EMG Terms

Electrodiagnosis
1. The use of electronic devices for diagnostic purposes.
2. By convention, the studies performed in the EMG laboratory, i.e., nerve conduction studies and needle electrode examination (EMG proper). SYN: electroneurography.
3. Determination of the nature of a disease through observation of changes in electrical activity. SYN: evoked electromyography.

Electromyography
1. The recording of electrical activity generated in muscle for diagnostic purposes; both surface and needle recording electrodes can be used, although characteristically the latter is employed, so that the procedure is also called needle electrode examination.
2. Umbrella term for the entire electrodiagnostic study performed in the EMG laboratory, including not only the needle electrode examination, but also the nerve conduction studies. [electro- + G. mys, muscle, + grapho, to write]

Electromyogram (EMG)
A graphic representation of the electric currents associated with muscular action.

Nerve Conduction
The transmission of an impulse along a nerve fiber.

Nerve
[TA] A whitish cordlike structure composed of one or more bundles (fascicles) of myelinated or unmyelinated nerve fibers, or more often mixtures of both, coursing outside the central nervous system, together with connective tissue within the fascicle and around the neurolemma of individual nerve fibers (endoneurium), around each fascicle (perineurium), and around the entire nerve and its nourishing blood vessels (epineurium), by which stimuli are transmitted from the central nervous system to a part of the body or the reverse. Nerve branches are given in the definition of the major nerve; many are also listed and defined under branch. SYN: nervus [TA] . [L. nervus]

Conduction
1. The act of transmitting or conveying certain forms of energy, such as heat, sound, or electricity, from one point to another, without evident movement in the conducting body.
2. The transmission of stimuli of various sorts by living protoplasm. [L. con- duco, pp. ductus, to lead, conduct]

cranial nerves[TA] those nerves that emerge from, or enter, the cranium or skull, in contrast to the spinal nerves, which emerge from the spine or vertebral column. The twelve paired cranial nerves are the olfactory [CN I], optic [CN II], oculomotor [CN III], trochlear [CN IV], trigeminal [CN V], abducent [CN VI], facial [CN VII], vestibulocochlear [CN VIII], glossopharyngeal [CN IX], vagal [CN X], accessory [CN XI], and hypoglossal [CN XII] nerves. SYN: nervi craniales [TA] .

motor nerve[TA] a nerve composed mostly or entirely of efferent (motor) nerve fibers conveying impulses that excites muscular contraction; motor nerves in the autonomic nervous system also elicit secretions from glandular epithelia.

upper extremity SYN: upper limb.

lower extremity SYN: lower limb.

thorax
gen. thoracis, pl. thoraces. [TA] The upper part of the trunk between the neck and the abdomen; it is formed by the 12 thoracic vertebrae, the 12 pairs of ribs, the sternum, and the muscles and fasciae attached to these; below, it is separated from the abdomen by the diaphragm; it contains the chief organs of the circulatory and respiratory systems. [L. fr. G. thorax, breastplate, the chest, fr. thoresso, to arm]

[All definitions are from Stedman’s Medical Dictionary]