Dalley, 10th Edition

Chapter 2 ■ Back

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This bony or cartilaginous growth during advanced age has traditionally been viewed as a disease process ( spondy losis in the case of the vertebral bodies and osteoarthrosis in the case of the zygapophysial joints), but it may be more realistic to view it as an expected morphological change with age, representing normal anatomy for a particular age range. Correlation of these ndings with pain is often dif cult. Some people with these manifestations present with pain, others demonstrate the same age-related changes but have no pain, and still others exhibit little morphological change but complain of the same types of pain as those with evi dent change. In view of this and the typical occurrence of these ndings, some clinicians have suggested that such age related changes should not be considered pathological but as the normal anatomy of aging (Bogduk, 2012). Anomalies of Vertebrae Sometimes the epiphysis of a transverse process fails to fuse. Therefore, caution must be exercised so that a persistent epiphysis is not mistaken for a vertebral fracture in a radiograph or CT scan. A common birth defect of the vertebral column is spina bi da occulta , in which the neural arches of L5 and/or S1 fail to develop normally and fuse posterior to the vertebral canal. This bony defect, present in up to 24% of the popula tion (Greer, 2010), usually occurs in the vertebral arch of L5 and/or S1. In a minor form of spina bi da, the only evidence of its presence may be a small dimple with a tuft of hair arising from the lower back. The defect is concealed by the overlying skin. Most infants with this minor type of spina

bi da have back problems (Persaud & Torchia, 2025). When examining a neonate, adjacent vertebrae should be palpated in sequence to be certain the vertebral arches are intact and continuous from the cervical to the sacral regions. In severe types of spina bi da, spina bi da cystica , one or more vertebral arches may fail to develop completely. Spina bi da cystica is associated with herniation of the meninges ( meningocele , a spina bi da associated with a meningeal cyst) and/or the spinal cord ( meningomyelocele ) (Fig. B2.10). Neurological symptoms are usually present in severe cases of meningomyelocele (e.g., paralysis of the limbs and distur bances in bladder and bowel control). Severe forms of spina bi da result from neural tube defects , such as the defective closure of the neural tube during the 4th week of embryonic development (Persaud & Torchia, 2025).

FIGURE B2.10. An infant with spina bi da cystica with meningomyelocele in lumbar region.

The Bottom Line: Vertebrae

Typical vertebrae: Vertebrae consist of vertebral bodies, which bear weight and increase in size proportionately, and vertebral arches, which collectively house and protect the spinal cord and the roots of the spinal nerves. ■ Processes extending from the vertebral arch provide attachment and leverage for muscles, or direct movements between vertebrae. Regional characteristics of vertebrae: The chief regional characteristics of vertebrae are ■ foramina transversarii for cervical vertebrae, ■ costal facets for thoracic vertebrae, ■ the absence of foramina transversarii and costal facets for lumbar vertebrae, ■ the fusion of adjacent sacral vertebrae, and ■ the rudimentary nature of coccygeal vertebrae. Ossi cation of vertebrae: Vertebrae typically ossify from three primary ossi cation centers within a cartilaginous model: a centrum that will form most of the body and a

center in each half of the neural arch. ■ Thus, by the time of birth, most vertebrae consist of three bony parts united by hyaline cartilage. ■ Fusion occurs during the rst 6 years in a centrifugal pattern from the lumbar region. ■ During puberty, ve secondary ossi cation centers appear: three related to the spinous and transverse processes and two anular epiphyses around the superior and inferior margins of the vertebral body. ■ Costal elements formed in association with the ossi cation center of the transverse process usually form ribs only in the thoracic region. They form components of the transverse processes or their equivalents in other regions. ■ Knowledge of the pattern of ossi cation of vertebrae allows understanding of the normal structure of typical and atypical vertebrae as well as variations and malformations.

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