Radius (bone) in the grooves on the lower end of the bone. The lateral surface ("facies lateralis; external surface") is convex throughout its entire extent and is known as the convexity of the radius, curving outwards to be convex at the side. Its upper third gives insertion to the supinator muscle. About its center is a rough ridge, for the insertion of the pronator teres muscle. Its lower part is narrow, and covered by the tendons of the abductor pollicis longus muscle and extensor pollicis brevis muscle. The upper extremity of the radius (or proximal extremity) presents a head, neck, and tuberosity.
Occipitalis muscle Occipitalis muscle The occipitalis muscle (occipital belly) is a muscle which covers parts of the skull. Some sources consider the occipital muscle to be a distinct muscle. However, Terminologia Anatomica currently classifies it as part of the occipitofrontalis muscle along with the frontalis muscle. The occipitalis muscle is thin and quadrilateral in form. It arises from tendinous fibers from the lateral two-thirds of the superior nuchal line of the occipital bone and from the mastoid process of the temporal and ends in the epicranial aponeurosis. The occipitalis muscle is innervated by the facial nerve and its function is to move