Lab 2, Station 2: Vertebral Column 2

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David Conley
PhD · Clinical Associate Professor, Department of Translational Medicine & Physiology
Office: PBS 41A
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Headshot of Shannon Helbling, PhD · Clinical Assistant Professor, Department of Translational Medicine & Physiology
Shannon Helbling
PhD · Clinical Assistant Professor, Department of Translational Medicine & Physiology
Office: PBS 41C
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Sacrum (5 fused vertebrae)

Promontory

Alae (singular is Ala = “wing”). There are two of these, on either side of the promontory

Anterior and posterior sacral foramina

Sacral canal

Sacral hiatus

Coccyx (4 vertebrae fused into 1-2 pieces)

Figure 2.7. Sacrum and coccyx, anterior view. From Gilroy, Atlas of Anatomy, 2nd ed., Illustrator: Karl Wesker, ©2018 Thieme Medical Publishers, Inc. All rights reserved.

Figure 2.8. Sacrum and coccyx, posterior view. From Gilroy, Atlas of Anatomy, 2nd ed., Illustrator: Karl Wesker, ©2018 Thieme Medical Publishers, Inc. All rights reserved.

Joints of the Vertebral Bodies

Study these on an isolated cadaver vertebral column specimen.

Adjacent vertebral bodies are joined together by intervertebral discs—producing an intervertebral joint. Each of these joints is technically known as a symphysis. An IV disc also joint L-5 to the sacrum.

Question

What is the definition of a symphysis? Hint: it is defined by its cartilage.

IV joints firmly unite the vertebral bodies and prevent them from moving on one another. They also function to absorb and dissipate forces transmitted along the vertebral column.

Each IV disc has two parts:

Annulus fibrosis: Composed of rings of fibrocartilage

Nucleus pulposus: The super-hydrated gelatinous core of the disc

Figure 2.9.

Question

Do you recall the embryonic origin of the nucleus pulposus?

Also, locate these features on the spine specimen:

Intervertebral foramina: These transmit spinal nerves

Dura mater

Epidural space

Question

What is a herniated disc? In which direction do disc herniations usually occur? Why? What is the neurological danger?

Joints of the Vertebral Arches

Zygapophyseal (facet) joints: Articulations between superior and inferior articular processes of adjacent vertebrae. These are plane joints that allow gliding movements. Locate these on the skeleton in lab.

Degenerative changes in facet joints are common sources of back pain.

Note

Although only a small amount of movement is possible at an individual facet joint—together, the joints allow flexion, extension, lateral bending, and rotation of the vertebral column.

Craniovertebral Joints

Atlanto-occipital joint: The articulation between C-1 and the skull (condyles of the occipital bone).

Atlantoaxial joint: The articulation between C-1 and C-2.

Question

These joints facilitate movements of the head on the spine. What are these? [Don’t shake your head—you got this!]

Ligaments of the Vertebral Column

Complete anatomy

Ligaments of the vertebral column

Identify these on the isolated lumbar spine cadaveric specimen.

Anterior longitudinal ligament: Limits spine extension (prevents hyperextension) and anterior movement of IV discs

Posterior longitudinal ligament: Limits spine flexion and posterior movement of the IV discs.

 

The longitudinal ligaments run vertically along the anterior and posterior aspects of the vertebral bodies—from skull to sacrum.

Ligamentum flavum: Segmental, they run between the laminae of adjacent vertebrae. Best seen within the vertebral canal. They contain an abundance of elastic fibers—this gives the ligament a yellow color (thus the name!). They limit flexion of the spine and provide recoil to return the spine to vertical after it has been flexed.

Figure 2.10. Netter, Atlas of Human Anatomy, 7th ed., Plate 168.

Figure 2.11. Netter, Atlas of Human Anatomy, 7th ed., Plate 168.