1,240 articles
Misophonia
Misophonia is a disorder of intense anger or disgust triggered by specific sounds like chewing or breathing, first named in 2001, defined by a 2022 Delphi consensus, and treatable with cognitive behavioral therapy.
Mitomycin C
Mitomycin C (MMC, NSC 26980) is an antitumor antibiotic activated by quinone reduction into a DNA-cross-linking bis-electrophile; FDA-approved 1974 for cancers and widely used off-label as an antiscarring agent in glaucoma trabeculectomy surgery.
Mitral cell
Mitral cell: principal excitatory projection neuron of the vertebrate olfactory bulb, named for its miter-shaped soma. One primary dendrite reaches a single glomerulus; axons form the lateral olfactory tract to olfactory cortex.
Moderate and severe traumatic brain injury
Moderate and severe traumatic brain injury (moderate-severe TBI) is head trauma more severe than mild TBI, defined by GCS below 13 or prolonged loss of consciousness or amnesia.
Monomelic amyotrophy
Monomelic amyotrophy (Hirayama disease) is a rare juvenile lower motor neuron disorder causing unilateral distal upper limb atrophy sparing the brachioradialis, from flexion-induced cervical cord ischemia; collar or surgery, self-limiting course.
Morning glory disc anomaly
Morning glory disc anomaly (MGDA) is a rare congenital optic nerve malformation with a funnel-shaped, flower-like optic disc, usually affecting one eye and impairing vision.
Moro reflex
Moro reflex, also called the startle or embrace reflex (Umklammerungsreflex), is a primitive newborn reflex elicited by sudden head drop, with arm extension-abduction then flexion; it disappears by 2–5 months and signals clavicle fracture, brachial plexus palsy, or brain injury when absent or asymmetric.
Morphogen
Morphogen: a signaling molecule forming a concentration gradient that gives cells positional information during embryonic development. Term coined by Turing (1952); French Flag model by Wolpert (1969); examples include Bicoid, Shh, Dpp, BMP, and Nodal.
Morton's neuroma
Morton's neuroma, or interdigital neuroma, is a thickening of tissue around an irritated common plantar digital nerve between the toes, usually the third web space. Treated first with footwear changes, then steroid injections or neurectomy; not a true nerve tumor.
Mosaic schwannomatosis
Mosaic schwannomatosis (MNF3, mosaic SWN) is a rare mosaic form of schwannomatosis caused by postzygotic SMARCB1 or LZTR1 variants, producing multiple schwannomas with a milder phenotype; ORPHA:634492, ICD-11 LD2D.1Y.
Motion sickness
Motion sickness (seasickness, car sickness) is nausea, vomiting, dizziness, pallor, and cold sweating from real or perceived motion conflicting vestibular, visual, and proprioceptive inputs; treated with habituation, scopolamine, and sedating antihistamines.
Motor control
Motor Control (ISSN 1087-1640) is a peer-reviewed quarterly Human Kinetics journal, official journal of the International Society of Motor Control since 1997, publishing multidisciplinary research on human movement control and motor disorders; MEDLINE-indexed, 2024 impact factor 1.4.
Motor cortex
Motor cortex: frontal lobe region for voluntary movement, comprising primary motor cortex (M1, Brodmann area 4), premotor cortex, and supplementary motor area; somatotopic map, Betz cells, corticospinal output, discovered by Fritsch and Hitzig in 1870.
Motor neuron
A motor neuron, also called an efferent neuron or motor nerve cell, carries command signals from the central nervous system to muscles and glands, forming the final common path.
Motor neuron diseases
Motor neuron diseases (MNDs) are progressive neurological disorders destroying upper and lower motor neurons, causing weakness, wasting, and fasciculations. Main types are ALS (80–90% of cases), progressive bulbar palsy, primary lateral sclerosis, and progressive muscular atrophy; ALS is usually fatal within 3–5 years.
