Decayed mandibular 3rd molar
A 26-year-old male went to the dentist to have a decayed mandibular 3rd molar (wisdom) tooth extracted. The dentist explained he would likely experience considerable pain with the removal of the tooth and informed the patient that he was going to inject a “local” anesthetic to desensitize the tooth and associated soft tissues. When agreeing to the extraction, the patient asked that plenty of anesthetics be given because he was extremely sensitive to pain. The dentist inserted the needle through the mucous membrane on the inside of the patient’s mouth, where the needle came to rest near the lingula, a bony projection on the medial surface of the ramus of the mandible. In a few minutes, the patient verbalized that his gum, lip, chin, and tongue on the affected side were numb (anesthetized).
During the extraction procedure, the patient stated he felt pain; the dentist injected more anesthetic. The tooth was removed without further incident. As the patient was preparing to leave, he happened to look in the mirror. He was surprised to find
that he was unable to close his eye and lips on the affected side and that his mouth sagged on this side, particularly when he attempted to expose his teeth. He also noted that his ear lobule was numb. When he reported these unusual symptoms, the dentist explained that because of the large amount of anesthetic injected, other nerves in addition to those that supply the teeth had been anesthetized. He assured the patient that these effects would disappear in 3 to 4 hours.
1. State the name of the nerve supplying the mandibular molar and premolar teeth.
2. Why were the patient’s chin and lower lip also anesthetized?
3. When anesthetizing this nerve, what other nerve might be affected? Why was the tongue on the injected side also anesthetized?
4. What probably caused the patient’s facial paralysis and loss of sensation in his ear lobule?
