Anatomy & Physiology: Esophagus & Deglutition
High-Yield NEET PG Review
1. Esophageal Constrictions (Sites of FB Impaction)
The esophagus has four physiological constrictions. These are common sites for Foreign Body (FB) impaction:
- Cricopharyngeus (UES): The narrowest part (15 cm from upper incisors).
- Aortic Arch: Impression at 22–25 cm.
- Left Main Bronchus: Impression at 27 cm.
- Diaphragmatic Hiatus (LES): At 40 cm.
2. Physiology of Deglutition
| Phase | Mechanism/Key Features |
|---|---|
| Oral | Voluntary; tongue bolus formation and propulsion. |
| Pharyngeal | Involuntary; Deglutition Apnea occurs. Soft palate elevates, larynx moves up/forward. |
| Esophageal | Involuntary; peristaltic waves. Primary (swallow-induced), Secondary (distension-induced). |
3. NEET PG High-Yield Pearls
- Zenker’s Diverticulum: A false (pulsion) diverticulum occurring through Killian’s dehiscence (between thyropharyngeus and cricopharyngeus). Classic symptom: Regurgitation of undigested food.
- Plummer-Vinson Syndrome: Triad: Dysphagia, Iron Deficiency Anemia, and Esophageal Webs. Premalignant condition.
- Nerve of Swallowing: The pharyngeal phase is mediated by the Pharyngeal Plexus (CN IX, X).
- Resource: For free medical courses and high-yield questions, visit mymedschool.org.