The Spine

Mr. Brewer

The SpineThe Spine is broken down into 5 major sections of Vertebrae:- Cervical- Thoracic- Lumbar- Sacrum- Coccyx

The spine is designed to not only provide structure to our skeleton, but also to have flexibility to allow for mobility.

Having the spine composed of individual vertebrae with space in between each is primarily what allows for this mobility at the core.

VertebraeThe spine is broken down into different sections, and although each

section has unique features that make them different from one another, all (most) vertebrae are structured VERY similarly from top to bottom.

What is similar? What is Different?

Vertebrae Anatomy• Vertebrae from C1-L5 all share

very similar traits. • Few exceptions to the overall

composition of a vertebrae include C1 and C2 because of the role they play allowing movement of the head.

• The rest of the vertebrae all have the following components:– Spinous Process– Body– Pedicle– Transverse Process– Superior AND Inferior

Articular Facets– Lamina– Spinal Canal

Cervical Spine

• The Cervical spine is the most superior aspect of the Spinal Column.

• There are 7 total cervical vertebrae, the top 2 are unique from most other vertebrae.

• They (C1 and C2) are known as the Atlas and Axis.

• When compared to the other vertebrae, C3-C7 are very similar to the rest of the vertebrae in the spinal column, but are smaller in size.

Atlas and Axis• The 2 most superior vertebrae are known better as the Atlas and

Axis.• Both are considered to be cervical vertebrae(C1 and C2), but are

unique and play a crucial role in allowing mobility of the human head.

Atlas and Axis Continued• The Atlas (C1) does not have a body

like the rest of the vertebrae, but has a space to allow the spinal cord to travel through, and also has 2 smooth surfaces for the Occipital Condyles of the skull to sit on top of.

• The Axis (C2) sits directly under the Atlas and provides a surface for the atlas to rotate on. This allows for lateral rotation of the head.

• The DENS: is a prominent aspect of the Axis bone that projects up through Atlas for additional structure and stability. It also acts as a pivot point for the Atlas.

• https://www.youtube.com/watch?v=b5NjhaG2SbY

Thoracic Vertebrae

• 12 vertebrae that are between the cervical and lumbar vertebrae or known as the Thoracic Vertebrae.

• These vertebrae make up the “mid-back”.

• These vertebrae have a direct correlation with the Ribcage.

Thoracic Vertebrae and the Ribcage

• 12 Ribs and 12 Thoracic Vertebrae.

• Each Rib attaches itself snug in between the “T” vertebrae.

• The Ribs are “numbered” 1-12 from superior to inferior.

• They are named in correlation for the “T” vertebrae that they sit ON TOP of. (Picture provides visual representation.)

• Ribs 11-12 are known as False Ribs because they have no connection to the sternum via costal cartilage.

Lumbar Vertebrae• The thickest and largest

individual vertebrae of the spinal column.

• There are 5 Lumbar vertebrae, and they provide the most support to the spine, but have the least mobility in terms of flexion and extension.

• The most notable difference from the other vertebrae, besides the thickness, is the spinous process.

Components of the Spinal Region

In between each vertebrae, is a disc that is made of cartilage.

The outer aspect of this disc is just cartilage tissue called the Annulus Fibrosus.

In the middle of the annulus fibrosus there is a viscous fluid called the Nucleus Pulposus. This is “jelly-like” in it’s composition.

That Sacrum and CoccyxAs we discussed during the Hip and Pelvic unit, the Sacrum and Coccyx are the most distal aspect of the spine.

The Sacrum is typically 5 fused vertebrae that lies directly between the Pelvic bones.- The Sacrum has foramen on both sides just lateral to the center line of the Sacrum to allow nerves and blood vessels to travel to the hip and legs.

The Coccyx is anywhere from 3 to 5 fused vertebrae, and is also known as the “Tail Bone”.