Disease and conditions 

Marcus Gunn’s phenomenon is a reflexive elevation of a ptotic upper eyelid on one side, linked to jaw movement. It occurs in misdirectional syndrome involving cranial nerves III and V and is elicited by jaw opening and lateral movements.

Mannkopf’s sign is an increase in pulse rate when pressure is applied to a painful area. It helps differentiate genuine pain from simulated pain, as the sign is absent in the latter.

Mania is a mood disturbance marked by heightened energy, euphoria, rapid thoughts, and pressured speech. It typically occurs during the manic phase of bipolar disorder.

Malingering is the intentional exaggeration or feigning of symptoms to avoid responsibilities or gain attention or other benefits.

Malaise is a nonspecific feeling of listlessness, fatigue, or general discomfort. It may develop gradually or suddenly and often precedes signs of infectious, endocrine, or neurologic disorders.

Maisonneuve’s sign is hyperextension of the wrist seen in Colles’ fracture. It occurs due to posterior displacement of the distal radius fragment.

Macewen’s sign is a “cracked-pot” sound heard on light percussion over an infant’s anterior fontanel. It is an early indicator of hydrocephalus and may also be seen in cerebral abscess.

A lumbosacral hair tuft is an abnormal patch of hair over the lower spine, sometimes with skin depression or discoloration. It may indicate underlying spina bifida occulta or spina bifida cystica.

Ludloff’s sign is the inability to raise the thigh while sitting, accompanied by edema and ecchymosis at the base of Scarpa’s triangle. In children, it indicates traumatic separation of the epiphyseal growth plate of the greater trochanter.

Low-set ears are defined by the superior helix lying below the level of the eyes. They are a common feature in genetic syndromes such as Down, Turner, Noonan, Apert’s, and Potter’s, as well as other congenital anomalies.

Loose association is a thought disorder where speech lacks logical connections between ideas. It is commonly seen in schizophrenia, bipolar disorder, and other psychotic conditions.

Lloyd’s sign is referred loin pain triggered by deep percussion over the kidney. It is commonly associated with renal calculi.

Linder’s sign is pain in the lower back or leg triggered by passive neck flexion, indicating sciatica. It is elicited with the patient supine or sitting and legs extended, stretching the irritated sciatic nerve.

Lichtheim’s sign is the inability to speak seen in subcortical aphasia. Patients can, however, indicate the number of syllables in a word using their fingers.

Lhermitte’s sign is a sudden, transient, electric-like shock sensation radiating down the spine and limbs, triggered by neck flexion. It is associated with multiple sclerosis, spinal cord degeneration, and cervical spinal injuries.

Leichtenstern’s sign is pain elicited by gentle tapping of an extremity’s bones. It is seen in cerebrospinal meningitis, often causing the patient to wince, withdraw, or cry out.

Lead-pipe rigidity is a smooth, constant resistance to passive movement of muscles. It is typically seen in Parkinson’s disease.

Laugier’s sign is an abnormal alignment of the radial and ulnar styloid processes due to a distal radius fracture. The radial styloid may migrate proximally, becoming level with the ulnar styloid, unlike the normal distal position.

Lasègue’s sign is pain triggered by specific leg movements that helps differentiate hip joint disease from sciatica. Pain on hip flexion with the knee bent suggests hip pathology, while pain on knee extension with the hip flexed indicates sciatic nerve irritation.

Large for gestational age (LGA) refers to a neonatal weight above the 90th percentile for gestational age. Affected infants face increased risks of birth trauma, respiratory distress, metabolic disturbances, and polycythemia.

Langoria’s sign is relaxation of the thigh and hip extensor muscles due to an intracapsular femoral fracture. It is elicited by palpating the gluteus maximus and hamstrings in the prone position, with greater softness noted on the affected side.

Kussmaul’s sign is paradoxical jugular vein distention during inspiration, indicating impaired right ventricular filling. It is classically seen in constrictive pericarditis and other causes of right heart dysfunction.

Kussmaul’s respirations are deep, rapid, and sighing breaths, typically associated with diabetic ketoacidosis.

Koplik’s spots, or Koplik’s sign, are small red spots with bluish-white centers on the lingual and buccal mucosa, characteristic of measles. They typically appear 1–2 days before the measles rash erupts.

Kleist’s sign is the flexion or “hooking” of the fingers when passively raised, indicating frontal lobe or thalamic lesions. It is elicited by turning the patient’s palms down and gently raising the fingers.

Keen’s sign is an increased ankle circumference, typically seen in Pott’s fracture of the fibula. It’s detected by measuring and comparing the circumferences of both ankles at the malleoli.

Kanavel’s sign is tenderness in the palm over the tendon sheath of the little finger, indicating flexor tenosynovitis. It’s detected by applying pressure proximal to the metacarpophalangeal joint.

Joffroy’s sign is immobility of the facial muscles when the eyes rotate upward, seen in Graves’ disease with exophthalmos. It may also indicate early organic brain disorder when associated with inability to perform simple mathematics.

Jellinek’s sign, or Rasin’s sign, is brownish pigmentation on the eyelids, more prominent on the upper lid. It indicates Graves’ disease.

Illusion is a misperception of real external stimuli, often visual or auditory. It occurs in normal individuals as well as in schizophrenia and toxic states.

Idea of reference is a delusion in which a person believes that others’ statements, actions, or events hold a special personal significance. It commonly occurs in schizophrenia and paranoid disorders.

Hypoesthesia is a reduced sensitivity of the skin to touch, temperature, or pain, indicating possible nerve or sensory pathway impairment.

Hypernasality is a speech abnormality caused by excessive airflow through the nose, often linked to neuromuscular disorders, cleft palate, or velar paralysis. It may accompany dysarthria or swallowing difficulties.

Hyperesthesia is an abnormal increase in sensitivity to touch, temperature, or pain. It may indicate nerve or central nervous system disorders.

Hyperacusis is abnormally acute hearing due to increased irritability of the auditory neural pathway, resulting in an unusually low hearing threshold.

Hoover’s sign is inward movement of one or both costal margins during inspiration, indicating diaphragmatic flattening from intrathoracic disorders or emphysema. In a contralateral leg-lifting test, absent movement suggests hysteria or malingering.

Hoffmann’s sign is flexion of the thumb and fingers when the nail of the index, middle, or ring finger is flicked. A positive response suggests a pyramidal tract disorder, such as spastic hemiparesis. It may also refer to increased sensitivity of sensory nerves to electrical stimulation, as in tetany.

Hoehne’s sign is the absence of uterine contractions during delivery despite repeated doses of oxytocic drugs. It indicates a ruptured uterus.

Hill’s sign is a markedly higher femoral systolic pulse pressure (60–100 mmHg) in the right leg compared to the right arm. It indicates severe aortic insufficiency.

Subungual hemorrhage is a bleeding beneath the nail plate, appearing as splinter-like lines or larger hemorrhagic areas. It may indicate subacute bacterial endocarditis, trichinosis, or direct nail bed trauma.