Embryology Videos & Books 2021

2022-10-28 08:24:02 A 15-year-old boy comes to the office due to right ear itching and discomfort for the past several days. He has no fever or hearing loss but has noted scant drainage of thin, whitish fluid. The patient has been taking swimming lessons at a local gym. On examination, there is no redness around the ear, but gentle traction of the pinna elicits pain. During inspection of the external auditory canal, a speculum is inserted into the meatus in close contact with its posterior wall, causing the patient to suddenly become lightheaded and faint. He recovers spontaneously within a few minutes with no residual confusion. Open / Comment

2022-10-27 21:03:02 Educational objective: Expanding space occupying lesions within the temporal lobe can cause elevated intracranial pressure with transtentoria1 herniation of the uncus. Uncal herniation often compresses the ipsilateral third cranial nerve as it exits the midbrain, resulting in oculomotor nerve palsy with a fixed dilated pupil (eg, due to preganglionic parasympathetic fiber damage). Open / Comment

2022-10-27 08:02:02 Open / Comment

2022-10-27 08:02:01 A 65-year-old man comes to the emergency department due to sudden onset headache. The patient has not had any recent falls or head trauma. His past medical history includes hypertension and lung adenocarcinoma with abdominal metastasis. His initial noncontrast head CT reveals a small temporal lobe hemorrhage. Over the next 24 hours, he becomes progressively obtunded and develops generalized tonic-clonic seizures. His blood pressure is 190/96 mm Hg, pulse is 38/min, and respirations are 6/min with brief episodes of apnea. A repeat noncontrast head CT reveals acute hematoma expansion with brain herniation. Open / Comment

2022-10-26 22:01:03 Educational objective: The third cranial nerve (oculomotor) carrying general somatic efferent fiber and general visceral efferent parasympathetic fiber exits the midbrain and courses between the posterior cerebral and superior cerebellar arteries. An aneurysm arising from either artery can lead to a non-pupil-sparing third nerve palsy, which clinically presents with unilateral headache, eye pain, diplopia, dilated nonreactive pupil, and ptosis with the ipsilateral eye in a down and out position. Open / Comment

2022-10-26 08:02:01 Open / Comment

2022-10-26 08:01:01 A 55-year-old, right-handed man comes to the emergency department because of recent onset of severe, throbbing, right-sided orbrtofrontal headache and diplopia. His other medical problems include poorty controlled hypertension and chronic tobacco use. Neurologic examination shows that he is awake, alert, and oriented and follows both simple and complex commands. Testing of the cranial nerves reveals intact visual acuity bilaterally. Visual fields and optic fundl are normal. Examination shows anisocoria, with the right pupil being dilated and nonreactive to both light and accommodation. He has evidence of both vertical and horizontal binocular diplopia. The right eye is down and out with ipsi1ateral ptosis. The rest of the neurologic examination is within normal limits. CT angiography of the head reveals a large aneurysm in the posterior fossa. A normal CT angiogrem of the head is shown below. Open / Comment

2022-10-13 08:45:02 Open / Comment

2022-10-13 08:45:02 A highly agitated 54-year-old man is brought lo lhe emergency department by his family because he is unable to effectively communicate. He speaks clearly and with conviction but his sentences are incomprehensible. He does not appear to understand the doctor's questions, does not follow oral or written instructions, and cannot repeat simple phrases. Open / Comment

2022-10-12 21:44:02 Educational objective: The hypothalamus is a key region responsible for homeostasis. The ventromedial nucleus (VMN) is thought to be the center of satiety. Lesions of the VMN can result in hyperphagia and obesity. Open / Comment