A 23-year-old woman is brought to the emergency department unconscious after a motor vehicle accident. The patient was texting on her cell phone and was not wearing a seatbelt during the incident. She has no known medical problems and takes no medications. Her temperature is 36.7 C (98 F), blood pressure is 155/90 mm Hg, pulse is 62/min, and respirations are 10/min. A linear skull fracture at the junction of the frontal, parietal, temporal, and sphenoid bones is seen on head CT scan. A branch of which of the following arteries is most likely severed in this patient?
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This patient has suffered a fracture at the pterion, a region where the frontal, parietal, temporal, and sphenoid bones meet in the skull. The bone is thin in this region, and fractures there risk lacerating the middle meningeal artery and causing an epidural hematoma. Epidural hematomas require prompt treatment as they are under systemic arterial pressure and can expand rapidly, leading to elevated intracranial pressure (can cause Cushing reflex), brain herniation (eg, uncal herniation with oculomotor nerve palsy), and death.
The middle meningeal artery is a branch of the maxillary artery (one of the terminal branches of the external carotid artery), which enters the skull at the foramen spinosum and supplies the dura mater and periosteum.
(Choice A) The facial artery is a branch of the external carotid artery, which courses over the mandible anterior to the insertion of the masseter muscle to supply the oral, nasal, and buccal regions.
(Choice C) The middle cerebral artery is a branch of the internal carotid artery and supplies much of the parietal and temporal regions of the brain. Injury to this artery or its branches can cause subarachnoid or intracerebral hemorrhage.
(Choice D) The occipital artery arises opposite the facial artery from the external carotid, coursing posteriorly instead of anteriorly. This vessel supplies the posterior scalp and the sternocleidomastoid muscles.
(Choice E) The ophthalmic artery is the first branch of the internal carotid artery, supplying the eye and orbital contents as well as the eyelids, forehead, and nose. The internal carotid artery has no branches in the neck.
(Choice F) The sphenopalatine artery is a branch of the third part of the maxillary artery and supplies much of the nasal mucosa. It anastomoses with branches of the ophthalmic and facial arteries within the anterior part of the nasal septum in a region known as Kiesselbach's plexus (a frequent site of nosebleeds).
Educational objective:
The middle meningeal artery is a branch of the maxillary artery, which enters the skull at the foramen spinosum and courses intracranially deep to the pterion (where the frontal, parietal, temporal, and sphenoid bones meet). Skull fractures at this site may cause laceration of this vessel, leading to an epidural hematoma.