The most important infection of muscle is gangrene, which may complicate deep wounds (especially those contaminated by soil).
The most important infection of muscle is gangrene, which may complicate deep wounds (especially those contaminated by soil).
Tetanus is acquired in a similar way, causing widespread muscle spasm through the release of a powerful toxin.
Viruses (especially influenza B) may also infect muscles (causing myalgia), as may the organism causing toxoplasmosis. Trichinosis is an infestation of muscle with the worm trichinella spirilus, which is acquired by eating undercooked meat (usually pork).
Muscle injuries, such as tears and sprains, are very common, they cause bleeding into the muscle tissue.
Muscle injuries, such as tears and sprains, are very common, they cause bleeding into the muscle tissue.
Healing leads to formation of a scar in the muscle which shortens its natural length.
Blunt muscle injury may result in hematoma formation from bleeding into the muscle.
Rarely, bone may form in the hematoma causing
myositis ossificans.
Primary muscle tumors may or may not be cancerous.
Primary muscle tumors may or may not be cancerous.
Noncancerous tumors are called myomas,
those affecting smooth muscle are leiomyomas,
and those affecting skeletal muscle are
rhabdomyomas.
Myomas of the uterus are among the most common of all tumors.
Muscle contraction depends on the maintenance of proper levels of sodium (Na+), potassium (K+), and calcium (Ca++) in and around muscle cells. Any alteration in the concentration of these substances affects muscle function. For example, a severe drop in the level of potassium (hypokalemia) causes profound muscle weakness and may stop the heart. A drop in blood calcium (hypocalcemia) causes increased excitability of muscles and occasionally spasm.
Muscle contraction depends on the maintenance of proper levels of sodium (Na+), potassium (K+), and calcium (Ca++) in and around muscle cells. Any alteration in the concentration of these substances affects muscle function. For example, a severe drop in the level of potassium (hypokalemia) causes profound muscle weakness and may stop the heart. A drop in blood calcium (hypocalcemia) causes increased excitability of muscles and occasionally spasm.