Before fusion occurs, the coccygeal vertebra articulate just like any other section of the spinal column.
The coccyx can be a source of pain in many people.
There are usually four coccygeal vertebrae that attach to the apex (small, bottom part) of thesacrum.
Illustration by Alexandra Gordon, Verywell
Most of the time, they are referred to as Co1-Co4.
Viewed as a single bone, the coccyx resembles a bull’s head.
It has two “horns” on top (the base) that are called the coccygeal cornua.
The “ears” would be the transverse processes that provide a fulcrum point for articulation with the sacrum.
The base of the coccyx articulates with the apex of the sacrum.
Some articulation is possible between coccygeal vertebrae until they are fused, but they do not move very much.
It is connected to the sacrum via the sacrococcygeal ligament.
Anatomical Variations
As mentioned above, the coccyx is usually comprised of four coccygeal vertebrae.
One study found four coccygeal vertebrae in 76% of healthy coccyges (the plural of coccyx).
The shape and curvature of the coccyx can vary between individuals and is noticeably different between sexes.
The joint between Co1 and Co2 is only fused in 17% of coccyges.
Function
If humans had tails, the coccyx would have a much more satisfying job.
Several pelvic floor muscles are attached to the coccyx, but every muscle has multiple redundant attachment points.
Most of those redundant attachment points are considerably stronger and more stable than the coccygeal vertebrae.
Contraction of those muscles can create enough movement of the coccyx to cause pain in some individuals.
Associated Conditions
The most common condition associated with the coccyx is pain, which is calledcoccydyniaor coccygodynia.
Traumais the most common cause.
The location of the coccyx makes it vulnerable to trauma if a person falls to a sitting position.
It can become broken or bruised.
The movement of muscles can lead to movement of the coccyx itself, causing pain.
Idiopathic painof the coccyx is pain caused for no discernible reason.
It is more common in females than in males.
Not every coccyx gets completely fused.
In some people, the coccyx remains mobile and can continue to move as the person sits and moves.
Teratomas generally appear when the patient is very young.
Treatment
Treatment options depend on which condition is causing pain in the coccyx.
It is probably a good idea to give conservative treatment a long leash.
It is thought to be successful in 90% of cases of coccydynia.
There is not a standard timeline for how long you should wait to consider surgery.
Some healthcare providers will consider it in as little as two months if nothing seems to be working.
Other healthcare providers might want to continue to try other options for as long as a year.
Patients that have the procedure have good outcomes.
About 75% of coccygectomies have a complete reduction of pain.
It is up to you to decide if a 75% success rate is sufficient to undergo surgery.
Evidence suggests that complete coccygectomies lead to better outcomes than partial removal of the coccyx.
The coccyx is connected to muscles and ligaments that assist in supporting weight while we sit.
Additionally, it provides positional support for the anus and assists in giving us control of the bowels.
The sacrum is a large bone located at the end of the lumbar vertebrae.
It connects to the pelvis to provide support and stabilization.
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