muscular atrophy

muscular atrophy,

a condition of motor unit dysfunction, usually the result of a loss of efferent innervation.

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muscular atrophy,

n decrease in size and number of muscle fibers as a result of aging, reduction in blood supply, malnutrition, or denervation. See also innervation.

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atrophy (at´rōfē),

n/v a progressive, acquired decrease in the size of a normally developed cell, tissue, or organ. Atrophy may result from a decrease in cell size, number of cells, or both.

atrophy, adipose

n an atrophy resulting from a reduction in fatty tissue.

atrophy, alveolar,

n a depletion of the size of the alveolar process of the jaws from disuse, overuse, or pathologic disturbance of the bone.

atrophy, bone,

n 1. the bone resorption internally (in density) and externally (in form) (e.g., of residual ridges).
n 2. a loss of bone substance or volume. Atrophy of bone ordinarily occurs without a corresponding change in the volume or external dimensions of bone, but the mass of bone tissue may be reduced by as much as 75%. The internal architecture of the bone gradually becomes attenuated and finally disappears. Atrophied bone is brittle and has a more spongy consistency than normal bone. In cross-section the cortex is thin, and the periosteal surface is smooth and unchanged, but the intramedullary substance is composed of a yellow, fatty, cancellous bone tissue. Bone atrophy may be systemic, regional, or local.

atrophy, central papillary,

n a lesion on the central dorsum of the tongue, possibly due to a fungal infection, not a developmental disorder; it may be raised or flat. Formerly called
median rhomboid glossitis.

atrophy, diffuse alveolar,

n See periodontosis.

atrophy, facial,

n the failure of facial development. If it is bilateral, it may produce brachygnathia; unilateral types, although rare, are more common than the bilateral type. Causes include physical injury, neurovascular disease, and paralysis.

atrophy, gerodontic mucosal

n an oral degeneration in which the tissue of the epithelium in the oral cavity thins and loses some of its vascular structure and elasticity.

atrophy, muscular,

n a wasting of muscle tissue, especially resulting from lack of use. There are numerous causes for simple atrophy of muscle, such as chronic malnutrition, immobilization, and denervation.

atrophy, of disuse,

n an atrophy resulting from a lack of function of a tissue, organ, or body part.

atrophy, periodontal,

n the quantitative degenerative changes that occur in the periodontium of a tooth as a result of disease or disuse. When a tooth loses its antagonist, osteoporotic changes in the supporting bone, an afunctional change in the direction of periodontal fibers, and a narrowing of the periodontal ligament.

atrophy, postmenopausal,

n a thinning of the oral mucosa after menopause.

atrophy, pressure,

n the tissue destruction and reduction in size as a consequence of prolonged or continued pressure on a local area or group of cells.

atrophy, pressure, by epithelial attachment,

n a theoretical type of atrophy. The theory, advanced to explain destruction of gingival fibers during gingival inflammation, states that gingival fiber degeneration is produced by pressure exerted by the proliferating pocket epithelium. It is now generally conceded that proteolytic substances produced in the tissues during inflammation are responsible for gingival fiber destruction; subsequently, the epithelium can proliferate apically.

atrophy, senile,

n the atrophy or diminution of all tissues characteristic of advanced age.

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muscular

1. pertaining to a muscle.

2. having well developed muscles.

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muscular asymmetry

due usually to neuronal or disuse atrophy on one side of the body.

muscular atrophy

wasting away of muscle or a muscle because of reduction in cross sectional area of muscle fibers; may be due to disease of the muscle or its nerve supply, or to disuse or nutritional inadequacy. See also hereditary spinal muscular atrophy (below).

muscular degeneration

varies in severity from degeneration of only the myofibrils or degeneration of the myofibrils plus sarcoplasm, leaving satellite cells and myonuclei and sarcolemmal laminae unaffected, or further levels of increasing severity.

muscular denervation

destruction or congenital absence of the motor nerve supply to the muscle; manifested by paralysis and atrophy and absence of spinal reflexes.

muscular denervation atrophy

progressive shrinkage of muscle fibers when the nerve supply to the muscle is severed.

Duchenne muscular dystrophy

an X-linked inherited disease in humans, which is believed to be due to a deficiency of a membrane-associated protein, dystrophin. An analogous disease has been identified in Irish terriers, Golden retrievers and mice.

muscular dystrophy

any degenerative muscular disorder due to faulty nutrition of the muscles. Causes muscle weakness, liberation of myoglobin into the circulation from skeletal muscle and subsequent wasting and possible contracture. In humans there are a group of genetically determined, painless, degenerative myopathies that are progressively crippling because muscles are gradually weakened and eventually atrophy. In food animals the principal disease in this group is enzootic muscular dystrophy caused by a nutritional deficiency of selenium and/or vitamin E. Sporadic cases of muscular dystrophy of unknown etiology occur rarely in dogs.

muscular fascicle

see fascicle.

muscular fasciculation

see fasciculation.

muscular fatigue

during brief, intense exercise probably due in large part to the accumulation of lactate.

hereditary spinal muscular atrophy

progressive degeneration of the motor cells of the spinal cord. It is an inherited, slowly progressive flaccid tetraparesis from an early age, with muscular atrophy. Occurs as an autosomal recessive trait in Swedish lapland dogs, a dominant trait in Brittany spaniels. Also reported in German shepherd dogs, English pointers and Rottweilers. See also hereditary neuronal abiotrophy of Swedish Lapland dogs. In cattle, inherited as an autosomal recessive trait and reported in Brown Swiss, Holstein-Friesian and Red Danish calves with an onset at 3 to 8 weeks of age. There is hind limb ataxia progressing to recumbancy. Associated with lesions in the lower motor neurons of the cervical and lumbar spinal cord.

muscular hernia

hernia through an enclosing muscle sheath.

muscular hyperplasia

an increase in the size of a muscle mass due to an increase in the number of muscle cells. See also myofiber hyperplasia, ileal muscular hypertrophy.

muscular hypertrophy

an increase in the size of a muscle mass due to an increase in the length and thickness of each muscle cell without any increase in the number of cells.

muscular ischemia

short duration or temporary or partial cessation of blood supply causes loss of muscle power and possibly some muscle fiber necrosis; long duration or severe or complete cessation cause ischemic muscle necrosis and atrophy. See also compartment syndrome, downer cow syndrome.

muscular ischemic necrosis

see ischemic myonecrosis.

muscular mineralization

ectopic deposition of minerals in muscle. See mineralization.

myelopathic muscular atrophy

muscular atrophy due to a lesion of the spinal cord, as in spinal muscular atrophy.

nutritional muscular dystrophy

see muscular dystrophy (above).

muscular parasitic diseases

includes cysticercosis, hepatozoonosis, Neosprum caninum myositis, sarcocystosis, toxoplasmosis, trichenellosis.

muscular receptors

muscle spindles which respond to stretch.

muscular steatosis

excess fat deposits in muscle; a problem only at meat hygiene inspection.

muscular vascular occlusive syndrome

see ischemic myonecrosis.

muscular weakness

see weakness.

X-linked muscular dystrophy

see Duchenne muscular dystrophy (above).