Glossary of the Terminologies Related to Bone Health

A glossary is a dictionary of terms specific to a certain subject. In this bone health related glossary you can quickly look up all those technical words :

Bone health related glossary

Arthritis

The term arthritis does not refer to a single disease. Arthritis is any joint disorder caused by inflammation of the bones and joints. There are nearly 100 types of arthritic conditions and related disorders including osteoarthritis (OA) and rheumatoid arthritis (RA).

People of all ages, genders, and races can develop arthritis. It is one of the leading causes of chronic disability across the world. Some forms of arthritis, like osteoarthritis, are more common in women. The risk of osteoarthritis increases with age while rheumatoid arthritis can affect younger individuals.

Athletic Energy Deficit

Athletic Energy Deficit or AED refers to the gaps in energy when sustained activity (energy output) is not balanced by the proportional rise in proper nutrition (energy input). AED usually develops when eating habits to reduce weight are emphasized, particularly in athletes for whom a low body weight is considered favorable.

Athletic Energy Deficit can increase the risk of bone loss making the bones porous and prone to fractures. Early detection and treatment of Athletic Energy Deficit can help people follow appropriate dietary habits and prevent osteoporosis.

Bisphosphonates

Bisphosphonates are a group of drugs that help to improve bone health by slowing down the activity of the cells that break down bone tissues. These medications are usually prescribed to patients diagnosed with osteoporosis to prevent further loss of bone mass.

Bone

The bones are the rigid organ that forms the skeleton. Bones play a prominent role in facilitating body movement. They protect internal organs, store minerals, produce white and red blood cells and provide support and structure to the body.

Bone mineral content

Bone mineral content, or BMC, is the measurement of the bone minerals found in specific bone tissues. BMC is measured in grams.

Bone mineral density

Bone mineral density, or BMD, is a measurement of the density of bone tissue within the mass that forms bones. It is measured in grams per square centimeter, indicating the weight of bone mass per area or volume of bone tissue.

Low bone mineral density indicates a higher risk of osteoporosis. It also signifies that the bones could be prone to fractures given their low density or porousness.

Calcium

Calcium is the most important mineral for bone health. It is also one of the plentiful minerals found in the human body. An optimum level of calcium is essential for maintaining the strength of bones and teeth. Other body tissues such as nerve cells, blood, and some fluids also contain calcium, though in lesser amounts.

Calcium helps to build bone mass. A deficit of this key nutrient is a common precursor to osteoporosis. A calcium deficiency can reduce the bones’ mass, making them porous and weaker thereby increasing the risk of fractures. Lack of an adequate amount of calcium in the body can also increase the risk of other forms of arthritis and loss of teeth.

The functions performed by calcium include:

Building stronger bones and teeth
Contracting and relaxing muscles
Sending and receiving nerve impulses
Supporting blood clotting processes
Maintaining a normal heartbeat
Releasing hormones and chemicals such as neurotransmitters

Calcitonin

Calcitonin is the hormone secreted by the thyroid. It is used in the treatment of osteoporosis. It can help to improve bone health by increasing bone density. It can also reduce pain caused by fractures. It works by inhibiting the loss of calcium from the bones.

Cortical bone

Cortical bone is the part of the bone tissue that forms its dense, hard outer shell. Cortical bone is generally found in the long bones such as the femur and tibia and the outer part of the vertebrae.

Dual-energy x-ray absorptiometry (DXA)

DXA is a quantitative imaging technique, which uses small amounts of radiation to measure bone mineral density.

Dual-energy x-ray absorptiometry is also called bone density scanning or bone densitometry. It is an enhanced x-ray technology that can measure bone loss more accurately than other imaging techniques. DXA is usually recommended to evaluate the bone mineral density of the hips and lower spine.

Femur scan

A femur scan a diagnostic test recommended for measuring 3 regions of the femur including the femoral neck, the greater trochanter, and Ward’s triangle, an area in the femoral neck region.

