"Pes anserinus" of the right phrenic nerve innervating the serous membrane of the liver: a case report (anatomical study).
Level 5 - mechanism / opinion, no new human data
Single cadaver anatomical dissection and mechanism-based reasoning.
PubMed 15693425 · doi:10.1016/s1286-0115(04)98150-7
What was done
Anatomical dissection following the pathway of the right phrenic nerve during routine educational cadaveric preparation in a 72-year-old female cadaver.
What was found
The authors observed a branch originating from the thoracic portion of the right phrenic nerve that traversed the two layers of the falciform ligament and terminated on the superior serous layer of the liver in a "pes anserinus" branching pattern. The abstract reports no numerical or quantitative metrics beyond the single subject (n = 1).
Why it matters
This anatomical variant provides a potential mechanistic explanation for how hepatic pathology can produce referred pain to the right shoulder through shared C4 neurotome pathways.
Limits
This is a single cadaveric case report (n = 1), so population prevalence and anatomical frequency cannot be determined. The link between this anatomical pathway and clinical pain referral patterns is theoretical and was not tested in vivo.
Cited by
- supports Liver pain can refer to the shoulder because of branching nerve pathways.