Pain from the gallbladder is referred to the tip of the right shoulder (Kehr's sign equivalent region). The afferent pain fibers from the gallbladder travel via which route?

• A Pelvic splanchnic nerves directly to L1
• B Greater splanchnic nerves to T5–T9 spinal segments, with referred pain to right shoulder via C3-C4 dermatome through the phrenic nerve irritation ✓
• C Vagus nerve to medulla with referred pain via vagal afferents
• D Right phrenic nerve carrying all biliary pain fibers directly

Explanation

Gallbladder visceral pain afferents travel with the greater splanchnic nerves to T5-T9 dorsal root ganglia (accounting for epigastric/right hypochondriac colicky pain). Referred shoulder pain occurs because the inflamed gallbladder or bile-related peritoneal irritation of the diaphragm activates phrenic nerve afferents (C3–C5), which share spinal segments with the right shoulder dermatome. The phrenic nerve does not carry biliary pain per se; vagal afferents are non-pain (nociception). Pelvic splanchnics are parasympathetic and unrelated.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.