What type of pain does Kehr's Sign refer to?

Kehr's Sign refers specifically to pain in the left shoulder, which is indicative of irritation of the diaphragm and may suggest the presence of internal bleeding, particularly associated with splenic injuries or other intra-abdominal pathology. The pain radiates to the left shoulder due to shared nerve pathways between the diaphragm and the left supraclavicular region.

The anatomical reason behind this is that the phrenic nerve, which innervates the diaphragm, also receives sensory fibers from the cervical spine, particularly from the C3 to C5 segments, which overlap with the areas that supply the shoulder region. When there is blood or fluid in the abdominal cavity that irritates the diaphragm, the resulting pain may be referred to the left shoulder, hence the manifestation of Kehr's Sign.

This sign is clinically significant as it helps healthcare providers recognize potential splenic rupture or other abdominal emergencies that require prompt evaluation and treatment. Identifying this type of referred pain aids in the triage and management of patients presenting with abdominal trauma.