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