Merrill's Chapter 8

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What are the function(s) of the vertebral column?

What holds the vertebral column together?

How many vertebrae make up the sacrum?

The coccyx is made up of 3 vertebrae.

The 24 vertebral segments in the upper three regions are termed the [blank_start]true[blank_end] or [blank_start]movable[blank_end] vertebrae. The pelvic segments in the lower regions are called [blank_start]false[blank_end] or [blank_start]fixed[blank_end] vertebrae.

The vertebral column is made up of three curves.

The cervical and lumbar curves, which are [blank_start]convex[blank_end] anteriorly, are called [blank_start]lordotic[blank_end] curves. The thoracic and pelvic curves are [blank_start]concave[blank_end] anteriorly and are called [blank_start]kyphotic[blank_end] curves

The [blank_start]thoracic[blank_end] and [blank_start]pelvic[blank_end] curves are called primary curves because they are present at birth. The [blank_start]cervical[blank_end] and [blank_start]lumbar[blank_end] curves are called secondary or compensatory curves because they develop after birth.

The [blank_start]cervical[blank_end] curve, which is the least pronounced of the curves, develops when an infant begins to hold the head up at about [blank_start]3[blank_end] or [blank_start]4[blank_end] months of age and begins to sit alone at about [blank_start]8[blank_end] or [blank_start]9[blank_end] months of age. The [blank_start]lumbar[blank_end] curve develops when the child begins to walk at about [blank_start]1[blank_end] to [blank_start]1.5[blank_end] years of age.

The lumbar and pelvic curves are more pronounced in females, who have a more acute angle at the lumbosacral junction.

Any abnormal increase in the anterior concavity (or posterior convexity) of the thoracic curve is termed [blank_start]kyphosis[blank_end]. Any abnormal increase in the anterior convexity (or posterior concavity) of the lumbar or cervical curve is termed [blank_start]lordosis[blank_end].

The superior and inferior surfaces of the vertebra bodies are flattened and are covered by a thin layer of articular cartilage.

In the articulated spine, the vertebral bodies are separated by intervertebral disks, forming the cartilaginous interver­tebral joints. These disks account for approximately one fourth of the length of the vertebral column. Each disk has a central mass of soft, pulpy, semigelatinous material called the [blank_start]nucleus pulposus[blank_end], which is surrounded by an outer fibrocartilaginous disk called the [blank_start]anulus fibrosus[blank_end].

It is common for the pulpy nucleus to rupture or protrude into the vertebral canal, impinging on a spinal nerve. This condition is called herniated nucleus pulposus (HNP) or, more commonly, [blank_start]slipped disk[blank_end].

The vertebral arch is formed by two pedicles and two laminae that support four articular processes, two transverse processes, and one spinous process.

A congenital defect of the vertebral column in which the laminae fail to unite posteriorly at the midline is called [blank_start]spina bifida[blank_end].

What cervical vertebra is a ringlike structure with no body and a very short spinous process?

Which cervical vertebra is termed the vertebra prominens?

The bodies of the typical ([blank_start]third through ninth[blank_end]) thoracic vertebrae are approximately triangular in form.

Although the size and degree of curvature of the sacrum vary considerably in different patients, the bone is normally longer, narrower, more evenly curved, and more vertical in position in [blank_start]males[blank_end] than in [blank_start]females[blank_end].

The male sacrum is more acutely curved.

Which of the following are cartilaginous joints?

The atlantoaxial joint is both a gliding and pivot type of joint.

The zygapophyseal joint is the only slightly movable joint.

[blank_start]Jefferson[blank_end]: Comminuted fracture of the ring of C1. [blank_start]Sponylolisthesis[blank_end]: Forward displacement of a vertebra over a lower vertebra. [blank_start]Spina bifida[blank_end]: Failure of the posterior encasement of the spinal cord to close. [blank_start]Hangman's[blank_end]: Fracture of the anterior arch of C2 owing to hyperextension. [blank_start]Spondylolysis[blank_end]: Breaking down of the vertebra. [blank_start]Subluxation[blank_end]: Incomplete or partial dislocation. [blank_start]Scoliosis[blank_end]: Lateral deviation of the spine with possible vertebral rotation. [blank_start]Clay shoveler's[blank_end]: Avulsion fracture of the spinous process in the lower cervical and upper thoracic region. [blank_start]Scheuermann disease[blank_end]: Kyphosis with onset in adolescence.