Brain Lobes and Functions

• Assessment date: 3/28/25, 11:15 AM

Cerebrum

• Location: Left and right hemisphere.
• Functions: Motor, Cognitive, Sensory.
• Nuclei for cranial nerves I and II
• Frontal lobe: Motor cortex and Broca's Area (motor control of speech function), concentration, abstract thought, information storage, memory, motor function, essential for affect, judgment, personality, and inhibitions
• Parietal lobe: Sensory cortex posterior to the frontal lobe; analyzes sensory information, relays info to other cortical areas, essential for awareness of body position in space, size and shape discrimination, and left-right orientation.
• Occipital lobe: Visual cortex; posterior to the parietal lobe; visual interpretation and memory.
• Temporal lobe: Auditory cortex and Wernicke's area (comprehension of verbal/written language); inferior to the frontal and parietal lobes; auditory receptive areas, memory of sound, understanding language and music

Diencephalon

• Central brain, 3rd ventricle.
• Basal Ganglia: Deep in the cerebral hemispheres; controls fine motor movements (hands and lower extremities).
• Thalamus/Thalami: Either side of the third ventricle; the primary relay station for all sensations except smell; all memory, sensation, and pain impulses pass through this section
• Hypothalamus: Anterior and inferior to the thalamus, beneath the lateral to the third ventricle; endocrine (regulates the pituitary secretion of hormones that influence metabolism, reproduction, stress response, and urine production), maintains fluid balance, temperature regulation (vasoconstriction or dilation), hunger center/appetite control, sleep-wake cycle, blood pressure, Limbic control (aggressive and sexual behavior, emotional response), autonomic nervous system, optic chiasm (point where two optic tracts cross), and mammillary bodies (olfactory reflexes and emotional response)

Brainstem

• Midbrain, Pons, Medulla.
• Midbrain location: Connects the pons and the cerebellum with the cerebral hemispheres.
• Pons: Front of the cerebellum, between the midbrain and the medulla; regulates autonomic functions, facilitates communication between the cerebrum/cerebellum and the spinal cord, auditory/visual reflexes
• Midbrain cranial nerves: III and IV
• Pons cranial nerves: V through VIII; motor and sensory pathways, helps regulate respiration
• Medulla cranial nerves: IX through XII; motor fiber from the brain to the spinal cord, sensory fibers from the spinal cord to the brain, reflex centers for respiration, BP, HR, cough, vomiting, swallowing and sneezing

Cerebellum

• Location: Posterior to the midbrain and pons, below the occipital lobe.
• Function: Integrates sensory information to provide smooth and coordinated movement, fine movement, balance, position (postural sense), and proprioception

Spinal Cord

• Location: Continuous with the medulla, Foramen magnum at the base of the skull to the lower boarder of the first lumber vertebra.
• Function: Connection between the brain and the periphery.
• Anterior horns: Voluntary and reflex activity of the muscles.
• Posterior horns: Relay station in the sensory/reflex pathway.

Peripheral Nerves

• Spinal nerves: Combined motor-sensory nerve, transmit signals between the CNS and PNS.
• Ventral root: Motor and transmit impulses from the spinal cord to the body; somatic, visceral (autonomic; controls cardiac muscles and glandular secretions).
• Dorsal root: Sensory and transmit sensory impulses from dermatomes to the dorsal horn ganglia.

Cranial Nerves

• Cerebral hemisphere:
• Olfactory I: Sensory, Sense of smell
• Optic II: Sensory, Sense of vision
• Midbrain:
• Oculomotor III: Motor, Pupil constriction
• Trochlear IV: Motor/proprioceptor , downward and inward eye movement
• Pons:
• Trigeminal V: Motor, Jaw movements; Sensory, sensation on the face and neck
• Abducens VI: Motor, Lateral movement of the eye
• Facial VII: Motor, muscles of the face; Sensory, sense of taste on the anterior two-thirds of the tongue
• Acoustics VIII: Sensory, sense of hearing
• Medulla:
• Glossopharyngeal IX: Motor, pharyngeal movement and swallowing; Sensory, sense of taste on the posterior one-third of the tongue
• Vagus X: Motor/Sensory, swallowing and speaking
• Spinal Accessory XI: Motor, movement of the shoulder muscles
• Hypoglossal XII: Motor, movement of the tongue; strength of the tongue

Cerebrospinal Fluid

• Location: Produced in the choroid plexus of the ventricles and circulates around the surface of the brain and spinal cord.
• Function: Immune and metabolic functions in the brain, cushions the brain and spinal cord, carries nutrients through passive diffusion and active transport.

Assessment of the Nervous System

• Common Symptoms: Pain, seizures, dizziness and vertigo, visual disturbances, muscle weakness, abnormal sensation.
• Includes: Family, medical, and social history, physical assessment.
• Physical Assessment: Consciousness and cognition (mental status, intellectual function, thought content, emotional status, language ability, impact on lifestyle, level of consciousness), examining the cranial nerves, examining the motor system (motor ability, muscle strength), balance and coordination, examining the sensory system, examining the reflexes (deep tendon, biceps reflex, triceps reflex, brachioradialis reflex, patellar reflex, Achilles reflex, clonus), superficial reflexes, pathologic reflexes.

Diagnostic Evaluation: CT Scan

• Narrow x-ray beam to scan body parts in successive layers
• Contrast medium may be used to enhance visualization
• Detects: Hemorrhage, tumor, cyst, edema, infarction, brain atrophy, displacement of ventricles, cortical atrophy, brain lesions, visualization of blood vessels.
• NSG:
• Pre - Note renal function and allergies if contrast medium is used. NPO 4hrs prior if contrast used. Hold metformin to prevent kidney damage. Educate about the need to lie quietly throughout procedure. Sedation if agitation, restlessness or confusion.
• During - Warn pt that contrast injection may cause warm flushed feeling.
• Post - Encourage fluids to avoid renal problems with contrast.

