On the dorsal side, the skin can be moved across the hand up to 3 cm (1.2 in); an important input the cutaneous mechanoreceptors.The web of the hand is a "fold of skin which connects the digits". These webs, located between each set of digits, are known as skin folds (interdigital folds or plica interdigitalis). They are defined as "one of the folds of skin, or rudimentary web, between the fingers and toes". Variation
The ratio of the length of the index finger to the length of the ring finger in adults is affected by the level of exposure to male sex hormones of the embryo in utero. This digit ratio is below 1 for both sexes but it is lower in males than in females on average. Clinical significance
A number of genetic disorders affect the hand. Polydactyly is the presence of more than the usual number of fingers. One of the disorders that can cause this is Catel-Manzke syndrome. The fingers may be fused in a disorder known as syndactyly. Or there may be an absence of one or more central fingers—a condition known as ectrodactyly. Additionally, some people are born without one or both hands (amelia). Hereditary multiple exostoses of the forearm—also known as hereditary multiple osteochondromas—is another cause of hand and forearm deformity in children and adults.There are several cutaneous conditions that can affect the hand including the nails. The autoimmune disease rheumatoid arthritis can affect the hand, particularly the joints of the fingers. Some conditions can be treated by hand surgery.
A generalized tonic–clonic seizure, or GTCS, previously known as a Grand mal seizure, is a type of generalized seizure that produces bilateral, convulsive tonic and then clonic muscle contractions. Tonic-clonic seizures are the seizure type most commonly associated with epilepsy and seizures in general and the most common seizure associated with metabolic imbalances. It is a misconception that they are the sole type of seizure, as they are the main seizure type in approximately 10% of those with epilepsy.These seizures typically initiate abruptly with either a focal or generalized onset, the former being known as focal to bilateral tonic-clonic seizure. The seizure itself includes tonic (sustained) and then clonic (repetitive short) contractions. In some seizures, the tonic phase may be preceded by brief, arrhythmic muscle jerks (myoclonus), by a clonic phase or by an absence seizure. After the GTCS, there is an extended postictal state where the person is unresponsive and commonly sleeping with loud snoring. There is usually pronounced confusion upon awakening. Causes
The vast majority of generalized tonic-clonic seizures have a focal origin they start as a smaller seizure that occurs solely on one side of the brain and is referred to as a focal (or partial) seizure. These unilateral seizure types (formerly known as simple partial seizure or a complex partial seizure and now referred to as focal aware seizure and focal impaired awareness seizure, respectively) can then spread to both hemispheres of the brain and cause a generalized tonic-clonic seizure.