Educational objective: The facial nerve (CN VII) exits the stylomastoid foramen and courses through the substance of the parotid gland, where it divides into its 5 terminal branches that innervate the muscles of facial expression. Malignant tumors of the parotid gland often compress and disrupt the facial nerve and its branches, causing ipsilateral facial droop.

A 22-year-old man comes to the emergency department due to sudden-onset pain and stiffness on one side of his neck. He was diagnosed with a psychiatric disorder 2 days ago and has been adherent with his newly prescribed medication. For the past few months, the patient has heard voices telling him to quit his job, and he believes that his girlfriend's parents are monitoring his sexual thoughts with a special device. He has been socially withdrawn and has difficulty showering regularly. Vital signs are within normal limits. The head is tilted to one side and cannot be straightened without considerable pain.

Educational objective: Acute extrapyramidal symptoms (eg, dystonia, akathisia, parkinsonism) are due to 02 blockade in the nigrostriatal pathway. First-generation, high-potency antipsychotics (eg, haloperidol, fluphenazine) strongly block 02 receptors and are most likely to cause extrapyramidal symptoms.

A 38-year-old woman is brought to the emergency department after a motor vehicle collision. She sustained no injuries in the collision but is adamant that she did not see the car that hit her along the front side of her vehicle. The patient also reports that she has been having daily headaches and has not menstruated in 4 months. On physical examination, there is bitemporal hemianopsia but no other abnormalities. MRI of the brain is shown below.

Educational objective: All adult cells and tissues can be traced back to the 3 primary germ layers: ectoderm, mesoderm, and endoderm. The ectoderm gives rise to the surface ectoderm, neural tube, and neural crest.

A 16-year-old boy with mild intellectual disability is brought to the office to be evaluated for attention deficithyperactivity disorder. The parents state that he has always been impulsive and inattentive and that teachers are concerned about his inattentiveness and poor grades. Review of medical records shows a history of gross motor and speech delay for which he received physical and speech therapies during childhood. On physical examination, the boy has a long and narrow face, a prominent mandible, and large testes. There is hyperlaxity of his finger and thumb joints.

Educational objective: Fragile X syndrome is an X-linked disorder that presents with a long, narrow face, a prominent chin and forehead, and large testes. Patients often have developmental delay and neuropsychiatric findings that overlap with anxiety disorders, autism, and attention deficit-hyperactivity disorder.

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A 41-year-old man with trisomy 21 is evaluated in the clinic due to cognitive decline. The patient has a history of moderate intellectual disability, but his higher cognitive functions have become progressively impaired in the past several years. He previously volunteered at a community library but recently lost his position as he could no longer perform his duties. The patient is now completely dependent on a caregiver for assistance with his activities of daily living such as getting dressed, bathing, and using the toilet. The patient keeps wandering in the group home and has become lost on several occasions.

Educational objective: Patients with trisomy 21 (Down syndrome) have 3 copies of the amyloid precursor protein gene located on chromosome 21. This increases amyloid-beta accumulation in the brain, placing these patients at high risk for developing early-onset Alzheimer disease.

Educational objective: Delayed cerebral ischemia due to cerebral vasospasm usually presents 3-12 days after the initial subarachnoid hemorrhage (SAH) with an acute change in mental status and/or new focal neurological deficits. Nimodipine, a selective calcium channel blocker, improves outcomes in patients with cerebral vasospasm by inducing cerebral vasodilation and decreasing calcium-dependent excitotoxicity.