shadow

1. A surface area defined by the interception of light or x-rays by a body. SEE ALSO: density (3). 2. In jungian psychology, the archetype consisting of collective animal instincts. 3. SYN: achromocyte.

- acoustic s. sonographic appearance of reduced echo amplitude from regions lying beyond an attenuating object. Cf.:acoustic enhancement.

- Gumprecht shadows SYN: smudge cells, under cell.

- hilar s. radiographic hilum of the lung; a composite radiographic s. of the central pulmonary arteries and veins, with associated bronchial walls and lymph node s, within the right or left lung.

- Ponfick s. SYN: achromocyte.

- radiographic parallel line s. SYN: tram lines, under line.

* * *

shad·ow 'shad-(.)ō, -ə(-w) n

1 a) partial darkness or obscurity within a part of space from which rays from a source of light are cut off by an interposed opaque body

b) a dark outline or image on an X-ray photograph where the X-rays have been blocked by a radiopaque mass (as a tumor)

2) a colorless or scantily pigmented or stained body (as a degenerate cell or empty membrane) only faintly visible under the microscope

shadow vt to perform shadow-casting on <freeze-dried and \shadowed myosin molecules>

* * *

shad·ow (shadґo) 1. an attenuated image of an actual object, as a faded or colorless erythrocyte. 2. a figure or image created by the interruption of light or other rays, such as the representation on a radiograph of radiopaque structures.