Lab 12 Nervous System II: Brain and Cranial Nerves PDF

**LAB 12 NERVOUS SYSTEM II: BRAIN AND CRANIAL NERVES** 1. 2. 3. 4. 5. 6. PART A: THE MENINGES ==================== +-----------------------------------+-----------------------------------+ | | DESCRIPTION AND FUNCTION | +==========================...

**LAB 12 NERVOUS SYSTEM II: BRAIN AND CRANIAL NERVES** 1. 2. 3. 4. 5. 6. PART A: THE MENINGES ==================== +-----------------------------------+-----------------------------------+ | | DESCRIPTION AND FUNCTION | +===================================+===================================+ | | **Structure**: The tough outer | | | layer of the meninges. Has to | | | layers inner layer is the | | | periosteal layer and the outer | | | layer is called the meningeal | | | layer | | | | | | **Function**: Protects the | | | brain and spinal cord and helps | | | keep everything in place. | | | | | | **Structure**: A fold of the | | | dura mater that separates the two | | | sides of the brain. | | | | | | **Function**: Helps hold the | | | brain in place and separates the | | | brain\'s hemispheres. | | | | | | **Structure**: A thin, web-like | | | middle layer. | | | | | | **Function**: Protects the | | | brain and spinal cord and helps | | | hold the cerebrospinal fluid | | | (CSF) in place. | | | | | | **Structure**: The delicate | | | innermost layer that is very | | | close to the brain and spinal | | | cord. | | | | | | **Function**: Nourishes the | | | brain and spinal cord by | | | providing blood vessels. | +-----------------------------------+-----------------------------------+ | | **Structure**: Small | | | finger-like projections of the | | | arachnoid mater. | | | | | | **Function**: Absorb | | | cerebrospinal fluid (CSF) into | | | the bloodstream. | +-----------------------------------+-----------------------------------+ | subarachnoid space | **Structure**: The space | | | between the arachnoid mater and | | | pia mater, filled with | | | cerebrospinal fluid (CSF). | | | | | | **Function**: Cushions the | | | brain and spinal cord, and helps | | | circulate CSF. | +-----------------------------------+-----------------------------------+ | venous sinus | **Structure**: Channels in the | | | dura mater that collect blood | | | from the brain. | | | | | | **Function**: Drain blood and | | | CSF from the brain to return it | | | to the bloodstream. | +-----------------------------------+-----------------------------------+ PART B: MAJOR BRAIN STRUCTURES ============================== +-----------------------------------+-----------------------------------+ | cerebrum | **Description**: The | | | **cerebrum** is the largest part | | cerebral hemispheres | of the brain, divided into two | | | hemispheres (left and right). | | | | | | **Description**: The brain is | | | divided into two **cerebral | | | hemispheres** (left and right), | | | each responsible for controlling | | | the opposite side of the body. | +-----------------------------------+-----------------------------------+ | frontal lobe | **Description**: The **frontal | | | lobe** is located at the front of | | | the brain, just behind the | | | forehead. | +-----------------------------------+-----------------------------------+ | parietal lobe | **Description**: Located just | | | behind the frontal lobe, the | | | **parietal lobe** is at the top | | | of the brain. | +-----------------------------------+-----------------------------------+ | temporal lobe | **Description**: The **temporal | | | lobe** is located on the sides of | | | the brain, near the ears. | +-----------------------------------+-----------------------------------+ | occipital lobe | **Description**: Located at the | | | back of the brain, the | | | **occipital lobe** is primarily | | | responsible for vision. | +-----------------------------------+-----------------------------------+ | central cerebral sulcus | **Description**: A deep groove | | | that separates the **frontal | | | lobe** from the **parietal | | | lobe**. | +-----------------------------------+-----------------------------------+ | lateral cerebral sulcus | **Description**: A prominent | | | groove that separates the | | | **frontal lobe** and **parietal | | | lobe** from the **temporal | | | lobe**. | +-----------------------------------+-----------------------------------+ | parieto-occipital sulcus | **Description**: A