Cephalometry

Cephalometry is the study and measurement of the head, usually the human head, especially by medical imaging such as radiography. Craniometry, the measurement of the cranium (skull), is a large subset of cephalometry. Cephalometry also has a history in phrenology, which is the study of personality and character as well as physiognomy, which is the study of facial features. Cephalometry as applied in a comparative anatomy context informs biological anthropology. In clinical contexts such as dentistry and oral and maxillofacial surgery, cephalometric analysis helps in treatment and research; cephalometric landmarks guide surgeons in planning and operating.

Cephalometry is the study and measurement of the head, usually the human head, especially by medical imaging such as radiography. Craniometry, the measurement of the cranium (skull), is a large subset of cephalometry. Cephalometry also has a history in phrenology, which is the study of personality and character as well as physiognomy, which is the study of facial features. Cephalometry as applied in a comparative anatomy context informs biological anthropology. In clinical contexts such as dentistry and oral and maxillofacial surgery, cephalometric analysis helps in treatment and research; cephalometric landmarks guide surgeons in planning and operating. ==Machine Dimensions== To carry out cephalometry, the X-ray source is placed a steady five feet away from the mid sagittal plane, with film situated just 15 cm from there. This allows for accurate measurements to be taken and recorded. Distance has a direct impact on cephalometric image magnification. With an object-to-film interval of 15 cm and a source-to-object span of 5 feet, magnification of anatomical landmarks will be reduced in all three dimensions.When attempting to analyze a patient's anatomy through lateral and frontal cephalograms, the challenge arises due to these images being two-dimensional projections of three-dimensional structures. Magnification and distortion as an outcome of traditional radiography further complicates the process by blurring important details. ==Applications== ===Dentistry=== Cephalometric analysis is used in dentistry, and especially in orthodontics, to gauge the size and spatial relationships of the teeth, jaws, and cranium. This analysis informs treatment planning, quantifies changes during treatment, and provides data for clinical research. Cephalometry focuses on linear and angular dimensions established by bone, teeth, and facial measurements. It has also been used for measurements of hard and soft tissues of the craniofacial complex. ===Obstetrics=== Ultrasound cephalometry is useful for determining baby growth in utero. Cephalometry can also determine if an unborn child will pass through the birth canal. Certain 3D imaging applications are now used in obstetric cephalometry. In 1961, Donald and Brown employed ultrasound technique for measurement of the fetal head. Other scientists tried the method and found that the ultrasound technique was 3mm different than the post-natal measurement with calipers. This method requires that the transponder be placed on the maternal abdomen over the area of the fetal head. The transponder is moved until a pair of echos are strong and equal. This indicates that the parietals are perpendicular to the transmitting beam. The distance of the reflections equal the biparietal diameter. From this, the size of the head and the fetal weight can be determined with incredible accuracy. The use of ultrasound cephalometry is meant to be used in addition to other radiographic techniques. Thus far, no ill effects have been reported to the fetus or the mother using the ultrasound fetal cephalometry. ==See also== Anthropometry Cranial vault Craniofacial anthropometry Phrenology Robert M. Ricketts MW Definition (Archived 2009-10-31) ==References==

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