Search results
Results from the WOW.Com Content Network
The ulna is ossified from three centers: one each for the body, the wrist end, and the elbow end, near the top of the olecranon. Ossification begins near the middle of the body of the ulna, about the eighth week of fetal life, and soon extends through the greater part of the bone. At birth, the ends are cartilaginous.
The styloid process of the ulna projects from the medial and back part of the ulna. It descends a little lower than the head. The head is separated from the styloid process by a depression for the attachment of the apex of the triangular articular disk, and behind, by a shallow groove for the tendon of the extensor carpi ulnaris muscle.
In mammals and non-human primates, the pisiform is an enlarged and elongated bone that articulates with the distal ulna. [5] In some taxa, the pisiform even articulates with the hammate or radius. [5] In these non-human taxa, the pisiform develops from two ossification centers that are divided by a palmar epiphyseal plate. [5]
The radius or radial bone (pl.: radii or radiuses) is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna. The ulna is longer than the radius, but the radius is thicker.
The ulnar bones are then ossified before the radial bones, while the sesamoid pisiform arises in the tendon of the flexor carpi ulnaris after more than ten years. [6] The commencement of ossification for each bone occurs over period like other bones. This is useful in forensic age estimation.
The olecranon is situated at the proximal end of the ulna, one of the two bones in the forearm. [1] When the hand faces forward the olecranon faces towards the back (posteriorly). It is bent forward at the summit so as to present a prominent lip which is received into the olecranon fossa of the humerus during extension of the forearm. [2] [3]
The humerus (/ ˈ h juː m ər ə s /; pl.: humeri) is a long bone in the arm that runs from the shoulder to the elbow.It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections.
The appendicular skeleton forms during development from cartilage, by the process of endochondral ossification. The appendicular skeleton is divided into six major regions: Shoulder girdle (4 bones) - Left and right clavicle (2) and scapula (2). Arms and forearms (6 bones) - Left and right humerus (2) (arm), ulna (2) and radius (2) (forearm).