Glossary of Terms

Abduct or abduction - to move a limb or any other part away from the midline of the body
Abductor tendon - runs down the inside of the thigh and moves the leg away from the midline of the body
Acetabular Rim - outer edge of acetabulum (socket)
Acetabulum - cup-shaped cavity that ball-shaped femur fits into (socket part of hip joint)
Adduct or adduction - to move a limb or any other part of the body toward another or toward the midline of the body
Adductor tendon - runs down the outside of the thigh and moves the leg toward or across the midline of the body
Arthrogram - injection of dye into hip joint (while child is anaesthetised). Progression of dye viewed by x-ray
Articular Cartilage - name of the cartilage in joints. Gets its nutrients from synovial fluid in joint
Asceptic Necrosis - cell or bone death of the femur
Atrophy - the wasting of normally developed organ tissue due to degeneration of cells or occuring due to dis-use of organ or tissue
Avascular - lacking blood vessels or having a poor blood supply
Avascular Necrosis - temporary or permanent loss of blood supply to bones
Bilateral - affecting both legs
Caput - see femoral head
Cartilage - is a type of dense connective tissue that supplies a smooth surface for the movement of bones in a joint
Clicky Hips - is a term used for a condition which includes congenital dislocation of the hips (CDH) and developmental dysplasia of the hip (DDH). It occurs when the femoral head does not sit properly in the acetabulum, or the acetabulum is shallow, allowing easy dislocation.
Coxa Magna - broadening of the head and neck of the femur
Coxa Plana - osteochondrosis of the capitular epiphysis of the femur
Diaphysis - is the main or mid section (shaft) of a long bone
Dysplasia - when the femoral head (caput) does not fit tightly into the acetabulum or there is some deformity of either the femoral head or acetabulum which causes abnormal wear and tear or friction
Epiphysis - is an area at the end of a long bone that is separated from the main part of the bone by the physeal plate
Femoral Head (caput) - ball part of hip joint, fits into acetabulum (hip socket)
Femoral Osteotomy - see Varus & Valgus listed below, also more information on Treatments page
Femur - long bone in thigh
Flexor - a muscle that when contracted, acts to bend a joint or limb in the body
Gait - is a particular way of walking
Greater Trochanter - situated at the junction of the neck of the femur on the outside of the femur
Growth Plate - (physeal plate) is an area of developing tissue near the ends of long bones, between the widened part of the shaft of the bone (the metaphysis) and the end of the bone (the epiphysis)
Hinged Abduction - occurs when the femoral head subluxes and impinges against the edge of acetabular rim when the hip is abducted
Idiopathic - arising spontaneously or from an obscure or unknown cause
Iliac Crest - is at the highest point of the pelvis (at the back)
Iliac Fossa - is a large, smooth, concave surface on the internal surface of the ilium (part of the hip bone)
Iliacus - is a flat, triangular muscle, which fills the iliac fossa
Impingement - catching of bone on bone
Innominate - hip bones that make up pelvis (means un-named bone)
Ischium - lower and back part of the hip bone
Lateral Extrusion - partial dislocation (see sublux)
Leg Length Discrepancy (LLD) - difference in leg length, which in Perthes, is generally due to the premature closure of the upper femoral growth plate and is most likely to be seen in unilateral perthes
Metaphysis - is the body of cartilage that separates the epiphyses and the diaphysis of long bones during growth
Meyer Dysplasia - is a disorder of the hip that generally appears around 2 years of age and usually disappears around 6 years. It is characterised by irregular ossification of the femoral head. The child may have a waddling gait and little or no pain. No treatment is needed, although this condition is often misdiagnosed as perthes disease and then the child is subjected to unnecessary procedures
Moribund - near death of bone
Multiple Epiphyseal Dysplasia (MED) - is a condition that affects the "growing portion" or head of the long bones. In order to confirm bi-lateral perthes, x-rays will be taken, generally of the knee, wrist and spine to rule MED out before surgery is undertaken
Musculoskeletal - relating to or involving the skeletons and the muscles
Necrosis - cell or bone death
Orbturator foramen - is the hole created by the ischium and pubic bones of the pelvis
Orthopaedic - is the branch of medicine associated with the musculoskeletal system

Ossification - the formation or conversion into bone or a bony substance
Osteochondritis - inflammation of a bone and cartilage
Osteotomy - cutting of bone for re-alignment (see treatments)
Paediatric - infant or child, to age of 16 generally
Pelvic Osteotomy - cut made through innominate bone, above acetabulum and bone graft pinned into place to change angle of acetabulum slightly for better coverage of femoral head (also known as Salter Osteotomy). More information available on Treatments page
Physeal Plate - see growth plate
Prognosis - is your doctors prediction of how the condition will progress and what the predicted outcome will be
Psoas - is the primary hip flexor, assisted by the iliacus
Re-ossification - regeneration of bone (also called regrowth)
Revascularisation - encourage new blood vessel to form
Salter Osteotomy - see Pelvic Osteotomy
Shenton's Line - a curved line formed by the inner side of the neck of the femur and the obturator foramen part of the pelvis (seen in x-rays)
Stasis - a stoppage or restriction of the flow of blood
Sublux or Subluxation - partial dislocation of a joint such as hip
Synovial Fluid - thick, stringy fluid found in hip joint (and others), it has an egg-like consistency and its there to reduce friction between the articular cartilage and other tissue in the joint, to lubricate and cushion during movement
Trendelenburg Gait/Limp - an abnormal gait caused by weakness of the abductor muscle. The pelvis tilts to the side without the weakened muscles and this causes a 'lurch' to maintain a level pelvis throughout the gait cycle
Unilateral - affecting one leg
Valgus Osteotomy - changing position of femoral head by cutting through the femoral neck, to reposition it more to the outside of acetabulum (not so deep). This can be done as a reversal for a varus osteotomy if LLD is too great
Varus Osteotomy - changing position of femoral head by cutting through the femoral neck, to reposition it more to the inside of the pelvis (deeper). This can affect LLD and may need to be reversed when the child is older
Vascularisation - growth of blood vessel into tissue with the result that the oxygen and nutrient supply is improved



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