Why patients with Gastric Ulcer will feel pain over the epigastrium and over the shoulder (Referred)

Pain of gastric ulcer is referred to the skin over the epigastrium,

because the T6 - T9 sympathetic fiber that supplies the stomach via greater splanchnic nerve shares the same dermatomal origin with the cutaneous nerve supply to the skin over the epigastrium, hence the pain is referred to the epigastric region

Parietal peritoneum is derieved from somatopleuric layer of lateral plate mesoderm and is supplied by phrenic nerve.

Due to its somatic innervation, it is therefore pain sensitive.

Therefore, the anatomical basis for pain over the shoulder could be that, the phrenic nerve that supplies the pain sensitive parietal peritoneal, also shares the same dermatomal origin with the supraclavicular nerve that innervate the skin over the shoulder.

#Gastriculcer #Referredpain