Sonoanatomy of the Posterior Cutaneous Nerve of the Forearm: A Proposed Approach for Blockade in Lateral Epicondylitis (LEPI-Block)

Lateral epicondylitis (LE), commonly known as tennis elbow, is a prevalent cause of chronic lateral elbow pain and functional limitation.Despite a range of conservative and interventional treatments, many patients experience persistent symptoms, and there is no universally accepted gold standard therapy.This descriptive anatomical study aimed to establish an ultrasound-guided technique to identify and target the posterior cutaneous nerve of the forearm (PCNF), a sensory branch of the radial nerve implicated in lateral epicondylar innervation.Twenty elbows from healthy volunteers were evaluated using high-resolution ultrasound to visualize the PCNF and determine its anatomical relationship to the lateral epicondyle.A structure consistent with the PCNF was identified in all 20 ultrasound examinations, with a mean PCNF depth of 6.03 ± 0.26 mm from the skin surface and a mean distance of 9.40 ± 0.95 mm from the lateral epicondyle.In one case, hydrodissection followed by low-voltage sensory stimulation enabled functional sensory mapping, providing preliminary functional evidence supporting the sensory distribution of the PCNF in the lateral epicondylar region.These findings support the feasibility of ultrasound-guided identification and targeting of the PCNF using the proposed LEPI-Block technique and establish a standardized sonoanatomical approach that may serve as a foundation for future diagnostic studies in patients with LE.