Cranial Nerves, Eye Exam & Vital Signs: OmpathStudy

MOUNT KENYA UNIVERSITY — Bachelor of Medicine & Bachelor of Surgery (MBChB) Department of Internal Medicine — Unit: MBIM 3100 Clinical Techniques This is a full syllabus-based revision (not just past-paper extraction). Where a fact was repeatedly tested in your past papers, it's marked with ( ) and a number showing how many times it appeared — but every topic area is covered completely, including parts never directly asked, so you're prepared for new variations too. --- SECTION 1: CRANIAL NERVES, EYES, GENERAL/VITAL SIGNS, RESPIRATORY SYSTEM A. Cranial Nerves (full set, 4 — heavily tested) CN Name Function --- --- --- I Olfactory Smell II Optic Vision III Oculomotor Motor to most eye muscles (SR, IR, MR, IO), levator palpebrae, pupil constriction (parasympathetic) IV Trochlear Motor to Superior Oblique (SO4) V Trigeminal Sensory: face, forehead, cheeks, jaw. Motor: muscles of mastication VI Abducens Motor to Lateral Rectus (LR6) VII Facial Motor: facial expression. Sensory: taste anterior 2/3 tongue. Parasympathetic: lacrimal/salivary glands VIII Vestibulocochlear Hearing & balance IX Glossopharyngeal Taste posterior 1/3 tongue, pharynx sensation, swallowing X Vagus Parasympathetic to thorax/abdomen, gag reflex, voice XI Accessory Motor: sternocleidomastoid, trapezius XII Hypoglossal Motor to tongue muscles Mnemonic for eye muscles: SO4, LR6, rest are CN III (oculomotor). Key exam logic ( 4 tested heavily on V, VI, VII, IX): Sensory face + motor mastication → Trigeminal (V) Taste anterior 2/3 tongue → Facial (VII) Taste posterior 1/3 tongue → Glossopharyngeal (IX) Lateral rectus weakness (can't abduct eye) → Abducens (VI) lesion Ptosis + dilated pupil + poor accommodation + poor light reflex → Oculomotor (III) lesion (consider Horner's as differential if pupil is constricted, not dilated) Facial nerve palsy — UMN vs LMN ( 3, frequently tested): Feature UMN (e.g. stroke) LMN (e.g. Bell's palsy) --- --- --- Forehead Spared (can still wrinkle) Affected (cannot wrinkle) Cause examples Stroke, brain tumour, subdural haematoma Bell's palsy, otitis media, parotid disease, infections (HSV/EBV/Ramsay Hunt), bulbar polio Reason Bilateral cortical innervation to upper face Single nerve trunk supplies entire side Meninges (superficial → deep): Dura mater → Arachnoid mater → Pia mater (Dura is most superficial — frequently tested trap). --- B. Eye Examination Pupillary light reflex: Direct = constriction of the pupil light is shone into. Consensual = constriction of the opposite pupil. On accommodation, pupils constrict and converge bilaterally. PERRLA = Pupils Equal, Round, Reactive to Light and Accommodation. Snellen chart = tests visual acuity, NOT colour blindness (Ishihara plates test colour blindness — common distractor). Nystagmus = repetitive involuntary eye movement; can be congenital/idiopathic or acquired (cerebellar, vestibular, drug-induced). Ptosis (drooping eyelid): Can be congenital or acquired Causes: injury/stretching of muscle, Myasthenia gravis , apical lung tumour (Pancoast tumour → Horner's syndrome) , CN III palsy Horner's syndrome triad: ptosis + miosis (constricted pupil) + anhidrosis. CN III (Oculomotor) palsy: ptosis (complete), dilated fixed pupil, eye "down and out," poor accommodation. --- C. General Examination / Vital Signs Vital signs: temperature, pulse, BP, respiratory rate, O2 saturation, weight — essential for assessing diagnostic state; abnormal parameters point to underlying pathology. BP 200 systolic or 120 diastolic → malignant hypertension. Pallor: check via capillary refill or palpebral conjunctiva — positive (pale) in anaemia. Jaundice: best checked at the sclera ( 3 — repeatedly tested; not conjunctiva, nail beds, or palm). Cyanosis: Central — tongue, mucous membranes, lips → serious cardiac/respiratory disease. Peripheral — fingers/toes → cold exposure, poor peripheral circulation. Oedema: can be pitting or non-pitting; pressed 5cm above medial malleolus; suggests kidney failure, heart failure, or hypoalbuminaemia (Kwashiorkor in children = generalized oedema). Capillary refill: normal = less than 3 seconds in someone with good cardiac function and perfusion. BMI = weight (kg) ÷ height² (m²) Underweight: <18.5 Normal: 18.5–24.9 Overweight: 25–29.9 Obese: ≥30 Posture is the best indicator of acute or chronic respiratory distress (better than height/weight/hair loss). --- D. Respiratory System Examination Order of chest exam: Inspection → Palpation → Percussion → Auscultation (note: this differs from the abdomen order — see Section 2). Percussion notes Note Conditions --- --- Resonance Normal air-filled lung Hyperresonance Pneumothorax, COPD, emphysema, bronchial asthma Dullness Consolidation, pneumonia Stony dullness Pleural effusion Tympany Pneumothorax Breath sounds Vesicular — normal, soft, low-pitched, heard over most of both lungs. Bronchial — louder, harsher, with a clear pause between inspiration and expiration; normal over the trachea, abnormal in the periphery (sugge