JOINT MUSCLE SOFT TISSUE
sway-backed posture. The cartilaginous growth plates contain hypoplastic or disorganized aggregates of chondrocytes instead of the long, orderly columns normally seen at this site.
Osteogenesis Imperfecta OI or brittle bone disease, is a group of hereditary conditions characterized by abnormal development of type I collagen. Type I collagen is
present in many different tissues, including skin, joints and eyes. OI characterized by the present of multiple bone fractures. Other tissues containing type I collagen are also affected,
resulting in abnormal dentition, hearing loss, and blue appearance to the sclera.
Osteoporosis is a skeletal disorder characterized by low bone mass and microarchitectural deterioration with a subsequent increase in bone fragility and
susceptibility to fracture. It occurs most commonly as primary disorders or secondary. Osteoporosis result when imbalance occurs between bone formation and resorption. The
hallmark of osteoporosis is a loss of bone, the bony trabeculae are thinning and widening of haversian canal.
Both rickets and osteomalacia are manifestations of vitamin D deficiency. The fundamental change in these diseases is defective mineralization of bone, accompanied by
an increase in nonmineralized osteoid. In rickets, the defective mineralization involves the developing bones in children, but osteomalacia involves the bone that has completed its
normal development.
Osteomyelitis designated as inflammation of the bone and marrow cavity by infectious agents. Osteomyelitis may be an acute or chronic. The most common etiologic agents are
pyogenic bacteria and mycobacterium tuberculosis. Morphologically acute pyogenic osteomyelitis characterized by an intense, neutrophilic inflammatory infiltrate. Chronic
osteomyelitis show sequestrum, involucrum and Brodie abscess. Tuberculous osteomyelitis causes the granulomatous inflammatory reaction.
Bone tumors divided in two categories : bone-forming tumors osteoma, osteoid osteoma and osteoblastoma, and osteosarcoma and cartilaginous tumors
osteochondroma, chondroma, and chondrosarcoma. -
Osteosarcoma is malignant mesenchymal neoplasm in which the neoplastic cells produce osteoid. Most unknown etiology. The lesion usually in the mataphyseal region
of the bone, often elevates the periosteum toproduce the Codman triangle on radiographs. The hallmark of osteosarcoma is the formation of osteoid by malignant
mesenchymal cells, that may be spindle shaped, pleomorphic, bizarre, and giant cell often present.
- Osteochondroma is benign proliferations composed of mature bone and a
cartilaginous cap. Probably represent malformations rather than true neoplasm. -
Chondrosarcoma is malignant neoplasm populated by mesenchymal cells that produce a cartilaginous matrix. Microscopically, chondrosarcoma vary great in
appearance. There are well, moderately or poorly differentiated malignant cells, multinucleate cells are present with lacunae containing 2 or more chondrocytes.
- Ewing sarcoma occurs predominantly in children and adolescents, with a peak
incidence in the second decade of life. Ewing sarcoma arises within the medullary cavity of the affected bone to produce a soft, expansile mass. Microscopically it
composed of sheets of primitive cells, with small, fairly uniform nuclei and only scant cytoplasm.
- Fibrous dysplasia is an uncommon, benign, tumor-like lesion of bone, in which the
normal trabecular bone is replaced by proliferating fibrous tissue and disorderly islands of malformed bone.