Nerve compression syndrome or compression neuropathy, also known as entrapment neuropathy, is a medical condition caused by direct pressure on a single nerve. It is known colloquially as a trapped nerve, though this may also refer to nerve root compression (by a herniated disc, for example).erve compression syndrome or compression neuropathy, also known as entrapment neuropathy, is a medical condition caused by direct pressure on a single nerve. It is known colloquially as a trapped nerve, though this may also refer to nerve root compression (by a herniated disc, for example).