Many people can happily live their lives without ever giving their diaphragm much thought at all. You don’t have to think much about breathing, it just happens automatically. But when you take in air, your diaphragm lowers to allow room for your lungs to expand. It is attached to the lower six ribs, the xiphoid process (bottom part) of the sternum, and the first three lumbar vertebrae. There is also a connection between the diaphragm and the psoas (hip flexor) muscle and the quadratus lumborum (stabilization) muscle.
A Physiotherapist can quite easily examine if your diaphragm is functioning properly by placing their hands around your ribcage with thumbs next to the spine, and watching if there is symmetry in the movement when you take a deep breath. It is also helpful to examine the psoas and QL muscles for tightness and trigger points. The nerve that supplies the diaphragm, namely the phrenic nerve, arises from C3-C5 in your neck, and those vertebrae should be examined to see if mobilization there has any influence on diaphragmatic symptoms. The junction of the thoracic and lumbar spine (T12/L1) should be assessed as that area often develops stiffness or less mobility– remember the diaphragm attaches to L1-L3. If you have lower back pain, it could be in part due to a restriction of normal movement in this area of the spine.
