The sacrum and the coccyx each consist of multiple bones that fuse over time. L5-S1 consists of the last bone in the lumbar ...

That’s because C1 (in your neck) doesn’t provide sensory function. At the lower end, the 11 lumbar, sacral, and coccygeal dermatomes are often grouped together as the lower extremity dermatomes.

The spine (aka backbone) is a linked column of bones running from the head down to the lower back. Bone segments form the column. One bone segment is a vertebra, and multiple bone segments are ...