A femur scan is recommended to assess the strength of the femur bone and to detect any fractures that are not visible by X-rays or other imaging techniques. A femur scan is an efficient diagnostic tool to detect osteoporosis.

Fracture

A break in the bone is called a fracture. It usually occurs as a result of trauma. A fracture may also be caused without any significant trauma when the bones have become weak or porous.

Hypercalcemia

Hypercalcemia is a condition caused by increased levels of calcium in the blood. When the calcium levels rise significantly above normal, it can lead to the formation of “stones” or calcified masses in bones, muscles, and kidneys.

The calcified mass can cause pain and other symptoms depending on its location. A kidney stone is a common result of high calcium levels in the blood. Too much calcium in the body can also weaken bones and interfere with heart and brain functions.

Ipriflavone

Ipriflavone is a synthetic isoflavone that can mimic estrogen. It is used to improve bone density and reduce the risk of osteoporosis and fractures. The use of Ipriflavone is also recommended for improving muscle strength. However, Ipriflavone is not meant to replace healthier alternatives to improve bone health like a healthy diet containing calcium and vitamin D-rich foods.

Kidney stone

A kidney stone is the formation of hard objects in the kidneys. The stones are usually made of calcium and other chemicals in the urine. The abnormal levels of various metabolites and minerals in the blood are responsible for the formation of kidney stones.

The common stone-forming chemicals include calcium, oxalate, cystine, urate, phosphate, and xanthine. The possible risk factors include not drinking enough water, without enough water, urine becomes concentrated with higher levels of stone-forming chemicals.

Increased calcium levels in the body, particularly due to the long-term use of calcium and vitamin D supplements, is commonly linked to a higher risk of developing kidney stones.

Patients with osteoporosis, who are using calcium or vitamin D supplements, need to be cautious about the possible risk of kidney stones.

Kyphoplasty

Kyphoplasty is a treatment for the management of painful compression fractures in the vertebral column or spine. A compression fracture causes the collapse of all or a part of the vertebrae. Kyphoplasty is a surgical procedure that involves injecting acrylic bone cement into the fracture. It can be performed in a hospital or an outpatient clinic.

The goal of the kyphoplasty procedure is to relieve the pain caused due to a spinal fracture and stabilize the bone. It can also help to restore all or some of the vertebral body height that was lost due to the fracture. Kyphoplasty is an effective procedure for restoring Vertebral Augmentation in patients with Compression Fractures.

Kyphosis

Kyphosis is the abnormal curvature of the spine in which there is bowing out or rounding of the vertebral column. Kyphosis can result in a slouching posture or hunchback. Kyphosis usually affects the thoracic vertebrae. It can occur at any age, though it is rare in children.

In adults, kyphosis is often caused by:

Degenerative conditions of the spine like arthritis and disk degeneration
Fractures caused due to osteoporosis such as osteoporotic compression fractures
Injury to the vertebral column
Spondylolisthesis caused due to the forward slipping of one vertebra on another

Some rare causes of kyphosis include hormonal imbalances, connective tissue disorders, chronic infections affecting the lungs like tuberculosis, and muscular dystrophy.

Neurofibromatosis, tumors in the tissues of the back, Paget disease caused due to the abnormal bone regrowth and destruction, and genetic conditions, like spina bifida, can also cause kyphosis.

Magnesium

Magnesium is one of the essential minerals the body needs to function optimally. Magnesium is required for nearly 300 biochemical processes in the body. It plays a role in maintaining the normal functions of nerves and muscles. It also supports the immune system, maintains a regular heartbeat, and enhances bone strength.

Magnesium can also regulate blood sugar levels and help in the production of proteins and energy.

Adequate levels of Magnesium are essential for the prevention of hypertension, heart diseases, and diabetes. Lack of magnesium in the diet can result in weaker bones, increasing the risk of osteoarthritis and osteoporosis.

Malabsorption

Malabsorption is a condition that prevents the efficient absorption of nutrients through the intestine.

