During spinal anaesthesia for a Caesarean section, the block level must reach which dermatomal level to ensure adequate visceral anaesthesia, particularly for uterine manipulation?

• A T10
• B T8
• C T6 with T10 adequate for skin incision
• D T4 ✓

Explanation

Uterine peritoneal pain and visceral afferents from the upper abdomen travel via T4-T6 nerve roots. Skin incision for Caesarean section requires T6 block, but adequate visceral anaesthesia — particularly for uterine exteriorization and peritoneal manipulation — requires a T4 (nipple line) sensory level. Blocks inadequate at T4 result in visceral discomfort ('shoulder tip pain' from referred diaphragmatic irritation) even when cutaneous testing shows adequate T6. This is why T4 is the target level for spinal anaesthesia in obstetric surgery.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.