The muscle attached to the lateral supracondylar ridge is the "Brachioradialis" with an insertion point in styloid process of the radius.

ridge is crista (cristae) in latin

With humerus bone scapula is envolved in two situations:

Medial supracondylar ridle and lateral supracondylar ridge

The deltoid tuberosity is proximal to the lateral condyle of the humerus. It's the site of attachment for the deltoid muscle.

Medial Supracondylar Ridge

(Source: Saladin Anatomy Physiology: The Unity of Form and Function Laboratory Manual Sixth Edition page 113.)

this muscle is otherwise known as supinator longus. it is one among the 7 superficial extensors of the posterior forearm.

origin : upper 2/3rd of the lateral supracondylar ridge of the humerus bone.