Omohyoid muscle the body of the hyoid bone, lateral to the insertion of the sternohyoid. The central tendon of this muscle varies much in length and form, and is held in position by a process of the deep cervical fascia, which sheaths it, and is prolonged down to be attached to the clavicle and first rib; it is by this means that the angular form of the muscle is maintained. The tendon overlies the internal jugular vein, and can be used as a landmark for this vein during surgery. Doubling; absence; origin from clavicle; absence or doubling of either belly. The inferior
Splenius capitis muscle of the temporal bone, and into the rough surface on the occipital bone just below the lateral third of the superior nuchal line. The splenius capitis is deep to sternocleidomastoideus at the mastoid process, and to the trapezius for its lower portion. It is one of the muscles that forms the floor of the posterior triangle of the neck. The splenius capitis muscle is innervated by the posterior ramus of spinal nerves C3 and C4. The splenius capitis muscle is a prime mover for head extension. The splenius capitis can also allow lateral flexion and rotation of the cervical spine.