Muscle Function Diagnostics

Muscle function diagnostics is used to check the muscle function or muscle strength of individual muscles or even muscle groups. It provides information about damage to peripheral motor nerves, performance and the healing process of functionally or organically damaged muscles.

Indications (areas of application)

The field of application is very wide; the muscles may be damaged, for example, by a sports injury or an accident. Prolonged immobilization (e.g., bed confinement) leads to muscle atrophy (muscle atrophy) and thus to a loss of function.In principle, the diagnosis is particularly suitable for monitoring progress in the context of therapeutic muscle training.

  • Sports injuries / accidents, eg muscle strain, muscle fiber tear.
  • Muscle atrophy (muscle atrophy)
  • Muscular dystrophies (degenerative muscle diseases characterized by progressive muscle weakness), such as Duchenn`sche muscular dystrophy or Becker`sche muscular dystrophy.
  • Metabolic diseases that lead to myopathies e.g. by drugs, toxins (poisons) and nutritional deficiencies.
  • Myasthenia gravis (progressive muscle disease; characteristic feature is abnormal strain-dependent muscle weakness that resolves at rest).
  • Myotonia disorders (Increased tone of skeletal muscles: muscle relaxation is slowed and patients can no longer open their closed fist, for example), e.g., paramyotonia congenita (also called paramyotonia congenita Eulenburg; belongs to the group of forms of sodium channel myotonia. It is manifested in humans by a more difficult relaxation of the muscles after contraction and in cold).
  • Polymyositis (belongs to the collagenoses; systemic inflammatory disease of skeletal muscle with perivascular lymphocytic infiltration).
  • Dermatomyositis (chronic systemic disease belonging to the collagenoses; an idiopathic myopathy (= muscle disease) or myositis (= muscle inflammation) with skin involvement).
  • Hyperkalemic periodic paralysis (periodic paralysis disease that occurs both isolated to one part of the body and generalized. Frequency varies, usually regular attacks at intervals of a few days, occasionally daily paralysis).
  • Perineuritis (inflammation of the connective tissue surrounding nerves).

The procedure

There are a variety of ways to quantify the condition of a muscle. For example, muscle thickness and muscle strength are thought to correlate, and thus thickness provides information about functional status. By manually testing muscle strength (manual muscle function diagnostics according to V. Janda), a physiotherapist can estimate muscle strength very well with the help of several tests.Muscle function or strength is expressed in values from 0 – 6, especially in manual muscle function diagnostics, and is precisely defined:

  • 0: No visible or palpable tension of a muscle involved in the movement.
  • 1: Visible or palpable muscle contraction, movement is not possible.
  • 2: Movement can be performed in a horizontal plane with the cancellation of gravity.
  • 3: The movement can be performed completely without resistance to gravity.
  • 4: The movement can be performed completely against gravity and moderate resistance.
  • 5: The movement can be performed completely against gravity and strong resistance.
  • 6: The movement can be performed 10 times completely against gravity and strong resistance.

The following diagnostic methods give a meaningful picture of the condition of the musculature:

  • Muscle cross-sectional measurements:
    • Measurement of the circumference of the extremities: a very simple method, but it does not take into account any swelling or fat mass.
    • Ultrasound thickness measurement: muscle, fat and bone can be clearly separated.
    • Computed tomography (CT) or magnetic resonance imaging: muscle cross-section can be determined very accurately.
  • Measurement of neuromuscular function: here, electromyography (EMG) is used, a technical examination procedure in which the electrical activity of a muscle is measured at rest and in motion. Especially nerve damage can be detected in this way.
  • Measurement of histological and biochemical properties: Here, a muscle biopsy leads to the goal.Determined pathological (disease-related) changes in the tissue.
  • Force measurements:
    • Isometric (static) force measurement: this measurement records the greatest voluntary muscle tension that the patient can exert against immobile resistance, i.e., without shortening the muscle. The maximum isometric force is recorded via a force sensor.
    • Dynamic force measurement: the functional muscle force is determined in connection with the movement of the muscles, for example, weight lifting. There are also devices that measure muscle force during a movement. This measurement has the greatest informative value about the functionality of the muscles in everyday life.
    • Isokinetic force measurement: this is a complex apparative procedure. The dynamic force development at constant speed is measured. The measuring device adapts to the force development of the patient’s muscles and logs a force curve.

Benefit

Both for an athlete and for the everyday life of a normal patient, muscle function diagnostics provides valuable information. Especially for the follow-up of muscle damage, regular diagnostics is important.