The Vertebral Column

Copyright © 2010 Pearson Education, Inc.

The Vertebral Column

Yes, this is a Predator Ewok….


The Vertebral Column

• Supports weight of trunk and distributes weight to lower limbs

• Surrounds and protects spinal cord

• Flexible curved structure composed of 26 irregular bones (vertebrae)

• Cervical vertebrae (7)—vertebrae of the neck

• Thoracic vertebrae (12)—vertebrae of the thoracic cage

• Lumbar vertebrae (5)—vertebra of the lower back

• Sacrum—bone inferior to the lumbar vertebrae

• Coccyx—end of vertebral column

General Characteristics


Vertebral Column: Curvatures

• Increase the resilience and flexibility of the spine

• Two concave curvatures

• Cervical and lumbar

• Two convex curvatures

• Thoracic and sacral


Kyphosis LordosisScoliosis

Abnormal Spine Curvatures


Ligaments

• Anterior and posterior longitudinal ligaments

• From neck to sacrum

• Ligamentum flavum

• Connects adjacent vertebrae


Intervertebral Discs

• Cushionlike pad between vertebrae; acts like a shock absorber

• Composed of two parts

1. Nucleus pulposus

• Inner gelatinous nucleus that gives the disc its elasticity and compressibility

2. Anulus fibrosus

• Outer collar composed of collagen and fibrocartilage

• Limits the expansion of the nucleus pulposus when the spine is compressed

• Withstands twisting forces on the spine and resists tension on spine

Copyright © 2010 Pearson Education, Inc. Figure 7.17a

Supraspinous ligamentIntervertebraldisc

Anteriorlongitudinalligament

Intervertebral foramen

Posterior longitudinalligament

Anulus fibrosus

Nucleus pulposus

Sectioned bodyof vertebra

Transverse process

Sectionedspinous process

Ligamentum flavum

Interspinousligament

Inferior articular process

Median section of three vertebrae, illustrating the composition of the discs and the ligaments

Copyright © 2010 Pearson Education, Inc. Figure 7.17c

Vertebral spinous process(posterior aspect of vertebra)

Spinal nerve root

Anulus fibrosusof disc

Herniated portionof disc

Nucleuspulposusof disc

Spinal cord

(c) Superior view of a herniated intervertebral disc

Transverseprocess


General Structure of Vertebrae

• Body or centrum

• Anterior weight-bearing region

• Vertebral arch

• Composed of pedicles and laminae that, along with the body, enclose vertebral foramen

• Vertebral foramina

• Together make up vertebral canal for spinal cord

• Intervertebral foramina

• Lateral openings between adjacent vertebrae for spinal nerves


General Structure of Vertebrae

• Seven processes per vertebra:

• Spinous process—projects posteriorly

• Transverse processes (2)—project laterally

• Superior articular processes (2)—protrude superiorly inferiorly

• Inferior articular processes (2)—protrude inferiorly

Copyright © 2010 Pearson Education, Inc. Figure 7.18

Posterior

Anterior

Lamina

Superiorarticularprocessandfacet

Transverseprocess

Pedicle

Spinousprocess

Vertebralarch

VertebralforamenBody(centrum)


CHECK POINT!!!

What are the 5 major regions of the vertebral column?

How many curvatures of the spine are there? And what are they?

Which structure of the spine acts as a shock absorber?


Bell Ringer!!!!(All Bell Ringers Due Friday)

• What ligaments (that we talked about) support and reinforce the spinal column and describe their location?

• How many spinal processes does each typical vertebra have?

• List and describe the 2 major components of the intervertebral discs


Cervical Vertebrae

• C1 to C7: smallest, lightest vertebrae

• C1 (atlas) and C2 (axis) have unique features

• C3 to C7 share the following features

• Oval body

• Spinous processes are bifid (except C7)

• Large, triangular vertebral foramen

• Transverse foramen in each transverse process


Cervical Vertebrae

Atlas (C1)

• No body or spinous process

• No intervertebral disk between C1 and C2

• Consists of anterior and posterior arches, and two lateral masses

• Superior surfaces of lateral masses articulate with the occipital condyles

• Allow you to nod your head “yes”

Copyright © 2010 Pearson Education, Inc. Figure 7.19a-b

Anterior arch

Superiorarticularfacet

Transverseforamen

Posterior arch

Posteriortubercle

Anteriortubercle

Posterior

Lateralmasses

(a) Superior view of atlas (C1)

C1

Facet for dens

Transverseprocess

Lateralmasses

Transverseforamen

Posterior archPosteriortubercle

Posterior

Anterior tubercle

Anteriorarch

(b) Inferior view of atlas (C1)

Inferiorarticularfacet


• Dens projects superiorly into the anterior arch of the atlas

• Dens is a pivot for the rotation of the atlas

• Allows you to rotate head from side to side to say “no”

Axis (C2)