groove that | | | separates the **parietal lobe** | | | from the **occipital lobe**. | +-----------------------------------+-----------------------------------+ | pre-central gyrus | **Description**: Located just | | | in front of the **central | | | sulcus**, in the **frontal | | | lobe**. | +-----------------------------------+-----------------------------------+ | post-central gyrus | **Description**: Located just | | | behind the **central sulcus**, in | | | the **parietal lobe**. | +-----------------------------------+-----------------------------------+ | | **Description**: A deep groove | | | that runs along the midline of | | | the brain, dividing the left and | | | right hemispheres. | +-----------------------------------+-----------------------------------+ | transverse fissure | **Description**: A deep groove | | | that separates the **cerebrum** | | | from the **cerebellum**. | +-----------------------------------+-----------------------------------+ | insula | **Description**: A region deep | | | within the **lateral sulcus**, | | | hidden beneath the temporal lobe. | +-----------------------------------+-----------------------------------+ | cerebral white matter | **Description**: The white | | | matter consists of myelinated | | | axons that connect different | | | parts of the brain. | +-----------------------------------+-----------------------------------+ | cerebral cortex | **Description**: The outermost | | | layer of the **cerebrum**, made | | | up of gray matter (nerve cell | | | bodies). | +-----------------------------------+-----------------------------------+ 2. **The Cerebellum** 3. **The Brain Stem** +-----------------------------------+-----------------------------------+ | | **Description**: | | | | | | - The **cerebellum** is a | | | large, cauliflower-shaped | | | structure located at the back | | | of the brain, beneath the | | | occipital lobes. | | | | | | - The **arbor vitae** is the | | | tree-like, white matter | | | structure within the | | | cerebellum. | | | | | | **Function**: | | | | | | - The **cerebellum** | | | coordinates voluntary | | | movements, balance, and motor | | | control. | | | | | | - The **arbor vitae** contains | | | the pathways for | | | communication within the | | | cerebellum, helping transmit | | | signals that manage | | | coordination and balance. | +-----------------------------------+-----------------------------------+ | | **Description**: | | | | | | - The **pituitary gland** is a | | | small, pea-sized gland | | | located at the base of the | | | brain, beneath the | | | hypothalamus. | | | | | | - The **infundibular stalk** | | | (or **infundibulum**) is the | | | stalk that connects the | | | pituitary gland to the | | | hypothalamus. | | | | | | **Function**: | | | | | | - The **pituitary gland** | | | produces and releases | | | hormones that regulate | | | various bodily functions, | | | such as growth, metabolism, | | | and reproduction. | | | | | | - The **infundibular stalk** | | | acts as the physical | | | connection between the | | | hypothalamus and the | | | pituitary gland, allowing | | | hormone signals to be sent | | | between the two. | +-----------------------------------+-----------------------------------+ | midbrain | **Description**: The | | | **midbrain** is a small region of | | *(Note: this structure is found | the brainstem located above the | | on Figure 12.5.)* | pons and below the thalamus. | | | | | | **Function**: | +-----------------------------------+-----------------------------------+ | pons | **Description**: The **pons** | | | is a bulbous structure in the | | | brainstem, located between the | | | midbrain and medulla oblongata. | | | | | | **Function**: | | | | | | - The **pons** acts as a relay | | | station, connecting different | | | parts of the brain. It helps | | | regulate breathing and is | | | involved in sleep, arousal, | | | and facial movements. It also | | | connects the cerebellum with | | | the rest of the brain. | +-----------------------------------+-----------------------------------+ | medulla oblongata | **Description**: The **medulla | | | oblongata** is the lower part of | | | the brainstem, just above the | | | spinal cord. | | | | | | **Function**: | | | | | | - The **medulla oblongata** | | | controls essential | | | life-sustaining functions | | | such as heart rate, blood | | | pressure, and respiration. It | | | also manages reflexes like | | | swallowing, coughing, and | | | vomiting. | +-----------------------------------+-----------------------------------+ | spinal cord | **Description**: The **spinal | | | cord** is a long, cylindrical | | | structure that extends from the | | | base of the brain (medulla | | | oblongata) down the vertebral | | | column. | | | | | | **Function**: | | | | | | - The **spinal cord** serves as | | | the main communication | | | pathway between the brain and | | | the rest of the body. It | | | transmits sensory information | | | to the brain and motor | | | commands from the brain to | | | muscles. It also manages | | | reflexes independent of the | | | brain. | +-----------------------------------+-----------------------------------+ Brain lateral 2 4. **The Diencephalon** ### Anterior Pituitary: 1. Growth Hormone (GH) 2. Thyroid-Stimulating Hormone (TSH) 3. Adrenocorticotropic Hormone (ACTH) 4. Follicle-Stimulating Hormone (FSH) 5. Luteinizing Hormone (LH) 6. Prolactin (PRL) 7. Melanocyte-Stimulating Hormone (MSH) ### Posterior Pituitary: 1. Antidiuretic Hormone (ADH or Vasopressin) 2. Oxytocin +-----------------------------------+-----------------------------------+ | | DESCRIPTION AND FUNCTION | +===================================+===================================+ | corpus callosum | **Structure**: A thick band of | | | nerve fibers connecting the two | | | halves of the brain. | | | | | | **Function**: Allows | | | communication between the left | | | and right sides of the brain. | +-----------------------------------+-----------------------------------+ | thalamus | **Structure**: Two small oval | | | structures in the center of the | | | brain. | | | | | | **Function**: Acts as a relay | | | station for sensory signals | | | (except smell) to the brain and | | | helps with sleep and alertness. | | | | | | **Structure**: A small | | | connection between the two | | | thalami. | | | | | | **Function**: Helps connect the | | | two thalami, although its exact | | | role is not fully clear. | +-----------------------------------+-----------------------------------+ | hypothalamus | **Structure**: Located below | | | the thalamus. | | | | | | **Function**: Controls vital | | | functions like hunger, thirst, | | | body temperature, sleep, and the | | | release of hormones from the | | | pituitary gland. | +-----------------------------------+-----------------------------------+ | | **Structure**: Located above | | | the thalamus, includes the pineal | | | gland. | | | | | | **Function**: The pineal gland | | | produces melatonin to regulate | | | sleep patterns. | +-----------------------------------+-----------------------------------+ PART C: THE VENTRICLES ====================== 1. **Cushioning and Protection**:\ CSF acts as a shock absorber, protecting the brain and spinal cord from mechanical injury and sudden impacts. +-----------------------------------+-----------------------------------+ | | **Description**: | | | | | | - **Lateral ventricles** are | | | the two large, C-shaped | | | cavities located in each | | | hemisphere of the brain, | | | filled with cerebrospinal | | | fluid (CSF). | | | | | | - The **septum pellucidum** is | | | a thin membrane that | | | separates the two lateral | | | ventricles. | | | | | | **Function**: | | | | | | - The **lateral ventricles** | | | produce and contain CSF, | | | which cushions and nourishes | | | the brain. | | | | | | - The **septum pellucidum** | | | separates the ventricles but | | | doesn't have a significant | | | functional role. | +-----------------------------------+-----------------------------------+ | interventricular foramen | **Description**: A small hole | | | that connects the **lateral | | | ventricles** to the **third | | | ventricle**. | +-----------------------------------+-----------------------------------+ | 3^rd^ ventricle | **Description**: A narrow, | | | midline cavity located between | | | the two halves of the | | | diencephalon (the part of the | | | brain that includes the thalamus | | | and hypothalamus). | +-----------------------------------+-----------------------------------+ | 4^th^ ventricle | **Description**: A | | | diamond-shaped cavity located | | | between the brainstem (pons and | | | medulla) and the cerebellum. | | | | | | **Function**: Holds CSF and | | | allows it to flow into the | | | central