Anatomy and Physiology of the Gastrointestinal System

Abdominal Nervous System and Regional Anatomy

• The abdominal wall and parietal peritoneum are innervated by the thoracic nerves (T7-L1).
• The suprapubic area is also known as the hypogastric region.
• The abdominal surface is divided into nine regions by the two midclavicular lines and the subcostal plane.

Anatomy and Organs

• The alimentary canal extends from the mouth to the anus.
• The left iliac region is also known as the left lower quadrant.
• The diaphragm is responsible for pain localized above the umbilicus.

Types of Pain

• Colicky pain is associated with obstruction of a muscular conducting tube such as the bowel or the ureter.
• Intermittent pain lasts for a short time, eases off, and then returns.
• Migrating pain, which moves from the umbilicus to the right iliac fossa and becomes sharp and severe, is indicative of acute appendicitis.

Organ-Specific Pain

• The gallbladder is associated with referred pain to the right shoulder.
• Severe acute abdominal pain with sudden onset suggests a surgical emergency, such as a perforated viscus or intestinal obstruction.
• The ureter is responsible for lower abdominal pain.
• Abdominal pain that is midline and radiates through to the back may indicate pancreatitis.
• The stomach causes epigastric pain.
• Pain associated with inflammation and neoplastic infiltration is dull, aching, and constant.