MD 2017

Bones & Joints of the Back

A/Prof Chris Briggs

Department of Anatomy & Neuroscience

WARNING

This material has been provided to you pursuant to section 49 of the Copyright Act 1968 (the Act) for the purposes of research or study. The contents of the material may be subject to copyright

protection under the Act.

Further dealings by you with this material may be a copyright infringement. To determine whether such a communication

would be an infringement, it is necessary to have regard to the criteria set out in Part 3, Division 3 of the Act.

Learning Objectives • Appreciate the normal curvatures of the vertebral column and

abnormal curves

• Describe the features of typical thoracic and lumbar vertebrae and the sacrum.

• Appreciate the location of centres of ossification.

• Describe the features and functions of intervertebral discs and (zygapophyseal) joints of vertebral arches

• Describe the attachments & functions of vertebral ligaments

• Describe the boundaries & contents of the vertebral canal & intervertebral foramen

Suggested pre-reading Clinically Orientated Anatomy, Moore 7th ed. Chapter 4, Back.

T1 vertebra - coccyx Medial border scapula Posterior surfaces ribs Iliac crest

Bony landmarks

Skin of back

Back

• Arrangement:

Vertebral column (supporting axis)

- intervertebral joints (& discs)

- vertebral canal & intervertebral foramen

2 x muscle compartments: - superficial (extrinsic) muscles

- deep (intrinsic) muscles

Bony framework – vertebral column

Basmajian J & Slonecker C Grant’s Method of Anatomy 11th ed Williams & Wilkins 1986 Ch 1 Fig 1.19 ISBN 0-683-00374-7

From primary (foetal) C-shaped curvature, secondary (lordotic) curves develop in cervical & lumbar regions. Abnormal curves may develop

Typical lumbar vertebra

Basmajian J & Slonecker C Grant’s Method of Anatomy 11th ed Williams & Wilkins 1986 Ch 1 Fig 1.19 ISBN 0-683-00374-7

epiphyseal ring

Pars inter-articularis

foraminae for basivertebral veins

Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1-929007-15-9, Figs. 143A

Typical thoracic vertebra

Sacrum & coccyx

Note: -orientation of S1 facet surfaces (in coronal plane) -anterior & posterior sacral IV foraminae – for nerve roots & vessels (including sacral veins) -sacral canal & hiatus -variable # coccygeal vertebrae

Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1-929007-15-9, Figs. 145

Spina Bifida (from L: split spine)

Anatomedia Back Systems Frame 9

0.1% - meningocele - meningomyelocele

2%

Defect usually L5/S1

‘hidden’ ‘sac’

Centres of ossification • 3 primary centres in body and each neural arch. 5 secondary centres (at puberty)

at tips of spinous & transverse processes, + upper and lower margins of body (annular epiphysis).

• Secondary centres normally close during late adolescence, when vertebral growth is complete.

• Clinical significance?

Moore KL, Before we are born WB Saunders 1989 Fig 16.4

Visible Human Project - National Library of Medicine

Joints of Vertebral Bodies (intervertebral discs)

Image from Anatomedia ‘Back’ module

Nucleus pulposus (remnant of notochord)

Annulus fibrosus (fibrocartilage)

Kapandji IA, The Physiology of the Joints Fig 25 Churchill Livingstone1980

Intervertebral disc

Cartilage end-plate (epiphyseal ring)

Functions of intervertebral discs • Weight-bearing forces cause

nucleus to bulge – resisted by annular fibres

• Some loads also supported by cartilage end-plate

Basmajian J & Slonecker C Grant’s Method of Anatomy 11th ed Williams & Wilkins 1986 Ch 1 Fig 1.19 ISBN 0-683-00374-7

•Annulus in layers ~ perpendicular to each other. Twisting movements while lifting are hazardous as only 50% annular fibres positioned to resist load

Joints & ligaments Lumbar Joints & Ligaments

Intervertebral disc

Facet or zagopophyseal joints

Intertransverse ligaments

Anterior Longitudinal ligament

Posterior Longitudinal ligament

Interspinous ligaments

Supraspinous ligament

Primal Pictures 2007

Ligaments within vertebral canal

Posterior longitudinal Ligamentum ‘flavum’ (yellow elastic)

Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1-929007-15-9, Figs. 146B & C

Note expansion over IV disc

Iliolumbar ligament

Recurrent meningeal nerve

- contains sensory & sympathetic fibres

Nerve & blood supply to disc

Images from Anatomedia ‘Back’ module

Vessels & nerves only to outer third

Joints of vertebral arches

• Synovial joints • Fibrous capsule – lax to permit

movement

Basmajian J & Slonecker C Grant’s Method of Anatomy 11th ed Williams & Wilkins 1986 Ch 1 Fig 1.20 ISBN 0-683-00374-7

Joints of vertebral arches

Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed. New Jersey, Icon Learning Systems, 2003, ISBN: 1-929007-15-9, Figs. 143A & 144A 145D

Orientation of facet surfaces dictates direction of movement: thoracic mainly in coronal plane, lumbar facets mainly in sagittal plane. Note changed orientation at L5/S1

Image from Anatomedia ‘Back’ module

Regions & Viscera

• Intervertebral foramen

- boundaries

- contents

• Vertebral canal

- boundaries

- contents

Vertebral canal

Netter, F.H. Interactive Atlas of Human Anatomy. 3rd ed.

End 1st trimester S5

End 2nd trimester S1

Birth L3

Intervertebral foramen

Image from Anatomedia ‘Back’ module (Note L5/S1 foramen)