A 59-year-old man comes to the office for evaluation of a facial skin lesion. The lesion is a mole-like spot that has been on the patient's face for the past several months and has slowly enlarged. He reports no pain or bleeding from the lesion. Family medical history is positive for skin cancer. Physical examination findings are shown in the exhibit.

Biopsy of the lesion with a local nerve block for anesthesia is planned. Which of the following injection sites is most likely to provide adequate anesthesia for the procedure?

Question

A 59-year-old man comes to the office for evaluation of a facial skin lesion. The lesion is a mole-like spot that has been on the patient's face for the past several months and has slowly enlarged. He reports no pain or bleeding from the lesion. Family medical history is positive for skin cancer. Physical examination findings are shown in the exhibit.

Biopsy of the lesion with a local nerve block for anesthesia is planned. Which of the following injection sites is most likely to provide adequate anesthesia for the procedure?

Biopsy of the lesion with a local nerve block for anesthesia is planned.  Which of the following injection sites is most likely to provide adequate anesthesia for the procedure?

Quizplus · Accepted Answer

11ec160b_35cc_fb0f_9249_6730e8ee376d_MD0001_00 This patient is undergoing excision of a skin lesion located on his cheek, just lateral to his nose, in an area supplied by the maxillary branch of the trigeminal nerve (CN V2). Nerve blocks are often performed using bony landmarks (eg, foramina) as an anatomic guide. The trigeminal nerve divides into 3 branches that then travel as follows: Ophthalmic nerve (CN V1): exits the cranium through the superior orbital fissure (Choice E), passes superiorly along the orbit, and then exits the orbit through the frontal bone via the supraorbital foramen. Maxillary nerve (CN V2): leaves the skull through the foramen rotundum and then traverses the pterygopalatine fossa to enter the maxilla via the infraorbital canal. It then exits the facial bones through the infraorbital foramen. The infraorbital artery also runs along the infraorbital groove and canal and exits the infraorbital foramen together with the infraorbital nerve. Mandibular nerve (CN V3): exits the cranium through the foramen ovale. One branch (the inferior alveolar nerve) enters the mandibular foramen (Choice B) on the internal surface of the mandible and then exits at the mental foramen (Choice C) at the anterior mandible. A more general maxillary nerve (CN V2) block can be performed at the pterygopalatine fossa near where the nerve exits the skull at the foramen rotundum, but it is technically more difficult and will also block other maxillary branches (eg, zygomatic, palatine) in addition to the infraorbital nerve. (Choice D) The facial nerve (CN VII) exits the skull at the stylomastoid foramen and provides motor innervation to the muscles of facial expression. It does not contribute to sensory innervation of the face. Educational objective: The maxillary division of the trigeminal nerve (CN V2) provides sensory innervation to the cheek. It passes through the foramen rotundum, then the pterygopalatine fossa, and then exits the maxilla through the infraorbital foramen. Nerve blocks to provide anesthesia to the cheek are frequently performed at the infraorbital foramen.

A 59-Year-Old Man Comes to the Office for Evaluation of a Facial