While the event is extremely rare, a forceful sneeze can medically cause a rib to break. This phenomenon almost exclusively occurs when a person has an underlying medical condition that has significantly weakened the bone structure, transforming the powerful muscular contraction of the sneeze into an injury trigger. The sneeze is the final stressor, not the primary cause of a break in an otherwise healthy adult.
The Force Generated by a Sneeze
The sneeze reflex is an involuntary physiological event that begins with a deep inspiration, followed by the rapid and simultaneous contraction of numerous muscle groups. The diaphragm and the intercostal muscles contract powerfully, creating a rapid buildup of pressure within the chest cavity. This sudden muscular action creates a significant spike in both intrathoracic and intra-abdominal pressure. The air is then forcefully expelled through the nose and mouth, reaching velocities of approximately 16 meters per second (36 miles per hour). This rapid pressure change exerts immense, short-lived stress on the chest wall, making a sneeze a plausible mechanism for injury to chest and abdominal structures.
Underlying Conditions That Enable Rib Fracture
A healthy rib cage is flexible and resilient enough to withstand the pressure generated by even the most violent sneeze. A rib fracture from sneezing is classified as a pathological fracture, meaning it occurs in a bone already compromised by disease. The break typically happens when the bone’s density or structural integrity has been significantly diminished. One of the most common predisposing factors is severe osteoporosis, which causes low bone mass and structural deterioration, making bones fragile.
Postmenopausal women are particularly susceptible, as estrogen loss accelerates bone density decline, making them more vulnerable to these non-traumatic fractures. Chronic use of corticosteroid medications, often prescribed for inflammatory conditions, can also decrease bone mineral density over time. Other serious conditions, such as underlying metastatic disease or multiple myeloma, can weaken the bone structure at specific points. These diseases create focal lesions or tumors within the bone, causing a structural flaw that yields under the stress of a sneeze.
The sneeze provides a sudden, twisting force that the weakened bone cannot absorb. The most commonly affected ribs are the fourth through ninth, as they are the longest and have the least structural support.
Other Musculoskeletal Injuries Caused by Sneezing
While a rib fracture is uncommon, the powerful muscular contractions frequently lead to more common, non-bony musculoskeletal injuries. The most frequent complaint is an intercostal muscle strain, involving the small muscles located between the ribs. A sudden, violent sneeze can cause these muscles to overstretch or tear, resulting in sharp, localized chest pain. The intense increase in intra-abdominal pressure during a sneeze can also affect the spine and abdominal wall.
Pre-existing weaknesses in the abdominal wall (due to age, prior surgery, or genetics) may be exploited by the sudden pressure spike, potentially triggering or worsening a groin or hiatal hernia. The force can also be transmitted through the torso, contributing to or aggravating back pain by placing extreme stress on the spinal discs. This extreme pressure can cause a sudden prolapse or bulging of a vertebral disc, particularly in the vulnerable lumbar region of the lower back. The explosive movement can also compress a nerve, leading to radiating pain known as sciatica. Injuries involving soft tissue, cartilage, and discs are far more likely than a broken bone.