Overview Illustration by Ava Yap Snapshot A 35-year-old woman presents to the emergency department with left eye vision loss and headache. She was in her usual state of health until 3 hours prior to presentation, when she developed vision loss and eye pain that worsened with eye movement. She reports that approximately 8 months ago she had left arm numbness that self resolved. On physical exam, her visual acuity is 20/185, and a sluggish response to light on the left eye with the swinging flash-light test is noted. (Optic neuritis likely secondary to multiple sclerosis.) Introduction Cranial Nerves Cranial Nerve Type Function Cranial Exit Notes Olfactory nerve (I) Sensory Olfaction Cribiform plate Only CN without thalamic relay to the cortex Optic nerve (II) Sensory Vision Optic canal - Oculomotor nerve (III) Motor Eye movement via the superior, inferior, and medial rectus inferior oblique muscle Pupillary constriction Accomodation Eyelid opening via innervation of the levator palpebrae muscle Superior orbital fissue Center contains output to ocular muscles which is affected primarily 1st by vascular disease Periphery contains parasympathetic output which is affected 1st by compression Trochlear nerve (IV) Motor Eye movement via innervation of the superior oblique muscle Superior orbital fissue - Trigeminal nerve (V) Motor and sensory Mastication via the mandibular nerve (V3) Facial sensation via the ophthalmic nerve (V1) maxillary nerve (V2) mandibular (V3) Ophthalmic nerve (V1) superior orbital fissure Maxillary nerve (V2) foramen rotundum Mandibular nerve (V3) foramen ovale - Abducens nerve (VI) Motor Eye movement via innervation of the lateral rectus Superior orbital fissure - Facial nerve (VII) Motor and sensory Facial movement Taste from the anterior 2/3 of tongue Lacrimation Salivation via innervation of the submandibular gland sublingual gland Eyelid closing via innervation of the orbicularis oculi muscle Stapedius dampens excessive sound Internal auditory meatus Visceral sensation recieved by nucleus solitarius Vestibulocochlear nerve (VIII) Sensory Hearing Balance Internal auditory meatus - Glossopharyngeal nerve (IX) Motor and sensory Taste from posterior 1/3 of tongue Swallowing Salivation parotid gland Monitoring carotid body and sinus chemo- and baroreceptors Stylopharngeus elevates pharynx and larynx Jugular foramen Motor output orginates in nucleus ambiguus Visceral sensation recieved by nucleus solitarius Vagus nerve (X) Motor and sensory Taste from epiglottic region Swallowing Palate elevation Midline uvula Talking Coughing Thoracoabdominal viscera Monitoring aortic arch chemo- and baroreceptors Stimulation of auricular branch can cause vasovagal syncope Jugular foramen Motor output orginates in nucleus ambiguus Visceral sensation recieved by nucleus solitarius Parasympathetic fibers to heart, lungs, and upper GI orginates from dorsal motor nucleus Gives recurrent laryngeal nerve which innervates all laryngeal muscles except cricothyroid Accessory nerve (XI) Motor Head turning and shoulder shrugging sternocleidomastoid muscle trapezius Jugular foramen Motor output orginates in nucleus ambiguus Hypoglossal nerve (XII) Motor Tongue movement Hypoglossal canal -
