Reflexes and Cranial Nerves PDF

REFLEXES BICEPS TENDON C5 TO C6 TRICEPS TENDON C7 TO C8 BRACHIORADIALIS C5 TO C6 PATELLAR REFLEX L2 TO L4 ACHILLES REFLEX ( L5 TO S2 ) Deep tendon reflexes (DTRs) are muscle stretch reflexes that assess the integrity of the nervous system. There are several common types of DTRs, each correspon...

REFLEXES BICEPS TENDON C5 TO C6 TRICEPS TENDON C7 TO C8 BRACHIORADIALIS C5 TO C6 PATELLAR REFLEX L2 TO L4 ACHILLES REFLEX ( L5 TO S2 ) Deep tendon reflexes (DTRs) are muscle stretch reflexes that assess the integrity of the nervous system. There are several common types of DTRs, each corresponding to a specific muscle group and spinal cord level. Here are the major types of deep tendon reflexes: 1. Biceps Reflex (C5-C6)  Technique: The patient's arm should be relaxed, with the elbow slightly flexed. The examiner places their thumb on the biceps tendon in the cubital fossa and taps it with a reflex hammer.  Normal Response: Contraction of the biceps muscle and slight flexion of the elbow.  Significance: Tests the integrity of the C5 and C6 spinal nerve roots and the musculocutaneous nerve. 2. Brachioradialis Reflex (C5-C6)  Technique: The forearm is resting, and the examiner strikes the brachioradialis tendon directly (approximately 1-2 inches above the wrist on the radial side).  Normal Response: Flexion and supination of the forearm.  Significance: Tests the integrity of the C5 and C6 nerve roots, particularly focusing on the radial nerve. 3. Triceps Reflex (C6-C7)  Technique: The patient's arm is relaxed, with the elbow flexed. The examiner strikes the triceps tendon directly above the elbow.  Normal Response: Contraction of the triceps muscle and extension of the elbow.  Significance: Tests the integrity of the C6 and C7 nerve roots and the radial nerve. 4. Patellar (Knee-Jerk) Reflex (L2-L4)  Technique: The patient sits with legs dangling, and the examiner strikes the patellar tendon just below the kneecap.  Normal Response: Contraction of the quadriceps muscle and extension of the knee.  Significance: Tests the integrity of the L2, L3, and L4 nerve roots and the femoral nerve. 5. Achilles (Ankle-Jerk) Reflex (S1-S2)   Technique: The patient can be sitting or kneeling with the foot slightly dorsiflexed. The examiner strikes the Achilles tendon at the back of the ankle.  Normal Response: Contraction of the gastrocnemius muscle and plantar flexion of the foot.  Significance: Tests the integrity of the S1 and S2 nerve roots and the tibial nerve. 6. Jaw Jerk Reflex (Trigeminal Nerve, CN V)  Technique: The patient's mouth is slightly open, and the examiner taps the chin with a reflex hammer while placing a finger on the patient's jaw.  Normal Response: A brief closing of the mouth.  Significance: Tests the motor function of the trigeminal nerve (CN V). A hyperactive response may indicate upper motor neuron lesions, such as seen in conditions like ALS or multiple sclerosis. 7. Plantar Reflex (Babinski Sign) (L5-S2)  Technique: The sole of the foot is stroked from the heel to the toes along the lateral side using a blunt object.  Normal Response: In adults, the toes should curl downward (flexion). In infants, or in cases of neurological damage, the toes may fan out and the big toe dorsiflexes (positive Babinski sign).  