Reid's base line is used for an unambiguous definition of the orientation of the
human skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...
in
conventional radiography
Projectional radiography, also known as conventional radiography, is a form of radiography and medical imaging that produces two-dimensional images by x-ray radiation. The image acquisition is generally performed by radiographers, and the images ...
,
computer tomography
A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...
(CT), and
magnetic resonance imaging
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio wave ...
(MRI) studies. It is defined as a line drawn from the inferior margin of the orbit (''Orbitale'' point) to the auricular point (center of the orifice of the external acoustic meatus, ''Auriculare'' point) and extending backward to the center of the occipital bone. Reid's base line is used as the zero plane in computed tomography. Paediatric base line is an anatomic line that maintains a fixed relation to facial bones throughout the period of growth
In 1962, the World Federation of
Radiology
Radiology ( ) is the medical discipline that uses medical imaging to diagnose diseases and guide their treatment, within the bodies of humans and other animals. It began with radiography (which is why its name has a root referring to radiat ...
defined it as the line between the
infraorbital margin
The infraorbital margin is the lower margin of the eye socket.
Structure
It consists of the zygomatic bone and the maxilla, on which it separates the anterior and the orbital surface of the body of the maxilla.
Function
It is an attachment for ...
and the upper margin of the
external auditory meatus
The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the pinna to the eardrum and is about in length and in diameter.
Struc ...
.
With the head upright, it is typically tilted about 7 degrees nose up with respect to the horizontal plane.
See also
*
Frankfurt plane
The standard anatomical position, or standard anatomical model, is the scientifically agreed upon reference position for anatomical location terms. Standard anatomical positions are used to standardise the position of appendages of animals with r ...
External links
* {{Chorus, 00345
Radiology