Skull - SMV (Submentovertex) (Basal)

Radiographic Positioning

Adult

Other related pages of interest Applied Radiography Radiographic Anatomy Radiographic Protocols

Name of projection	Skull - SMV (Submentovertex) (also called Basal)
Area Covered	This view looks at the base of the skull, including structures such as the foramen ovale, foramen spinosum, and sphenoid sinuses
Pathology shown	Some pathologies of the base of the skull and sphenoid sinuses
Radiographic Anatomy	Skull Radiographic Anatomy
IR Size & Orientation	24 x 30 cm Portrait
Film / Screen Combination	Regular (CR and DR as recommended by manufacturer)
Bucky / Grid	Moving or Stationary Grid
Filter	No
Exposure	70 kVp 20 mAs
FFD / SID	100 cm
Central Ray	Directed to the midsaggital plane at the point midway between the angles of mandible, which is also approximately the point midway between the external auditory meatus (EAMs). Perpendicular to the IR/bucky
Collimation	Laterally, to the soft tissue margins of the skull, including the mandible and occiput
Markers	Superior and Lateral Marker orientation AP
Shielding	Gonadal (check your department's policy guidelines)
Respiration	Suspended
Positioning	The aim is to get the IOML (Infraorbitomeatal Line) 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.
Critique PACEMAN	Positioning No rotation is evidenced by The lateral borders of the foramen magnum are equidistant from the lateral borders of the skull. 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 Occiput, foramen magnum, sphenoid sinuses, foramen ovale, foramen spinosum, mandible, Collimation Centre: Midway between the EAMs Shutter A: Open to include the soft tissue and lateral borders of the skull Shutter B: Open to include the mandible superiorly and the occiput of the skull 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