Cervical Vertebrae Anatomy and Function Quiz

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Questions and Answers

What is the primary function of the uncovertebral joints?

To maintain the central position of the disc during rotation.

What types of forces can uncovertebral joints not tolerate due to their structure?

Repetitive or large forces.

How many pairs of apophyseal joints are present in the human spine?

24 pairs.

What specific role do subcapsular fat pads play in the lumbar spine?

They fill spaces between the capsule and synovial membrane. Signup and view all the answers

What is the composition of the nucleus pulposus?

It consists of 70% to 90% water. Signup and view all the answers

What happens during excessive motion of the apophyseal joints related to fibro-adipose meniscoids?

They can become impinged, restricting or locking the joint. Signup and view all the answers

What are the unique features of cervical vertebrae?

Cervical vertebrae have transverse foramina, uncinate joints, and short bifid spinous processes. Signup and view all the answers

How does neural canal volume vary with spinal positions?

Neural canal volume is greatest in full flexion and least in full extension. Signup and view all the answers

What is the significance of proteoglycans in the nucleus pulposus?

They provide a gel-like consistency and help in water retention. Signup and view all the answers

Where is the orientation of the apophyseal joints near-vertically located, and what does it prevent?

In the lower thoracic and lumbar regions; it prevents excessive anterior translation of vertebrae. Signup and view all the answers

What is the function of the atlas (C1)?

The atlas supports the head and allows for its nodding motion. Signup and view all the answers

Describe the characteristic feature of the axis (C2).

The axis has a large, tall body and an upwardly projecting dens that acts as a pivot for the atlas. Signup and view all the answers

What distinguishes the vertebra prominens (C7) from other cervical vertebrae?

The vertebra prominens is the largest cervical vertebra, featuring large transverse processes and a prominent spinous process. Signup and view all the answers

What is the significance of the transverse foramina in cervical vertebrae?

Transverse foramina allow for the passage of the vertebral artery. Signup and view all the answers

Why are individuals with neural canal stenosis at risk during extension?

They are more vulnerable to spinal cord injury and myelopathy during extension due to reduced canal volume. Signup and view all the answers

What unique structural feature does the atlas possess that aids its function?

The atlas has large lateral masses joined by anterior and posterior arches to support the head. Signup and view all the answers

What is the primary composition of the annulus fibrosus?

The annulus fibrosus is primarily composed of 50% to 60% collagen and elastin protein. Signup and view all the answers

What is the effect of dehydration and thinning of the disc?

Dehydration and thinning of the disc increase compression on the apophyseal joints, raising the risk of arthritis. Signup and view all the answers

How are the collagen rings oriented in the lumbar region?

In the lumbar region, collagen rings are oriented at 65 degrees from vertical. Signup and view all the answers

What percentage of movement in flexion occurs at the atlanto-occipital and atlanto-axial joints?

Approximately 25% of flexion movement occurs at the atlanto-occipital and atlanto-axial joints. Signup and view all the answers

What happens during flexion of the spine?

During flexion, the ligamentum nuchae stretches and the anterior annulus fibrosus compresses. Signup and view all the answers

How does prolonged protraction affect posture?

Prolonged protraction can lead to chronic forward head posture and strain on the extensor muscles. Signup and view all the answers

What is the range of rotation in young adults?

Young adults have a range of rotation of 65 to 75 degrees to each side. Signup and view all the answers

What occurs during the extension of the spine?

During extension, the apophyseal joints approximate and the posterior annulus fibrosus compresses. Signup and view all the answers

What percentage of movement occurs at the atlanto-axial joint during cervical rotation?

50–60% Signup and view all the answers

Describe the coupling that occurs during right side bending in the cervical spine.

Right side bending occurs with right rotation (ipsilateral coupling) and is compensated by left rotation (contralateral coupling) at the atlanto-axial joint. Signup and view all the answers

How do the upper and lower trapezius muscles influence cervical and upper thoracic spine movement?

They rotate the spine to the left during right upper limb movement, demonstrating contralateral coupling. Signup and view all the answers

What is the role of the sternocleidomastoid muscle when acting unilaterally?

It causes side bending and rotation to the opposite side. Signup and view all the answers

What anatomical features do the scalenes have concerning their origin and insertion?

They originate from the transverse process tubercles of middle to lower vertebrae and insert on the first two ribs. Signup and view all the answers

How do the scalenes function when the cervical spine is stabilized?

