Bone Radius

211. The bones of the forearm are the radius, ulna and ligament bones located in the armpit: the wrist joint, carpometacarpal joints and intermetacarpal muscles. The radius bone is unpaired, located on the back surface of the forearm between the ulna and radius bones. The articular circumference is larger than the articular circumference of the ulna, so when turning it is less stable to varus loads. Its inferior articular surface articulates with the lunate surface of the head of the radius. The lower articular surface has a spongy structure. The semilunar fossa on the head serves to connect with the base of the deep plate of the radial bone. The ulnar fossa is located on the posteroinferior edge of the bone and connects it to the ulna. Between them is articular cartilage. The cartilage is slightly more than 4 mm thick. The sharply defined boundary between the cortical plates of the radius and ulna is the interosseous line. The anterior edge of the radial bone is formed by a spiral groove along which the canal for the radial bone (canalis radialis) is located. The canal is made of spongy bone tissue; inside the bone there is a narrow canal through which the neurovascular bundle passes; the bundle is surrounded by epiphyseal cartilage. At the back, the epiphysis is covered with a bone-fibrous membrane covered with peritoneum. At the ends the bone is covered with hyaline cartilage in the shape of a crescent. The anterior ends of the fingers articulate with the processes of the anterior ends of the metacarpal bones; the lower ends end in nail phalanges with claws. The lateral surface of all the bones of the foot bones is convex and limited by the plantar surface. There is a tuberosity in the distal part of the lateral side of the outer edge of the tibia. On the backs of the proximal phalanges there are special digital processes, which include the lower phalanges of the small and big toes.\n\nThe skeleton of the skull head is formed by paired and unpaired bones, which are connected by sutures, as well as by fixed bone joints using synostoses in the unpaired and paired bones. \n\nThe skull is an independent organ and is a bone box (sutura cranii), which in certain areas has sutures to create its strength. Below the cranial vault is the cranial cavity, where the head is located.