Full Ball & Socket Joint Description. [Continued from above] . . . In the shoulder joint, the spherical head of the humerus (upper arm bone) fits into the glenoid cavity of the scapula (shoulder blade). The glenoid cavity is a small and shallow cavity that permits the shoulder joint the greatest range of motion in the human body.
Lumbar lordosis refers to the inward curvature of the spine just above the buttocks. The National Institutes of Health reports that lordosis is caused by spondylolisthesis. Spondylolisthesis is a condition in which a spinal bone slips out of its normal space and onto the bone below it.
Lordosis is a backward curvature of the spine, while kyphosis is a forward curvature of the spine. The term lumbar referrs to the lower back. In the lumbar region the back i â¦ s supposed to have lordosis. So loss of lordosis is when the natural curvature of the spine is absent. In other words, instead of the normal and necessary inward curve, the spine is straight. This can lead to misalignment of the pelvis causing lower back or knee pain.