Glossary of terms

Glossary of terms for this AVN Avascular Necrosis website and explanations in almost standard English.

Acetabulum – In the pelvis, the hip socket is called the acetabulum and forms a deep cup that surrounds the ball or femoral head of the upper thigh bone.

Acute pain – Pain that is rapid to develop, and for a shorter duration than Chronic pain.
Ref – Wikipedia

Analgesic – A member of a group of drugs to give relief from pain.

Arthroplasty – Surgical repair of joint., also referred to as a joint replacement. The affected bone is removed and replaced with an artificial joint. This treatment may be needed in the late stages of AVN, or when a joint has collapsed.

Articular Cartilage – White smooth tissue that covers the ends of bones in joints. It enables bones in a joint to glide over one another with very little friction, allowing easy movement. See Cartilage

Aseptic Necrosis – Another name for Avascular Necrosis or Osteonecrosis.

Asymptomatic – A disease is considered Asymptomatic if a patent is a carrier for a disease or infection but experiences no symptoms. A condition might be considered Asymptomatic if it fails to show the noticeable symptoms of which it is usually associated. The term clinically silent is also used.

Atherosclerosis – Condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol.
Ref – Wikipedia

Avascular – Having few or no blood cells.
Ref – Encycopædia Britannica

Bisphosphonates – These are a group of drugs that affect bone remodeling, the process in which bone cells are constantly resorbed and new bone cells laid down. They block the action of osteoclast cells which are responsible for bone resorption. Bisphosphonates are now commonly prescribed for the treatment of osteoporosis and they are also used in the treatment of bone tumors.

Bone Marrow Oedema – Only cited since 1988 after the introduction of advanced MRI scans – it is bruising of the bone or additional fluid (water) content in the bone marrow. This condition often accompanies avascular necrosis. On the MRI image, it is shown as light areas of the bone which should normally be seen as dark.

Bone Infarct – Bone Infarct is another name for AVN. It’s a more descriptive term for what has happened, a blockage of blood circulation leading to the death of part of the bone.
Ref – Avascular Necrosis AVN Charity UK – Murnaghan

Bilaterally – With avascular necrosis AVN in both hips, or both knees etc.

BRONJ – Biphosphonate-Related OsteoNecrosis of the Jaw (BRONJ). This usually only occurs in people receiving high dose intravenous biphosphonate injections for bone cancers and is often associated with a dental operation. If taking bisphosphonates it is important to inform your dentist and to take extra care with dental hygiene.
Ref – Avascular Necrosis AVN Charity UK – Murnaghan & Barker

Cartilage – Flexible tissue between the joint bones. It is not as hard and rigid as a bone but is stiffer and less flexible than muscle.

Caisson disease – Name was given to a variety of symptoms suffered by a person exposed to a reduction in the pressure surrounding their body. Typically it occurs when a person subjected to great atmospheric pressure suddenly has that pressure removed – as when a scuba diver returns rapidly to the surface after a long-submerged period. Also known as Barotrauma.

Calve Perthes disease – Avascular Necrosis (AVN) in young children and can lead to Osteoarthritis in adults, also known as Legg Calve Perthes or Perthes disease.
Ref – Wikipedia

Chronic pain – This is pain that has lasted for a long time, the distinction between acute and chronic pain has traditionally been determined as Acute pain lasts for 30 days while Chronic pain lasts much longer.
Ref – Wikipedia

Coccygeal – Referring to the coccyx, the small tail-like bone at the bottom of the spine, that is made up of 3-5 (average of 4) rudimentary vertebrae. There is a coccygeal nerve that originates in the spinal cord and emerges at the level of the coccyx.

Condyle – Smooth surface area at the end of a bone-forming part of a joint with another bone.

Cortex (bone) – The dense outer surface of bone that forms a protective layer around the internal cavity. This type of bone also known as compact bone makes up nearly 80% of skeletal mass and is imperative to body structure and weight-bearing because of its high resistance to bending and torsion.
Ref – Spine Health

Corticosteroid – Corticosteroids, more often known as steroids, are an anti-inflammatory medicine prescribed for a wide range of conditions.

Cyst – A cyst is a sac-like pocket of membranous tissue that contains fluid, air, or other substances. Cysts can grow almost anywhere in your body or under your skin. There are many different types of cysts. Most cysts are benign, or noncancerous.

Dexamethasone – A type of medicine known as a corticosteroid. These medicines are man-made versions of the corticosteroid hormones, cortisol and aldosterone, produced naturally by the adrenal glands. They are often referred to as steroids. Dexamethasone is a generic medicine, available as tablets, liquid, eye drops and injection.

