CLASSIFICATION OF SOMATIC SENSES
The somatic senses can be classified into three physiologic types: (1) the mechanoreceptive somatic senses, which include both tactile and position sensa-tions that are stimulated by mechanical displacement of some tissue of the body; (2) the thermoreceptive senses, which detect heat and cold; and (3) the painsense, which is activated by any factor that damages the tissues.
The tactile senses include touch, pressure, vibration, and tickle senses, and the position senses include static position and rate of movement senses.
Other Classifications of Somatic Sensations. Somatic sensations are also oftengrouped together in other classes, as follows.
Exteroreceptive sensations are those from the surface of the body. Proprio-ceptive sensations are those having to do with the physical state of the body,including position sensations, tendon and muscle sensations, pressure sensations from the bottom of the feet, and even the sensation of equilibrium (which is often considered a “special” sensation rather than a somatic sensation).
Visceral sensations are those from the viscera of the body; in using this term,one usually refers specifically to sensations from the internal organs.
Deep sensations are those that come from deep tissues, such as from fasciae,muscles, and bone. These include mainly “deep” pressure, pain, and vibration.