Intestinal disorders, especially inflammatory bowel diseases, like ulcerative colitis and Crohn’s disease, can prevent the breakdown and absorption of calcium and other nutrients. As a result, patients develop osteoporosis in spite of consuming a calcium-rich diet.

The use of calcium and vitamin D supplements may not help patients if the nutrients from supplements will not be absorbed. It is important to detect malabsorption during the management of osteoporosis, especially when a patient suffers from weak and porous bones in spite of eating nutritious foods or taking supplements.

Sometimes, patients need administration of calcium and vitamin D in the form of injections so that the nutrients can reach the blood and bones directly by skipping the process of digestion.

At the same time, it is essential to address the underlying cause of osteoporosis by treating the cause of malabsorption.

Menopause

Menopause is the phase in the life of a woman when her menstrual periods stop. It is a natural phase that occurs usually at the age of 45 to 55. After menopause, women no longer get menstrual periods and cannot get pregnant naturally.

Menopause is commonly linked to declining bone health resulting in osteoporosis.

During menopause, the woman’s ovaries stop producing eggs. This occurs due to the fluctuations in the levels of female reproductive hormones like estrogen and progesterone. The lower levels of these hormones can increase the risk of osteoporosis.

Treatment of menopause usually involves hormone replacement therapy aimed at maintaining healthy levels of estrogen and progesterone. The treatment should also include assessing bone health by performing bone mineral density to evaluate the effect of hormonal imbalances.

Women may need to use calcium and vitamin D supplements if the signs of osteoporosis or low bone mineral density are detected.

Women who have a higher risk of osteoporosis due to the existing musculoskeletal disorders, malabsorption syndrome, or family history are advised to use calcium supplements regularly to avoid the risk of osteoporosis and fractures.

Normal bone density

Bone mineral density (BMD) is usually reported as a “T” score.

Usually, the results of a bone mineral density test are compared to that of a healthy young adult. A T-score of 0 indicates the patient’s BMD is equal to what is considered normal for a healthy young person. The difference between the BMD of the patient and that of a healthy young adult’s normal can be measured in units known as standard deviations or SDs.

The standard deviation below 0 is indicated as a negative number. A negative T-score less than -1 measure shows that the patient has a lower bone mineral density compared to that of a healthy adult person.

A T-score between -1 and +1 is considered healthy or normal. It indicates that the patient may have a positive or negative deviation from the normal bone mineral density, though the deviation is not substantial to cause osteoporosis. The lower the bone mineral density, the higher is the risk of osteoporosis and fractures.

A T-score between −1 and −2.5 is considered an indication of very low bone mass, although it is not low enough to be diagnosed as osteoporosis. The T-score of less than −2.5 usually indicates that the patient has osteoporosis.

Knowing your BMD T score can help you assess your risk of developing osteoporosis.

Osteoarthritis

Osteoarthritis is an inflammatory disorder affecting the joints. Sometimes referred to as degenerative arthritis or degenerative joint disease, osteoarthritis is one of the most common chronic conditions affecting the joints. It is known to affect patients over 50 years old, especially women.

Women are more prone to develop osteoarthritis after menopause age due to fluctuations in the levels of hormones.

Osteoarthritis occurs when cartilage, the flexible tissues at the end of the bones, wears down. This occurs gradually, causing pain. The symptoms of this condition tend to become worse over time.

Osteoarthritis usually affects the weight-bearing joints in the body such as the hips and knees. The weight exerted on the hips and knees speeds up the wear and tear of the joints, triggering the development of osteoarthritis. This can also occur in the joints of the hands, neck, shoulders, and lower back.

Maintaining a healthy weight is an effective way to prevent and manage osteoarthritis. The use of medications, such as non-steroidal anti-inflammatory drugs to relieve pain, coupled with physiotherapy is recommended when the symptoms are severe. If osteoarthritis causes significant immobility, surgical procedures such as knee or hip replacement may be required.

Osteoblasts

The cells that build bone tissue are called osteoblasts. They are bone-forming cells that are produced by the bone marrow. Osteoblasts have only one nucleus. They work in teams to form new bone cells. The new bone tissue formed by osteoblasts is called osteoid. Osteoid is made of collagen and other proteins.

