THE TRUNK and SPINAL COLUMN

Chapter 12

Bones of the Spinal Column

33 bones, 24 are flexible

A. Cervical - 7B. Thoracic - 12C. Lumbar - 5D. Sacrum - 5 (false

vertebrae - fused together)E. Coccyx - 4 (false

vertebrae - fused together) LINK Click on

picture

Landmarks of the Vertebrae

General Landmarks

1. Spinous process

3. Transverse process - tubercle of rib articulates

5. Body

6. Vertebral foramen

General Landmarks Vertebral notch

Superior Inferior

General Landmarks

Intervertebral foramen

Cervical Vertebrae

Cervical Vertebrae

First 7 vertebrae Identified as C1 – C7 C1 = Atlas C2 = Axis

Atlas (C1)

• Large vertebral foramen

• Transverse ligament

Anterior

Posterior

Axial (C2)

Odontoid process or Dens

Thoracic (T1-T12)

Thoracic (T1-T12)

Lumbar (L1-L5)

Lumbar (L1-L5)

Note the differences:1. Transverse process2. Spinous process3. Body

Note the differences:1. Transverse process2. Spinous process3. Body

Sacrum

Intervertebral Disks

Intervertebral Disks

Actions of the Spinal Column

Flexion Extension Lateral Flexion Rotation

Same sideOpposite side

Flexion

1. Free in all three regions

2. Cervical and thoracic curves may be reduced to straight lines

3. Lumbar curve may be reversed in flexible subjects

Cervical flexion

Lumbar flexion

Extension

1. Free in all three regions

2. Cervical and thorasic curves may be reduced to straight lines

3. Lumbar curve may be reversed in flexible subjects

Cervical extension

Lumbar extension

Lateral flexion

1. Free in cervical and lumbar regions

2. Limited in thorasic region by rib attachments

3. Accompanied by torsion

Cervical lateral flexion

Lumbar lateral flexion

Rotation

1. Freest at top, least free at bottom

2. Accompanied by slight lateral flexion

Cervical rotation

Lumbar rotation

Joints of the Spinal Column

Atlantooccipital joint

Articulation between the head and neck i. Atlas (C1) ii. Occipital bone

Acts as a hinge joint; flexion and extension

No rotation at this joint

Atlantoaxial

Articulation between C1 and C2

a. pivot joint - rotation is here

b. the dens or ondontoid process fits into the inner, anterior portion of the vertebral foramen

with the help of the transverse ligament.

Arthordial or gliding-type joints

Composed of the synovial joint between superior and inferior articulating surfaces

Cartilaginous or synarthrodial joints

Intervertebral disks i. nucleus pulposus - gel ii. annulus fibrosus - covering

Shape and thickness varies with location

Make up approximately 25% of the column length

Allow limited motion in all three planes

Defects of the Spine

Kyphosis - hunchback

Increase anterior concavity ( or curvature) of the thoracic curve

Lordosis - swayback

Increase posterior concavity of the lumbar region. it causes

shortened back extensors

it causes lengthened abdominal

Scoliois Lateral curvatures or sideward

deviations of the spine. Decreases the ability of the

spin to support the body Distorts the body cavity and

that crowds the organs Puts pressure on the nerves Causes:

Imbalance of the deep back muscles and ligaments

Scoliois

Treatment Body cast Electrical stimulation

of deep muscles Harrington Rod

implant - ratchett effect

Sternum

Ribs

12 pairs 7 pair are ‘true’ ribs 5 pair are ‘false’ ribs

3 pair attach indirectly to the sternum 2 pair are ‘floating ribs’ that don’t attach to

the sternum

Ribs