Base for appendages

 Provides rigid support

1. Maintains mobility

Transmit forces from the upper body to legs

Each vertebrae articulates with adjacent vertebrae

1. Movement in all three planes

24 vertebrae which are all mobile

7 Cervical

12 Thoracic

5 Lumbar

9 vertebrae are fused

5 Sacrum - provides structure

4 Coccyx - vestigial

Curves of the spine exist in the sagittal plane

The thoracic and sacral vertebrae form the primary curves of the spine

The cervical and lumbar vertebrae form the secondary curves of the spine

Abnormalities in the spinal curvature can occur

1. Lordosis - extreme lumbar curvature

2. Kyphosis - extreme thoracic curvature

3. Scoliosis - lateral spinal curvature

Bone for each vertebrae will form:

1. Body

2. Pedicles (2)

3. Transverse Processes (2)

4. Laminae (2)

5. Spinous Process

The body, pedicles and laminae form the vertebral foramen for the spinal cord.

The shape of the adjacent pedicles will form the inter-vertebral foramen for nerve roots

The functional unit of the spine

Divided into anterior and posterior portions

The anterior portion is composed by

1. Two adjacent vertebral bodies

2. The intervertebral disc

2a. Anulus fibrosus - fibrocartilage outer covering

2b. Nucleus pulposus - gelatinous center

Bodies are both held together and seperated by a intervertebral disc

1. Withstands compressive forces

2. Resists torsional strains

3. Prevents excessive motion

Bodies are also held together by ligaments

1. Anterior longitudinal ligament

1a. Resists hyperextension

2. Posterior longitudinal ligament

2a. Resists flexion

3. Both span from the axis to the sacrum

Posterior portion of the motion segment guides movement of the vertebrae and includes

1. vertebral foramen

1a. Pedicles

1b. Laminae

2. Transverse processes

3. Spinous processes

Transverse and spinous processes serve as attachment sites for ligaments and muscles

Five ligaments connect the posterior motion

1. The supraspinous and interspinous ligaments connect spinous process to spinous process

1a. Resist shearing and flexion forces

2. Intertransverse ligaments connect transverse process to transverse process

2a. Resist lateral bending

3. Ligamentum flavum connects laminae to laminae and spans from sacrum to axis

3a. Resists flexion

Two synovial (apophyseal) joints are formed between adjacent vertebrae

1. The superior articulating facet of the inferior vertebrae is concave

2. The inferior articulating facet of the superior vertebrae is convex

Facets are oriented at different angles within the different regions of the spine

Difference in orientation accounts for most of the differences in mobility between regions

Anterior motion segment

1. Amphiarthrodial-symphesis

1a. Little motion

1b. Simulated ball and socket

1c. Triaxial

Posterior motion segment

1. Diarthrodial-synovial (2)

1a. Non-axial or irregular joint

1b. Movements allowed in all three planes (gliding)

Combined movements of all the motion segments in a closed chain system will produce motion at the trunk/neck:

1. Flexion/Extension/Hyperextension

2. Rotation Left/Right

3. Lateral Flexion Left/Right

Combined movemnets of all the motion segments in an open chain system will produce motion at the pelvis:

1. Pelvic tilt (forwards/backwards)

2. Rotation Right/Left

3. Lateral tilt (left/right)

Sagittal plane

1. Flexion/Extension

1a. Free movement in cervical and lumbar

1b. Restricted movement in thoracic (Increased ROM moving inferiorly)

Frontal plane

1. Lateral Flexion (Left/Right)

1a. Mostly in cervical and some thoracic

1b. Restricted movement in lumbar

Transverse Plane

1. Rotation Right/Left

1a. Free movemnt in cervical

1b. Restricted thoracic and lumbar (need lateral flexion)

During the first 50 degrees of trunk flexion - movement occurs with flattening of our lumbar curve

After the first 50 degrees of trunk flexion - movement occurs with anterior tilt of the pelvis

On the return trunk extension - pelvic posterior tilt begins the movement

The last 50 degrees of trunk extension occurs with the re-establishment of the lumbar curve

O: Superior ramus of pubis

I: Xiphoid process & cartilage of ribs 5-7

O: Surface of ribs 5-12

I: Linea alba, illiac crest & inguinal ligament

O: Lumbodorsal fascia, anterior illiac crest & inguinal ligament

I: Linea alba superior ramus of pubis & ribs 8-10

O: Illiac crest, lumbodorsal fascia, lateral inguinal ligament & lower 6-7 ribs

I: Superior ramus of pubis & linea alba

Erector spinae group

1. Iliocostalis group - lumborum, thoracis, cervicis

2. Longissimus group - Thoracic, cervicis, Capitis

3. Spinalis group - haracis, cervicis, capitis

Spans from lumbodorsal fascia, posterior illiac crest and posterior sacrum to the occipital bone of the skull

O: posterior iliac crest, posterior sacrum, lumbar vertebrae

I: Thoracic ribs 7-12

O: Thoracic ribs 7-12

I: thoracis ribs 1-6

O: Thoracic ribs 3-6

I: transverse process of cervical vertebrae 4-6

O: Posterior illiac crest, Posterior sacrum, All lumbar vertebrae

I: Transverse proccess of all thoracic vertebrae

O: Transverse process of thoracic vertebrae 1-5

I: Cervical vertebrae 2-6

O: Cervical vertebrae 4-7, thoracic vertebrae 1-4

I: Mastoid process of the temporal bone

O: Spines of Thoracic vertebrae 11-12 & lumbar 1-2

I: Spines of Thoracic vertebrae 1-8

Spinalis cervicis

O: Seventh cervical vertebrae & thoracic vertebrae 1-2

I: Spine of axis (2nd cervical)

O: Transverse process of thoracic vertebrae 1-6 & clavicle vertebrae 4-7

I: Occipital bone (between nuchal lines)

O: Posterior illiac crest

I: Transverse process of the lumbar vertebrae, 12th rib

O: Manubrium & anterior, superior surface of clavicle

I: Mastoid process

O: ligamentum nuchae, spinous process of 7th cervical & thoracic vertebrae 1-3

I: Mastoid process & occipital bone

O: Spinous processes of thoracic vertebrae 3-6

I: Transverse process of cervical vertebrae 1-3

Rectus Abdominius

Both external obliques

Both internal obliques

Psoas Major

Rectus Abdominus

External oblique

Internal oblique

Erecter spinal group

Quadratus lumborum

External oblique (controlateral)

Internal oblique (ipsilateral)

Erector spinae gropu (ipsilateral)

Splenius group

Sternocleidomastoid

Sternocleidomastoid (contralateral)

Splenius group (ipsilateral)

Splenius group

Erector spinae group

Anulus fibrosus becomes weakened

Nucleus pulposus pushes out

Occurs with trauma

Also occurs with pathological conditions

Cancer