Tuesday, August 9, 2011

Ice-cream cone sign

The ear functions to capture sound waves from the environment and to convert them into nerve impulses for transmission to the brain. Anatomically, the ear can be divided into three parts, the outer ear which captures sound waves, the middle ear which amplifies and transmits these waves to the inner ear that then converts them into nerve impulses.
The middle ear is an air-filled space that contains the body’s smallest bones, the malleus (hammer), incus (anvil) and stapes (stirrup). These tiny bones (ossicles) transmit sound waves from the outer to inner ear.
When viewed with high resolution computed tomography (HRCT) scanning – a specialized type of X-ray imaging technique – the head of the malleus and the body of the incus resemble an ice-cream cone – ice-cream cone sign.
The ear also functions as an organ of balance.
Chavan GB, Shroff MM: Twenty classic signs in neuroradiology: A pictorial essay. Indian J Radiol Imaging, 2009 19(2): 135–145. Go to reference

Human ear anatomy
Ice-cream cone sign A (arrow)

No comments: