Now, on the posterior side, you find, as well, another line, letâs say, but this time called the intertrochanteric crest that is also between the neck of the femur and the shaft and runs, as well, from the greater trochanter all the way down to the lesser trochanter.
The upper back has the most structural support, with the ribs attached firmly to each level of the thoracic spine and very limited movement. The lower back (lumbar vertebrae) allows for flexibility and movement in back bending (extension) and forward bending (flexion).
There are 5 major regions of the spine: 1  Cervical: The 7 vertebrae in the neck form the cervical region of the spine. 2  Thoracic: The 12 vertebrae in the chest region form the spineâs thoracic region.  Lumbar: The 5 vertebrae in the lower back form the lumbar region of the spine. Lumbar vertebrae are even larger and stronger than thoracic vertebrae, but are more flexible due to the lack of ribs in the lumbar region. All of the upper bodyâs weight bears down on the lumbar vertebrae, leading to many back problems in this region despite the size and strength of the vertebrae.