Anatomy of bone system. The manual for medical students / Анатомия костной системы. Учебное пособие для медицинских вузов

They articulate with the auricular surfaces of the pelvic bone. There is the sacral tuberosity, tuberositas ossis sacri, behind the auricular surfaces. It is connected by ligaments with the tuberosity of the pelvic bone. In the process of the fusion of the sacral vertebrae into a single bone, the vertebral foramina form the sacral canal, canalis caralis (fig. 2.7). It terminates with the sacral hiatus, hiatus sacralis. The sacral horns, cornua sacralia, are on both sides of the hiatus. They are rudiments of the inferior articular processes.

The anterior and posterior sacral foramina are connected with the sacral canal by the intervertebral foramina, foramina intervertebralia (fig. 2.8).

2.6. Coccyx

The coccyx, os coccygis (Co

– Co

), consists of 3–5 rudimental vertebrae in adults. Only the I vertebra has rudiments of superior articular processes named coccygeal horns, cornua coccygea, besides the body. The coccygeal horns are connected with the sacral horns by ligaments. The I vertebra also has lateral projections which are rudiments of transverse processes.

The other vertebrae are round-shaped and small, they have no arch and no processes.

2.7. Anomalies and Developmental Defects of Vertebrae

Anomalies and developmental defects may be classified according to the following criteria:

I. Vertebral size anomalies:

1. Microspondylia – reduction in size of one or more vertebrae.

2. Brachyspondylia – reduction in width of one or more vertebrae.

3. Platyspondylia – flattening of some vertebrae which get a truncated cone shape.

4. Macrospondylia – increase in size of some vertebrae.

II. Slit-like Defects of Vertebrae:

1. Splitting of vertebral bodies (anterior splitspine, spina bifida anterior) – a slit-like defect of the vertebral body located more often in the sagittal plane.

2. Splitting of the vertebral arch (posterior split spine, spina bifida posterior) – a slit-like defect of the vertebral arch (near a spinous process or on its place).

3. Spondylolysis – in this case, the vertebral body is not fused with the pedicles of the vertebral arch: this anomaly may be observed either on one or on both sides, it happens most often in the V lumbar vertebra or in the I sacral vertebra; in case of bilateral spondylolysis, the posterior part of the arch with the inferior articular processes are separated from the pedicles of the arch with the superior articular processes.

4.