Osteoblasts control the deposition of calcium and minerals in the bone and are found on the superficial surface of the new bone. When a cluster of osteoblasts finishes filling in a cavity in the bone, the cells become flat looking like pancakes to form a lining on the surface. These old osteoblasts are called the lining cells.

Osteoblasts, once converted into the lining cells, perform the function of regulating the passage of calcium in and out of the bone mass. They also respond to hormones released in the body by producing specific proteins that can activate the osteoclasts. This is how osteoblasts play an important role in the formation of bones and maintaining bone strength.

Osteoclasts

The large multinuclear cells associated with the absorption and removal of bone tissues are called Osteoclasts. They are primarily responsible for bone resorption.

Osteoclasts are large cells that cause the breakdown of old or damaged bone tissues. These cells are produced in the bone marrow. They are closely related to white blood cells.

Osteoclasts are formed from the fusion of two or more cells. So osteoclasts have more than one nucleus. These cells are found on the surfaces of the bone minerals near the dissolving bone. The role of osteoclasts and osteoblasts is vital during the aging processes.

The osteoclasts remove the existing bone through the process of resorption. This is followed by the replacement of the bone by osteoblasts through a process called formation.

Bone formation and bone absorption are some of the cell-based changes people experience as they age. These cell-based changes in the rate and amount of bone remodeling can lead to a decline in bone health.

With age, the number of bone cells deposited during each bone remodeling cycle is reduced, possibly due to the reduction in the number of precursor cells of osteoblasts, the reduced number of stem cells, and the lower lifespan of osteoblasts. As a result, fewer bone cells are formed compared to the number of cells lost. These changes can lead to degenerative conditions like osteoarthritis.

Osteocytes

Osteocytes are the cells inside the bone formed from osteoblasts. Some osteoblasts are converted into osteocytes during the process of formation of new bone. The osteocytes are later surrounded by new bone tissues.

However, they are not isolated as they tend to send out branches, they are connected to other osteocytes. These cells have the ability to sense cracks and pressures in the bones and help to determine the location where osteoclasts need to dissolve bone.

Osteonecrosis

Osteonecrosis is defined as death, or necrosis, of the bone tissue due to the lack of proper blood supply. Osteonecrosis of the jaws typically occurs after tooth extraction and other dental procedures. In some cases, it may occur spontaneously.

Osteonecrosis usually manifests as moderate to severe pain in the affected part with purulent discharge. However, some patients with osteonecrosis may not develop any symptoms.

Osteopenia

Osteopenia is a common joint disorder and can be a precursor to osteoporosis. Osteopenia is diagnosed when a patient has a T-score of bone mineral density ranges between -1.1 and -2.4

Even though osteopenia does not indicate an extremely low bone mineral density, it is still cause for concern due to the risk of fractures. The risk of osteopenia increases with age. People should check their bone mineral density regularly to assess the T-score to detect osteopenia before it becomes worse and causes osteoporosis.

Patients with osteopenia usually do not have any symptoms. Sometimes the condition is detected when fractures or other complications occur. Ensure an adequate supply of vitamin D and calcium and assess bone mineral density regularly to prevent this condition.

Osteoporosis

Osteoporosis is a systemic bone disorder characterized by low bone density and the deterioration of bone tissues at the micro-architectural level. Osteoporosis causes bones to become fragile making them susceptible to fracture.

The risk of osteoporosis increases in women after menopause. The hormonal fluctuations occurring during menopause reduce the absorption of calcium and vitamin D in the intestine. Advancing age is another risk factor commonly linked with a higher risk of osteoporosis. The decline in the ability of the bone tissue to form new cells coupled with an increased rate of degeneration of the bone tissues results in a reduced bone mass and can cause osteoporosis.

Women are advised to ensure their body receives an adequate supply of vitamin D and calcium, especially after the age of 40, to prevent the development of osteoporosis. Regular tests to assess bone mineral density should be performed to detect osteoporosis so that complications like fractures can be avoided.