Significance: A positive Babinski sign in adults is abnormal and may indicate an upper motor neuron lesion affecting the corticospinal tract. Deep tendon reflexes (DTRs) are significant in clinical medicine as they help assess the integrity of the nervous system, particularly the reflex arc, which includes sensory and motor pathways. Their evaluation provides important insights into the function of the central and peripheral nervous systems. Here are key points regarding their significance: Neurological Assessment: DTRs are used to assess the health of the nervous system. Normal reflexes suggest intact pathways, while abnormal reflexes may indicate issues such as nerve damage, spinal cord injury, or brain pathology. Detecting Neurological Disorders: 1. Hyperreflexia (exaggerated reflexes): Often seen in upper motor neuron lesions (e.g., stroke, multiple sclerosis). 2. Hyporeflexia or Areflexia (diminished or absent reflexes): Typically seen in lower motor neuron lesions, peripheral neuropathy, or conditions like Guillain-Barré syndrome. 2. Diagnosing Specific Conditions: Abnormal DTRs can help diagnose conditions such as: 1. Spinal cord injuries 2. Nerve root compression (radiculopathy) 3. Peripheral neuropathies 4. Myopathies Localizing Lesions: By testing specific reflexes (e.g., patellar, Achilles), clinicians can localize lesions in the nervous system, as different reflexes correspond to different spinal cord levels. The grading of deep tendon reflexes (DTRs) follows a standardized scale from 0 to 4+. This system helps healthcare professionals quantify reflex responses during neurological exams. The most commonly used scale is: 0: Absent reflex — No response, which may suggest a problem with the peripheral nervous system or nerve root. 1+: Hypoactive or diminished reflex — A slight but clearly present response, which may indicate a lower motor neuron lesion or peripheral neuropathy. 2+: Normal reflex — A typical response; this is the expected finding in a healthy individual. 3+: Hyperactive reflex without clonus — A brisk response that may be considered normal in some individuals or indicate a potential upper motor neuron lesion. 4+: Hyperactive reflex with clonus — A very brisk reflex response accompanied by repetitive muscle contractions (clonus), often indicating an upper motor neuron lesion, such as in cases of stroke or spinal cord injury. 1. CRANIAL NERVE I ( OLFACTORY ) - CLOSE EYES AND SMELL TEST 2. CRANIAL NERVE II ( OPTIC ) - CONFRONTATION VISUAL FIELD TEST 3. CRANIAL NERVE III ( Oculomotor ) 4. CRANIAL NERVE IV ( Trochlear ) SIX CARDINAL FIELDS OF GAZE 5. CRANIAL NERVE VI ( Abducens ) PUPILS REACTION TO LIGHT LOOK AT THE DISTANCE ( PERRLA ) SHINE THE PUPIL ON THERIGHT SIDE, IT WILL CONSTRICT, LOOKING AT THE LEDT IT ALSO CONSTRICTS ACCOMODATION LOOK AT THE DISTANCE HAVE THE PATIENT LOOK AT THE PEN 1 FT FROM THE NOSE THEN SLOWLY MOVE IT TOWARDS THE PATIENTS NOSE, EYES SHOULD CROSS 6. CRANIAL NERVE V ( TRIGEMINAL ) - HAVE PATIENT CLENCHED TEECH, FEEL THE MASSETER MUSCLE AND TEMPORAL MUSCLE OPEN THE MOUTH, HOLD JAW AND FEEL IF THERE IS RESISTANCE 7. CRANIAL NERVE VII ( FACIAL NERVE VII ) - HAVE PATIENT CLOSED EYES TIGHTLY, HAVE THE PATIENT SMILE, FROWN AND PUFF OUT HIS CHEEKS 8. CRANIAL NERVE VIII ( VESTIBULOCOCHLEAR ) - OCCLUDE RIGHT EAR, WHISPER AFAR FROM THE OPPOSITE EAR AND VICE VERSA, AND HAVE PATIENT STATE WHAT YOU HAVE SAID 9. CRANIAL NERVE IX ( GLOSSOPHARYNGEAL ) - USING A TONGUE DEPRESSOR, LET THE PATIENT “AHH” AND STIMULATE THE GAG REFLEX 10. CRANIAL NERVE 10 ( VAGUS NERVE ) - CAN TALK WITHOUT HOARSENESS AND IS ABLE TO SWALLOW 11. CRANIAL NERVE XI ( ACCESSORY NERVE ) - MOVE HEAD SIDE TO SIDE, UP AND DOWN, SHRUG SHOULDERS AGAINST RESISTANCE 12. CRANIAL NERVE XII ( HYPOGLOSSAL ) - STICK OUT TONGUE AND MOVE IT SIDE TO SIDE Cranial Nerve I: Olfactory Nerve (Sense of Smell) Technique:  Ask the patient to close their eyes.  Occlude one nostril at a time and present a familiar smell (e.g., coffee, mint, vanilla).  