Is it true that the diaphragm can refer pain into the shoulder?

The diaphragm can indeed refer pain into the shoulder, which is primarily due to its embryological development and its innervation. The diaphragm is innervated by the phrenic nerve, which originates from the cervical spinal roots, specifically C3 to C5. These cervical roots also supply sensation to the shoulder area.

When there is irritation or injury to the diaphragm, such as with diaphragmatic irritation, referred pain may manifest in the shoulder region. This type of referred pain is a well-documented phenomenon due to shared neural pathways in its innervation. The brain can misinterpret the source of pain, resulting in the sensation being felt in areas that are not directly affected.

Therefore, the ability of the diaphragm to refer pain to the shoulder aligns with anatomical and physiological principles observed in clinical practice. Thus, stating that it is true that the diaphragm can refer pain into the shoulder is accurate.