Coordinated Movement of Diaphragm and Pelvic Floor Muscles in Relation to Respiratory Function

Background: It is known that the diaphragm affects pulmonary function, trunk stabilization, and other systems found in the thoracic and abdominal cavities. The pelvic floor muscles (PFM) aid in function and stabilization of the urinary, excretory, and reproductive organs. The purpose of this literature review is to determine the connection between the function of the diaphragm and PFM and the role that the PFM may play in common thoracic and abdominal diagnoses. Methods: The review was conducted using databases and specific keywords from peer-review articles between 2008 and 2018. Many of the studies used real time magnetic resonance imaging (MRI) and electromyography (EMG) to determine activation and function of the diaphragm and PFM during different activities. Results: The diaphragm and pelvic floor muscles (PFM) have been shown to work together in many aspects of respiration and postural control and move in parallel during quiet breathing. It was noted that stronger PFM resulted in faster respiratory rates due to increased muscle recruitment and strength of respiratory muscles. In a different study, EMG results showed that the anterior diaphragm contributes more to respiratory function, while the middle and posterior diaphragm assist with trunk stabilization. Subjects with larger and stronger diaphragms had better postural stability and experienced less low back pain. The diaphragm and PFM also contribute to intra-abdominal pressure (IAP). When the diaphragm and PFM move cranially during expiration, abdominal muscles contract and thicken causing an increase in IAP. Discussion: The results showed that the diaphragm and PFM are vital in respiration, organ support, bladder and bowel control, and postural support. The diaphragm and PFM move synchronously in healthy individuals but can become dysfunctional with many pathologies. These two muscle groups, along with abdominal muscles, form a bridge and work synergistically, which could explain the association of symptoms between the three. Clinical Implications: It is important during diagnosis and treatment of the thoracic and abdominal cavity that the diaphragm and pelvic floor muscles should be assessed. Use of real time MRI and EMG can help increase strength and decrease irregular contractions in the bridge of the abdominal muscles, the diaphragm, and PFM. Focusing on all three muscles as a group instead of isolating one can increase postural stability in patients.