Ask the patient to identify the smell. Purpose: Tests the ability to detect and differentiate odors, assessing the olfactory nerve. Cranial Nerve II: Optic Nerve (Vision) Technique:  Visual acuity: Use a Snellen chart to test visual sharpness.  Visual fields: Have the patient cover one eye and test peripheral vision by wiggling your fingers in each quadrant.  Fundoscopy: Examine the retina and optic disc with an ophthalmoscope. Purpose: Assesses central and peripheral vision, and optic nerve health. Cranial Nerves III, IV, VI: Oculomotor, Trochlear, and Abducens Nerves (Eye Movement) Technique:  Pupil reaction: Use a penlight to check pupil constriction (direct and consensual response).  Eye movement: Ask the patient to follow your finger or an object through the six cardinal fields of gaze (H-pattern).  Check for ptosis (drooping eyelid, CN III) and strabismus (misalignment). Purpose: Tests extraocular muscle control and pupillary reactions, assessing nerve function in eye movements. Cranial Nerve V: Trigeminal Nerve (Facial Sensation and Jaw Movement) Technique:  Sensory test: Lightly touch the forehead, cheeks, and jaw with cotton or a blunt object while the patient closes their eyes, asking if they feel it equally on both sides.  Motor test: Ask the patient to clench their jaw while palpating the masseter and temporalis muscles.  Corneal reflex: Gently touch the cornea with a wisp of cotton (blink reflex). Purpose: Assesses facial sensation and motor function for mastication. Cranial Nerve VII: Facial Nerve (Facial Movement) Technique:  Ask the patient to raise their eyebrows, close their eyes tightly, smile, puff out their cheeks, and frown.  Observe for asymmetry or weakness in facial movements. Purpose: Tests facial muscle strength and symmetry, assessing the function of facial nerve branches. Cranial Nerve VIII: Vestibulocochlear Nerve (Hearing and Balance) Technique:  Hearing test: Perform a whispered voice test or use a tuning fork (Rinne and Weber tests) to assess air and bone conduction.  Balance: Romberg test—ask the patient to stand with feet together and eyes closed, checking for swaying. Purpose: Evaluates auditory function and balance, assessing the cochlear and vestibular branches. Cranial Nerves IX and X: Glossopharyngeal and Vagus Nerves (Swallowing, Gag Reflex, and Voice) Technique:  Gag reflex: Lightly touch the back of the throat with a tongue depressor, observing the gag response (both nerves).  Ask the patient to say "Ah": Observe for uvula elevation; deviation may suggest vagus nerve damage.  Listen to the patient’s voice: Hoarseness or changes in voice tone may indicate vagus nerve damage. Purpose: Assesses motor function for swallowing, gag reflex, and vocal cord function. Cranial Nerve XI: Accessory Nerve (Shoulder Shrug and Head Turn) Technique:  Ask the patient to shrug both shoulders against resistance to test the trapezius muscle.  Ask the patient to turn their head against resistance to test the sternocleidomastoid muscle. Purpose: Tests strength of the trapezius and sternocleidomastoid muscles, assessing motor function of the accessory nerve. Cranial Nerve XII: Hypoglossal Nerve (Tongue Movement) Technique:  Ask the patient to stick out their tongue and observe for deviation (tongue deviates toward the side of the lesion).  Ask the patient to move their tongue from side to side. Purpose: Assesses motor function of the tongue, checking for atrophy, fasciculations, or weakness. BICEPS REFLEX CN I TRICEPS REFLEX CN II BRACHIORADIALIS REFLEX CN III PATTELA REFLEX CN IV ACHILLES REFLEX CN V BICEPS REFLEX CN VI TRICEPS REFLEX CN VII BRACHIORADIALIS REFLEX CN VIII PATTELA REFLEX CN IX ACHILLES REFLEX CN X CN XI CN XII