Oxidative stress

Oxidative stress comes from damage to healthy organs and cells due to free radicals (also called reactive oxygen species) released into the body during natural metabolic processes. Oxidative stress is a disturbance in the balance between the free radicals and the body’s antioxidant defenses.

Oxidative stress, sometimes called free radical damage or oxidative damage, is one of the primary processes involved in the development of cancer. Various forms of bone cancers are linked to the higher oxidative stress caused due to the exposure of bone tissues to free radicals and other cancer-causing agents.

PARS stress fracture

The PARS stress fracture, also called spondylolysis, usually affects the lumbar spine (lower back). PARS stress fractures can result from repetitive lifting and unusual back movement, especially bending backward or hyperextension and rotation. It is a kind of fracture considered to be an “overuse injury”.

The PARS stress fracture is more common in young athletes who perform strenuous physical activities that involve a lot of bending and rotation of the back. It may also occur in women who have weak bones. You can lower your risk by maintaining good posture while sitting, sleeping, and walking.

Paget’s disease

Paget’s disease is a condition that involves abnormal destruction and regrowth of the bone tissues. It results in bone deformities.

The exact cause of Paget’s disease is not known. Paget’s disease can be genetic. It can also occur because of an infection by come viruses early in life.

Paget’s disease causes an abnormal breakdown of normal bone tissue in the affected areas. This can cause the formation of abnormal bone tissues. The new area of the bone is larger than the broken-down tissues. This occurs because the underlying abnormality causes the stimulation of the body’s normal immune system to increase the processes the formation of bone. The new bone tissues are usually weaker and the new bone may also be filled with small, new blood vessels.

This condition may affect the bones in just one or two areas of the body. It often affects the bones of the arms, legs, pelvis, collarbones, spine, and skull.

Phosphorus

Phosphorus is one of the essential minerals needed to maintain bone health. It makes up about 1% of a person’s body weight. Phosphorus is the second most abundant mineral in the body. Every cell contains Phosphorus in small amounts. Most of the body’s phosphorus content is in the teeth and bones.

Phosphorus helps form bones and teeth.

It also plays a role in how the body utilizes fats and carbohydrates. Phosphorus helps to synthesize proteins needed for the maintenance, growth, and repair of organs and tissues.

Phosphorus can help regulate the production of ATP molecules. ATP molecules store and release intracellular energy. A deficiency of Phosphorus can affect the health of the bones and teeth and also reduce a person’s energy levels.

A lack of Phosphorus can also affect the metabolism of fats and carbohydrates and the synthesis of proteins.

RANKL Inhibitors

RANKL Inhibitors are the group of drugs that help to slow down the rate at which the bones are broken down. These medications work by blocking the development of osteoclasts, the cells involved in the breakdown of bones.

Recommended Dietary Allowance

Recommended Dietary Allowance, or RDA, refers to the average daily intake of nutrients needed to meet the requirements of the body. The RDA of vitamins and minerals are specified by healthcare authorities like the WHO (World Health Organization), and the CDC (Centers for Diseases Control and Prevention) can provide guidelines about the nutrition a person needs to receive in the form of diet or supplements. RDA for some nutrients is specified for people of different ages and genders.

Bone resorption

Bone resorption is a process during which osteoclasts break down bone tissue and release minerals resulting in the transfer of calcium from the bones to the blood.

Rheumatoid Arthritis

Rheumatoid arthritis or RA is an autoimmune disorder in which the immune system fails to recognize bone tissues as the body’s own and attacks them. Normally, immune cells protect the body attack external factors like bacteria and viruses. For people with RA, immune cells do not recognize healthy bone cells and they attack these tissues.

The result is inflammation and the tissue lining the inner side of the joints, called the synovium, becomes swollen and thick. As a result, patients develop symptoms like swelling and pain in the joints.

The damage to the synovium also reduces its ability to form the fluid that could lubricate the joints and help them move smoothly. Patients with RA experience pain and increased friction between the ends of the bones because of the loss of synovial fluid.

