What is the anterior column of the acetabulum?
Answer: It is the strut formed by the entire pubic and the anterior portion of the iliac bone, extending from the iliac crest and wing down the superior obturator ramus to the pubic symphysis.

Where do the anterior and posterior columns join?
Answer: At the tri-radiate cartilage and acetabular tectum/roof. The center of the tectum consists of compact bone and forms the keystone of the arch.

How many fracture patterns are in the Letournel-Judet classification system?
Answer: There are a total of 10 injury patterns. However, some fractures are more common than others, with the five most prevalent patterns encompassing 90% of acetabular injuries.

Which are the two most prevalent fracture patterns?
Answer: Both column (19 – 29%) and isolated posterior wall (13 – 27%) fractures.

What are posterior wall fractures associated with?
Answer: Posterior hip dislocation, marginal impaction, and entrapped intra-articular fragments.

Which two fracture patterns injure both columns?
Answer: Transverse and both column fractures

On axial CT images of the acetabular tectum in the both column injury pattern, what is the orientation of the fracture plane?
Answer: Coronal.

What is the spur sign?
Answer: The inferolateral-most point of the iliac fragment that is still attached to the sacrum exposed by the medially-displaced iliac wing fragments. It signifies a both column injury pattern.

Compared to both column fractures, what is not broken in transverse fractures?
Answer: The iliac wing and ischiopubic ramus.

What is additionally involved in the t-type fracture as compared to pure transverse fractures?
Answer: The ischiopubic ramus is fractured in the t-type injury pattern but not in pure transverse fractures.