hyperparathyroidism

Most people have four pea-sized glands, called parathyroid glands, on the thyroid gland in the neck. Though their names are similar, the thyroid and parathyroid glands are completely different. The parathyroid glands make parathyroid hormone (PTH), which helps your body keep the right balance of calcium and phosphorous.

If your parathyroid glands make too much or too little hormone, it disrupts this balance. If they secrete extra PTH, you have hyperparathyroidism, and your blood calcium rises. In many cases, a benign tumor on a parathyroid gland makes it overactive. Or, the extra hormones can come from enlarged parathyroid glands. Very rarely, the cause is cancer.

If you do not have enough PTH, you have hypoparathyroidism. Your blood will have too little calcium and too much phosphorous. Causes include injury to the glands, endocrine disorders, or genetic conditions. Treatment is aimed at restoring the balance of calcium and phosphorous.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases

Your bones help you move, give you shape and support your body. They are living tissues that rebuild constantly throughout your life. During childhood and your teens, your body adds new bone faster than it removes old bone. After about age 20, you can lose bone faster than you make bone. To have strong bones when you are young, and to prevent bone loss when you are older, you need to get enough calcium, vitamin D, and exercise. You should also avoid smoking and drinking too much alcohol.

Bone diseases can make bones easy to break. Different kinds of bone problems include:

• Low bone density and osteoporosis, which make your bones weak and more likely to break
• Osteogenesis imperfecta makes your bones brittle
• Paget's disease of bone makes them weak
• Bones can also develop cancer and infections
• Other bone diseases, which are caused by poor nutrition, genetics, or problems with the rate of bone growth or rebuilding

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Your jaw is a set of bones that holds your teeth. It includes:

• The maxilla, which is the upper part of your jaw. It holds your top teeth in place and doesn't move. It also supports the muscles involved in chewing and facial expressions.
• The mandible, which is the lower part of your jaw. You move it when you talk or chew. It also holds your lower teeth in place.
• The temporomandibular joints (TMJs), which are two joints (one on each side) that connect your mandible to your skull.

Jaw problems can include:

• Fractures (broken bones).
• Dislocations, which are joint injuries that force the ends of your bones out of position.
• Temporomandibular disorders (TMDs), which are conditions that affect your TMJs.
• Osteonecrosis, which happens when the blood flow to part of your bone is disrupted. It can cause the bone to break down.
• Jaw tumors, which can be benign (not cancer) or cancer.
• Jaw defects, which are birth defects in which your jaw could be missing or deformed.

Diagnostic imaging tests are often used to diagnose jaw injuries and disorders. Your treatment will depend on which jaw problem you have.