The length of an epidural needle typically ranges from about 9 to 11 centimeters (approximately 3.5 to 4.3 inches) for normal-weight adults, with longer needles (up to around 6 inches or 15 cm) used for obese patients to reach the epidural space effectively

. Commonly used epidural needles, such as the Tuohy needle, are often around 3.5 inches (9 cm) long, with some variations depending on the gauge and manufacturer

. In summary:

• Typical length: 9–11 cm (3.5–4.3 inches) for most adults
• Up to 15 cm (6 inches) for obese patients
• Needle gauge commonly 17 or 18 gauge

This length allows the needle to reach from the skin surface to the epidural space near the spine while being thin and designed to minimize tissue damage