Diabetes – A group of diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced. This high blood sugar produces the classical symptoms of frequent urination, increased thirst, and increased hunger.
Ref – Wikipedia

Diaphysis – Shaft of the bone.
In Anatomy. ‘The shaft of a long bone, as distinct from the extremities’.
Ref – Oxford English Dictionary OED

Distal – The more (or most) distant of two (or more) things. For example, the distal end of the femur (the thigh bone) is the end down by the knee; the end more distant from the torso.
Ref –

Ellipsoidal – Joint that can move in two planes, for example wrist, and ankle. The ellipsoid joint has two types of movement but allows opposition movement only to a small degree. Its surfaces are ovoid and vary in both length and curvature as they are traced from front to back or from side to side, just as the diameter and curvature of an ellipse vary in directions at right angles to each other (hence the name). The joint between the second metacarpal and the first phalanx of the second finger is a good example. It allows the finger to flex and extend, to swing toward or away from its neighbouring finger, and to swing forward with a slight amount of rotation.
Ref – Encycopædia Britannica

Epiphysis – Ends of the bone.

Femoral head – The ball at the upper end of the thigh bone that sits inside the hip socket or acetabulum.

Gaucher disease – Disease in which a fatty substance accumulates in cells and certain organs. Symptoms may include enlarged spleen and liver, liver malfunction, skeletal disorders and bone lesions that may be painful, severe neurologic complications, swelling of lymph nodes and (occasionally) adjacent joints, distended abdomen, a brownish tint to the skin, anaemia, low blood platelets and yellow fatty deposits on the white of the eye. Persons affected most seriously may also be more susceptible to infection.
Ref – Wikipedia

Gout – Condition usually characterised by recurrent attacks of acute inflammatory arthritis – a red, tender, hot, swollen joint. The joint at the base of the big toe is the most commonly affected (approximately 50% of cases). It is caused by elevated levels of uric acid in the blood which crystallises, and the crystals are deposited in joints, tendons, and surrounding tissues.
Ref -Wikipedia

Idiopathic – An adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause.
In Greek; Idios translates to one’s own and Pathic translates to suffering or disease; so together becomes “a disease of its own” or “it comes from nothing” and medical jargon for “we don’t know what the cause is”.

Infarct – Bone infarct is another name for AVN. It’s a more descriptive term for what has happened, a blockage of blood circulation leading to the death of part of the bone.
Ref – Avascular Necrosis AVN Charity UK – Murnaghan

Ischaemic – Restriction in blood supply to the tissue, causing a shortage of oxygen and glucose needed to keep tissue alive. Local anæmia caused by obstruction of the blood.
Ref – Oxford English Dictionary OED

Legg Perthes disease – Avascular Necrosis (AVN) in young children and can lead to Osteoarthritis in adults, also known as Calve Perthes or Perthes Disease.
Ref – Wikipedia

Lesions – Any abnormality in the tissue of an organism, for AVN we mean the bone structure at the joint site has started to break away. Usually caused by disease or trauma. A lesion is derived from the Latin word laesio which means injury.

LigamentsFibrous tissue that connects bones to other bones.

Medial Condyle – Inner side of the lower extremity of the femur (thigh), see Condyle.

Medulla (bone) – The innermost part of a structure or organ, in the case of bones, the bone marrow.

MRI – Magnetic Resonance Imaging, is a medical imaging technique used in radiology to visualise internal structures of the body in detail. MRI makes the use of the property of nuclear magnetic resonance (NMR) to image nuclei of atoms inside the body.

MRI provides good contrast images between the different soft tissues inside the body, which makes it especially useful in imaging the brain, muscles, heart, and cancers; compared with other medical imaging techniques such as computed tomography (CT) or X-rays. Unlike CT scans or traditional X-rays, MRI does not use ionising radiation.
Ref – Wikipedia

Multifocal – Having many focal points. With regard to avascular necrosis AVN, it means that it has affected many different joints in the body,. For example the hips, shoulders, knees, and jaw.

Multilateral – Having many focal points. With regard to avascular necrosis AVN, it means that it has affected many different joints in the body,. For example the hips, shoulders, knees, and jaw.

Necrosis – Death of living tissue.
Ref – Encycopædia Britannica

Oedema – also known as edema – Bone marrow oedema occurs when excess fluid builds up in the bone marrow and causes swelling. Caused by the body’s reaction to a trauma or other condition. Symptoms are pain and/or swelling at the bone site.
In Medicine – localized or generalized accumulation of excessive fluid in tissues or body cavities; an instance or case of this. Frequently with distinguishing word indicating the site, nature, etc., of the oedema.
Ref – Oxford English Dictionary OED

Osteoarthritis – Group of abnormalities including degradation of a joint from partial loss of cartilage and damage to the bone joint surface.

Osteonecrosis – Another name for Avascular Necrosis.

Osteoradionecrosis ORN – Another name for Avascular Necrosis caused by radiotherapy.

Osteopenia – Condition where bone mineral density is lower than normal. It is considered by many doctors to be a precursor to osteoporosis. However, not every person diagnosed with osteopenia will develop osteoporosis.

Osteophytes – Commonly referred to as bone spurs, they are bony projections that form along the joint margins.

Osteoporosis – Condition of fragile bones.

