A Morphological Study of the Structures Comprising the Adult Hip Joint

Abstract

With 77 hip joints of Korean adults available, anatomical study was carried out to clarify morphological variations of the acetabular labrum, the acetabular articular cartilage, the penetrating sites, the purchasing lengths of transacetabular screws including dangerous neurovascular structures, and the theoretical safe space of the acetabular fossa. The results were as follows; 1. The posterior superior region of the acetabulum through which the screw could be inserted more than 50 mm in length was the safest region. However, depending on the insertion angle, the screw could penetrate the psoas muscle with an average 30 mm of intervening space. 2. The average purchasing length of the screws penetrating the mid point (B) of the articular surface which was located on the inferior portion of the line (AB) connecting the anterior superior iliac spine and the center of the acetabulum; the= mid points (C and D) of the. articular surface which was located on the anterior and posterior portion of the line (CD) perpendicular to the line AB; and the mid point (G) of the articular surface which was located on the posterior inferior portion of the acetabular articular surface, was more than 20 mm. The screws penetrating the point "C" had a risk to damage the bladder and the screws penetrating the points "D" and "G" had a risk to endanger gluteal neurovascular bundles. 3, The screw placed in the anterior superior region of the acetabulum could be directed toward the external iliac vessels. The perpendicular bony thickness of this region averaged 13 mm. The topographical relationship of the external iliac artery and vein was variable and classified into 6 types. 4. At the center of the acetabulum, the most vulnerable structure was the obturator neurovascular bundle and the average thickness of bone at this point was measured as 6.5 mm. 5. The thickness of the compact bone became wider from the inner side to the outer side of the lunate surface. 6. The posterior inferior portion of the acetabular fossa would be a danger area when we used the screws for internal fixation of the acetabular fracture through the acetabular fossa. 7. The morphological variations of the acetabular labrum which were measured differently at different locations should be considered during reading magnetic resonance images. 8. The anterior, anterosuperior and posterosuperior portion of the acetabular labrum might be easily torn.