Column Concept of Acetabulum

2 Column Concept or Principle of Acetabulum (Letournel and Judet)

According to this concept, “C” shaped acetabular structure is contained between the limbs of lamda [λ] or inverted “y”. The longer limb represents anterior column and the shorter limb represents the posterior column. The anterior and posterior walls are extensions of the respective column and forms the cup of the acetabulum.

acetabulum two columns

Anterior (Iliopubic) column

Marker: Iliopectineal line

Demarcation: Extending from the iliac crest down the iliac wing and through the superior obturator (pubic) ramus towards the pubic symphysis

Parts: Large portion of ilium and entire pubis

  1. Anterior half of iliac crest and iliac wing
  2. Iliac spines
  3. Anterior wall of acetabulum
  4. Pubis

Posterior (Ilioischial) column

Marker: Ilio-ischial line (Kohler’s line)

Demarcation: Posterior iliac body just below the angle of the greater sciatic notch down the ischial body into the inferior obturator (ischiopubic) ramus

Parts: Small portion of ilium and mainly of ischium

  1. Ischial tuberosity
  2. Ischial spine
  3. Posterior wall of acetabulum
  4. Dense bone forming greater sciatic notch

Above the sciatic notch, the anterior and the posterior columns meet at the sciatic buttress – which is a continuation of the iliac bone that communicates with the sacro-iliac joint. Although not a part of acetabulum, it is often employed as an anchor point in acetabular reconstruction.

The roof (dome) of the acetabulum which includes part of both the anterior and posterior column is the weight bearing area that supports the femoral head.

Approach to classifying acetabular fractures according to Letournel and Judet classification:

1. Obturator ring intact:

a. Posterior wall disruption: Posterior wall fracture
b. Iliopectineal line disruption: Anterior wall fracture
c. Both iliopectineal line and ilio-ischial line disrupted: Transverse fracture (with ot without posteior wall fracture)

2. Obturator ring disrupted:

a. Iliopectineal line disruption: Anterior column fracture
b. Ilioischial line disruption: Posterior column fracture
c. Both iliopectineal and ilioischial line disruption: Anterior column with posterior hemitransverse fracture or T-shaped fracture
d. Extension to iliac wing: Both column fracture (Spur sign)

3 Column Concept or Principle of Acetabulum – Zhang

This new concept of column is simple and proposed to have higher intertester reliability while classifying acetabular fractures.

acetabulum three column

Branch of ilium: Roof column

Branch of pubis: Anterior column

Branch of ischium: Posterior column

Medial part: Buttress column

Junction between roof & anterior column: Anterior wall

Junction between roof & posterior column: Posterior wall

Junction between anterior & posterior column: Medial wall


1. Fractures of the Acetabulum – Emile Letournel and Robert Judet (2nd Edition)

2. Zhang R, Yin Y, Li A, et al. Three-Column Classification for Acetabular Fractures: Introduction and Reproducibility Assessment. J Bone Joint Surg Am. 2019;101(22):2015‐2025. doi:10.2106/JBJS.19.00284

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