Radiology - Conditions (Subscribe)  

Interruption of vascular supply to a bone has a greater effect at the bone ends where the perfusion arrives from one side only. Osteonecrosis frequently involves joints. The local geometry and the covering of cartilage must be relevant. Weight bearing over a small area of bone is also related to...

The osteosarcoma is the commonest of the primary malignant bone tumours. Its peak incidence is before epiphyseal fusion, particularly the years between 10 -25. There is a later peak which is associated with Paget's disease or previous radiotherapy. Visible Paget's disease does not have to be present before one can...

Paget's disease is a disease of bone, which develops disordered architecture and is found more commonly in the elderly and in males. The mechanism for this pathology is unknown. Under the microscope, the disease shows disorder of the basic structural unit, normally an arrangement of concentric Haversian Systems. Radiographically, this...

This tumour has an onset later than osteosarcoma. 50% of cases are over 30 yrs old. It comprises 4% of all osteosarcomas. The commonest site is in the femur or tibia, although the humerus can be involved. The tumour may be large and may affect between 2 - 10 cms....

Despite the strength of the composite material that is bone, there are many processes that can weaken it; from simple destruction to deficiencies of its components. The appearance of the bone in a case of deficient materials is often altered by the attempts at repair. The development of a Looser zone...

Lack of Vitamin D will reveal itself in those areas in the bone that show the greatest activity. Growth processes in the immature skeleton cause Rickets and structural responses to stress in the mature skeleton give rise to Osteomalacia. In the immature skeleton, the greatest activity is the ossification boundary...

These tumours as a bone present in the 3rd or 4th decades or later. Males have a greater frequency as much as 2x that of females. The sites of predilection are long bones and primarily diaphyseal affecting the medulla of the bone. The lesion is destructive and shows a patchy...

Scleroderma is a disorder which is characterised by a thickening and stiffening of the skin. It is an autoimmune process, involving antibodies to intracellular structures, including the nucleolus. There is fibrosis, particularly of smooth muscle.
It takes two general forms:
a widespread progressive systemic disorder.
...

Sclerotic metastases are easily identified on the plain film, except when their density is interpreted as other overlying structures or pathology, perhaps osteoarthrosis. The microscopy of affected bone usually shows a proliferative bone reaction to the spread of tumour over the bone trabeculae. This results in the visible diffuse sclerosis...

Sickle cell disease is one of the more common abnormalities of haemoglobin. The single substitution of valine for glutamic acid alters the folding of the protein and its response to deoxygenation. The inheritance is autosomal dominent, but generally the disease is more severe in homozygous individuals. Other haemoglobinopathies may affect...

The simple bone cyst is a benign unilocular lytic area in the proximal end of a long bone with a well defined and narrow endosteal margin. There is some expansion of the bone and thinning of cortex from below. This can occasionally give rise to a scalloped appearance appearance to...

Slip of Femoral capital epiphysis.
The length and angle of the neck of the Femur is useful for an erect hominid, especially when carrying things. Standing, the curves of both femora, pelvic rings and sacrum conduct the lines of force up into the spine. Moving requires the support to come from...

Failure of spinal or neural tube fusion
The first feature to appear on the embryological plate is the neural groove that deepens with in-folding of its edges to form the neural tube. The openings of the tube close at 26-28 days after conception. Failure of closure at the top end causes...

Degenerative change in the spine is, as elsewhere, primarily an attempt to get more stability by newbone formation, primarily at the edges of failing joints. There is a particular significance of instability and newbone formation in the spine, since the spinal canal and neural foramina can be compromised. In the...

Bone self-repair and self strengthening involves first osteoclastic activity to take down the inappropriate microstructure and followed by osteoblastic activity to lay down the matrix, which will ossify to become the new, mechanically appropriate bone architecture. During this process, the bone is temporarily vulnerable to the mechanical stress, if it...