Motor neuroprosthetics
Motor neuroprosthetics: devices restoring movement after stroke or spinal cord injury by stimulating muscles, nerves, spinal cord, or brain, or decoding brain signals (BCIs), from Liberson's 1961 foot-drop stimulator to Utah-array robotic arm control.
Motor skill
Motor skill: learned ability to perform movements efficiently, assessed by retention and transfer. Covers Fitts-Posner stages, contextual interference (random vs blocked practice, SMD 0.55), implicit vs explicit learning, and cortex-basal ganglia-cerebellum mechanisms.
Motor unit number estimation
Motor unit number estimation (MUNE), including MUNIX, MScanFit, and MPS variants, estimates the number of functioning motor units in a muscle from surface EMG, mainly to track lower motor neuron loss in ALS.
Mucopurulent conjunctivitis
Mucopurulent conjunctivitis (ICD-11 9A60.3, ICD-10 H10.0), bacterial conjunctival infection with mucus-and-pus discharge and matted eyelids; usually self-limited, antibiotics modestly speed cure.
Multifocal Intraocular Lenses
Multifocal intraocular lenses (MIOLs), including bifocal, trifocal, refractive, and diffractive designs, are implanted IOLs giving near, intermediate, and distance vision after cataract surgery, trading reduced contrast sensitivity and halos for spectacle independence.
Multifocal pattern dystrophy simulating fundus flavimaculatus
Multifocal pattern dystrophy simulating fundus flavimaculatus (MPDSFF), also called pseudo-Stargardt pattern dystrophy, is a rare autosomal dominant PRPH2-related retinal pigment epithelium dystrophy with adult-onset yellow flecks, hyperautofluorescence, no dark choroid, and a better prognosis than Stargardt disease.
Multiple evanescent white dot syndrome
Multiple evanescent white dot syndrome (MEWDS) is a rare, acute, usually unilateral, self-limiting outer retinal inflammatory disease of young women, first described by Jampol in 1984, diagnosed by ICGA/FAF/OCT imaging and resolving within weeks.
Muscle spindle
Muscle spindle (Muskelspindeln): encapsulated stretch receptor in skeletal muscle, built of intrafusal bag and chain fibers with Ia and II afferents and gamma motor innervation; signals muscle length and stretch velocity for proprioception and the stretch reflex.
Muscular hypertonia
Muscular hypertonia, also called muscle hypertonia or increased muscle tone, is abnormally stiff, resistant muscles from upper motor neuron lesions, classified as spasticity, rigidity, dystonia, or paratonia; ICD-11 code MB47.8.
Mydriasis
Mydriasis is abnormal pupil dilation, caused by iris dilator stimulation, sphincter paralysis, trauma, third nerve palsy, Adie tonic pupil, or pharmacologic agents; dilute pilocarpine testing distinguishes pharmacologic from neurologic causes.
Myelomalacia
Myelomalacia is softening of the spinal cord after ischemia, compression, or contusion; seen on MRI as T2 hyperintensity, it marks chronic cord injury in degenerative cervical myelopathy and predicts white cord syndrome after decompression.
Myelopathy
Myelopathy is spinal cord dysfunction, usually from compression; types are cervical, thoracic, and lumbar, with degenerative cervical myelopathy the most common cause in adults, treated with bracing, therapy, medication, or decompression surgery.
Myokymia
Myokymia is involuntary, fine, rippling muscle contraction from repetitive motor-unit discharges; eyelid myokymia, the commonest form, is a benign eyelid twitch triggered by fatigue, stress, and caffeine, treated with botulinum toxin if persistent.
Myotome
Myotome: the group of skeletal muscles innervated by one spinal nerve ventral root, and the somite compartment forming skeletal muscle; used clinically to localize radiculopathy, though maps vary between patients.
Myringotomy
Myringotomy, or tympanotomy, is a surgical incision in the eardrum to drain middle ear fluid or ventilate the ear, often with a tympanostomy tube (grommet). First recorded in 1649; reintroduced by Schwartze and Politzer in the 19th century.