Nerve Distribution Map

Trace nerve pathways and innervation territories. Explore sensory dermatomes, motor innervation, and nerve distribution patterns.

Clinical

Course
Motor Territory
Sensory Territory
Key Branches
Injury / Clinical

Select a nerve above to view its distribution, motor and sensory territories.

How to Use

  1. 1
    Select a nerve or plexus

    Choose a peripheral nerve, spinal nerve, or nerve plexus (brachial, lumbar, sacral, or cervical) from the catalogue; the tool retrieves its origin, course, branches, and the specific structures it innervates in both motor and sensory territories.

  2. 2
    Trace the nerve pathway

    Follow the nerve's anatomical course through named compartments, fascial planes, and anatomical tunnels, noting clinically significant sites of vulnerability such as the radial nerve in the spiral groove or the common fibular nerve at the fibular head.

  3. 3
    Examine motor and sensory territories

    View the full motor distribution (muscles innervated with root levels) and sensory distribution (cutaneous territory mapped to dermatomes), and cross-reference with adjacent nerves to understand overlap zones and distinguish complete from partial nerve lesions.

About

The peripheral nervous system carries motor commands from the spinal cord to skeletal muscles and relays sensory signals from the body surface and deep structures back to the central nervous system. This bidirectional communication occurs through a precisely organized network of spinal nerves, plexuses, and peripheral nerve trunks, each following a defined anatomical course that determines its vulnerability to injury and its clinical presentation when damaged. Terminologia Anatomica 2nd edition catalogues over 800 named neural structures in the peripheral nervous system, reflecting the complexity of this network.

The Nerve Distribution Map provides interactive access to the full peripheral nerve catalogue, organized by plexus, spinal nerve level, and anatomical region. For each nerve, the tool displays the course through fascial compartments and anatomical tunnels, identifies all motor branches with their target muscles and root levels, and maps the cutaneous sensory territory using both dermatome charts (following Keegan-Garrett reference standards) and peripheral nerve territory maps (following the Head-Sherren convention). The juxtaposition of these two overlapping but distinct maps is essential for clinical neurological examination and differential diagnosis.

Clinical correlations throughout the tool reflect the most common peripheral nerve pathologies: brachial plexus injuries from motor vehicle accidents and obstetric trauma, entrapment neuropathies at anatomically constrained sites, and the neurological consequences of orthopedic procedures. The autonomic nerve distribution panels support understanding of conditions such as Horner syndrome, reflex sympathetic dystrophy, and the bladder and bowel complications of sacral nerve injuries — areas where anatomical knowledge directly informs management according to the American Association of Electrodiagnostic Medicine (AANEM) and the International Association for the Study of Pain (IASP).

FAQ

What is the difference between a dermatome and a peripheral nerve sensory territory?
A dermatome is the area of skin supplied by a single spinal nerve root (e.g., C6 supplies the thumb and radial forearm), while a peripheral nerve cutaneous territory is the area supplied by a specific peripheral nerve formed from multiple roots (e.g., the median nerve supplies the palmar surface of the lateral 3.5 digits). These maps overlap but are clinically distinct — a C6 radiculopathy affects a different pattern than a median nerve injury at the wrist. The Nerve Distribution Map displays both dermatomes (following Keegan and Garrett's reference maps) and peripheral territories to support differential diagnosis of sensory complaints.
Which nerve plexuses does the tool cover?
The tool covers all major peripheral nerve plexuses: the cervical plexus (C1–C4, giving rise to the phrenic nerve and cutaneous cervical branches), brachial plexus (C5–T1, the most complex and clinically important plexus), lumbar plexus (L1–L4, giving femoral, obturator, and lateral femoral cutaneous nerves), sacral plexus (L4–S3, giving the sciatic, gluteal, and pudendal nerves), and coccygeal plexus. The brachial plexus receives the most detailed treatment, including its roots, trunks, divisions, cords, and terminal branches, reflecting its clinical importance in birth injuries, thoracic outlet syndrome, and penetrating trauma.
What are the most clinically important nerve compression sites?
The tool documents all major entrapment neuropathy sites: the carpal tunnel (median nerve), cubital tunnel (ulnar nerve at elbow), radial tunnel (posterior interosseous nerve), piriformis muscle (sciatic nerve), fibular head (common fibular nerve), and tarsal tunnel (tibial nerve). Each site includes the anatomical boundary of the tunnel or aperture, the provocative examination maneuvers that reproduce symptoms, electrodiagnostic criteria for confirmation (nerve conduction velocity thresholds per AANEM guidelines), and conservative versus surgical management principles.
How does the tool represent autonomic nerve distribution?
The autonomic nervous system is represented with separate panels for sympathetic and parasympathetic distributions. The sympathetic division is organized by paravertebral ganglia levels (T1–L2 outflow) and the sympathetic chain, while parasympathetic coverage includes the four cranial nerves with parasympathetic fibers (CN III, VII, IX, X) and the sacral splanchnic nerves (S2–S4). This is particularly useful for understanding neurogenic bladder, Horner syndrome, and the autonomic consequences of spinal cord injury at various levels.
Can the tool help interpret nerve conduction study findings?
Yes — the tool provides reference data supporting electrodiagnostic interpretation, including the motor and sensory branch territories used as recording sites in standard nerve conduction studies. For each major nerve (median, ulnar, radial, fibular, tibial, sural), the anatomical course of electrodes used in standard NCS protocols is shown alongside the muscle or skin territory being assessed. While clinical normative values vary by laboratory, the anatomical substrate displayed here aligns with the AANEM practice guidelines and standard electrodiagnostic textbooks such as Preston and Shapiro's Electromyography and Neuromuscular Disorders.

Educational Disclaimer

This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical decisions.

Data sources: Terminologia Anatomica, Foundational Model of Anatomy, Wikidata.