They raise the ribs to assist in inspiration. Signup and view all the answers

What impact does forward head posture have on the sternocleidomastoid's function?

It doubles the muscle's flexion torque by increasing the moment arm, exaggerating forward head posture. Signup and view all the answers

What can happen if there is hypertrophy or spasm in the scalenes?

It can compress the brachial plexus. Signup and view all the answers

Study Notes

Cervical Biomechanics

Cervical biomechanics examines the movement, structure, and function of the cervical spine.
This includes the vertebrae, their junctions, the movement they allow, and the muscles involved.

Vertebrae

Cervical vertebrae are the smallest and most mobile vertebrae in the spine.
Unique features include transverse foramina, which allow the passage of the vertebral artery, and uncinate joints.
Spinous processes are short and bifid.
C1 (atlas) supports the head, lacks a body, and has large lateral masses.
C2 (axis) has a large body and a dens (odontoid process), which acts as a pivot point for rotation.
C7 (vertebra prominens) is the largest cervical vertebra and has a prominent spinous process.

Neural Canal Volume

The neural canal is largest in flexion and smallest in extension.
People with neural canal stenosis are more vulnerable to spinal cord injury and myelopathy, particularly during extension.

Vertebral Junction

The cervical spine's junctions include uncovertebral joints and apophyseal joints.
Uncovertebral joints, or Luschka joints, are located between C2-3 to C6-7.
Discs act as spacers between vertebrae, unloading them. Increased loading can cause osteophyte growth, which compresses nerve roots.
Uncovertebral joints maintain the central position of the disc during rotation and function as a mechanical coupling between axial rotation and lateral flexion.

Apophyseal Joints

Apophyseal joints are plane synovial joints connecting adjacent vertebrae.
They are primarily oriented near-vertically in the lower thoracic and lumbar regions, preventing excessive anterior translation (spondylolisthesis).
In the upper cervical region, they are more horizontally oriented, favoring axial rotation.
Accessory structures in lumbar apophyseal joints include subcapsular fat pads and fibro-adipose meniscoids, which protect and help lubricate the joints.

Discs

The nucleus pulposus, the central part of the disc, is made up of 70-90% water, acting as a hydraulic shock absorber.
Proteoglycans provide a gel-like consistency, and type II collagen fibers form a network for support.
The annulus fibrosus, consisting of 15-25 layers of collagen and elastin, provides strength and flexibility to the disc.
Inner layers of the annulus fibrosus contain more water and less collagen for gradual transformation into nucleus pulposus characteristics.
Dehydrated discs increase compression on apophyseal joints, which can increase the risk of arthritis.
In the lumbar region, collagen rings are oriented at 65 degrees from the vertical to distribute force and prevent shear force. Fibers in adjacent layers travel in opposite directions, allowing for rotation without injuring the layers

Movement

Resting position of the cervical spine is 30-35 degrees of extension (lordosis).
Flexion ranges from 45-50 degrees, and extension ranges from 75-80 degrees.
25% of this movement occurs at the atlanto-occipital and atlanto-axial joints.
Cervical flexion stretches the ligamentum nuchae and interspinous ligaments, and compresses the anterior annulus fibrosus.
Cervical extension approximates apophyseal joints and compresses the posterior annulus fibrosus.
Protraction moves the head forward by 6.23 cm, flexing the lower to mid-spine and extending the upper cervical region.
Retraction moves the head backward by 3.34 cm, extending the lower to mid-spine and flexing the upper cervical region.
Prolonged protraction can lead to chronic forward head posture and extensor muscle strain.

Cervical Rotation

Rotation in children (3.5-5 years) is 100° to each side. For young adults, this is 80° to each side, with visual fields reaching 330°.
50-60% of rotation occurs at the atlantoaxial joint.
Full rotation stretches vertebral arteries. Side bending in the mid-to-low cervical regions occurs with right and left rotation. This coupling helps stabilize the eyes' fixation on stable objects during neck movement.

Muscles

Several muscles support and facilitate cervical movement.
The sternocleidomastoid muscle acts unilaterally to perform side bending and rotation to the opposite side, and bilaterally for cervical flexion and upper cervical extension.
Scalene muscles, particularly the anterior scalene, assist with inspiration by raising the first two ribs.
Muscle function and the initial posture of the spine are intricately linked.

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Description

Test your knowledge on the anatomy and function of cervical vertebrae with this quiz. Explore various structural features, functions, and the significance of joints and ligaments in the cervical region. Perfect for students studying human anatomy or related fields.