Bone DZ and Disorders Flashcards
Periosteum consists of dense irregular connective tissue. Periosteum is divided into an outer “fibrouslayer” and inner “cambium layer” (or “osteogeniclayer”). The fibrous layer contains________, while the cambium layer contains progenitor cells that develop into osteoblasts.
fibroblasts
(A progenitor cell is a biological cell that, like a stem cell, has a tendency to differentiate into a specific type of cell, but is already more specific than a stem cell and is pushed to differentiate into its “target”cell.)
Periosteal response with a smooth, even shape and well-defined margin. New bone production appears multilaryered and suggestive of ____ growing disease.
intermittenly
Irregular-shaped periosteal response with well-defined margins, no cortical destruction, and abssence of soft tissue swelling is indicative of?
Incactive, nonaggressive disease process.
Irregular-shaped periosteal response with ill-defined margins, cortical destruction, and soft tissue swelling indicates?
active and aggressive disease process.
What do you call a well-defined wedge-shaped area of new bone at the perihery of an active, aggressive lesion. Underlying cortex is lytic but visible.
Codman’s triangle
What is the definition of Osteopetrosis?
Congenital metabolic bone dz in which endochondral ossification continues, but bone absorption is decreased due to abnormal osteoclastic activity.
What is the difference b/t Osteopetrosis vs. Osteoporosis?
(osteoporotic bone)
Osteopetrosis is a rare congenital and familial developmental abnormality of skeletal growth of man and animals. The formation and production of the growth plate cartilage cells and matrix and the primary trabeculae are normal. Bone length and shape are relatively normal. There is, however, marked retardation of the remainder of the enchondral ossification cycle which includes bone maturation, resorption of immature bone, bone remodeling and cortex formation beyond the primary trabecular stage. The accumulation and persistence of cores of calcified cartilage, osteoid and primitive bone in the medullary cavities results in abnormally dense bone and has led to the radiographic diagnosis of this disease by such synonyms as osteosclerosis fragilis, marble bones and chalk bones
Osteoporosis is a nonspecific term referring to a condition that is characterized by quantitative loss of bone, that is, atrophy of bone. The bone that is present is entirely normal, since the organic and inorganic phases diminish in equal proportion. The reduced amount of bone is manifested by thinning of the cortex or reduced number and caliber of cancerous trabeculae, or more commonly both. Thus, affected bones are thin, porous, and brittle. The volume of bone remains constant, however.
(Osteoptetrosis)
What is OSTEOSCLEROSIS?
What is the difference b/t osteoSCLEROSIS vs. osteoPETROSIS?
Abnormal hardening or increased density of bone (eburnation)
scleosis=mostly locaised bone deposition, may be generalised too=pathological
petrosis=stony hard bone still easily fragile=generalised bone overdeposition =hereditary/genetic condition
(generalized osteosclerosis)
What are the 3 patterns of osteolysis?
What is Osteomyelitis and how does ot occur?
Osteomyelitis is an infection in a bone. Infections can reach a bone by traveling through the bloodstream or spreading from nearby tissue. Infections can also begin in the bone itself if an injury exposes the bone to germs. Infections mainly affects, marrow, Haverisian canals and periosteal spaces.
What is osteomylitis?
or OM) is infection and inflammation of the bone and bone marrow.[1] It can be usefully subclassified on the basis of the causative organism (pyogenic bacteria or mycobacteria) and the route, duration and anatomic location of the infection. Osteomyelitis usually begins as an acute infection, but it may evolve into a chronic condition
With chronic otits, external auditory canal may be narrowed or obscured due to presence of what?
fluid, exudate, debris in lumen or thickening of ear canal lining
Enchondroma is a benign cartilaginous tumor that develops from displaced growth ______? It is a wxpansile, well-defined area of decreased opacity in the medullary cavity of a long bone.
cartilage
Abnormal differentiation of physeal cartilage leads to development of a bony mass near the physis (mass can develop away from physis if fragment of physeal cartilage breaks off and remains in place as bone grows and physis moves is called?
Osteochondroma
A nodular proliferation of synovial membrane- ossible from fragments of articular cartilage. Proliferating synovium can extend into surrounding soft tissue. More common in cats than dogs. What is it?
Synovial osteochondromatosis
What does a premature closing of the distal unlar physis look like?
What do you call a joint space between the humerous and ulna which is widened and wedged shape?
Humeral subluxation
What do you call a sclerotic fragment of bone sequestrum which is surrounded by a less opaque zone (invulcrum) within a bone?
sequestrum
What can cause a shortened radius and a humeroulnar joint subluxation?
Premature closure of the distal radial physis?
Primary bone tumors (osteosarcomas) are COMMON in dogs and cats. About ____%.
80%
What is the “Zone of Transition”
The appearance of the zone of transition between a lesion and the host bone is probably the single best indicator of a lesion’s aggressiveness. An abrupt transition from normal to abnormal is a feature of benignancy. A wide transition is a feature of malignancy. The zone of transition is a direct reflection of the lesion’s aggressiveness and the response of the host bone to the lesion infiltration
FIG 13-4 Periosteal reaction of bone. A, Thin lamellar. B, Thick lamellar. C, Cortical buttressing (arrows). D, Codman triangles (arrows). E, Aggressive lamellar. F, Hair-on-end spiculated.G, Sunburst. Patterns A through C are associated with benign lesions of bone. Patterns D through G are associated with aggressive lesions of bone (e.g., Ewing sarcoma and osteosarcoma). From Juhl JH, Crummy AB: Paul and Juhl’s essentials of radiologic imaging, ed 6, Philadelphia, 1993, JB Lippincott.
What does a sunburst periosteal reaction indicate?
Osteosarcoma
Skull lesion with a sunburst aggressive periosteal reaction (arrows). Courtesy Steven P. Brownstein, MD, Springfield, NJ.
Why is margination and zone of transition linked?
Margination describes the presence and thickness of the rim around the lesion. Malignant tumors typically are nonmarginated, a feature of their wide zone of transition (Figs. 13-8 and 13-9). Conversely, a lesion is most likely benign if surrounded by a sclerotic rim of varying thicknesses producing a narrow zone of transition. The presence of a thick margin is always accompanied by a short zone of transition and represents an attempt of the host bone to surround and limit a lesion’s growth. However, a short zone of transition is not always accompanied by a thick margin (e.g., giant cell tumor). The zone of transition should not be used as the sole criteria for determining the aggressiveness of the lesion. Even a well-marginated lesion can prove to be malignant in selected clinical circumstances.
For example, a painful lesion presenting with a narrow zone of transition in a 60-year-old patient who has a previous history of a primary tumor should be considered bone metastasis until proved otherwise.FIG 13-8 Margination of bone lesions. A, Thick. B, Thin. C, Absent. A to C demonstrate a short zone of transition between normal bone and the lesion. D, Ill-defined. Demonstrates a long zone of transition between normal bone and the lesion. A long zone of transition is most often associated with an aggressive lesion. From Juhl JH, Crummy AB: Paul and Juhl’s essentials of radiologic imaging, ed 6, Philadelphia, 1993, JB Lippincott.
What is the second most common primary bone tumor in cats after osteosarcoma?
periosteal osterosarcoma (a.k.a. juxtacortical osteosarcoma)
