Nerve Plexi Flashcards
What are the characteristics of Intercostal Nerves
Come from anterior Rami
Between the ribs
Have lateral and anterior branches
*Intercostobrachial (T2) has a lateral branch that runs from torso to armpit
*Subcostal Nerves=T12 nerves b/c they are under the floating ribs (not b/w ribs)
What are the 3 ways in which spinal nerves are distributed in the body
1) Intercostal Nerves
2) Dorsal Rami
3) Spinal Nerve Plexuses
Dorsal Rami are also known as…
Posterior Rami
Ventral rami are also known as…
Anterior rami
Nerve Plexuses
Interweaving anterior rami of spinal nerves
They split into various “named” nerves that innervate various body structures
Main Plexuses=Cervical, Brachial, Lumbar, & Sacral
Cervical Plexus
C1-5, Consists of nerve branches
Hypoglossal, Accessory, Lesser Occipital, Great Auricular, Transverse Cervical, Ansa Cervicalis, Supraclavicular, Phrenic, & Branch to Brachial Plexus
What nerve extension of the cervical plexus controls motor muscles of the front of the neck?
Ansa Cervicalis (C2/C3)
C1 of the cervical plexus has which nerve(s)?
Hypoglossal & Accessory Nerves
C2 of the cervical plexus has which nerve(s)?
Lesser Occipital & the Superior and Inferior roots of the Ansa Cervicalis
C3 of the cervical plexus has which nerve(s)?
Greater auricular, Transverse cervical, & Phrenic nerve
C4 of the cervical plexus has which nerve(s)?
Supraclavicular Nerves & Branch to Brachial Plexus
C5 of the cervical plexus has which nerve(s)?
Mainly brachial plexus
What do cervical nerves 3-5 control?
Diaphgram
Brachial Plexus
Consists of C5-T1 and 5 main nerves
Musculotaneous nerve, Axillary nerve, Radial nerve, Median nerve, & Ulnar nerve
What are the 5 components of the nerves in the brachial plexus?
Real Texans Drink Cold Beer Roots Trunks Divisions Cords Branches
C5 of the brachial plexus has which nerve(s)?
Musculotaneous nerve, Median nerve, & Long thoracic nerve
C6 of the brachial plexus has which nerve(s)?
Musculotaneous nerve, Median nerve, & Long thoracic nerve
C7 of the brachial plexus has which nerve(s)?
Musculotaneous nerve, Median nerve, Axillary and Radial nerves, and Long thoracic nerve
*Axillary and Radial nerves are dorsal nerves
C8 of the brachial plexus has which nerve(s)?
Contributions to Axillary, Radial, & Median nerve…Contains Ulnar nerve
T1 of the brachial plexus has which nerve(s)?
Contributions to Ulnar nerve and Long thoracic nerve
In the brachial plexus, which nerves (of 5 main) go Lateral, Medial, & Posterior?
Lateral- Musculotaneous & Median
Medial- Ulnar & Median
*Lateral and Medial nerves are also anterior nerves
Posterior- Radial & Axillary
Lumbar Plexus
L1-L4 & contains 6 major nerves
*L5 unites lumbar plexus and sacral plexus (Lumbrosacral Trunk)
L1 of the Lumbar plexus has which nerve(s)?
Iliohypogastric & Ilioinguinal nerves & contributions to Genitofemoral nerve
L2 of the lumbar plexus has which nerve(s)?
Contributions to Genitofemoral, Lateral femoral cutaneous, & Femoral nerves
L3 of the lumbar plexus has which nerve(s)?
Contributions to the Lateral Femoral Cutaneous, Femoral, & Obturator nerves
L4 of the lumbar plexus has which nerves?
Lumbosacral nerve (connects lumbar and sacral plexuses)
L5 of the lumbar plexus has which nerves?
Lumbosacral trunk & component of sciatic nerve
Sacral Plexus
L5-S4, contains 6 main nerves
L5 of sacral plexus contains which nerves?
Lumbosacral trunk & component of the sciatic nerve
S1 of the sacral plexus contains which nerves?
Contributions to the Superior gluteal, Inferior gluteal, Posterior femoral cutaneous, & both the Common fibular division & the Tibial division of the sciatic nerve
S2 of the sacral plexus contains which nerves?
Contributions to the Inferior gluteal, Piriformis, Posterior femoral cutaneous, Pudendal, & both the Common fibular and Tibial divisions of the sciatic nerve
S3 of the sacral plexus contains which nerves?
Contributions to the Posterior femoral cutaneous, Pudendal, & Tibial division of sciatic nerve
S4 of the sacral plexus contains which nerves?
Pudendal nerve
What are the characteristics of Reflexes?
Rapid, automatic, involuntary reactions of muscles or glands to a stimulus
Awareness of stimulus occurs after reflex action has completed
Have 3 main properties
What are the 3 main properties of Reflexes?
Stimulus: A stimulus is required to initiate a response
Rapid Response: Few neurons are involved and synaptic delay is minimal
Automatic Response: Occurs the same way every time
Ipsilateral Arc
When both receptor and effector organs of the reflex are on the same side of the spinal cord
EX: Left arm muscles contract to move left hand off something hot
Contralateral Arc
Sensory impulses from receptor organ cross over the spinal cord to activate the effector organ on the opposite side
EX: Step on sharp object with right foot and muscles in left leg contract to help you balance as you raise your right foot
Monosynaptic Reflexes
Interneurons are not involved
EX: Patellar knee jerk…muscle spindles in the quadriceps are stretched upon tapping with reflex hammer
Polysynaptic Reflex
Complicated neural pathways that exhibit a number of synapses involving interneurons with the reflex arc
EX: Pulling hand away from hot stove
Stretch Reflexes
Monosynaptic reflexes where if a stimulus results in stretching of a muscle, that muscle reflexively contracts
EX: Patellar knee reflex
Golgi Tendon Reflex
Prevent skeletal muscles from tensing excessively
Nerve endings near muscle-tendon junctions
When activated, signal is sent to CNS that inhibits the action of the motor neurons and causes the muscle to relax
