Exam 2 Spinal Nerves/ Cervical Plexus Flashcards
What are the numbers for each spinal group that make up the spinal nerve pairs
- 8 cervical pairs
- 12 thoracic pairs
- 5 lumbar pairs
- 5 sacral nerve pairs
- 1 coccygeal nerve pair
What do the anterior (ventral or motor) roots carry
Efferent axons from cell bodies
Where are the cell bodies located from the efferent information carried by the anterior (ventral or motor) roots
In the anterior (ventral) or lateral (if present) horns
How is the anterior roots of the spinal nerves connected to the spinal cord
By a series of rootlets
What do the posterior roots of spinal nerves cary
Axons from cell bodies in the dorsal root ganglion
What is another name for the dorsal (posterior) root ganglion
Just spinal ganglion
What is type of roots are carried in the posterior/dorsal roots of the spinal nerves
Sensory
Where do the posterior roots attach after being separated into a number of rootlets
Posterolateral sulcus
Where are spinal ganglia typically located
Either inside or just medial to the IVF beyond the dura mater innervated by the epineuranium
For the posterior roots of C1 and C2 where are their ganglia located
On their respective vertebral arches
Where are the sacral ganglia located for the posterior roots
Within the vertebral column outside the dura
Where are the coccygeal ganglia located for the posterior roots
Located inside the dura mater
After combining the spinal nerves become what type of spinal nerve
Mixed!
What branch is given off shortly after the spinal nerves combine to make it mixed
A meningeal branch is given off
What are two other names for the meningeal branch given off
- recurrent meningeal
- sinuvertebral
What is present at all spinal nerves
The meningeal branch
Where does the meningeal branch re-enter the vertebral canal and what happens to it
The IVF and divides into ascending, descending, and transverse branches
What does the meningeal branch do
Provides somatosensory and sympathetic supply to the dura, blood vessels, periosteum, ligaments, and IVD’s in the anterior and lateral portions of the canal
The mixed spinal nerve divides into two primary rami what are they
- posterior (dorsal) primary ramus
- anterior (ventral) primary ramus
The posterior (dorsal) primary ramus splits into what with what exception
Lateral and medial branches EXCEPT C1, so C2 and below
The posterior (dorsal) primary ramus is smaller or larger than the anterior ramus except where
Smaller EXCEPT C1, S4, and S5
The posterior (dorsal) primary ramus carries motor innervation to where
Deep back muscles
The posterior (dorsal) primary ramus carries sensory info from where
The skin paraspinally (either side of the spine)
Where does the anterior (ventral) primary ramus motor fibers innervate
Anterior and lateral trunk muscles as well as extremities
Where does the anterior (ventral) primary ramus carry sensory info to
Skin of extremities and anterior/lateral trunk
What does the anterior rami contribute to
The great plexuses
Where is the sympathetic chain communications located
Either at or just medial to bifurcation of the mixed spinal nerve
What does the white ramus communicans carry
Myelinated axons from cell bodies located in lateral horn cells at cord levels T1 - L2
Where do preganglionic sympathetic fibers of the sympathetic chain enter
Via the white rami communicans
What do preganglionic sympathetic fibers entering the sympathetic chain do?
- synapse in a sympathetic chain ganglion
- pass through via splanchnic nerves
What do gray ramus communicans carry
Unmyelinated postganglionic sympathetic axons from cell bodies in sympathetic chain to the spinal nerve
Are preganglionic sympathetic fibers of the white ramus communicans myelinated or unmyelinated?
Usually myelinated
Gray communicans is associated with what in regards to spinal nerve levels
Associated with every spinal nerve = meaning every spinal nerve carries post gang symp fibers
For cervical posterior rami C1 is named what?
Suboccipital nerve
For cervical posterior rami what is C1 motor supply
To the suboccipital muscles
What suboccipital muscles does C1 spinal nerve supply
- rectus capitis posterior major and minor
- obliquus capitis superior and inferior
- semispinalis capitis
For cervical posterior rami what is the name of C2 medial branch and what does it do
The greater occipital nerve, sensory innervation to posterior neck and scalp
What is the theme associated with cervical posterior rami
Medial=sensory
Lateral = motor
For cervical posterior rami what does the C2 lateral branch do
it is Motor supply to semispinalis capitis, longissimus capitis, splenius capitis muscles
For cervical posterior rami what is the name of C3 medial branch and what does it do
Least occipital nerve; sensory supply from skin of posterior neck
For cervical posterior rami what does the C3 lateral branch do
Motor supply to muscles same as C2 = semispinalis capitis, longissimus capitis, splenius capitis muscles
For cervical posterior rami what does the C4-C8 medial branches do
Sensory from skin of posterior neck
For cervical posterior rami what does the C4-C8 lateral branches do
Motor supply to iliocostalis cervicis, longissimus cervicis, and captitis
What forms the cervical plexus
Anterior (primary) rami of C1-C4 spinal nerves
What do the nerve roots of the cervical plexus do?
