Sensory Assessment

Reflex Action vs Reflex Arc 🔄

REFLEX ACTION = functional unit of NS - an INVOLUNTARY response to a stimulus ⚡ - REFLEX ARC = structural (anatomical) unit of NS - the physical pathway the signal travels through - 5 components: Receptor → Afferent nerve → CNS center → Efferent nerve → Effector organ
الفعل الانعكاسي = وحدة وظيفية - استجابة لاإرادية لمنبه - القوس الانعكاسية = وحدة تشريحية - مساره: مستقبل ← عصب وارد ← مركز ← عصب صادر ← عضو مستجيب

Reflex Arc - 5 Components 🔁

1. RECEPTOR 👆: specialized structure at afferent nerve termination - detects the stimulus - 2. AFFERENT NERVE 📩: SENSORY nerve - carries info FROM receptor TO CNS - 3. CENTER 🧠: neurons in CNS - receive info + send orders - 4. EFFERENT NERVE 📤: MOTOR nerve - carries signals FROM CNS TO effector - 5. EFFECTOR ORGAN 💪: muscle or gland that produces the reflex response
   مكونات القوس الانعكاسية: 1. مستقبل 👆 2. عصب وارد (حسي) 3. مركز CNS 🧠 4. عصب صادر (حركي) 5. عضو مستجيب 💪

4 Types of Sensations 🌟

1. SOMATIC sensations: from skin + deep tissues (muscles - tendons - joints) 2. VISCERAL sensations: from viscera (stomach - gallbladder - kidney) 3. SPECIAL sensations: vision 👁️ - hearing 👂 - smell 👃 - taste 👅 4. ORGANIC sensations: hunger 🍔 - thirst 💧 - sexual desire - All somatic sensations reach conscious perception via somatic nerves
   أنواع الإحساس الأربعة: جسدي (جلد وعضلات) + حشوي (أحشاء) + خاص (حواس الرؤية والسمع والشم والتذوق) + عضوي (جوع وعطش)

Somatic Sensations - 3 Categories 🏷️

1. SUPERFICIAL (from skin): pain 🩸 - touch 👆 - temperature 🌡️ 2. DEEP (from muscles - joints - tendons): position (proprioception) - movement - pressure - muscle tension 3. COMBINED: stereognosis (identify objects by touch) - vibration sense 🔊 - texture discrimination - two-point discrimination - All conducted by somatic nerves to conscious perception
   تصنيف الإحساس الجسدي: سطحي (ألم-لمس-حرارة) + عميق (وضع-حركة-ضغط) + مركب (التعرف بالملمس-الاهتزاز-التمييز)

Dermatome (DER-ma-tome) 🗺️

Definition: area of SKIN supplied/served by a SINGLE afferent (sensory) nerve (single spinal cord segment) - Clinical use: map the level of spinal cord or nerve root injury - Key levels: C5=clavicles - C6=thumb - C8=ring + little fingers - T4=nipples - T10=umbilicus - T12=inguinal region - L4=medial great toe
الحزمة الجلدية - منطقة جلدية يغذيها عصب وارد واحد من الحبل الشوكي - تُستخدم لتحديد مستوى الإصابة في الحبل الشوكي - أهم المستويات للحفظ

4 General Rules of Sensory Examination 📋

BEFORE any sensory test - Rule 1: Eyes CLOSED 👁️‍🗨️ (no visual compensation) - Rule 2: Examination area EXPOSED (clothing removed - skin visible) - Rule 3: Examine DISTAL to PROXIMAL (follow dermatomal distribution - start from fingers/toes) - Rule 4: Test BOTH sides + COMPARE (look for asymmetry between right and left)
القواعد الأربعة العامة للفحص الحسي: العينان مغمضتان + المنطقة مكشوفة + من البعيد للقريب + الجانبان معاً للمقارنة

Pain Sensation Test (Fast/Immediate Pain) 📌⚡

Type: SUPERFICIAL sensation - Fast (immediate) pain - Equipment: sterile PIN 📌 - Principle: pain is an unpleasant protective sensation → initiates WITHDRAWAL REFLEX - Procedure: eyes closed → PRICK skin with pin → patient reports if felt → test each DERMATOME on both sides - Abnormal: patient does not feel pin on one area = sensory loss in that dermatome
اختبار الألم السريع (الفوري) - إحساس سطحي 🔵 - الأداة: دبوس معقم 📌 - العينان مغمضتان - يُخز الجلد - ينبغي أن يشعر المريض بالألم فوراً - اختبار كل حزمة جلدية من الجانبين

Temperature Sensation Test 🌡️🔴🔵

Type: SUPERFICIAL sensation - Equipment: TWO TEST TUBES - one HOT 🔴 + one COLD 🔵 (different temperatures) - Procedure: eyes closed → touch skin with each tube → patient DIFFERENTIATES between hot and cold - Principle: external thermoreceptors (cold + warm receptors under skin) detect direct temperature stimuli - Internal thermoreceptors: hypothalamus - spinal cord - abdominal viscera
اختبار الإحساس بالحرارة - إحساس سطحي - الأداة: أنبوبتان (ساخنة 🔴 وباردة 🔵) - العينان مغمضتان - المريض يميز بين الحار والبارد