MRI

• Image of brain, spinal cord, and spinal canal using magnetic energy
• Detects: Strokes, trauma, multiple sclerosis, herniation, tumors, seizures, chemical changes within cells, brain blood flow and metabolism, cerebral vasculature.
• NSG:
• Pre - Oral and/or IV contrast may be used. Check for pregnancy, allergies, and renal function. Have pt remove all metal objects. Ask about surgical hx of implanted metal objects (aneurysm clips, orthopedic hardware, artificial heart valves, intrauterine device). Remove metallic foil patches (e.g., nicotine patches). Patient may need to be fasting. Assess for claustrophobia and need for antianxiety meds, working hx with metal fragments, and cardiac implantable electronic device safety.
• No metal objects allowed in the MRI room, including oxygen tanks, IV poles, ventilators, or stethoscopes.
• During - Pt must lie completely still.
• Cochlear implants are inactivated by MRI; other imaging procedures are considered instead.

PET Scan

• Computer-based nuclear imaging that produces images of actual organ functioning. Measures metabolic activity of the brain to assess cell death or damage, uses radioactive material that shows up as a bright spot on the image.
• Inhales radioactive gas or is injected with a radioactive substance.
• Detects: Dx Stroke (blood flow and oxygen metabolism), dx Parkinson's disease, blood flow and changes in glucose use, dx Alzheimer's, dx Seizure disorders, tumors, brain lesions, tissue composition, and brain metabolism.
• NSG:
• Pre - Explain procedure to pt. Educate pt about inhalation techniques and the sensations (e.g., dizziness, lightheadedness, headache) that may occur. Tell pt not to take sedatives or tranquilizers. Have pt empty bladder. Insert 2 IV lines.
• During - Pt may be asked to perform different activities during the test.

SPECT

• 3D imaging that uses radionuclides and Gamma photons to detect single photons. Captures a moment of cerebral blood flow at the time of injection of a radionuclide. Allows areas behind overlying structures or background to be viewed (increases the contrast between normal and abnormal tissue).
• Detects: Abnormally perfused areas of the brain, localization of seizure foci in epilepsy, evaluation of perfusion before and after neurosurgical procedures, localization and sizing of stroke, and detection of tumor progression.
• NSG: Same as PET; Pregnancy and breast-feeding are contraindications; Patient is monitored during and after the procedure for allergic reactions to the radiopharmaceutical agent.

Cerebral Angiography

• X-ray of the cerebral circulation with a contrast agent injected into a selected artery.
• Visualization of the intracranial and extracranial blood vessels done to detect vascular lesions (aneurysms, hematomas, arteriovenous malformations) and brain tumors.
• A catheter is inserted into the femoral or radial artery, passed through the aortic arch into the base of the carotid or vertebral artery for injection of contrast medium.
• Direct puncture of the carotid artery may be performed.
• Can visualize: Carotid and vertebral arterial systems, venous drainage, determine vessel patency, collateral circulation, vascular anomalies, vascular lesions (aneurysms, hematomas, arteriovenous malformations), and/or brain tumors.
• NSG:
• Pre - Check BUN and Creatinine to ensure adequate kidney function for contrast. Ensure pt is well hydrated. Clear liquids up to the time of test. Void immediately before the test. Location of the appropriate peripheral pulses are marked with a pen. Assess for stroke risk (thrombi may be dislodged during procedure). Hair in the groin is clipped for femoral access. Local anesthetic is given to minimize pain and reduce arterial spasm; femoral catheter is flushed with Heparinized Saline and filled with contrast agent. For wrist access use meds to relax and dilate the vessel for the catheter.
• During - Remain immobile during the angiogram. Pt may feel warmth in the face, behind the eyes, or in the jaw, teeth, tongue, and lips, and a metallic taste when the contrast is injected. Neuro assessment during procedure to observe for embolism or arterial dissection.
• After - Neuro assessment immediately after to observe for embolism or arterial dissection. Observation of the injection site for bleeding or hematoma. Monitor marked pulses frequently. Assess the color and temperature of the involved extremity to detect possible embolism. Encourage fluids to clear contrast. Monitor for allergic reactions and hypotension if vasodilatory meds were used in radial approach. S/S of complications = new onset of alterations in LOC, weakness on one side of the body, motor or sensory deficits and speech disturbances.

Myelography

• X-ray of the spinal subarachnoid space taken after the injection of contrast into the spinal subarachnoid space through a lumbar puncture.
• Shows distortion of the spine from tumors, distortion of Spinal dural sac from tumors, cysts and herniated vertebral discs lesions.
• NSG:
• Pre - Educate pt that changes in position may be made during the procedure.
• After - Pt lies in bed with HOB elevated 30-45 degrees. Must remain in bed 4-24hrs after testing. Liberal fluids for rehydration and replacement of CSF may decrease the incidence of post-lumbar puncture headache. BP, HR, RR, and temperature are monitored. Monitor I/O's.
• Complications - N/V, headache, fever, stiff neck, seizures, paralysis of one side of the body, and/or changes in LOC.
• Other diagnostic studies: Noninvasive carotid flow studies, transcranial doppler, electroencephalography, electromyography, nerve conduction studies, evoked potential studies, lumbar puncture and examination of cerebrospinal fluid, cerebrospinal fluid analysis, post-lumbar puncture headache, and other complications of lumbar puncture.

Promoting Home, Community-Based, and Transitional Care

• Focus on educating patients about self-care and providing continuing and transitional care.