Skull (Towne view)

The Towne view is an angled anteroposterior radiograph of the skull and visualizes the petrous part of the pyramids, the dorsum sellae and the posterior clinoid processes, which are visible in the shadow of the foramen magnum.

Indications

This projection is used to evaluate for medial and lateral displacements of skull fractures, and radiopaque foreign bodies ².

Patient position

• supine position. Remove all foreign bodies around the head ²

• nuchal ridge is placed against the image detector

• the infraorbitomeatal line perpendicular to the image receptor

• the beam travels 30° caudad to the orbitomeatal line ² or 37° caudad to the infraorbital meatal line ²

Technical factors

• anteroposterior axial projection

• centering point

  • midway between the external auditory meatuses and exits the foramen magnum ²

• collimation

  • superior to include skin margins

  • inferior to include base of skull

  • lateral to the skin margins 

• orientation  

  • portrait ²

• detector size

  • 24 cm x 30 cm ²

• exposure

  • analog at 75-85 kVp, digital at 80-90 kVp ²

  • 10-20 mAs

• SID

  • 100 cm ²

• grid

  • yes ²

Image technical evaluation

• dorsum sella overlies the foramen magnum ²

• petrous ridges are symmetrical 

Practical points

• if the dorsum sella projects above the foramen magnum it requires an increase in angle

• if the anterior arch of C1 is laying in the foramen magnum, less angle is required

Advantages

• occipital bone and posterior fossa space better evaluated than with a non angulated AP view, which would have more skull base and facial bone overlap

• better than a conventional AP view for evaluating an occipital plagiocephaly involving the lambdoid suture 

• may be a useful additional view for evaluating skull fractures ¹