Tailbone pain (coccydynia) can cause constipation due to the intimate physical and functional relationship between the coccyx and the muscles that control bowel movements. Coccydynia is pain in the coccyx region, often caused by a fall, prolonged sitting, or childbirth. Constipation, characterized by infrequent bowel movements or difficulty passing stool, can occur as a direct result of this pain. This creates a complex cycle of discomfort and dysfunction in the lower pelvis.
Proximity of the Coccyx to Bowel Structures
The coccyx is a small, triangular bone at the bottom of the spinal column, anchoring soft tissues that support the pelvic floor. It provides attachment points for several muscles, ligaments, and tendons, including portions of the levator ani muscle group. This group forms a sling across the base of the pelvis and supports the rectum and anus.
The proximity of the coccyx means that inflammation, trauma, or misalignment in the tailbone region can directly irritate adjacent structures, including the terminal end of the large intestine. During defecation, the coccyx is designed to move slightly backward to allow the pelvic outlet to widen for stool passage. If this movement is restricted due to injury or pain, it can physically impede normal bowel evacuation, contributing to functional difficulty.
How Pain Triggers Pelvic Muscle Dysfunction
Tailbone pain causes constipation through a neuromuscular mechanism involving the pelvic floor muscles, not a digestive one. When the coccyx is injured or painful, the body guards the area, causing surrounding muscles to involuntarily tighten. These protective contractions occur in pelvic floor muscles, such as the puborectalis, which maintain fecal continence.
For a normal bowel movement, these muscles must relax and lengthen to straighten the anorectal angle, allowing stool to pass easily. If tailbone pain causes the muscles to spasm or remain tense, they cannot relax appropriately during defecation. This inability to coordinate the relaxation of the pelvic floor and anal sphincter muscles is known as dyssynergic defecation, a common cause of chronic constipation.
The pain-spasm cycle perpetuates the problem, as the difficulty and straining associated with constipation further irritate the sensitive coccyx and tense muscles. This cycle can lead to a learned behavior where a person subconsciously tightens their pelvic floor muscles in anticipation of defecation pain. This guarding pattern makes it physically difficult to expel stool, resulting in symptoms like incomplete emptying or excessive straining.
Conditions That Cause Both Symptoms
Sometimes, tailbone pain is not the direct cause of constipation, but both symptoms arise from a single, shared underlying issue involving the pelvic structures. Pelvic Floor Dysfunction (PFD) is one such condition where poor coordination or excessive tightness of the pelvic muscles leads to both chronic coccyx pain and bowel difficulties. In PFD, hypertonic muscles are constantly too tight, which pulls on the coccyx attachments and causes pain.
This muscular tightness impairs pelvic floor function, making it challenging to relax for a bowel movement and leading to constipation. Another possibility is nerve entrapment, such as pudendal neuralgia, where the pudendal nerve is irritated or compressed. This nerve supplies sensation to the pelvic region and can cause severe tailbone pain and pain during defecation, leading to functional constipation as the body avoids the painful act of bowel evacuation.
Chronic constipation itself can also cause coccyx pain, creating a complex bidirectional relationship. When stool accumulates in the rectum, it stretches the rectal wall and puts pressure on surrounding muscles and ligaments, including those attached to the coccyx. Excessive or chronic straining to pass hard stool can also stretch the pudendal nerve or place mechanical stress on the coccyx, aggravating or initiating coccydynia.
When to Consult a Healthcare Provider
If tailbone pain and constipation occur together and persist, consult a healthcare provider for an accurate diagnosis. It is important to differentiate between mechanical injury, a functional muscle issue, or a systemic problem. A medical professional can assess whether the pain is due to a structural problem with the coccyx, a muscle coordination disorder like dyssynergic defecation, or another underlying condition.
Specialists who treat these combined issues include colorectal specialists, physical medicine and rehabilitation physicians, and physical therapists specializing in pelvic health. A pelvic floor physical therapist can perform an evaluation to check for muscle hypertonicity or coordination deficits contributing to both the pain and constipation. Seeking timely professional guidance is important for effective treatment, which often involves pain management, muscle relaxation techniques, and bowel habit modification.