Temperature-Sensation Response Chart 🌡️📊

Below 10°C → PAIN (freezing) 🧊 - 10-25°C → COLD sensation ❄️ - 25-35°C → COLD + WARM mixed sensation - 35-45°C → WARM sensation 🌡️ - Above 45°C → PAIN (hot) 🔥 - Cold receptors: maximally active 10-40°C - Warm receptors: maximally active 30-45°C - Nociceptors (pain) activated at extremes
جدول الإحساس الحراري: أقل من 10°م = ألم تجمد - 10-25°م = برودة - 25-35°م = مزيج - 35-45°م = دفء - أكثر من 45°م = ألم حرارة 🔥

Crude Touch Sensation Test 🧶👆

Type: SUPERFICIAL sensation - POORLY localized - Equipment: blunt object - cotton 🧶 or soft brush - Procedure: STRIKE skin with cotton → patient reports TOUCH but CANNOT point to exact location (poor localization) - Compare sensation in HAIRY vs HAIRLESS areas (hairy areas more sensitive due to hair follicle receptors) - Abnormal: patient does not feel touch in that dermatome
اختبار اللمس الخشن - إحساس سطحي (ضعيف التوطين) - الأداة: قطن 🧶 - نضرب الجلد بالقطن - المريض يشعر باللمس لكن لا يحدد موقعه بدقة

Fine Touch - Tactile Localization 🖊️🎯

Type: COMBINED (fine) sensation - PRECISE localization - Equipment: marker pen OR single point of compass 🖊️ - Procedure: touch skin with marker → ask patient to POINT TO the exact touched spot with finger 👆 → repeat at different locations - Tests integrity of dorsal column pathway (posterior funiculus) - Abnormal: patient points to wrong location = lesion in dorsal columns or somatosensory cortex
التحديد اللمسي - إحساس دقيق مركب - الأداة: قلم تحديد أو طرف بوصلة واحد - نلمس الجلد ثم نطلب تحديد موقع اللمس بدقة

Tactile Discrimination - 2-Point Threshold 🧭✌️

Type: COMBINED sensation - Equipment: COMPASS 🧭 - Principle: ability to DISTINGUISH 2 simultaneous touch points as separate - Procedure: eyes closed → touch with 2 points simultaneously → ask "1 or 2 points?" → start CLOSED → gradually OPEN → find threshold - 2-Point Threshold = MINIMUM distance at which 2 points are felt as SEPARATE - Lip: 1.1 mm - Fingertip: 3-8 mm - Back: 36-75 mm - Smaller threshold = higher density of receptors = more sensitive area
عتبة النقطتين = أدنى مسافة يُحس فيها بنقطتين منفصلتين - الشفة: 1.1 مم (حساسة جداً) - طرف الإصبع: 3-8 مم - الظهر: 36-75 مم (أقل حساسية)

Vibration Sense Test 🔊🦴

Type: COMBINED sensation - Equipment: TUNING FORK 🔊 (vibrated before use) - Procedure: patient closes eyes → place BASE of vibrating tuning fork on BONY PROMINENCE (e.g. radial styloid - medial malleolus) → ask "do you feel a thrill/vibration?" - Placed on BONE to MAGNIFY the thrill by conduction (no vibration receptors in bone itself → vibrations conducted to nearby Pacinian corpuscles) - Result recorded in HERTZ (Hz) = number of cycles per second
اختبار حس الاهتزاز - إحساس مركب - الأداة: الشوكة الرنانة 🔊 - توضع على النتوء العظمي لتضخيم الإحساس بالتوصيل - لا توجد مستقبلات اهتزاز في العظم نفسه - النتيجة بالهيرتز

Dermatome Key Landmarks 🗺️📌

Memorization aid for key dermatome levels - C5: clavicles 🦴 - C6: thumb 👍 - C7: middle finger ✋ - C8: ring + little fingers 🖐️ - T1: medial upper arm - T4: NIPPLES 🎯 - T10: UMBILICUS 🎯 - T12: INGUINAL REGION - L1: groin - L4: medial great toe - S1: lateral foot + little toe - S2-4: perineum
نقاط مرجعية للحزمات الجلدية: C5=الترقوة - C6=الإبهام - T4=الحلمة - T10=السرة - T12=الإربية - L4=الإصبع الكبير للقدم داخلياً

Fast Pain vs Slow Pain ⚡🐌

FAST (immediate) pain: sharp and well-localized 🎯 - conducted by A-delta fibers (myelinated - rapid conduction) - tested with PIN 📌 - SLOW (delayed) pain: burning - aching - poorly localized - conducted by C fibers (unmyelinated - slow conduction) - Both types of pain are PROTECTIVE sensations - Fast pain initiates WITHDRAWAL REFLEX - Slow pain motivates treatment-seeking behavior
الألم السريع: حاد + محدد الموقع + يُنقل بألياف A-delta المايلينية 📌 - الألم البطيء: حارق + سيء التوطين + يُنقل بألياف C غير المايلينية - كلاهما واقٍ ⚠