mcburney point/ sign

The precise landmark matters: it is one-third of the distance from the anterior superior iliac spine to the umbilicus, not simply anywhere in the right lower quadrant. Appendicitis classically begins with poorly localized periumbilical pain, referred from visceral afferents entering at T10 because the appendix is a midgut structure, and then migrates to McBurney point once the inflamed appendix irritates the overlying parietal peritoneum, which is somatically innervated and precisely localizing. Associated signs include Rovsing sign (right lower quadrant pain on palpating the left), psoas sign (pain on right hip extension, suggesting a retrocaecal appendix), and obturator sign (pain on internal rotation of the flexed right hip, suggesting a pelvic appendix). Rebound tenderness and guarding indicate peritoneal irritation. Diagnosis is clinical, supported by CT in adults and ultrasound in children and pregnancy to limit radiation; treatment is appendicectomy, with antibiotics alone an option in selected uncomplicated cases.