1 / 14

The Peripheral Nervous System

PART 5. The Peripheral Nervous System. The Lumbar Plexus and Innervation of the Lower Limb. Lumbar plexus Arises from L 1 – L 4 Smaller branches innervate the posterior abdominal wall and psoas muscle Main branches innervate the anterior thigh

gwendolyn-winters
Download Presentation

The Peripheral Nervous System

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. PART 5 The PeripheralNervous System

  2. The Lumbar Plexus and Innervation of the Lower Limb • Lumbar plexus • Arises from L1– L4 • Smaller branches innervate the posterior abdominal wall and psoas muscle • Main branches innervate the anterior thigh • Femoral nerve – innervates anterior thigh muscles • Obturator nerve – innervates adductor muscles

  3. The Lumbar Plexus Figure 14.12a, b

  4. The Sacral Plexus • Arises from spinal nerves L4–S4 • Caudal to the lumbar plexus • Often considered with the lumbar plexus • Lumbosacral plexus

  5. Innervation of the Lower Limb • Sciatic nerve – the largest nerve of the sacral plexus • Actually two nerves in one sheath • Tibial nerve – innervates most of the posterior lower limb • Common fibular (peroneal) nerve – innervates muscles of the anterolateral leg

  6. Innervation of the Lower Limb • Superior and inferior gluteal nerves • Innervate the gluteal muscles • Pudendal nerve • Innervates muscles of the perineum

  7. The Sacral Plexus Figure 14.13

  8. Innervation of the Skin: Dermatomes • Dermatome – an area of skin • Innervated by cutaneous branches of a single spinal nerve • Upper limb • Skin is supplied by nerves of the brachial plexus • Lower limb • Lumbar nerves – anterior surface • Sacral nerves – posterior surface

  9. Map of Dermatomes – Anterior View Figure 14.14a

  10. Map of Dermatomes – Posterior View Figure 14.14b

  11. Disorders of the PNS • Shingles (herpes zoster) • Viral infection • Stems from childhood chicken pox • Often brought on by stress • Mostly experienced by those over 50

  12. Disorders of the PNS • Migraine headache • Relates to sensory innervation of cerebral arteries • Arteries dilate and compresses and irritate sensory nerve endings • Myasthenia gravis • Progressive weakening of the skeletal muscles • An autoimmune disorder • Antibodies destroy acetylcholine receptors

  13. The PNS Throughout Life • Spinal nerves form late in week 4 • Each of the 31 pairs of spinal nerves • Sends motor fibers to an individual myotome • Sends sensory fibers to the overlying band of skin • During week 5 nerves reach the organs they innervate

  14. The PNS Throughout Life • Embryonic muscles migrate to new locations • Some skin dermatomes become displaced • Muscles and skin always retain their original nerve supply

More Related