C2

Posterior

Dens

(c) Superior view of axis (C2)

Inferiorarticularprocess

Body

Superiorarticularfacet

Transverseprocess

Pedicle

Lamina

Spinous process

Figure 7.19c


Dens of axis

Transverse ligamentof atlasC1 (atlas)

C2 (axis)

Bifid spinousprocess

Transverse processes

C7 (vertebraprominens)

(a) Cervical vertebrae

C3

Inferior articularprocess


Thoracic Vertebrae

• T1 to T12

• All articulate with ribs at facets and demifacets

• Heart-shaped body

• The vertebral foramen is circular

• Long spinous process

• Location of articular facets allows rotation of this area of spine

Copyright © 2010 Pearson Education, Inc. Figure 7.20b

Transverseprocess

Spinousprocess

Superior articularprocess

Transversecostal facet (fortubercle of rib)

Body

Intervertebraldisc

Inferior costalfacet (for headof rib)Inferior articularprocess

(b) Thoracic vertebrae


Lumbar Vertebrae

• L1 to L5

• Short, thick pedicles and laminae

• Flat hatchet-shaped spinous processes

• Vertebral foramen is triangular

• Orientation of articular facets locks lumbar vertebrae together so as to prevent rotation

Copyright © 2010 Pearson Education, Inc. Figure 7.20c

Superiorarticularprocess

Transverseprocess

Spinousprocess

Intervertebraldisc

Body

Inferiorarticularprocess

(c) Lumbar vertebrae


Sacrum and Coccyx

• Sacrum

• 5 fused vertebrae (S1–S5)

• Forms posterior wall of pelvis

• Articulates with L5 superiorly, and with auricular surfaces of the hip bones laterally

• Coccyx

• Tailbone

• 3–5 fused vertebrae

• Articulates superiorly with sacrum


Coccyx

Anteriorsacralforamina

Apex

Sacral promontory

AlaBody offirstsacralvertebra

Transverseridges (sites of vertebral fusion)

(a) Anterior view


Coccyx

Posteriorsacralforamina

Mediansacralcrest

Sacralcanal

Sacralhiatus

Body Facet ofsuperiorarticular process

Lateralsacralcrest

Auricularsurface

Ala

(b) Posterior view


CHECK POINT!!!

What are the 1st two cervical vertebra called and what makes them different?

How can you tell the difference between a lumbar vertebrae and a thoracic vertebrae?


Bell Ringer!!!!(All Bell Ringers Due Friday)

• What distinguishing features do cervical vertebrae have that thoracic and lumbar vertebrae do not?

• Why to lumbar vertebrae have the larges bodies?

• How many cervical, thoracic and lumbar vertebrae do we have?

• How many vertebrae make up the sacrum and the coccyx?


Thoracic Cage

• Composed of

• Thoracic vertebrae

• Sternum

• Ribs and their costal cartilages

• Functions

• Protects vital organs of thoracic cavity

• Supports shoulder girdle and upper limbs

• Provides attachment sites for many muscles, including intercostal muscles used during breathing


Sternum (Breastbone)

• Three fused bones

• Manubrium

• Articulates with clavicles and ribs 1 and 2

• Body

• Articulates with costal cartilages of ribs 2 through 7

• Xiphoid process

• Site of muscle attachment

• Not ossified until ~ age 40


Ribs and Their Attachments

• 12 pairs

• All attach posteriorly to thoracic vertebrae

• Pairs 1 through 7

• True (vertebrosternal) ribs

• Attach directly to the sternum by individual costal cartilages


Ribs and Their Attachments

• Pairs 8 through12

• False ribs

• Pairs 8–10 also called vertebrochondral ribs

• Attach indirectly to sternum by joining costal cartilage of rib above

• Pairs 11–12 also called vertebral (floating) ribs

• No attachment to sternum


Intercostal spaces

Trueribs(1–7)

Falseribs(8–12)

Jugular notchClavicular notch

ManubriumSternal angleBodyXiphisternaljointXiphoidprocess

L1

Vertebra Floating ribs (11, 12)(a) Skeleton of the thoracic cage, anterior view

Sternum

Costal cartilage

Costal margin


Structure of a Typical Rib

• Main parts:

• Head

• Articulates posteriorly with facets (demifacets) on bodies of two adjacent vertebrae

• Neck

• Tubercle

• Articulates posteriorly with transverse costal facet of same-numbered thoracic vertebra

• Shaft


Spinous processArticular faceton tubercle of rib

Shaft

Ligaments

Neck of rib

Head of rib Body ofthoracicvertebra

Transversecostal facet(for tubercleof rib)

Superior costal facet(for head of rib)

(b) Superior view of the articulation between arib and a thoracic vertebra


CHECK POINT!!!

How does a true rib differ from a false rib?

Besides the ribs and sternum, there is a 3rd group of bones that makes up the thoracic cage. What is it?

What are floating ribs?

The Vertebral Column

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