Podcast
Questions and Answers
How many vertebrae are fused within the sacrum?
How many vertebrae are fused within the sacrum?
The sacral sulcus is a component of the sacrum.
The sacral sulcus is a component of the sacrum.
False
What shape does the sacrum resemble?
What shape does the sacrum resemble?
An inverted triangle
The ___ of the sacrum is typically tapering and located at the opposite end from the base.
The ___ of the sacrum is typically tapering and located at the opposite end from the base.
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Match the components of the sacrum with their characteristics:
Match the components of the sacrum with their characteristics:
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How many sacral sulci are present?
How many sacral sulci are present?
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The median sacral crest is deep to the sacral hiatus.
The median sacral crest is deep to the sacral hiatus.
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What structures run through the sacral canal?
What structures run through the sacral canal?
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The anterior sacral foramina are located __________ to the median sacral crest.
The anterior sacral foramina are located __________ to the median sacral crest.
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Match the following anatomical structures with their descriptions:
Match the following anatomical structures with their descriptions:
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Study Notes
Sacrum Structure
- The sacrum is formed by the fusion of five vertebrae.
- Although it resembles the vertebral column, the "discal" material between the vertebrae is non-functional.
- The sacrum is shaped like an inverted triangle with the base positioned superiorly.
- The base of the sacrum forms a circle resembling the vertebral body of the lumbar region.
- The promontory is a slight projection on the anterior aspect of the base.
- The apex of the sacrum is a tapering end, not a point.
- The coccyx is positioned distal and inferior to the sacrum.
Sacroiliac Joint Formation
- Auricular or articular surfaces on the lateral aspect of the sacrum articulate with the auricular surfaces of the ilia.
- These surfaces are irregular, increasing in irregularity over time, providing stability to the sacroiliac joints.
Sacral Sulcus
- The sacral sulcus is a space, not part of the sacrum, located posterior to the sacrum between the ilium and sacrum.
- It is medial to the PSIS, and may be described as medial, inferior, or superior to it.
- The depth of the sulcus varies along the sacrum due to the anterior curve of the upper portion.
- The sacral sulcus is identified through palpation.
- There are two sacral sulci, one on each side.
Sacral Cornua
- The sacral cornua are projections at the inferior end of the sacrum, projecting towards the midline.
- There is one on each side, forming an inverted U-shape.
Median Sacral Crest
- The median sacral crest is a series of bumps along the midline of the sacrum, posterior to the sacral canal.
- It is formed by the fusion of the spinous processes of the sacral vertebrae.
- The sacral canal houses the sacral nerve roots and coccygeal nerves.
Sacral Hiatus
- The sacral hiatus is a hole at the inferior end of the sacral canal formed by the sacral cornua.
- It allows for the passage of the terminal sacral and coccygeal nerves.
Inferior Lateral Angle
- The inferior lateral angle is a sharp medial angling of the lateral borders of the sacrum at its inferior aspect.
- Similar in concept to the inferior angle of the scapula, but less pointed.
Sacral Palpation
- Four structures are palpated for dynamic positional fault assessment of the sacrum:
- Left and right sacral sulci
- Left and right inferior lateral angles
Anterior Sacral Foramina
- The anterior sacral foramina are located lateral to the median sacral crest and extend through the anterior and posterior aspects of the sacrum.
- They allow passage for the anterior rami of the sacral nerves.
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Description
This quiz explores the structure and function of the sacrum, including its formation, shape, and articulation with the ilia at the sacroiliac joint. Understand the unique features of the sacral sulcus and the significance of irregular joint surfaces in maintaining stability. Test your knowledge of the anatomy and relationships of these critical components in the human skeletal system.
