Lateral supracondylar ridge

The lower part of the lateral border of the body of the humerus forms a prominent, rough margin, a little curved from behind forward, the lateral supracondylar ridge (or line), which presents an anterior lip for the origin of the Brachioradialis above, and Extensor carpi radialis longus below, a posterior lip for the Triceps brachii, and an intermediate ridge for the attachment of the lateral intermuscular septum.