Barognosis - MedFriendly.com

Barognosis is the ability to perceive and evaluate the

weight of objects (e.g., by looking at them) or to tell the

difference between objects of different weights

(especially those held in the hands). Sensory

information about weights is transmitted by a part of the

spinal cord known as the posterior column-medial

lemniscus (PCML) pathway. This is a nerve pathway

consisting of fast conducting fibers surrounded by a

fatty covering called myelin.

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The pathway transmits sensory information up the posterior column (back section) of the

spinal cord and from the medial lemniscus of the brainstem. The brainstem is an area in

the lower part of the brain that connects it with the spinal cord. The medial lemniscus is a

nerve pathway in the brainstem that carries sensory information to a sensory relay

station in the brain known as the thalamus.

Barognosis is tested by placing a small weighted object in each hand and asking the

patient which hand contains the heavier weight. The weight s can be the same size and

then modified so one weight is heavier than the other. Alternatively, two weights can be

placed in the same hand and the patient can be asked which weight is heavier. Another

technique is to have the patient pick up a series of weights with the fingertips and state

which one is heavier. Bargnosis is also known as baresthesia. The opposite of

barognosis is baragnosis, which is the inability to evaluate the weight of objects.

Barognosis comes from the Greek word "baros" meaning "weight," and the Greek word

"gnosis" meaning "knowledge." Put the words together and you have "weight knowledge."