Adults have 206 bones. Babies are born with about 300 bones, but many fuse together as the baby grows. According to St. Louis University's Practical Anatomy and Surgical Education Center, there are four types of bone: long bones, which are strong, compact and slightly curved; short bones, which are spongy; flat bones, which consist of layers of compact and spongy bone; and irregular bones, which contain various proportions of compact and spongy bone. These main types of bones, connected by joints, make up the human skeleton.
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The cranium is the flat bone that covers and protects the brain and forms the shape of the face. Eight bones, a frontal bone, two temporal bones, two parietal bones, an occipital bone, an ethmoid bone and a sphenoid bone, fuse together during early childhood. Babies have spaces between the bones in their skull to allow them to fit through the birth canal, explains KidsHealth. The maxilla, or upper jaw bone, and mandible, or lower jaw bone, as well as several small facial bones, connect to the cranium to make up the skull.
The spine is made up of 24 irregular bones called the vertebrae, the sacrum and the coccyx, according to Teacher Vision. The top seven vertebrae, called the cervical vertebrae, make up the neck. The next 12, the thoracic vertebrae, attach to the ribs, and the last five vertebrae are in the lumbar, or lower, region. Disks of cartilage separate all of the vertebrae. The sacrum is directly below the lumbar vertebrae, and the coccyx is below that. These lower sections of the spine help with balance and weight bearing. The sacrum is also the bone that is attached to the pelvis, or hipbone.
The ribs create a bony cage protecting organs such as the heart, lungs and liver. According to KidsHealth, while most people have 12 pairs of ribs, occasionally someone has one extra or one missing pair of ribs. The top seven ribs connect to the sternum, or breastbone. The sternum also attaches to the clavicle, or collarbone. The thoracic vertebrae hold all 12 ribs in place.
Several major bones make up your limbs. The arms each contain one humerus, which is the large bone at the top of the arm, and two long bones in the forearm, which are the ulna and radius. The carpals are the wrist bones. The long bone in the thigh, called the femur, and two long bones running from the knee to the ankle, called the tibia and the fibula, make up the legs. The ankle bones are called tarsals. The metacarpals and metatarsals are hand and foot bones, respectively, and the phalanges are the finger and toe bones.