After a long struggle with what was determined to be a virus, a 74-year-old female was admitted to the ER with heart attack-like symptoms. She was, however, diagnosed instead with pericarditis, an inflammation of the fibrous pericardium. Although the pericardium is an internal organ, distinct pain can be felt in cases of inflammation/lesions due to its inner action by somatic afferent fibers via the phrenic nerve. Why would this patient be experiencing referred pain in her shoulder (which is innervated by nerves from the cervical region of the spinal cord)?
After a long struggle with what was determined to be a virus, a 74-year-old female was admitted to the ER with heart attack-like symptoms. She was, however, diagnosed instead with pericarditis, an inflammation of the fibrous pericardium. Although the pericardium is an internal organ, distinct pain can be felt in cases of inflammation/lesions due to its inner action by somatic afferent fibers via the phrenic nerve. Why would this patient be experiencing referred pain in her shoulder (which is innervated by nerves from the cervical region of the spinal cord)?
Referred pain is pain percieved at a site other than the site of the painful stimulus. The exact mechanism is unknown, but one theory that explains this case is that of convergent projection, in which the pain caused at an \"upstream\" location of an afferent nerve nerve is felt at an organ located downstream in the same nerve system.
The phrenic nerve originates majorly from the cervical plexus (C3-C5), and innervates the pericardium and the diaphragm. The supraclavicular nerves, which contain the upper shoulder lateral affecting supraclavicular nerves, originate from the nerves C3 and C4, which are common with the phrenic nerves.
As in the case of Kehr\'s sign, a similar case of referred pain, the irritation is picked up by the phrenic nerve, and as the two nerves have the same area of origin, a painful stimulus is felt at the tip of the shoulder.
Homework Sourse
