Pelvis and femur geometry: Relationships with impact characteristics during sideways falls on the hip

While metrics of pelvis and femur geometry have been demonstrated to influence hip fracture risk, attempts at linking geometry to underlying mechanisms have focused on fracture strength. We investigated the potential effects of femur and pelvis geometry on applied loads during lateral falls on the hip. Fifteen female volunteers underwent DXA imaging to characterize two pelvis and six femur geometric features. Additionally, participants completed low-energy sideways falls on the hip; peak impact force and pressure, contact area, and moment of force applied to the proximal femur were extracted. No geometric feature was significantly associated with peak impact force. Peak moment of force was significantly associated with femur moment arm (p = 0.005). Peak pressure was positively correlated with pelvis width and femur moment arm (p < 0.05), while contact area was negatively correlated with metrics of pelvis width and femur neck length (p < 0.05). This is the first study to link experimental measures of impact loads during sideways falls with image-based skeletal geometry from human volunteers. The results suggest that while skeletal geometry has limited effects on overall peak impact force during sideways falls, it does influence how impact loads are distributed at the skin surface, in addition to the bending moment applied to the proximal femur. These findings have implications for the design of protective interventions (e.g. wearable hip protectors), and for models of fall-related lateral impacts that could incorporate the relationships between skeletal geometry, external load magnitude/distribution, and tissue-level femur loads.     

The relationship of the pre-auricular groove of the ilium to pregnancy

Two forms of pre-auricular groove may be distinguished on the iliac bone. One form occurs in both male and female, and marks the attachment of the inferior part of the ventral sacro-iliac ligament. The second form is found only in some female pelves. It resembles the markings of pregnancy and childbirth on the posterior aspect of the public symphysis, and like them is a result of the physiological and pathological changes occurring at the site of attachment of the pelvic joint ligaments during this time. However, because of the greater strain borne by the sacro-iliac joints, the pre-auricular groove, in conjunction with the marking of the interosseous ligament of the joint, is a more sensitive indicator of past pregnancy and childbirth than is the pubic bone.