canal of the spinal cord | | | and into the subarachnoid space | | | around the brain. | +-----------------------------------+-----------------------------------+ | choroid plexuses | **Description**: Specialized | | | tissue in the ventricles, made of | | | blood vessels and ependymal | | | cells, that produce CSF. | +-----------------------------------+-----------------------------------+ | | **Description**: A narrow | | | channel that runs through the | | | midbrain and connects the **third | | | ventricle** to the **fourth | | | ventricle**. | +-----------------------------------+-----------------------------------+ | central canal | **Description**: A small, | | | central channel that runs down | | | the spinal cord, directly | | | connected to the fourth | | | ventricle. | +-----------------------------------+-----------------------------------+ PART D: BLOOD SUPPLY TO THE BRAIN ================================= +-----------------------------------+-----------------------------------+ | | DESCRIPTION AND FUNCTION | +===================================+===================================+ | anterior communicating | **Description**: This is a | | | small artery that connects the | | | two **anterior cerebral | | | arteries** across the midline of | | | the brain. | | | | | | **Description**: The **anterior | | | cerebral artery** (ACA) is a | | | major artery that supplies blood | | | to the medial portions of the | | | frontal lobes and the parietal | | | lobes. | | | | | | **Description**: The **internal | | | carotid arteries** (one on each | | | side of the neck) are the main | | | sources of blood supply to the | | | brain, branching off from the | | | common carotid arteries. | | | | | | **Description**: The | | | **posterior communicating | | | arteries** connect the | | | **posterior cerebral arteries** | | | to the **internal carotid | | | arteries**, forming part of the | | | Circle of Willis. | | | | | | **Description**: The | | | **posterior cerebral arteries** | | | (PCAs) arise from the **basilar | | | artery** and supply blood to the | | | occipital lobe and parts of the | | | temporal lobe. | +-----------------------------------+-----------------------------------+ | anterior cerebral | | +-----------------------------------+-----------------------------------+ | internal carotid | | +-----------------------------------+-----------------------------------+ | posterior communicating | | +-----------------------------------+-----------------------------------+ | posterior cerebral | | +-----------------------------------+-----------------------------------+ | basilar | **Description**: The **basilar | | | artery** is formed by the union | | | of the two **vertebral arteries** | | | and runs along the brainstem. | +-----------------------------------+-----------------------------------+ | vertebral | **Description**: The | | | **vertebral arteries** are paired | | | arteries that arise from the | | | subclavian arteries and travel up | | | the neck through the vertebrae. | +-----------------------------------+-----------------------------------+ **Lateral ventricles** (one in each hemisphere of the brain), **Third ventricle, and** **Fourth ventricle**  **Gyrus**: Raised, ridge-like area of the brain.  A **sulcus** is a smaller, shallower groove.  **Redundancy in blood supply**: If one of the main arteries is blocked or narrowed (e.g., due to atherosclerosis or other vascular conditions), the Circle of Willis allows blood to be rerouted through alternative pathways to still supply oxygen and nutrients to the brain. Procedure 1: Testing Cerebellar Function ---------------------------------------- 1. Work on this procedure in pairs; one member of each pair will be the tester and the other will be the subject. Start each test facing each other while standing 2m apart. The subject should stand comfortably with feet at shoulder width and their arms at their sides with their eyes open. 2. The tester will read aloud each of the tasks found in the table below and the subject will follow the instructions. 3. The tester will gauge the difficulty with which the subject completed the tasks and record the responses in Table 12.1. 