Axial Skeleton: Vertebral Column

Axial Skeleton: Vertebral Column

Topics Covered

Introduction

Vertebrae

Cervical vertebrae

Axis

Atlas

Thoracic vertebrae

Lumbar vertebrae

Sacral and coccygeal vertebrae

The rib cage

Ribs

Sternum

Hyoid bone

Introduction (Linked to figure 7.20- Vertebral Column)

·      Made of 26 bones namely cervical, thoracic, lumbar, sacral and coccyx vertebrae

·      Protects your spinal cord

·      In humans the vertebrae increase in size from the cervical to the lower lumbar vertebrae – this is due to the increase in weight on the lower vertebrae.

·      The number of vertebrae in each section line up with times of day one eats meals à cervical = 7, thoracic = 12, lumbar = 5.

Vertebrae

·      Body or centrum

·       Spinous process

·       Vertebral foramen

·       Transverse process

Cervical Vertebrae (Linked to figure 7.25- Cervical Vertebrae)

**C1-C7**

·      3 foramina:

o   (1 vertebral foramen + 2 transverse foramina)

·      Some have bifid spinous processes (split in two – bifurcated)

·      Smaller, lighter weight bodies

·      All cervical vertebrae have three formina and they have the smallest and lightest bodies when compared to the other vertebrae.

Atlas

*C1*

·      1^st cervical vertebrae

·      Only cervical vertebrae without a body

·      Provides for the range of motion as nodding your head “yes”

·      Superior articular facets articulate with the occipital condyles of the skull

Axis

*C2*

·      The 2^nd cervical vertebra

·      Unique superior process, called the dens or odontoid process runs through the atlas

·      Dens allows the atlas to rotate on the axis

·      Provides for the range of motion as shaking your head “no”

Thoracic Vertebrae (Linked to figure 7.26- Thoracic Vertebrae)

**T1-T12**

·      Medium sized body with markings on the lateral, posterior surface (attach to ribs)

·      Long, narrow spinous process that commonly slants inferiorly

·      Facets on the transverse process that articulate with the ribs

Lumbar Vertebrae (Linked to figure 7.28- Lumbar Vertebrae)

**L1-L5**

·      No transverse foramina

·      No rib facets

·      Largest bodies

·      Thick spinous processes that extend horizontally

Sacrum & Coccyx (linked to figure 7.29- Sacrum and Coccyx)

·      The coccyx is actually 3-5 fused bones

The Rib Cage (Linked to figure 7.32- Thoracic Cage)

·      Made of 25 bones (24 ribs and the sternum)

Ribs (Linked to figure 7.32- Thoracic Cage)

•       Also called costae

•       First seven pairs – True ribs as their costal cartilage attaches directly to the sternum

•       Remaining five pairs – False ribs

•       Pairs 11 and 12  - Floating ribs as they do not join with sternum

Sternum (Linked to figure 7.32- Thoracic Cage)

•       3 parts

o   Manubrium (on top)

o   Body (middle, main part)

o   Xiphoid Process (lowest tip)

Hyoid Bone (Linked to figure 7.19- Hyoid Bone)

·      A horseshoe-shaped bone found in the neck between the chin and the thyroid cartilage

·      Only distantly articulates to other bones by muscles and ligaments

·      Important for swallowing and sound production