system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Macintosh indicator is used for ?
assistant
The correct answer is  Ans. is 'b' i.e., Localization of extradural space Various methods have been used to locate the epidural (extra dural space), most of which rely on subatmospheric pressure. These are :- Loss of resistance to air or saline (most common technique). Gutierrez's method : A hanging drop of saline on the hub of needle is drawn in as the epidural space is entered (more reliable in thorocic than lumbar region). Odom 's indicator : A fine-bore glass tube filled with saline and a bubble that moves in response to a drop in pressure. Macintosh's indicator : A small rubber balloon filled with air connected to an adaptor causing it to deflate on entering the epidural space. Macintosh's spring-loaded needle. Ultrasonic localization. Oxford epidular space detector.