4. Switch tester and subject positions and repeat. ------------------------------------------------------------------------------------------------------------------------------------ -- -- Abduct both arms and snap your fingers. Without looking at your feet, walk in a straight line placing the heel of one foot directly in front of the toe of the other foot. Close your eyes and stand erect with your feet together for one minute. With eyes closed, touch your nose with the index finger of your left hand. With eyes closed, touch your nose with the index finger of your right hand. Open your eyes and touch the index finger of the examiner's right hand. The examiner should move their hand accordingly. With eyes open, stand erect and move the heel of your right foot first up and then down the shin of your left leg. ------------------------------------------------------------------------------------------------------------------------------------ -- -- 2a: Category Clustering ----------------------- 1. On the side bench you will find a list of 30 words in a table. Read the list through [once] and either cover it with a piece of paper or flip it over. 2. Immediately after reading the list, write down as many terms as you can remember in table 12.2. When you are finished recalling as many terms as you can, compare your answers to the original table and note the correct answers. 1. ----- -- -- 2. 3. 4. 5. 6. 7. 8. 9. 10. Correct number recalled: [ ] 2b: Visual versus Verbal Coding ------------------------------- 1. Take a set of cards showing the images and a set of cards with terms back to your bench. 2. The tester will show the subject the images sequentially and only once. 3. Once complete, the subject will write down the names of all the images that they can recall in Table 12.3. 4. The tester will now take the set of cards with the anatomical terms. Show the cards to the subject one at a time and only once. 5. Once complete, the subject will write down all the anatomical terms they can remember in Table 12.3. 6. Switch tester and subject positions and repeat. -------------------------- -------------------------- correct number recalled: correct number recalled: -------------------------- -------------------------- PART A: LOCATION ================  **Nasal retinal fibers**: These cross to the opposite side at the optic chiasm. +-------------+-------------+-------------+-------------+-------------+ | **\#** | | | **BODY | **EFFECT ON | | | | | PART** | BODY PART** | | | | | | | | | | | **(INNERVAT | | | | | | ED | | | | | | OR ARISING | | | | | | FROM)** | | +=============+=============+=============+=============+=============+ | I | Olfactory | | Olfactory | conveys | | | bulbs and | | receptors | impulses | | | tracts | | in the | related to | | | | | nasal | smell | | | | | cavity. | | +-------------+-------------+-------------+-------------+-------------+ | II | Optic optic | | | Transmits | | | chiasm | | | visual | | | | | | information | | | | | | from the | | | | | | retina to | | | | | | the brain. | +-------------+-------------+-------------+-------------+-------------+ | III | Oculomotor | | | moves eye | | | | | | superiorly | | | | | | and | | | | | | medially, | | | | | | rotates | | | | | | them | | | | | | medially | +-------------+-------------+-------------+-------------+-------------+ | | | | | moves eyes | | | | | | medially | +-------------+-------------+-------------+-------------+-------------+ | | | motor | | moves eyes | | | | | | inferiorly | | | | | | and | | | | | | medially, | | | | | | rotates | | | | | | them | | | | | | medially | +-------------+-------------+-------------+-------------+-------------+ | | | | | moves eyes | | | | | | superiorly | | | | | | and | | | | | | laterally, | | | | | | rotates | | | | | | eyes | | | | | | laterally | +-------------+-------------+-------------+-------------+-------------+ | IV | Trochlear | motor | | moves eye | | | | | | inferiorly | | | | | | and | | | | | | laterally | | | | | | and rotates | | | | | | them | | | | | | medially | +-------------+-------------+-------------+-------------+-------------+ | V | Trigeminal | mixed | **Sensory | Provides | | | | | branches**: | sensation | | | | | | to the face | | | | | - **Ophth | and | | | | | almic | controls | | | | | branch | muscles for | | | | | (V1)**: | chewing | | | | | Sensati | (masticatio | | | | | on | n). | | | | | from | | | | | | the | | | | | | forehea | | | | | | d, | | | | | | eyes, | | | | | | and | | | | | | nose. | | | | | | | | | | | | - **Maxil | | | | | | lary | | | | | | branch | | | | | | (V2)**: | | | | | | Sensati | | | | | | on | | | | | | from | | | | | | the | | | | | | upper | | | | | | jaw, | | | | | | cheeks, | | | | | | and | | | | | | upper | | | | | | teeth. | | | | | | | | | | | | - **Mandi | | | | | | bular | | | | | | branch | | | | | | (V3)**: | | | | | | Sensati | | | | | | on | | | | | | from | | | | | | the | | | | | | lower | | | | | | jaw, | | | | | | lower | | | | | | teeth, | | | | | | and | | | | | | chin. | | | | | | | | | | | | **Motor | | | | | | function**: | | | | | | Controls | | | | | | muscles for | | | | | | mastication | | | | | | (e.g., | | | | | | temporalis, | | | | | | masseter). | | +-------------+-------------+-------------+-------------+-------------+ +-------------+-------------+-------------+-------------+-------------+ | | Abducens | | | moves eyes | | | | | | laterally | | | | | | (abduction) | +=============+=============+=============+=============+=============+ | | Facial | | | Controls | | | | | **Motor**: | muscles of | | | | | Muscles of | facial | | | | | facial | expression, | | | | | expression | provides | | | | | (e.g., | taste | | | | | orbicularis | sensation | | | | | oris, | to the | | | | | buccinator, | anterior | | | | | frontalis). | two-thirds | | | | | | of the | | | | | | tongue, and | | | | | | controls | | | | | | salivation | | | | | | and | | | | | | lacrimation | | | | | |. | +-------------+-------------+-------------+-------------+-------------+ | | Vestibuloco | | | Responsible | | | chlear | | **Cochlear | for hearing | | | | | branch**: | and | | | | | Hearing. | balance. | +-------------+-------------+-------------+-------------+-------------+ | | Glossophary | | | Provides | | | ngeal | | **Motor**: | taste | | | | | Muscles of | sensation | | | | | the pharynx | to the | | | | | for | posterior | | | | | swallowing. | one-third | | | | | | of the | | | | | | tongue, | | | | | | monitors | | | | | | blood | | | | | | pressure | | | | | | (via the | | | | | | carotid | | | | | | body), and | | | | | | controls | | | | | | some | | | | | | muscles | | | | | | involved in | | | | | | swallowing. | +-------------+-------------+-------------+-------------+-------------+ | | Vagus | | | Controls | | | | | **Motor**: | parasympath | | | | | Muscles of | etic | | | | | the | functions | | | | | pharynx, | of the | | | | | larynx, and | heart, | | | | | soft palate | lungs, and | | | | | involved in | digestive | | | | | swallowing | tract, and | | | | | and | also | | | | | speaking. | provides | | | | | | sensory | | | | | | information | | | | | | from the | | | | | | larynx, | | | | | | pharynx, | | | | | | and organs. | +-------------+-------------+-------------+-------------+-------------+ | | Accessory | | | Controls | | | | | | the | | | | | | sternocleid | | | | | | omastoid | | | | | | and | | | | | | trapezius | | | | | | muscles, | | | | | | involved in | | | | | | head | | | | | | movement | | | | | | and | | | | | | shoulder | | | | | | shrugging. | +-------------+-------------+-------------+-------------+-------------+ | | Hypoglossal | | | movement of | | | | | | tongue | | | | | | during | | | | | | speech and | | | | | | swallowing | +-------------+-------------+-------------+-------------+-------------+ 12-19 PART B: CONDUCTING CRANIAL NERVE TESTS ====================================== +-----------------------+-----------------------+-----------------------+ | **Olfactory Nerve** | | Able to identify | | | | smell | | 1. Sit with your | | | | eyes closed and | | | | one nostril | | | | plugged. | | | | | | | | 2. Have your partner | | | | pass a container | | | | of garlic then | | | | ground coffee | | | | under your nose | | | | one at a time and | | | | try to identify | | | | the smell. | | | | | | | | 3. Perform the same | | | | test with the | | | | other nostril | | | | with the | | | | substances in a | | | | different order. | | | +-----------------------+-----------------------+-----------------------+ | **Optic Nerve** | | Could not count the | | | | words properly | | 1. Find a paragraph | | | | in a textbook and | | | | a timer. | | | | | | | | 2. Read for one | | | | minute, then | | | | count the number | | | | of words you have | | | | read. | | | +-----------------------+-----------------------+-----------------------+ | **Oculomotor Nerve** | | Constrict pupil | | | | | | 1. Sit looking | | No drooping of the | | straight