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Lancefield classification

(lans′fēld″) [Rebecca Craighill Lancefield, U.S. bacteriologist, 1895–1981] A classification of hemolytic streptococci into various groups according to antigenic structure.


(lăn′sĕt) [L. lancea, lance] 1. A pointed surgical knife with two edges. 2. A spring-loaded or manual blade used to make a limited skin incision as for collection of blood specimen.


(lăn′sĭ-nāt″ĭng) [L. lancinare, to tear] Sharp or cutting, as pain.

Landau-Kleffner syndrome

(lan′dō-klef′nĕr, lan′dow-klef′nĕr) [William M. Landau, Frank R. Kleffner, contemporary U.S. neurologists] ABBR: LKS. A rare neurological disorder of childhood marked by loss of the ability to speak and comprehend spoken language usually without other cognitive deficits.

 INCIDENCE: The disease is very rare.

 CAUSES: LKS appears to be caused by a focus of seizure activity in the speech centers of the dominant lobe of the brain.

 SYMPTOMS AND SIGNS: After normal early growth and development, children between the ages of 3 and 7 lose previously acquired language skills. The age of onset helps distinguish the disease from most autism spectrum disorders, which first become obvious earlier in life. Repetitive seizures (esp. at night), hyperactivity, or other behavioral or psychiatric disorders may also develop.

 DIAGNOSIS: Receptive and expressive aphasia developing in childhood, along with abnormal electroencephalography (EEG) during sleep establishes the diagnosis.

 TREATMENT: Affected children are treated with anticonvulsant drugs and steroids.

 IMPACT ON HEALTH: Speech therapy, along with antiepileptic drugs and steroids should be provided as soon as the diagnosis is established. Children who develop the syndrome later in childhood and those who are treated the earliest appear to do the best. Surgery to divide the epileptic focus in the brain has also been demonstrated to result in recovery of language function. SYN: acquired epileptiform aphasia; infantile acquired aphasia.

Landau reflex

(lan′dō, ′dow) [A. Landau, Ger pediatrician] An infantile reflex in which the body flexes when the head is passively flexed forward in a prone position. It appears normally at 3 months and is absent in children with cerebral palsy and gross motor retardation.


A recognizable skeletal or soft tissue structure used as a reference point in measurements or in describing the location of other structures. SEE: cephalometry; craniometry.

bony l. A structure or spot on a bone used as a reference for measurement.

cephalometric l. A bony point that is used in living persons or radiographs for measurements of the head or face or orientation of the head in certain positions.

craniometric l. A bony point or area on the ...

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