CLASSIFICATION OF PAINPain can be categorized in several ways. These categorization schemes aid in pain assessment and treatment. Most commonly, pain is categorized as nociceptive or neuropathic based on underlying pathology Nociceptive PainNociceptive pain caused by damage to somatic or visceral tissue. Somatic pain, characterized as deep, aching, or throbbing that is well localized, arises from bone, joint, muscle, skin, or connective Tissue. Visceral pain, which may result from stimuli such as tumour Involvement or obstruction, arises from internal organs such as the intestine and bladder. Examples of nociceptive pain include pain from a surgical Incision, a broken bone, or arthritis. Nociceptive pain is usually responsive to non-opioid medications, such as NSAlDs, as well as opioids.Neuropathic PainNeuropathic pain is caused by damage to peripheral nerves or CNS. Common causes of neuropathic pain include trauma, inflammation (e.g., secondary to a herniated disk inflaming the adjacent nerve and dorsal root ganglion), metabolic disease such as diabetes mellitus, infections of the nervous system (e.g., herpes zoster), tumours, toxins, and neurologic disease such as multiple sclerosis. Deafferentation pain (injury to either the peripheral nervous system or CNS) and sympathetically maintained pain (associated with dysregulation of the autonomic nervous system) ate