auricular surface , auch: facies auricularis latin

Both sacroiliac joints, formed between the auricular surfaces of the sacrum and the two hip bones.

Fusion of the auricular surface of the ilium indicates post-pubertal age at death; absence of arthritic changes suggests that the individual was not aged.

The upper half presents in front an ear-shaped surface, the auricular surface, covered with cartilage in the immature state, for articulation with the ilium.

Two continuous trabecular systems emerging on auricular surface of the sacroiliac joint meander and criss-cross each other down through the hip bone, the femoral head, neck, and shaft.

There is a deep pre-auricular sulcus of the male type i.e. it does not extend the length of the auricular surface, has a flat angular contour and a conspicuous piriformis tubercle.

The auricular surface (articulating with the ilium) is limited to the first and second sacral vertebrae in the female, but in the male it often extends to the middle of the third vertebra.

The former serves for the attachment of the oblique portion of the posterior sacroiliac ligaments and the Multifidus; the latter corresponds with the posterior extremity of the auricular surface.

In adults, degenerative changes to the pubic symphysis, the auricular surface of the ilium, the sternal end of the 4th rib, and dental attrition are commonly used to estimate skeletal age.

The other system emerges on the lower part of the auricular surface, converges at the level of the superior gluteal line, and is reflected laterally onto the upper part of the acetabulum.

The anterior surface (auricular surface), so called from its resemblance in shape to the ear, is coated with cartilage in the fresh state, and articulates with a similar surface on the side of the sacrum.

Below and in front of the auricular surface is the preauricular sulcus, more commonly present and better marked in the female than in the male; to it is attached the pelvic portion of the anterior sacroiliac ligament.

In the hip bone, one system arises on the upper part of auricular surface to converge onto the posterior surface of the greater sciatic notch, from where its trabeculae are reflected to the inferior part of the acetabulum.

The anterior sacroiliac ligament consists of numerous thin bands, which connect the anterior surface of the lateral part of the sacrum to the margin of the auricular surface of the ilium and to the preauricular sulcus.

The arcuate line marks the border between the body (corpus) and the wing (ala) of the ilium, and, running inferior, anterior, and medial from the auricular surface to the area corresponding to the acetabulum, it also indicates where weight is transferred from the sacroiliac joint to the hip joint.