Spine Unit 2, Surgical Research Lab, Bordeaux University Hospital, 33076, Bordeaux, France.
Eur Spine J. 2011 Sep;20 Suppl 5(Suppl 5):558-63. doi: 10.1007/s00586-011-1939-7. Epub 2011 Aug 2.
Bipedalism is a distinguishing feature of the human race and is characterised by a narrow base of support and an ergonomically optimal position thanks to the appearance of lumbar and cervical curves.
The pelvis, adapted to bipedalism, may be considered as the pelvic vertebra connecting the spine to the lower limbs. Laterally, the body's line of gravity is situated very slightly behind the femoral heads laterally, and frontally it runs through the middle of the sacrum at a point equidistant from the two femoral heads.
Any abnormal change through kyphosis regarding the spinal curves results in compensation, first in the pelvis through rotation and then in the lower limbs via knee flexion. This mechanism maintains the line of gravity within the base of support but is not ergonomic. To analyse sagittal balance, we must thus define the parameters concerned and the relationships between them.
These parameters are as follows: for the pelvis: incidence angle, pelvis tilt, sacral slope; for the spine: point of inflexion, apex of lumbar lordosis, lumbar lordosis, spinal tilt at C7; for overall analysis: spino-sacral angle, which is an intrinsic parameter.
直立行走是人类的一个显著特征，其特点是支撑面较窄，由于腰椎和颈椎曲线的出现，人体处于一种符合人机工程学的最佳姿势。
适应直立行走的骨盆可被视为连接脊柱和下肢的骨盆椎体。从侧面看，人体的重力线位于股骨头的稍后方，从前向后看，它穿过骶骨中部，位于两个股骨头的中间。
任何脊柱曲线的异常弯曲都会导致代偿，首先是骨盆通过旋转，然后是下肢通过膝关节弯曲。这种机制将重力线保持在支撑面内，但不符合人机工程学。因此，为了分析矢状面平衡，我们必须定义相关参数及其之间的关系。
这些参数如下：对于骨盆：入射角、骨盆倾斜度、骶骨倾斜度；对于脊柱：拐点、腰椎前凸顶点、腰椎前凸、C7 脊柱倾斜度；对于整体分析：脊柱-骶骨角，这是一个内在参数。