ahead. | | eyelids | | | | | | 2. Cover one eye | | | | with your hand. | | | | | | | | 3. Shine a pen light | | | | in the other eye | | | | and note any | | | | change in the | | | | diameter of the | | | | pupil. | | | | | | | | Open both eyes as | | | | wide as possible. | | | | Note any drooping of | | | | the eyelids. | | | +-----------------------+-----------------------+-----------------------+ | **Trochlear & | | Able to track | | Abducens Nerve** | | | | | | | | 2. Have your partner | | | | hold a pencil in | | | | front of you and | | | | slowly move it | | | | up, down, | | | | medially, | | | | laterally, upper | | | | laterally and | | | | lower laterally. | | | | | | | | 3. Track the | | | | movement of the | | | | pencil with your | | | | eyes without | | | | moving your head. | | | | | | | | | | | | | | | | 1. Cover the left | | | | eye. | | | | | | | | 2. Look laterally | | | | with the right | | | | eye. | | | | | | | | 3. Switch eyes and | | | | repeat. | | | +-----------------------+-----------------------+-----------------------+ +-----------------------+-----------------------+-----------------------+ | **Trigeminal Nerve** | | Can open mouth | | | | | | ***Part B: (do in | | | | lab)*** | | | +-----------------------+-----------------------+-----------------------+ | **Facial Nerve** | | Can raise eyebrow | | | | successfully | | ***Part A:*** | | | | | | Can taste the cotton | | 1. Smile and show | | swab | | your teeth. | | | | | | | | 2. Inflate your | | | | cheeks. | | | | | | | | 3. Wrinkle your | | | | forehead. | | | | | | | | 4. Raise one or both | | | | of your eyebrows. | | | | Can you raise | | | | each eyebrow | | | | separately? | | | | | | | | ***Part B: (do at | | | | home)*** | | | | | | | | Dip a sterile cotton | | | | swab in a flask of | | | | sweet and swab the | | | | front of your | | | | partner's tongue. | | | +-----------------------+-----------------------+-----------------------+ | **Vestibulocochlear | | Can hear in both ears | | Nerve** | | and can identify | | | | direction of sound | | 2\. Have your | | | | partner hold a | | | | ticking clock | | | | approximately 1m | | | | from the right then | | | | the left ear. Is | | | | sound heard in both | | | | ears? Can you | | | | determine which | | | | direction the sound | | | | is coming from? | | | | | | | | ***Part B:** | | | | vestibular branch* | | | | | | | | Stand with your feet | | | | together and eyes | | | | closed, maintaining | | | | your balance. | | | +-----------------------+-----------------------+-----------------------+ | 1. Open your mouth | | Uvula remains in the | | and have your | | midline | | partner carefully | | | | touch the uvula | | Gag reflex is present | | with a sterile | | when touched | | cotton swab. | | | | | | | | 2. Open your mouth | | | | and have your | | | | partner hold your | | | | tongue down with | | | | a sterile tongue | | | | depressor. Say | | | | "ahhh". | | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | **Accessory Nerve** | | Able to raise | | | | shoulders and able to | | 1. Sit and have your | | turn head | | partner push down | | | | on your | | | | shoulders. | | | | | | | | 2. Try to raise your | | | | shoulders. | | | | | | | | | | | | | | | | 1. Have your partner | | | | hold the sides of | | | | your head. | | | | | | | | 2. Try to turn your | | | | head to the left, | | | | then to the | | | | right. | | | +-----------------------+-----------------------+-----------------------+ | **Hypoglossal Nerve** | | No deviation | +-----------------------+-----------------------+-----------------------+ PART C: CRANIAL NERVE DIAGNOSTIC TEST VIDEOS ============================================ The gag reflex tests both the sensory and motor components of CN 9 & 10. This involuntary reflex is obtained by touching the back of the pharynx with the tongue depressor and watching the elevation of the palate. CN 11 is tested by asking the patient to shrug their shoulders (trapezius muscles) and turn their head (sternocleidomastoid muscles) against resistance. When the patient contracts the muscles of the neck the left sternocleidomastoid muscle is easily seen but the right is absent. Looking at the back of the patient, the left trapezius muscle is outlined and present but the right is atrophic and hard to identify. These findings indicate a lesion of the right 11th cranial nerve.