Sacrum presentation

1. Sacrum
By- Sanju Sah
St. Xavier’s college, Maitighar, Kathmandu
Department of Microbiology

2. • The word sacrum comes from Latin word
sacer, meaning sacred or strong.
• It is a single bone formed by incomplete
fusion of five vertebrae to form triangular or
wedged-shaped bone with a concave anterior
surface.
Location:
• It is situated at the upper, back part of pelvic
cavity, between two wings of pelvis.

3. Anatomy
• The sacrum is a kyphotic bone, that is, it is
concave in shape, facing outwards and
forwards.
• There lies an inter-vertebral disc between the
base of the last lumbar vertebra and the
sacrum, which is known as the lumbosacral
disc.

4. • The canal for the passage of the spinal cord
extends into the sacrum.
• The sacral nerves exit through the bony
foramina, which are present along the outer
borders of the sacrum.
• If these nerves get pressed due to dislocation
or any other injury, then it can lead to intense
pain in that area, among other symptoms.

6. Articulations
The sacrum articulates with four bones:
• the last lumbar vertebra above
• the coccyx (tailbone) below
• the illium portion of the hip bone on either
side.

7. Function
• Several key muscles of the hip joint, including
the gluteus maximus, iliacus, and piriformis,
have their origins on the surface of the sacrum
and pull on the sacrum to move the leg.
• The sacrum also surrounds and protects the
spinal nerves of the lower back.

8. • Finally, the sacrum helps to form the pelvic
cavity that supports and protects the delicate
organs of the abdominopelvic cavity and
provides space for a fetus to pass through
during childbirth.

9. References
• Gray H: Anatomy of the Human Body.
Philadelphia: Lea & Febiger, 1918;
Bartleby.com, 2000 www.bartleby.com/107/
[July 18, 2003] 9.
• Rose and wilson, Anatomy and Physiology,
11th edition, Reprinted in 2011 , Pp: 393.