BNG-345: Lecture 13

The Spine

Anatomy

Test on Friday

Learning Objectives

Identify and describe the main regions of the spine

Identify the components of the vertebrae

Identify and describe the function of the components of the discs

Identify the main muscles of the spine

Identify the ligaments of the spine

Vertebral ColumnConsists of 33 vertebrae

Upper 24 are articulating and separated by intervertebral discs

The lower 9 are fused

5 at sacrum

4 at coccyx

VertebraeA vertebrae consists of 2 parts:

An anterior part known at the vertebral body

A posterior part known as the vertebral arch

encloses the vertebral foramen

Vertebral Arch

Formed by a pair of pedicles and a pair of lamina

These support 7 processes

Intervertebral Foramen

Curves of Vertebral Column

Cervical Curve

Convex forward

Starts at 2nd cervical vertebra and ends at 2nd thoracic vertebra

Thoracic CurveConcave forward

Starts at 2nd thoracic vertebra and ends at 12th thoracic vertebra

Most prominent point corresponds to spinous process of 7th vertebra

Kyphotic Curve

The thoracic curve is also known as the kyphotic curve

Lumbar CurveConvex forward

Starts at middle of last thoracic vertebra and ends at sacrovertebral angle

Convexity of lower 3 vertebrae much greater than upper 2

Lumbar Curve

More prominent in females

Curve also known as lordotic curve

Sacral CurveConcave downward and forward

Begins at sacrovertebral articulation and ends at coccyx point

Regions and Vertebrae

Shape

Cervical SpineC1 and C2 allow the head all its movement

Most mammals have 7 cervical vertebrae regardless of neck length

Atlas and Axis

Thoracic Spine

Transverse processes have surfaces to articulate with ribs

Can rotate some, but ribs prevent much flexion

Lumbar Spine

Sacral Spine

Intervertebral Discs

Located between adjacent vertebrae

Forms a fibrocartilaginous joint that allows slight movement between vertebrae

Acts as a ligament

Shock absorber

Disc Structure & Function

MusclesSpinal muscles attach themselves to many different vertebrae, arms, legs, head, rib cage, and pelvis

Movements of spine include flexion, extension, lateral bending

Erector SpinaeMost important extensor muscle group

Returns column to its erect position

It originates at many locations

Subdivisions blend in lower back giving good lumbar strength

Flexion Muscles

Located in cervical and lumbar region

Rectus abdominis and internal and external oblique contribute to spinal movement

Trunk Flexion Muscles

MultifidusLong muscle with fibers that extends from one vertebral process to spinous process of a vertebra several levels above

Helps with extension and rotation

Ligaments

Learning Objectives

Identify and describe the main regions of the spine

Identify the components of the vertebrae

Identify and describe the function of the components of the discs

Identify the main muscles of the spine

Identify the ligaments of the spine