QUESTIONS 1 of 11 1 2 3 4 5 6 7 8 9 10 11 Previous Next Lab Values Blood Hematologic Cerebrospinal Sweat, Urine, and BMI Blood, Plasma, Serum Reference Range ALT 8-20 U/L Amylase, serum 25-125 U/L AST 8-20 U/L Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL Calcium, serum (Ca2+) 8.4-10.2 mg/dL Cholesterol, serum Rec: < 200 mg/dL Cortisol, serum 0800 h: 5-23 μg/dL //1600 h: 3-15 μg/dL 2000 h: ≤ 50% of 0800 h Creatine kinase, serum Male: 25-90 U/LFemale: 10-70 U/L Creatinine, serum 0.6-1.2 mg/dL Electrolytes, serum Sodium (Na+) 136-145 mEq/L Chloride (Cl-) 95-105 mEq/L Potassium (K+) 3.5-5.0 mEq/L Bicarbonate (HCO3-) 22-28 mEq/L Magnesium (Mg2+) 1.5-2.0 mEq/L Estriol, total, serum (in pregnancy) 24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL 28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL Ferritin, serum Male: 15-200 ng/mLFemale: 12-150 ng/mL Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL Female: premenopause: 4-30 mIU/mL midcycle peak: 10-90 mIU/mL postmenopause: 40-250 pH 7.35-7.45 PCO2 33-45 mmHg PO2 75-105 mmHg Glucose, serum Fasting: 70-110 mg/dL2-h postprandial:<120 mg/dL Growth hormone - arginine stimulation Fasting: <5 ng/mLProvocative stimuli: > 7ng/mL Immunoglobulins, serum IgA 76-390 mg/dL IgE 0-380 IU/mL IgG 650-1500 mg/dL IgM 40-345 mg/dL Iron 50-170 μg/dL Lactate dehydrogenase, serum 45-90 U/L Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL Female: follicular phase: 5-30 mIU/mL midcycle: 75-150 mIU/mL postmenopause 30-200 mIU/mL Osmolality, serum 275-295 mOsmol/kd H2O Parathyroid hormone, serume, N-terminal 230-630 pg/mL Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L Phosphorus (inorganic), serum 3.0-4.5 mg/dL Prolactin, serum (hPRL) < 20 ng/mL Proteins, serum Total (recumbent) 6.0-7.8 g/dL Albumin 3.5-5.5 g/dL Globulin 2.3-3.5 g/dL Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h Thyroxine (T4), serum 5-12 μg/dL Triglycerides, serum 35-160 mg/dL Triiodothyronine (T3), serum (RIA) 115-190 ng/dL Triiodothyronine (T3) resin uptake 25%-35% Urea nitrogen, serum 7-18 mg/dL Uric acid, serum 3.0-8.2 mg/dL Hematologic Reference Range Bleeding time 2-7 minutes Erythrocyte count Male: 4.3-5.9 million/mm3Female: 3.5-5.5 million mm3 Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/hFemale: 0-20 mm/h Hematocrit Male: 41%-53%Female: 36%-46% Hemoglobin A1c ≤ 6 % Hemoglobin, blood Male: 13.5-17.5 g/dLFemale: 12.0-16.0 g/dL Hemoglobin, plasma 1-4 mg/dL Leukocyte count and differential Leukocyte count 4,500-11,000/mm3 Segmented neutrophils 54%-62% Bands 3%-5% Eosinophils 1%-3% Basophils 0%-0.75% Lymphocytes 25%-33% Monocytes 3%-7% Mean corpuscular hemoglobin 25.4-34.6 pg/cell Mean corpuscular hemoglobin concentration 31%-36% Hb/cell Mean corpuscular volume 80-100 μm3 Partial thromboplastin time (activated) 25-40 seconds Platelet count 150,000-400,000/mm3 Prothrombin time 11-15 seconds Reticulocyte count 0.5%-1.5% of red cells Thrombin time < 2 seconds deviation from control Volume Plasma Male: 25-43 mL/kgFemale: 28-45 mL/kg Red cell Male: 20-36 mL/kgFemale: 19-31 mL/kg Cerebrospinal Fluid Reference Range Cell count 0-5/mm3 Chloride 118-132 mEq/L Gamma globulin 3%-12% total proteins Glucose 40-70 mg/dL Pressure 70-180 mm H2O Proteins, total < 40 mg/dL Sweat Reference Range Chloride 0-35 mmol/L Urine Calcium 100-300 mg/24 h Chloride Varies with intake Creatinine clearance Male: 97-137 mL/minFemale: 88-128 mL/min Estriol, total (in pregnancy) 30 wks 6-18 mg/24 h 35 wks 9-28 mg/24 h 40 wks 13-42 mg/24 h 17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 hFemale: 2.0-8.0 mg/24 h 17-Ketosteroids, total Male: 8-20 mg/24 hFemale: 6-15 mg/24 h Osmolality 50-1400 mOsmol/kg H2O Oxalate 8-40 μg/mL Potassium Varies with diet Proteins, total < 150 mg/24 h Sodium Varies with diet Uric acid Varies with diet Body Mass Index (BMI) Adult: 19-25 kg/m2 Calculator ( ) xy AC 7 8 9 ÷ 4 5 6 × 1 2 3 - 0 . = + Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.NE.4756) A 4-year-old male is accompanied by his mother to a head and neck surgeon for a follow-up visit after the patient underwent a branchial cyst operation. The child’s immediate post-operative period was uneventful. However, the mother reports that the child has had trouble speaking since the operation. His words appear more slurred than before. The child’s pain has been well controlled with acetaminophen. The child was born at 34 weeks’ gestation and stayed one day in the neonatal intensive care unit for prematurity prior to being discharged without any abnormal findings. On examination, the incision is clean, dry, non-erythematous, and shows signs of healing. The child is asked to stick out his tongue and findings are shown in Figure A. Which of the following muscles is most likely affected in this patient? Review Topic QID: 108926 FIGURES: A 1 Mylohyoid 10% (20/205) 2 Palatoglossus 19% (39/205) 3 Genioglossus 50% (103/205) 4 Stylohyoid 6% (13/205) 5 Stylopharyngeus 7% (15/205) M1 Select Answer to see Preferred Response PREFERRED RESPONSE 3 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.NE.41) A 45-year-old man is brought to the emergency department after being found down in the middle of the street. Bystanders reported to the police that they had seen the man as he exited a local bar, and he was subsequently assaulted. He sustained severe facial trauma, including multiple lacerations and facial bone fractures. The man is taken to the operating room by the ENT team, who attempt to reconstruct his facial bones with multiple plates and screws. Several days later, he complains of the inability to open his mouth wide or to completely chew his food, both of which he seemed able to do prior to surgery. Which of the following is a characteristic of the injured nerve branch? Review Topic QID: 106262 1 Sensory component only 2% (2/100) 2 Voluntary motor component only 28% (28/100) 3 Voluntary motor and sensory components 66% (66/100) 4 Parasympathetic component only 2% (2/100) 5 Sympathetic component only 0% (0/100) M1 Select Answer to see Preferred Response PREFERRED RESPONSE 3 (M1.NE.26) Where does the only cranial nerve without a thalamic relay nucleus enter the skull? Review Topic QID: 101690 1 Foramen rotundum 5% (5/109) 2 Jugular foramen 4% (4/109) 3 Internal auditory meatus 2% (2/109) 4 Superior orbital fissure 2% (2/109) 5 Cribriform plate 85% (93/109) M1 Select Answer to see Preferred Response PREFERRED RESPONSE 5 (M1.NE.40) A 45-year-old man is brought to the emergency department after being found down in the middle of the street. Bystanders reported to the police that they had seen the man as he exited a local bar, where he was subsequently assaulted. He sustained severe facial trauma, including multiple lacerations and facial bone fractures. The man is taken to the operating room by the ENT team, who attempted to reconstruct his facial bones with multiple plates and screws. Several days later, he complains of the inability to open his mouth wide or to completely chew his food, both of which he seemed able to do prior to the surgery. Where does the affected nerve exit the skull? Review Topic QID: 106268 1 Foramen ovale 48% (97/202) 2 Foramen rotundum 17% (35/202) 3 Superior orbital fissue 7% (14/202) 4 Jugular foramen 15% (31/202) 5 Inferior orbital fissue 8% (16/202) M1 Select Answer to see Preferred Response PREFERRED RESPONSE 1 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK
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