Chapter 5c:The Skeletal System

2006

The Vertebral ColumnVertebrae separated by intervertebral discsRuns from skull to pelvisTransmits weight of body to lower limbsEach vertebrae is given a name according to its

locationProtects spinal cord

Figure 5.14

The Vertebral ColumnThere are 24 single vertebral bones separated by

intervertebral discsSeven cervical vertebrae are in the neckTwelve thoracic vertebrae are in the chest regionFive lumbar vertebrae are associated with the

lower backNine vertebrae fuse to form two composite bones:

Sacrumcoccyx

Note how the spine curves in within the thoracic region….Also note that numbering restarts within each section!!

Structure of a Typical Vertebrae, Superior View

2006 HobanFigure 5.16

Vertebral ColumnIntervertebral Discs

Made of Fibrocartilage Cushions each bone & flexibility 90% water (decreases with age) Loss of fluid in discs due to age can lead to “shrinking” in height

Regional Characteristics7 cervical vertebrae

1 = atlas C12 = axis C2C3-C7

Smallest & lightest bones of the vertebrae Include Foramina – vertebral arteries to brain

2006 Hoban

Thoracic – T1 – T12

Lumbar – L1 – L5Massive block-like bodiesSturdiest vertebrae

Sacrum – 5 fused vertebraeForm the posterior wall of pelvis

Coccyx – 3-5 fused vertebraeaka Tailbone – remnant of a tail that other

vertebrates have

2006 Hoban

Regional Characteristics of Vertebrae—Cervical V.

Regional Characteristics of Vertebrae—Thoracic V.

2006 Hoban

Regional Characteristics of Vertebrae—Lumbar V.

2006 Hoban

Regional Characteristics of Vertebrae—Sacrum & Coccyx

The Vertebral ColumnThe spine has a normal curvature:

Primary curvatures are the spinal curvatures of the thoracic and sacral regionsPresent from birth

Secondary curvatures are the spinal curvatures of the cervical and lumbar regionsDevelop after birth

The Vertebral Column

Abnormal Curvatures

The Bony ThoraxForms a cage to protect major organsConsists of three parts

SternumRibs

True ribs (pairs 1-7)False ribs (pairs 8-12)Floating ribs (pairs 11-12)

Thoracic vertebrae

Figure 5.19a

The Bony Thorax

Figure 5.19a

Sternum – attached to first 7 pair of ribsSternal puncture – for bone marrow biopsy12 pair of ribs

7 true – attach to sternum5 false – attach indirectly or not at all

2 floating

2006 Hoban