Pisiform bone Pisiform bone The pisiform bone ( or ), also spelled pisiforme (from the Latin "pisifomis", pea-shaped), is a small knobbly, sesamoid bone that is found in the wrist. It forms the ulnar border of the carpal tunnel. The pisiform is a sesamoid bone, with no covering membrane of periosteum. It is the last carpal bone to ossify. The pisiform bone is a small bone found in the proximal row of the wrist (carpus). It is situated where the ulna joins the wrist, within the tendon of the flexor carpi ulnaris muscle. It only has one side that acts as a
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.