Rheumatoid arthritis usually affects the smaller joints like the fingers and toes. It may also affect the wrists, ankles, and elbow joints. Symptoms of rheumatoid arthritis include pain and stiffness in the affected joints, especially in the morning.

Patients with rheumatoid arthritis usually have a family history of RA or another autoimmune disorder such as lupus, eczema, autoimmune thyroiditis, or psoriasis.

Rickets

Rickets is a common condition caused by the lack of calcium, vitamin D, and phosphate. A lack of vitamin D and other nutrients affects the development of bones. This may lead to the weakening and softening of the bones. Rickets usually affects children whose bones are still developing.

Vitamin D plays a role in controlling calcium and phosphate levels in the blood. When the level of these minerals in the blood becomes too low, the body produces hormones that stimulate the release of calcium and phosphate from the bones. This results in the weakening of the bones as it reduces bone mineral density. It can make the bones porous, soft, and prone to fractures.

The risk of deficiency of vitamin D is higher in children who suffer from lactose intolerance. Patients who are lactose intolerant have trouble digesting milk products and they have to avoid milk and dairy products, which are good sources of bone-friendly nutrients. This can result in a deficiency of vitamin D and calcium, triggering the development of rickets.

Patients who follow a vegetarian diet may also be prone to rickets due to the lack of an adequate amount of calcium and vitamin D in plant-based foods.

Disorders that affect the digestion and absorption of fats also make it more difficult for the body to absorb vitamin D and calcium and can result in rickets.

SERM

SERM or Selective Estrogen Receptor Modulators help to make the bones stronger by mimicking the effects produced by the female reproductive hormone called estrogen.

Sclerostin Monoclonal antibodies

Sclerostin Monoclonal antibodies work by inhibiting the activities of sclerostin, increasing bone formation and decreasing bone breakdown.

Spine scan

A spine scan is a diagnostic tool that can assess the health of the spinal vertebrae. The scan usually includes the vertebrae of the lumbar (lower back) region.

Stress fracture

Stress fractures are small cracks in the bone. A stress fracture may also occur due to severe bruising within the bone tissue. Stress fractures are usually caused by overuse of bones and repetitive activity. They are common in athletes and runners.

Stress fractures are caused by an imbalance in the turnover of bone tissues. Bones follow a continuous cycle of turnover through a process called remodeling. Remodeling involves the formation of new bone that can replace the old and damaged bone tissues. Sometimes, the breakdown of bone occurs so rapidly that it outpaces the ability of the body to repair and replace it by forming new bone. As a result, bones become weak and vulnerable to stress fractures.

Strontium

Although strontium is frequently found in bone health supplements, the use of strontium is not recommended. Excess strontium in the bones can make them brittle.

Strontium has a chemical similarity to calcium and will replace calcium in bones. Strontium is a heavier element than calcium. Strontium can cause bone density tests to falsely report a normal bone density.

T-score

T-score refers to the difference between the patient’s bone mineral density and its mean value in the reference population of young adults, divided by the standard deviation (SD) of reference. A T-score of –2 indicates that the patient’s bone mineral density is 2 SDs less than the reference population.

Trabecular bone

Trabecular bones are porous bones composed of an intricate network of calcified minerals and fibrous tissues. Trabecular bone is typically found at compression points like in the femoral head and lumbar vertebrae.

Vitamin D

Vitamin D is an essential nutrient needed for maintaining bone health. It is one of the fat-soluble vitamins stored in fatty tissue. Vitamin D plays a vital role in the absorption of calcium.

When a person does not get enough calcium through their diet, supplements or cannot absorb calcium from food, bones become weak. A lack of vitamin D can reduce the availability of calcium to the bones and the bones become porous and soft. Patients who need calcium supplements are usually advised to also take vitamin D supplements to support healthy bone formation.

A lack of Vitamin D can increase the risk of osteoporosis in adults and of rickets in children.

References:

https://www.ucsfhealth.org/education/orthopedic-glossary