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Large Calf Muscle Puzzles Doctors

Muscles contract because messages from motor nerves tell them what to do. These nerves come from the spinal cord and pass through openings in the bones of the spine on their way to the muscles. For example, the nerve to the calf muscle travels from the bottom of the spine, called the sacrum, to the lower leg.

Anything that changes the signals from the nerves to the muscles can affect the muscles. Pain and weakness are the usual signs of trouble. Difficulty walking or doing some activities may result. The affected muscles may get smaller and waste away.

In some rare cases, the muscle actually gets larger. This condition is called hypertrophy. Hypertrophy is unusual. It usually suggests a muscle disorder, rather than nerve problem.

A single case study brought this to the attention of a team of doctors. A 59-year-old man developed right leg weakness and calf hypertrophy over the course of several months. After much testing and study, doctors were able to tell that this was caused by pressure on the spinal nerve that goes to the calf muscle. Removing the pressure resulted in pain relief and return of muscle strength.

Doctors should be aware that muscle hypertrophy in the calf might be a sign of either muscle or nerve problems. Early diagnosis and treatment can prevent permanent nerve damage and muscle weakness.

References: Karin R. Swartz, MD, et al. Unilateral Calf Hypertrophy Seen in Lumbosacral Stenosis. In Spine. September 15, 2002. Vol. 27. No. 18. Pp. E406-E409.

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