TAP block performed under ultrasound guidance is used as part of multimodal analgesia to relieve pain after abdominal surgery in our hospital. Choices of local anaesthetic used include bupivacaine and ropivacaine. Local anaesthetic works by inhibiting nerve transmission of pain from the site of tissue injury. An important component of the pain experienced by patients after abdominal surgery derives from the abdominal wall incision. The abdominal wall sensory afferents course through the transversus abdominis (neurofascial) plane superficial to the transversus abdominis muscle. Single shot TAP block has been shown to provide pain relief of up to 24h in surgeries involving pfannenstiel incisions, hence a study period of 24h is chosen in patients undergoing hysterectomy.