Referred Pain Occurs when visceral pain sensation presents

Referred Pain • Occurs when visceral pain sensation presents as somatic pain. • Various patterns of distribution. • Due to autonomic nerve afferents travelling with somatic nerves, which have a welldefined dermatomal pattern.

Common Presentations • Left sided chest pain radiating into left arm and jaw – Heart supplied by thoracic sympathetic nerves T 1 – T 4. T 1 also ascends to supply cervical sympathetic chain hence radiation into left arm (C 8, T 1) and jaw (cervical chain). • Shoulder tip pain – Diaphragmatic irritation stimulating C 3 – 5. – Hepatic, gall bladder or subphrenic pathology • Epigastric pain – Foregut structures (Oesophagus to D 2, including liver and pancreas) innervated by greater splanchnic nerve (T 5 – T 8). • Central abdominal pain – Midgut structures (D 3 – proximal 2/3 transverse colon) – Innervated by lesser splanchnic nerve (T 9 – T 11)

Common Presentations • Lower abdominal and lower back pain – Hindgut structures (Distal 1/3 transverse colon to anorectal junction), Urinary bladder and prostate. – Innervated by lumbar splanchnic (L 1 – L 3) and pelvic splanchnic (S 2 –S 4) nerves. • Loin to groin pain – Referred from the ureter – Proximal ureter innervated by least splanchnic nerve (T 12) – Distal ureter innervated by lumbar splanchnic nerve (L 1 -L 2) • Anterolateral thigh pain – Often referred from psoas irritation of the L 1 nerve root (ilioinguinal nerve and genitofemoral nerve). – Involvement of L 2 nerve root (lateral cutaneous nerve of thigh) presents as meralgia paraesthetica