Many people will experience back pain of some description at some point during their life, for this reason I have chosen to right a quick blog about the anatomy of the spine and various pain generators within. This should help people better understand the range and possible causes of their back pain. In its most basic description the spine is made up of blocks of bone, known as vertebrae, stacked on top of each other, with the head at the top and pelvis at the bottom.
When we are born, we have one ‘C’ curve to our spine, which as we develop becomes two kyphoses and 2 lordoses, these can be seen in the image below. These four segments are then segregated into the four regions of the spine, starting at the bottom we have the sacral kyphosis, made up of 4 coccygeal segments and 5 sacral segments, these 9 segments are fused to some extent in all people, however some people may have variations to this. This brings us nicely to what is often described as the foundation of the spine, the pelvis. Attached to the sacrum via the sacro-iliac joints are the three bones which make up each side of the pelvic basin, the ischium, ilium and pubis, see image below.
Sitting on top of this ‘foundation’ is the lumbar spine, made up of 5 segments in a lordotic curve. It is this area of the spine which is one of the most common areas for back pain and this for a good reason, primarily this area is caught between two relatively stable structures, the big boney pelvis and the even bigger thoracic spine with adjoined rib cage, giving these 2 regions solid structural support, where as the lordotic lumbar spine is only supported by the muscles which act between the segments and across the entire region, so any loss of strength, support or control of these muscles will affect and increase the load passing through the lumbar spine.
And now we move on to a region of the spine, which as a consequence of modern sedentary living has become an increasing problem, with the desk bound population seated in a slumped forward posture. This region is the thoracic spine, made up of 12 segments, with 2 ribs per segment, and each rib having 2 joints with the spine. This region is naturally kyphotic as can be seen in the image below.
Finally we have the lordotic cervical spine, made up 7 segments, 2 of which are highly specialised. These 2 segments are C1 and C2, or atlas and axis as they are sometimes referred to. It is from these 2 segments that you get approximately 50% of your rotation through the neck. This region is often a pain generator during whiplash type injuries, as well as result of that slumped kyphotic posture of the thoracic spine while sitting at a desk. As the body flexes forward through the trunk the neck has to extend to look forward and see the computer screen.
The spine can be further broken down in to what are referred to individual motion segments, these consist of 2 vertebrae separated by a disc, this happens at the vast majority levels with the exceptions of the specialist atlas/axis complex and where the vertebrae are fused through the sacrum and coccyx. These motion segments are made up of a 3 joint complex, firstly the joint which most people have heard of, the disc, which is a the front, and then 2 facet joints, one left and one right, these sit posteriorly (see image below).
As you can see from the images above there are number of other knobbly bits, such as the transverse process and spinous process, these serve as both muscle and ligament attachments, and ultimately levers through which to create movement through the spine. Of the ligaments viewed on the right of primary importance are the anterior longitudinal, posterior longitudinal, supraspinous and ligamentum flavum as these extend through the full length of the spine, while between the vertebrae there are a number of ligaments which extend between various structures, such as the intertransverse ligament, and the interspinous ligament, the latter being continuous with the supraspinal ligament.
As you can see from the above the spine is a very complex structure, with a number of different elements which all could be possible pain generators, and this is before we add the muscles of the spine in to the equation. However I feel that there is enough information here to start with and I will go into more specifics at later date.
Tagged The Spine