Human skeleton: 206 bones account for 14% body’s weight
Babies are born with 270 bones but some of them join together in the first years. In the end, an adult person has 206 bones. In adults, bones account for 14% of the body’s total weight.
Bones stops growing in length during puberty. However, bone density and strength will change over the course of life. Bones are made up of calcium, phosporus, sodium, and other mineral, as well as, protein collagen.
- The largest bone is the femur, or tight bone, which can be 50 cm long. It is much stronger than concrete and as strong as granite. Although bones are surprisingly strong they are not the hardest subtance in the body. Tooth enamel, the substance that protects the crown of teeth it is the hardest.
- The smallest one, the stapes, is in the middle ear and is about 3 mm long.
- The Hyoid bone, in our throat, is the only joinless bone in our body, not attached to other bone. It is often consider the anatomical foundation of speech; because of where it is located, it can work with the larynx (voice box) and tongue to produce the range of human vocalizations.
- Human bone marrow produces approximately 500 billion blood cells per day. It is commonly found in the centre of many bones. Primarily in the ribs, vertebrae, sternum, and bones of the pelvis. It constitus 4% of all body mass.
- Hands and feet contain over half ot the body’s bones. Bones are not evently distributed throughout the body. Each hand has 27 bones and each foot has 26, which means together they have 106 bones.
- Most adults have 24 ribs (12 pairs) but 1 in every 500 people has an extra rib called cervical rib.
Most common bone disease
Osteoporosis is a bone disease that damages the skeleton and makes bones weak and prone to fracture due to low bone mass and bone structure deteroriation. This low bone mass is cause by the lost of minerals, like calcium.
Other related disease is Paget’s diseases, also known as osteogenesis imperfecta. It causes skeletal deformities and fractures.
More than 3 million people in the UK are estimated to have osteoporosis, a condition that causes around 500,000 broken bones every year – that’s one every minute.
Most common forms of bone cancer
- Osteosarcoma typically starts in bone cells in the arms, legs, or pelvis. Most frequently in individuals between the ages of 10 and 30, and it is more common in males than females.
- Chondrosarcoma forms in cartilage cells. This type of cancer rarely occur in people under the age of 20. The chances of developing increases with age.
- Ewing’s sarcoma. Although typically starts in the bones it can also appear in tissues and muscles. This is the third most common type of bone cancer and frequently in children and teenagers.