History and Timeline
- Cephalometry has its origins in the Renaissance, with Leonardo da Vinci studying facial proportions using grids.
- Petrus Camper in the 18th century introduced angles in the measurement of facial form.
- Anders Retzius defined the cephalic index and classified different head shapes.
- Cephalometry was consecrated by orthodontists in 1931.
- The era of computed cephalometric radiology began in the 1960s.
- In 1931, cephalometry became important in orthodontics.
- The 1960s saw the introduction of computed cephalometric radiology.
- In 1961, Donald and Brown used ultrasounds for fetal head measurement.

Machine Dimensions
- The X-ray source is placed 5 feet away from the mid sagittal plane.
- The film is situated 15cm from the X-ray source.
- Distance affects cephalometric image magnification.
- Lateral and frontal cephalograms are two-dimensional projections of three-dimensional structures.
- Traditional radiography can cause magnification and distortion.

Applications
- Cephalometry is used in orthodontics to gauge the size and spatial relationships of the teeth, jaws, and cranium.
- It informs treatment planning and quantifies changes during treatment.
- 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.
- Ultrasound cephalometry is used to determine baby growth in utero and if the child will pass through the birth canal.
- 3D imaging applications are now used in obstetric cephalometry.
- Ultrasound technique allows for accurate measurement of the fetal head and weight.
- Ultrasound cephalometry is used in addition to other radiographic techniques.
- Cephalometry can assist in forensic investigations by compiling databases of population-level craniometric data.
- Cranial measurements vary by population, making databases helpful in known regions.
- Cephalograms can be used for accurate age estimation, but not for sex estimation.
- Mandibular ramus length is strongly related to chronological age.
- Cephalometry is useful for facial reconstruction in cases of disputed identity.
- Cephalometric anthropomorphic parameters are related to the apnea-hypopnea index in children with sleep apnea.
- Hyoid position is important in pediatric sleep apnea.
- Hyoid location correlates with obstructive sleep apnea/hypopnea syndrome (OSAHS) in adults.
- People with reduced midface length and inferiorly placed hyoid tend to have smaller airways and are prone to obstructive sleep apnea.

Limitations
- Cephalometry has limitations in predicting sex and stature accurately.
- Dietary habits and genetic factors contribute to variations in cephalic indices among population groups.
- Cephalometry data gathered is only valid for the adult population.
- Cephalometry has potential applications in immigration, criminal and civil investigations, adoption, and old-age pension requests.
- Cephalometry remains the most popular and useful method for investigating craniofacial skeletal morphology.

Technology and Other Applications
- Advances in technology have enabled the use of statistical programs to estimate ancestry based on craniometric measurements.
- CRANID is a statistical program used for estimating ancestry when the origin of a cranium is unknown.
- Cranial measurements are entered into a worldwide craniometric database and compared to known cranial metrics.
- This technology is used in archaeological, forensic, and repatriation contexts.
- Accuracy is highest when sex can be determined.
- Overlaying older images can be used to study and predict facial growth.
- Computer programs can compare lateral cephalograms with growth algorithms to test their reliability.
- Cephalometry is used for diagnosing craniofacial anomalies.
- It is also used for evaluating the nasopharyngeal passage.
- Two-year predictions using growth algorithms have been found to be valid.

Cephalometry (Wikipedia)

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.