PNS Flashcards
How many spinal nerves total + in each region
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
31 total
How are cervical spinal nerves named
Named after vertebra below them
How are thoracic and lumbar spinal nerves named
After vertebra above them
What and why is a nerve plexus
Nerves serving a specific area originate from several different rami in order to ensure that some impulses arrive even if one ramus is damaged
Nerve plexus only stem from ventral rami
4 nerve plexus
Brachial, lumbar, sacral, cervical
Cervical plexus nerves
C1-C4
Phrenic nerve
Part of cervical plexus, C3-C5, innervates the diaphragm
“3, 4 & 5 keeps them alive”
Brachial plexus spinal nerves
C5-T1
Brachial plexus categories
Roots, trunks, divisions, cords, branches
Really tired drink coffee black
3 trunks of brachial plexus & their spinal nerves
C5 &C6 upper trunk
C7 middle trunk
C8 & T1 lower trunk
2 Brachial plexus divisions
Posterior: goes to muscles on back of arm- triceps, extensors
Anterior: goes to muscles on front of arm-biceps, deltoid, flexors
3 cords of brachial plexus
Posterior cord, behind axillary artery
Medial cord, closer to body than axillary artery
Lateral cord, lateral to axillary artery
5 branches of brachial plexus
Musculocutaneous Median Ulnar Radial Axillary
Brachial plexus Axillary branch function
Lift arm
Musculocutaneous branch function
Bend arm
Median branch function
Flex wrist
Ulnar branch function
Make fist
Radial branch function
Undoes everything
Where do spinal nerves exit spinal column
Intervertebral foramen
Roots vs rami & where do plexus originate
Roots are located within the spinal column, rami are located just outside. When talking about plexus, it’s referring to ventral rami and not roots or dorsal rami
Lumbar plexus spinal nerves
L1-L4
Lumbar plexus important nerves
Femoral nerve: goes to quadriceps, responsible for thigh flexion and knee extension
Obturator nerve: goes to adductors, responsible for opening and closing legs
Sacral plexus spinal nerves
L5-S4