Mapping Origins of Tendons on the Lateral Epicondyle

To map the dimensions of key structures in the lateral elbow, focusing on the relationships between the extensor carpi radialis brevis (ECRB), extensor digitorum communis (EDC), joint capsule, and lateral collateral ligament (LCL).

Six cadaveric arms were dissected to measure the lateral elbow structures: extensor carpi radialis longus (ECRL), ECRB, EDC, LCL, extensor carpi ulnaris, and anconeus. Each structure was isolated, and then, the origin dimensions were recorded in height, width, and distance from the lateral epicondylar prominence and joint capsule. Mean measurements and two standard errors for each tendon were calculated.

The ECRB was, on average, observed to be 8.3 ± 0.8 mm proximal to distal and 7.6 ± 0.3 mm anterior to posterior. The ECRB was 0 mm from the joint capsule. The EDC was observed to have average lengths of 5.1 ± 0.6 mm proximal to distal and 7.3 ± 0.9 mm anterior to posterior. The EDC, on its distal-most edge, touches the LCL's proximal edge. The mean distance from the LCL to the epicondyle was observed to be 10.3 ± 1.5 mm.

Avoiding dissection more than 1 cm distal to the lateral epicondylar prominence and 1 cm posterior to the capitellum will avoid injury to the LCL and will allow for debridement of both the ECRB and EDC.

These findings provide anatomical benchmarks to help surgeons avoid inadvertent damage to the LCL and joint capsule in lateral epicondylitis surgeries.