Nerve Plexuses Flashcards
What are the four types of nerves we have?
Cervical spinal nerves, thoracic spinal nerves, lumbar spinal nerves, sacral spinal nerves
Where do sensory signals/information enter the spinal cord from?
Dorsal ramus
Where do motor signals exit the spinal cord?
At the ventral rami
What are plexuses?
Networks of nerves originating from ventral rami of the spinal nerves
What are the four names for the nerve plexuses?
- Cervical plexus
- Brachial plexus
- Lumbar plexus
- Sacral plexus
What areas does the cervical plexus innervate?
C1-C4, some contribution from C5
What areas does the brachial plexus innervate?
C5-T1
What areas does the Lumbar plexus innervate?
T12-L4
What areas does the sacral plexus innervate?
L4-S4
What two plexuses can be combined and what is the name?
Lumbar and sacral plexus, form the lumbosacral plexus
What are the names of the nerves in the cervical plexus?
Lesser occipital nerve
Great auricular nerve
Transverse cervical nerve
Ansa cervicalis
Phrenic nerve
Supraclavicular nerve
Nerve to rhomboids and serratus
Cranial nerves
What is the organization of the brachial plexus?
Roots (Ventral rami)
Trunks (superior, middle, and inferior)
Divisions (anterior and posterior)
Cords (posterior, lateral, and medial)
Nerves
What are the nerves in the brachial plexus?
Median nerve
Axillary nerve
Musculocutaneous nerve
Radial nerve
Ulnar nerve
Other nerves associated with the brachial plexus
- Nerve to subclavius
- Dorsal scapular nerve
- Long thoracic nerve
- Suprascapular nerve
- Pectoral nerves (medial and lateral)
- Subscapular nerves
- Thoracodorsal nerve
What happens with radial nerve damage/compression?
Wrist drop
What happens with median nerve issues?
Wasting of thumb side muscles (thenar atrophy)
What are the nerves found in the lumbar plexus?
Iliohypogastric nerve
Ilio-inguinal nerve
Lateral femoral cutaneous nerve
Genitofemoral nerve
Femoral nerve
Obturator nerve
What are the nerves found in the sacral plexus?
Pudendal nerve
Posterior femoral cutaneous nerve
Inferior gluteal nerve
Superior gluteal nerve
Sciatic nerve
Where is the sciatic nerve?
Sacral plexus
What is the importance of the sciatic nerve?
Largest nerve in the body, branches into tibial and fibular nerve (motor and sensory for leg, ankle and foot)
What causes sciatica?
When the piriformis compresses the sciatic nerve
What are dermatomes?
Specific regions of skin that are supplied by certain spinal sensory nerves. There can be significant overlap between adjacent dermatomes.
What is a reflex?
An immediate involuntary motor response
What is a reflex arc?
The neural wiring of a single reflex. begins at a sensory receptor and ends at a peripheral effector