Osteotomy – Osteotomy surgery involves cutting and realigning the bone (usually shin bone/tibia) in order to re-distribute the weight going through the knee. Realignment can be achieved by either taking a slice of bone out of the tibia (shin bone) or femur (thigh bone) close to the knee joint (closing wedge) or opening a gap in the bone (opening wedge).
A hip osteotomy is a surgical procedure in which the bones of the hip joint are cut, reoriented, and fixed in a new position. Healthy cartilage is placed in the weight-bearing area of the joint, followed by reconstruction of the joint in a more normal position.

Perthes disease – Avascular Necrosis (AVN) in young children and can lead to Osteoarthritis in adults also known as Legg Calve Perthes or Calve Perthes Disease.
Ref – Wikipedia

Prednisolone – A type of medicine called a corticosteroid. Corticosteroids are hormones that are produced naturally by the adrenal glands. They have many important functions in the body, including control of inflammatory responses. Corticosteroid medicines like prednisolone are man-made derivatives of the natural hormones. They are often simply called steroids, but note they are not the same as anabolic steroids, which are abused by some athletes and body builders.
Ref –

Sacrum – Large triangular bone at the base of the spine and at the upper and back part of the pelvic cavity.

Sagittal – Imaginary line, used in MRI scans.

Sclerosis – Osteosclerosis, a condition where bone density is significantly increased. Sclerosis is the stiffening of a structure, usually caused by a replacement of the normal organ-specific tissue with connective tissue. The structure may be said to have undergone sclerotic changes or display sclerotic lesions, which refers to the process of sclerosis.
Ref – Wikipedia

Sickle cell disease – Sickle cell disease is a group of disorders that affects haemoglobin, the molecule in red blood cells that delivers oxygen to cells throughout the body. People with this disorder have atypical haemoglobin molecules called haemoglobin S, which can distort red blood cells into a sickle, or crescent, shape.
Signs and symptoms of sickle cell disease usually begin in early childhood. Characteristic features of this disorder include a low number of red blood cells (anaemia), repeated infections, and periodic episodes of pain. The severity of symptoms varies from person to person. Some people have mild symptoms, while others are frequently hospitalised for more serious complications.
Ref – Genetics Home Reference

SPONK – SPontaneous OsteoNecrosis of the Knee, a type of AVN or osteonecrosis specifically of the knee, either femur or tibia, and spontaneous means it occurred without an obvious cause
Ref – Avascular Necrosis AVN Charity UK – Murnaghan & Barker

Subchondral – Below the cartilage.

Systemic lupus erythematosus (SLE) – Often known just as lupus, is an autoimmune disease where your immune system produces antibodies that attack your body’s own tissues, causing inflammation. Lupus usually affects your skin and joints, but it may also involve your heart or kidneys when the effects can be severe. SLE isn’t the same as discoid lupus, which only affects the skin.

Synovial – Synovial tissue is found around the tendons (bands of fibre that connect muscle to bone), and can form bursa (fluid-filled cushioning pouches or sacs found in spaces between tendons, ligaments, and bones) found in the area of joints.
Synovial fluid is the clear, viscid, lubricating fluid secreted by synovial membranes.
Ref – Synovial Sarcoma Survivors Network

Trabecular – The inner part of the bone. The spongy bone, as it is frequently called, is highly vascular and is responsible for blood cell production. The trabecular bone contains the red bone marrow that is responsible for this blood cell production.

UKR – Unicompartmental Knee Replacement, or partial knee replacement.

Vertebrae – The Vertebral Column (Spinal Column) supports the head and encloses the spinal cord.
The spinal column is comprised of 26 individual bones, these bones are referred to as vertebrae. The spinal column is divided into five (5) different areas containing groups of vertebrae, and are grouped as follows:
Seven (7) Cervical vertebrae in the neck.
Twelve (12) Thoracic vertebrae in the upper back corresponding to each pair of ribs.
Five (5) Lumbar vertebrae in the lower back.
Five (5) Sacral vertebrae which are fused together to form 1 bone called the sacrum.
Four (4) Coccygeal vertebrae that are fused together to form the coccyx or tailbone.
Ref – Apparelyzed Spinal Cord Injury Association

X-Ray – A form of radiation that can pass through solid and semi-solid substances. In carefully controlled doses, they can be used to capture images of the body’s internal structures.X-ray is a safe and painless procedure often used to produce images of the inside of the body.
It is a very effective way of looking at fractured bones, such as a broken arm or wrist.
An X-ray can also be used to examine organs and identify problems. For example, an X-ray will show up an infection in your lungs, such as pneumonia.
X-rays are also often used during therapeutic procedures, such as coronary angioplasty, to help the surgeon guide equipment to the area being treated.
Ref – NHS UK

Zoledronic Acid a type of drug called a bisphosphonate. It can be used to help prevent bone loss, reduce the risk of cancer spreading to the bones in women with early breast cancer, treat bone weakness or pain caused by myeloma or cancer that has spread to the bones (secondary bone cancer) and, treat high levels of calcium in the blood.
Ref – Macmillan Cancer Support

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