Neurological · Patient education from the Pegasus Peak physiotherapy team.
Reviewed by the Pegasus Peak physiotherapy team — AHPRA-registered physiotherapists led by principal physiotherapist Kosta Logothetis. Last reviewed 2025-11-14.
Learn what the median nerve is, how it functions, and the most common injuries that affect it, including key symptoms and clinical patterns backed by evidence.
An overview of the median nerve, its path through the upper limb, and the most common conditions that involve it.
The median nerve is one of the most important nerves in the upper limb, running from the arm all the way down to the hand. Like other major nerves, it is responsible for both sensation and muscle activation, but due to its anatomical course through several tight spaces, it is also one of the more commonly injured nerves in the body.
The median nerve originates from the brachial plexus, specifically receiving contributions from the C5, C6, C7, C8 and T1 nerve roots. From there, it travels beneath the armpit, passes under the biceps brachii, and continues along the midline of the forearm until it reaches the wrist.
As it approaches the wrist, the nerve travels beneath the carpal tunnel, between the tendons of the forearm flexors. Because of this narrow passage, the nerve is highly susceptible to compression, especially in cases of carpal tunnel syndrome, where swelling or inflammation can cause pain to radiate from the hand up to the forearm or even the shoulder.
Median Nerve (Gray & Standring, 2020)
This interconnected pathway is why clinicians emphasise the importance of assessing joints above and below the site of pain when evaluating nerve injuries.
The median nerve provides motor innervation to several muscles of the forearm and hand, primarily those involved in flexion and pronation movements. Its distribution can be grouped according to muscular compartments (Ropper & Zafonte, 2025).
Superficial layer:pronator teres, flexor carpi radialis, and palmaris longus.
Intermediate layer:flexor digitorum superficialis.
Deep layer:flexor pollicis longus, pronator quadratus, and the lateral half of flexor digitorum profundus (the medial half of that muscle is innervated by the ulnar nerve).
Therecurrent branchof the median nerve innervates the thenar muscles, which control thumb movements.
Thepalmar digital branchesinnervate the lateral two lumbricals, which perform flexion at the metacarpophalangeal joints and extension at the interphalangeal joints of the index and middle fingers.
The sensory distribution of the median nerve is clinically significant. It supplies:
When this nerve is injured, these areas may become numb, tingle, or feel hypersensitive, depending upon the severity and duration of the injury.
When the median nerve is compromised, the resulting symptoms usually align with its sensory and motor territory. This means a person might experience:
Clinicians use these characteristic patterns to help localise the injury, determine its severity, and differentiate between peripheral entrapments and higher-level nerve root lesions.
Because of its long and exposed path, the median nerve can be injured at several key sites. The most common include:
This is the most well-known injury to the median nerve. Carpal tunnel syndrome occurs when the nerve is compressed beneath the transverse carpal ligament at the wrist. Common symptoms include numbness, tingling and weakness in the thumb and first three fingers (Dydyk, 2023).
Compression higher up in the forearm occurs as the nerve passes between the two heads of the pronator teres muscle. This is described by Dididze (2023) as pronator teres syndrome — presenting with forearm pain similar to carpal tunnel syndrome but a different anatomical location.
A purely motor branch of the median nerve, the anterior interosseous nerve can become compressed or injured, leading to weakness in pinching or gripping activities — particularly inability to form an “OK” sign with the thumb and index finger (Ulrich, Piatkowski & Pallua, 2011).
Compression of the median nerve can also occur more proximally in the arm or elbow, for example at the ligament of Struthers or under the lacertus fibrosus, which is described in the review by Miller (2010) and Tetro (1996) as “high median nerve entrapments”. These present with more extensive motor and sensory loss than wrist entrapments.
Direct trauma such as supracondylar humerus fractures, sharp lacerations or surgical procedures can injure the nerve at various levels. The StatPearls review notes that trauma to the arm or elbow may directly damage the median nerve trunk, resulting in paralysis of all its functions (Dydyk, 2023).
The median nerve plays a vital role in both movement and sensation throughout the forearm and hand. Its unique course through narrow anatomical spaces makes it vulnerable to several types of compression and injury, from carpal tunnel syndrome to traumatic lacerations.
Recognising the pattern of weakness and sensory loss is key to identifying where along its path the nerve is affected. Understanding its anatomy not only helps clinicians make accurate diagnoses but also ensures targeted rehabilitation and management for optimal recovery.
Binsaleem, S. (2025). Median nerve entrapment neuropathy: A review on the incidence, presentation, and management of median nerve compressive neuropathies.Journal of Peripheral Nerve Disorders, 2(1), 12–22.
Dididze, M. (2023). Pronator teres syndrome. InStatPearls. Treasure Island (FL): StatPearls Publishing.https://www.ncbi.nlm.nih.gov/books/NBK526090/
Dydyk, A. M. (2023). Median nerve injury. InStatPearls. Treasure Island (FL): StatPearls Publishing.https://www.ncbi.nlm.nih.gov/books/NBK553109/
Gray, H., & Standring, S. (Ed.). (2020).Gray’s anatomy: The anatomical basis of clinical practice(42nd ed.). Elsevier.
Lee, M. J., Lastayo, P. C., & Mayo, K. A. (2004). Pronator syndrome and other nerve compressions that mimic carpal tunnel syndrome.Journal of Orthopaedic & Sports Physical Therapy, 34(10), 601–614.https://doi.org/10.2519/jospt.2004.34.10.601
Miller, T. T., & Halpern, E. J. (2010). Nerve entrapment syndromes of the elbow, forearm, and wrist.AJR. American Journal of Roentgenology, 195(4), 862–871.https://doi.org/10.2214/AJR.10.4817
Tetro, A. M. (1996). High median nerve entrapments.Hand Clinics, 12(1), 107–118.
Ulrich, D., Piatkowski, A., & Pallua, N. (2011). Anterior interosseous nerve syndrome: retrospective analysis of 14 patients.Archives of Orthopaedic & Trauma Surgery, 131(11), 1561–1565.https://doi.org/10.1007/s00402-011-1322-5
Ropper, A. H., & Zafonte, R. D. (2025).Median nerve anatomy. InStatPearls[Internet]. Treasure Island (FL): StatPearls Publishing.https://www.ncbi.nlm.nih.gov/books/NBK448084/
Stretanski, M. F., Dydyk, A. M., & Cascella, M. (2025).Median nerve injury. InStatPearls[Internet]. Treasure Island (FL): StatPearls Publishing.https://www.ncbi.nlm.nih.gov/books/NBK553109/
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