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Bone: Dorsal surface of sacrum
Sacrum, dorsal surface.
Latin	facies dorsalis ossis sacri
Gray's	subject #24 107
Dorlands/Elsevier	f_01/12351903

The dorsal surface of sacrum is convex and narrower than the pelvic.

In the middle line it displays a crest, the middle sacral crest, surmounted by three or four tubercles, the rudimentary spinous processes of the upper three or four sacral vertebrae.

On either side of the middle sacral crest is a shallow groove, the sacral groove, which gives origin to the Multifidus, the floor of the groove being formed by the united laminae of the corresponding vertebrae.

The laminae of the fifth sacral vertebra, and sometimes those of the fourth, fail to meet behind, and thus a hiatus or deficiency occurs in the posterior wall of the sacral canal.

On the lateral aspect of the sacral groove is a linear series of tubercles produced by the fusion of the articular processes which together form the indistinct sacral articular crests.

The articular processes of the first sacral vertebra are large and oval in shape; their facets are concave from side to side, look backward and medialward, and articulate with the facets on the inferior processes of the fifth lumbar vertebra.

The tubercles which represent the inferior articular processes of the fifth sacral vertebra are prolonged downward as rounded processes, which are named the sacral cornua, and are connected to the cornua of the coccyx.

Lateral to the articular processes are the four posterior sacral foramina; they are smaller in size and less regular in form than the anterior, and transmit the posterior divisions of the sacral nerves.

On the lateral side of the posterior sacral foramina is a series of tubercles, which represent the transverse processes of the sacral vertebrae, and form the lateral crests of the sacrum.

The transverse tubercles of the first sacral vertebra are large and very distinct; they, together with the transverse tubercles of the second vertebra, give attachment to the horizontal parts of the posterior sacroiliac ligaments; those of the third vertebra give attachment to the oblique fasciculi of the posterior sacroiliac ligaments; and those of the fourth and fifth to the sacrotuberous ligaments.

• Dictionary at eMedicine dorsal+surface+of+sacrum
• SUNY Labs 43:st-0409 - "The Female Pelvis: Bones"

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

v • d • e Bones of torso

sternum: manubrium, body of sternum, xiphoid process, suprasternal notch rib: first rib, tenth rib, eleventh rib, twelfth rib, floating rib, false ribs, angle, tubercle, costal groove, neck, head general vertebral structures: body of vertebra, vertebral arch (pedicle, lamina, vertebral notch), foramina (vertebral, intervertebral), processes (transverse, articular, spinous) cervical vertebrae: C1 (anterior arch, posterior arch, lateral mass), C2 (dens), C7, anterior tubercle, posterior tubercle, foramen transversarium thoracic vertebrae: costal facets (superior, inferior, transverse) lumbar vertebrae: accessory process, mammillary process sacrum/coccyx: pelvic surface (anterior sacral foramina, dorsal surface (posterior sacral foramina, median sacral crest, medial sacral crest, lateral sacral crest), lateral surface, base, sacral hiatus