Mandible - SMV

Radiographic Positioning

Adult

Other related pages of interest Applied Radiography Radiographic Anatomy Radiographic Protocols

Name of projection	Mandible - SMV
Area Covered	Entire mandible, coronoid and condyloid process
Pathology shown	Fractures of mandible, neoplastic and inflammatory changes
Radiographic Anatomy	Mandible Radiographic Anatomy
IR Size & Orientation	18 x 24cm landscape
Film / Screen Combination	Regular (CR and DR as recommended by manufacturer)
Bucky / Grid	Moving or Stationary Grid
Filter	No
Exposure	70 kVp 18 mAs
FFD / SID	100cm
Central Ray	CR perpendicular to infraorbitomeatal line (IOML) Centre to a point midway between the angles of mandible, 4cm inferior to mandibular symphysis
Collimation	Collimate to area of mandible
Markers	Lateral Marker orientation AP
Shielding	Gonadal (check your department's policy guidelines)
Respiration	Suspended
Positioning	The aim is to get the Infraorbitomeatal Line (IOML) parallel to the IR and bucky. The method used to achieve this will depend on the presentation of the patient. The following description is for patients who are able to tip their head back, hyperextending their neck, and are able to sit. The patient sits in an AP position in front of the upright bucky The chin is raised and the head tipped back until the IOML is parallel to the bucky and the vertex of the skull is centred and resting against the bucky. If the patient is able to achieve this position then the central ray is perpendicular to both the bucky and the IOML. If the patient is unable to tip their head back far enough, then angle the central ray so that it is perpendicular to the IOML Ensure the midsagittal plane is perpendicular to the bucky Centre to a point midway between the angles of mandible, 4cm inferior to mandibular symphysis
Critique PACEMAN	Positioning No rotation is evidenced by Equal distance from mandible to lateral border of skull on both sides Mandibular coronoid processes visualised projecting laterally from the rami area equally on each side of mandible No tilt is evidenced by The vomer and the bony nasal septum are aligned with the long axis of the film. The central ray is at 90 degrees to the IOML, evidenced by The mandibular mentum superimposes the outer border of the frontal bone. Area Covered Entire mandible, coronoid and condyloid process Collimation Centre: Centre to a point midway between the angles of mandible Shutter A: Open to include the soft tissue and lateral borders of the mandible Shutter B: Open to include the mandible superiorly and condyloid process of mandible inferiorly Exposure Assess for adequate penetration of the thickest part of the skull Bony trabecular patterns and cortical outlines are sharply defined Soft tissues are visualised
Special Notes