Sacrum

Sacrum (PSF)

Sacrum: An Anatomical Overview

The sacrum is a sturdy, triangular-shaped bone nestled at the base of the vertebral column. It is intricately linked with several critical anatomical structures, including the tailbone (or coccyx), the ilium of the pelvis at the sacroiliac joints, and the lumbar section of the spine.

Human skeleton back

Structure and Features

The sacrum is not just a single bone but a fusion of five individual sacral vertebrae that typically coalesce between the ages of 18 and 30. Key features of the sacrum include:

• Foramina: These are holes present on both the anterior and posterior surfaces of the sacrum, which provide a pathway for sacral nerves and blood vessels.
• Sacral canal: A continuation of the vertebral canal, housing the sacral nerves.
• Lateral wings (alae): Broad surfaces connecting with the ilium of the hipbones.

Function and Significance

The sacrum serves multiple functions in human anatomy:

• Support and Stability: As a central component of the pelvis, it plays a pivotal role in weight bearing and transferring body weight from the spine to the lower limbs during activities like walking or standing.
• Protection: It provides shielding to the spinal nerves and membranes that lie within the sacral canal.
• Muscle Attachment: Several muscles, ligaments, and tendons find their anchoring points on the sacrum, ensuring the movement and stability of the hip and spine.

Clinical Relevance

Various medical conditions and injuries can affect the sacrum, including sacral fractures, sacroiliitis (inflammation of the sacroiliac joint), and sacral nerve disorders. Accurate knowledge of the sacral anatomy assists healthcare professionals in diagnosing and treating related conditions.

Relation to Other Spinal Structures

The sacrum is seamlessly integrated into the spine and forms a crucial part of the bony pelvis:

• Lumbar spine: The sacrum articulates superiorly with the fifth lumbar vertebra via the lumbosacral joint.
• Coccyx: Inferiorly, the sacrum connects with the coccyx, the terminal part of the vertebral column.
• Sacroiliac joints: Laterally, the sacrum forms robust articulations with the ilium of the pelvis.

See Also

• Spine
• Coccyx
• Pelvis
• Vertebral column

References

• Thompson, J.D. (2017). Human Anatomy: The Vertebral Column and Pelvis. Oxford Medical Publications.
• Williams, L. & Tandon, P. (2019). Clinical significance of the sacrum in spinal disorders. Spine Journal.

Sacrum Resources
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