1 / 25

Cranial and Spinal Nerves: Essential Functions and Implications

Explore the functions and implications of cranial and spinal nerves. Learn about the sensory and motor fibers, nerve injuries, and key functions of 12 pairs of cranial nerves. Understand the classification of spinal nerves and the significance of plexuses and dermatomes.

wendellhayes
Download Presentation

Cranial and Spinal Nerves: Essential Functions and Implications

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cranial and Spinal Nerves

  2. Cranial Nerves • emerge from the brain • emerge through holes in the cranium - cranial foramina • 12 pairs of cranial nerves • Contains: - sensory fibers (afferent) - motor fibers (efferent) - both sensory and motor fibers

  3. I Olfactory II Optic III Oculomotor IV Trochlear V Trigeminal VI Abducens VII Facial VIII Vestibulocochlear IX Glossopharyngeal X Vagus XI Accessory XII Hypoglosseal Cranial Nerves (cont.)

  4. I Olfactory • sensory nerve • Function: - smell (olfactory bulbs) anosmia - loss of sense of smell

  5. II Optic • sensory nerve • Function: - vision (retina) anopsia - defective vision

  6. III Oculomotor • mixed nerve (primarily motor) • Functions: - eyeball movement (4 eyeball muscles and 1 eyelid muscle) - lens accommodation - pupil constriction - muscle proprioception

  7. III Oculomotor (cont.) • Injury or lesion may cause: - strabismus - squinting - ptosis - drooping of upper eye lid - diplopia - loss of accommodation for near vision and double vision

  8. IV Trochlear • mixed nerve (primarily motor) • Functions: - eyeball movement (superior oblique muscles) - muscle proprioception

  9. V Trigeminal • mixed nerve • Functions: - sensations ( face, scalp, teeth, lips, eyeballs, nose and throat lining) - general sensations from the tongue - proprioception (face and scalp) - chewing (muscles of mastication)

  10. VI Abducens • mixed nerve (primarily motor) • Functions: - eyeball movement (lateral rectus muscle) - muscle proprioception

  11. VII Facial • mixed nerve • Functions: - taste (anterior 2/3 of tongue) - proprioception (face and scalp) - facial expression (muscles of the face) • Injury: Bell’s palsy - loss of taste, inability to close eyes

  12. VIII Vestibulocochlear • sensory nerve • Functions: - balance (vestibular apparatus of the internal ear) - hearing (cochlea of internal ear)

  13. VIII Vestibulocochlear (cont.) • Injury may cause: - tinnitus - ringing of the ear or deafness - vertigo - feeling of rotation, dizziness - ataxia and nystagmus - involuntary rapid movement of the eyeball

  14. IX Glossopharyngeal • mixed nerve • Functions: - taste (posterior 1/3 of the tongue) - proprioception for swallowing (throat muscles) - blood pressure receptors (carotid sinuses)

  15. X Vagus • mixed nerve • Functions: - chemoreceptors (blood oxygen concentration, aortic bodies) - pain receptors (respiratory and digestive tracts) - sensations (external ear, larynx, and pharynx) - taste (tongue)

  16. X Vagus (cont.) • Functions: - heart rate and stroke volume (pacemaker and ventricular muscles) - peristalsis (smooth muscles of the digestive tract) - airflow (smooth muscles in bronchial tubes) - speech and swallowing (muscles of larynx and pharynx)

  17. XI Accessory • mixed nerve (primarily motor) • Function: - head rotation (trapezius and sternocleidomastoid muscles

  18. XII Hypoglosseal • mixed nerve (primarily motor) • Functions: - speech and swallowing (tongue and throat muscles)

  19. Classification of Spinal Nerves • all emerge from spinal cord • emerge through holes formed by notches on adjoining vertebrae • 31 pairs • all mixed nerves (containing both sensory and motor) • named and numbered according to region and level of spinal cord from which they emerge

  20. Classification of Spinal Nerves (cont.) • 8 pairs of cervical nerves - first cervical pair emerges between atlas (first cervical vertebra) and occipital bone - first 7 emerge above vertebra of the same number - 8th emerges between 7th cervical vertebra and 1st thoracic vertebra

  21. Classification of Spinal Nerves (cont.) • 12 pairs of thoracic nerves • 5 pairs of lumbar nerves • 5 pairs of sacral nerves • 1 pair of coccygeal nerves - all emerge below vertebra of the same number - emerge through intervertebral foramina

  22. Plexuses (plexus = braid) network of adjacent nerves • cervical plexus: C1 - C5 • brachial plexus: C5 - T1 • lumbar plexus: L1 - L4 • sacral plexus: L4 - S4

  23. Brachial Plexus C 4 C 5 C 6 C 7 C 8 T 1

  24. Lumbo-Sacral Plexus

  25. Dermatomes • specific segment of skin which each spinal nerve innervates • knowledge can help physician determine which segment of the spinal cord or which spinal nerve is affected

More Related