FioricetInternational Classification of Headache Disorders: The International Classification of Headache Disorders (ICHD) is a detailed hierarchical classification of all headache-related disorders published by the International Headache Society. It is considered the official classification of headaches by the World Health Organization, and, in 1992, was incorporated into the 10th edition of their International Classification of Diseases (ICD-10).Falx cerebri: The falx cerebri is also known as the cerebral falx, named from its sickle-like form. It is a large, crescent-shaped fold of meningeal layer of dura mater that descends vertically in the longitudinal fissure between the cerebral hemispheres.Spinal anaesthesia: Spinal anaesthesia (or spinal anesthesia), also called spinal analgesia, spinal block or subarachnoid block (SAB), is a form of regional anaesthesia involving injection of a local anaesthetic into the subarachnoid space, generally through a fine needle, usually 9 cm long (3.5 inches).Clickfine pen needlesManagement of chronic headaches: Chronic headache, or chronic daily headache (CDH), is classified as experiencing fifteen or more days with a headache per month.Duckro, Paul N.Combined spinal and epidural anaesthesia: Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the benefits of both spinal anaesthesia and epidural anaesthesia and analgesia. The spinal component gives a rapid onset of a predictable block.Paracervical block: A paracervical block is an anesthetic procedure used in obstetrics and gynecology, in which a local anesthetic is injected into between two to six sites at a depth of 3–7 mm alongside the vaginal portion of the cervix in the vaginal fornices.paracervical block By Robert Nadelberg.