result in diminished tactile discrimination and an increased risk of inadvertent injury. Autonomic fibers within the nerve may also be affected, causing reduced sweating and vasomotor changes in the skin. These deficits collectively impair hand function and quality of life, making early recognition of the symptom complex critical for timely intervention.

Etiology and Pathophysiology of Median Nerve Injury

The causes of median nerve palsy are diverse, spanning traumatic, compressive, and systemic origins. The most common compressive syndrome is carpal tunnel syndrome, where the nerve is entrapped beneath the transverse carpal ligament at the wrist. Acute trauma, such as supracondylar fractures of the humerus or distal radius fractures, can directly injure the nerve. Lacerations at the volar wrist are another frequent cause. More proximal lesions occur in the pronator teres syndrome or within the forearm due to anatomical anomalies or repetitive strain. Systemic conditions, including diabetes mellitus, hypothyroidism, and amyloidosis, may predispose to nerve compression. Regardless of etiology, the pathophysiology involves a disruption of axonal transport and eventual demyelination or axon loss. External pressure or ischemia leads to endoneurial edema, impairing nerve conduction. In severe or prolonged cases, irreversible fibrosis and motor endplate degeneration develop, underscoring the importance of identifying the underlying cause promptly to guide appropriate management.

Therapeutic Strategies and Prognostic Outlook

Median nerve palsy treatment options are tailored to the specific etiology, severity of dysfunction, and chronicity. Conservative measures—including activity modification, wrist splinting in neutral position, and nonsteroidal anti-inflammatory drugs—are first-line for compressive neuropathies like carpal tunnel syndrome. Corticosteroid injections can provide transient relief by reducing local inflammation. When significant motor weakness or atrophy is present, or when nonoperative management fails, surgical decompression (e.g., carpal tunnel release or pronator teres release) is indicated. Acute lacerations or fractures require prompt microsurgical repair or nerve grafting to maximize functional recovery. Postoperatively, hand therapy and neuromuscular re-education are essential. The median nerve palsy recovery time varies widely based on the injury’s nature: mild compression may resolve within weeks after decompression, while severe axonotmetic or neurotmetic injuries can require months to years for regeneration—if at all. Long-term outcomes depend on patient age, comorbidities, and adherence to rehabilitation. Recovery of sensory function often precedes motor recovery, but permanent deficits remain common in advanced cases.