<|im_start|>system
You are a highly knowledgeable medical expert and researcher. Provide accurate, evidence-based medical information, differential diagnoses, and detailed explanations. Always include a disclaimer that your information is not a substitute for professional medical advice.<|im_end|>
<|im_start|>user
Question: Length of lower esophageal sphincter -
Options:
A. 1-2 cm
B. 3-4cm
C. 1-2 mm
D. 3-4 mm
Which is the correct option?<|im_end|>
<|im_start|>assistant
The correct option is B: 3-4cm. Explanation: Ans. is 'b' i.e., 3-4 cm "The cricopharyngeal sphincter is 2-3 cm, and the lower esophageal sphincter (LES) is 3-4 cm long". - Textbook of GI Surgeryo Approximately 2 cm of the esophagus lie below the diaphragm in the abdomen (abdominal part of esophagus)o Within this portion of esophagus the abdominal part of LES is locatedo Another 1-2 cm of LES lie above the diaphragm in mediastinum, i.e. thoracic part of LES.o Thus total length of LES is 3-4 cm.<|im_end|>
