The Lateral Cephalometric X-Ray View Projection (Lateral Ceph) is a standardized, reproducible radiographic view of the craniofacial complex in true lateral profile.
Utilizing a dedicated cephalostat (craniostat) headholder and a standardized long source-to-image distance (150 to 180 cm / 5 to 6 feet), this view minimizes magnification and eliminates geometric distortion. It allows precise anatomical tracing, linear and angular measurements (cephalometric analysis), and longitudinal evaluation of craniofacial growth, dentofacial deformities, and orthodontic/orthognathic treatment outcomes.
Detailed Indications:
Contraindications & Limitations:
Standardization is the core principle of cephalometry: the spatial geometry between the X-ray source, cephalostat ear rods, and image receptor must remain fixed to ensure 1:1 scale comparisons across multi-year treatment phases.
| Parameter | Recommended Specification | Radiographic Rationale |
|---|---|---|
| Patient Posture | Strictly Erect (Standing/Seated) | Natural Head Position (NHP) reflects genuine physiological posture |
| Image Receptor (IR) | 24×30 cm (10×12 inches), Portrait | Full coverage from calvarium down to C4 cervical vertebra |
| SID (Focal Distance) | 150 to 180 cm (5 to 6 feet) | Minimizes beam divergence, magnification (<5%), and penumbra |
| Source-to-Cephalostat Dist. | Fixed at 150 cm (5 feet) | Standardized international geometric baseline |
| Object-to-IR Dist. (OID) | Fixed at 15 cm (as close as possible) | Reduces magnification of lateral structures |
| Grid Ratio | 8:1 to 10:1 focused grid | Removes Compton scatter from cranial bones |
| Tube Potential (kVp) | 70−85 kVp | Penetrates dense facial bones while retaining soft-tissue profile |
| mAs Range | 10−20 mAs | Calibrated based on sensor type (CR/Direct Digital CCD/CMOS) |
| Soft Tissue Filter | Aluminum Wedge Filter (or Digital LUT) | Attenuates anterior beam to display soft-tissue facial profile |
| Breathing / Swallowing | Suspended respiration, no swallowing | Prevents elevation of the hyoid bone and soft palate blur |
Infraorbital margin to superior border of the EAM is positioned parallel to the horizontal floor.
Bilateral mechanical ear rods lock into the external acoustic meatus to eliminate head rotation.
MSP is aligned parallel to the IR with the nasion rest securing natural head position (NHP).
Teeth closed firmly in maximum intercuspation and lips relaxed without straining the perioral muscles.
| Landmark | Symbol | Anatomical Definition | Diagnostic Value |
|---|---|---|---|
| Sella | S | Midpoint of the hypophyseal fossa (sella turcica) | Center of cranial base reference |
| Nasion | N | Most anterior point of the nasofrontal suture in the midline | Anterior limit of the cranial base |
| Orbitale | Or | Lowest point on the infraorbital margin | Defines Frankfort Horizontal Plane |
| Porion | Po | Most superior point on the external acoustic meatus | Defines Frankfort Horizontal Plane |
| Subspinale (Point A) | A | Deepest midline concavity on the anterior border of the maxilla | Anterior apical limit of maxillary base |
| Supramentale (Point B) | B | Deepest midline concavity on the anterior border of the mandible | Anterior apical limit of mandibular base |
| Pogonion | Pog | Most anterior point of the bony mandibular chin (symphysis) | Evaluates chin prominence |
| Gnathion | Gn | Midpoint between Pogonion (Pog) and Menton (Me) | Intersection of facial & mandibular planes |
| Menton | Me | Lowest, most inferior point on the mandibular symphysis | Defines inferior mandibular baseline |
| Gonion | Go | Midpoint of the angle of the mandible | Posteroinferior junction of ramus & body |
| Basion | Ba | Lowest point on the anterior margin of the foramen magnum | Posterior limit of cranial base |
| Anterior Nasal Spine | ANS | Anterior tip of the sharp bony process of the maxilla | Anterior border of the palatal plane |
| Posterior Nasal Spine | PNS | Posterior tip of the bony hard palate | Posterior border of the palatal plane |
| Error Type | Radiographic Sign on Film | Clinical Impact | Correction |
|---|---|---|---|
| Head Rotation (MSP not parallel to IR) | Double contouring of the mandibular inferior borders (>2 mm split) and bilateral orbital roofs. | Invalidates angular and linear measurements; impossible to trace landmarks reliably. | Re-align ear posts securely inside both EAMs to lock rotation at 0∘. |
| Head Pitch Tilt (FHP not parallel to floor) | Excessive backward tilt (chin elevated) or downward flexion (chin depressed). | Distorts true natural head position (NHP) and alters soft-tissue profile aesthetics. | Align the Frankfort Horizontal Plane strictly parallel to the floor. |
| Incorrect Occlusion (Teeth in edge-to-edge / open) | Separation of posterior molars; false open-bite appearance. | Distorts vertical facial height and sagittal ANB skeletal relationship. | Instruct patient to swallow and bite fully on back teeth in centric occlusion. |
| Lip Straining / Pursed Lips | Flattening and unnatural thinning of the vermilion border of the lips. | Prevents accurate assessment of lip incompetence and soft-tissue profile. | Instruct patient to relax the perioral muscles naturally. |
Center of sella turcica & frontonasal junction (Cranial base baseline).
External auditory meatus midpoint & cephalostat ear rod position.
Maxillary basal bone with incisor apex (U1) and anterior/posterior spines.
Mandibular midline base, incisor (L1), anterior chin (Pog), and inferior symphysis (Me).
Mandibular angle apex, open C2–C4 vertebral space, and hyoid bone.