Hip (AP view)

The AP hip is part of a radiographic series examining the anatomy of the hip joint and proximal femur.

Indications

This view helps to visualize any potential fractures, dislocations, bone lesions or degenerative diseases to the hip joint. It is also often requested in post-operative examinations evaluating the placement of existing orthopedic devices. However, certain departments may favor the AP pelvis as it allows comparisons of both hips instead of unilaterally.

Patient position

• patient is supine
• lower limbs are internally rotated 15-25° from the hip (do not attempt this if a fracture is suspected)

Technical factors

• anteroposterior projection
• centering point
  • 2.5 cm distal to a line bisecting the anterior superior iliac spine (ASIS) and symphysis pubis (over the femoral pulse)
• collimation
  • laterally to the skin margins
  • superior to ASIS
  • inferior to the proximal third of the femur
• orientation  
  • portrait
• detector size
  • 24 cm x 30 cm
• exposure
  • 70-80 kVp
  • 8-15 mAs
• SID
  • 100 cm
• grid
  • yes

Image technical evaluation

• the entirety of the hip and proximal femur are seen on the image with the long axis of the femur running parallel to the long axis of the image
• greater trochanter should be seen in profile signifying adequate internal rotation of the limb 

Practical points

Internal rotation can be assisted with the use of sandbags over the lateral edges of the patient's feet.

If one obturator foramen appears ‘closed’, the patient could be rotated away from the image receptor on that side.