Form a series of communicating loops
In the cervical plexus what communicates with the loop formed by C1 and C2
The inferior vagal ganglion
In the cervical plexus what carries proprioceptive info to communicated with loop formed by C2/C3 and C3/C4
The spinal accessory nerve
Where does the spinal accessory nerve carry proprioceptive info from in the cervical plexus
The SCM to C2/C3 loop and the trapezius to C3/C4 loop
The hypoglossal nerve communicates with C1 fibers that later separate to become what
The superior root of the ansa cervicalis
What forms the superior root of the ansa cervicalis
The hypoglossal nerve communicates with C1 fibers that later separate from the hypoglossal nerve
What do C1 spinal nerve fibers supply when it remains with the hypoglossal nerve
Thyrohyoid and geniohyoid
What three gray rami communicans carry postgang symp fibers and to what loop
Vasomotor, sudomotor, pilomotor to loop between C1/C2 and roots of C3/C4 spinal nerves
The lesser occipital nerve carries fibers from where
C2 and occasionally C3 spinal nerve to supply skin on superior 1/3 of auricle and skin behind the ear
The lesser occipital nerve has communications with what
The greater occipital nerve and great auricular nerve
What may be implicated by communications of lesser occipital nerve with the greater occiptal nerve and great auricular nerve
May be implicated in cases of cervicogenic headache
The great auricular nerve carries fibers from where?
C2 and C3
Where does the great auricular nerve divide into anterior and posterior branches
Once entering the parotid gland
What does the anterior branch of the great auricular nerve combine with
The facial nerve to supply skin over parotid gland
What does the posterior branch of the great auricular nerve do
Supplies sin over mastoid process
The transverse cutaneous nerve of the neck carries fibers from where
C2/C3
After the transverse cutaneous nerve divides into ascending and descending branches what does it supply
Skin over the platysma muscle
The trunks of C3/C4 combine to form a trunk that gives rise to what
Medial, intermediate, and lateral supraclavicular nerves
What does the medial supraclavicular nerve supply
Skin inferior to sternal end of clavicle, as far inferior as the second rib
The intermediate supraclavicular nerve supplies what
Skin over deltoid and pectoralis major, as far inferior as second rib
Lateral supraclavicular nerve supplies what
Skin over superior and lateral aspects of the shoulder
Deep branches of the cervical plexus are divided into what
Medial and lateral series
Where does the lateral series of the cervical plexus pass
Into the posterior triangle consisting of communicating and muscular branches
Spinal accessory nerve may recieve communicating branches of the lateral series from where
C2-C4
What 4 muscles are associated with the muscular branches of the lateral series of the cervical plexus
SCM receives proprioception from C2/C3, trap receives proprioception fibers from C3/C4, levator scap is innervated by C3/C4 motor and sensory, middle scalene receives fibers from C3/C4
Where does the medial series of the cervical plexus pass through
Through the anterior triangle
Communicating branches of the medial series of the cervical plexus are between where
Vagus and loop between C1/C2
What are the communicating branches of the medial series
- vagus and loop of C1/C2
- 3/4 gray rami communicans from superior cervical ganglion to upper 4 cervical nerves
- fibers from C1 communicating with hypoglossal nerve, then separating from hypoglossal to form sup. Root of ansa cervicalis
Muscular brances of the medial series are sent to
- rectus capitis lateralis ; C1
- rectus capitis anterior ; C1,C2
- longus capitis; C1-3
- longus colli; C2-C4
What forms the inferior root of the ansa cervicalis
Medial series branches from C2/C3 combine
What does the ansa cervicalis supply
Sternohyoid, sternothyroid, and both bellies of omohyoid
What forms the phrenic nerve
Medial series fibers from C3, C4, C5 with C4 contributing the most
The phrenic nerve descends through the neck to where
Anteriorly to the anterior scalene muscle
The phrenic nerve receives postgang symp fibers from where
Cervical ganglia
The phrenic nerve supplies what
The diaphragm
