Surgical Anatomy and Physiology
Surgical anatomy and physiology tests layer-by-layer orientation, landmark recognition, and the physiologic consequences of retraction, resection, and fluid shifts. The RNFA uses anatomy to protect structures, not just to name them.
Core rules and concepts
- Work in planes: identify skin, subcutaneous fat, fascia, muscle, and peritoneum before dividing; stay in the intended plane to reduce bleeding and nerve injury.
- Danger zones: in the neck, the recurrent laryngeal nerve and parathyroids; in the groin, the femoral vessels and ilioinguinal nerve; in the abdomen, the bile duct and ureter. Confirm landmarks before clamping or dividing.
- Perfusion and healing: adequate oxygenation, normovolemia, normothermia, and glucose control support wound healing; ischemia, tension, and infection impair it.
- Fluid and electrolytes: third-space and insensible losses vary with open versus laparoscopic surgery; urine output, blood loss, and hemodynamics guide replacement.
- Physiology of pneumoperitoneum: increased intra-abdominal pressure reduces venous return and raises airway pressures; vagal response can cause bradycardia.
Worked example
During thyroidectomy, the RNFA sees a nerve-like structure near the inferior thyroid artery. Rather than retracting broadly, the team slows, identifies the recurrent laryngeal nerve by its course, and ligates the artery away from it. Traction injury is prevented by avoiding sustained pull and by checking the field before closure.
Traps
Assuming all white cord-like structures are nerves; retracting a vessel and nerve together; ignoring bradycardia during insufflation; and treating hypotension with fluid alone when blood loss is ongoing.