click below
click below
Normal Size Small Size show me how
The Cervical Plexus
Directly from Dr. T's review notes
Question | Answer |
---|---|
Where is the cervical plexus? (dorsal/ventral, levels) | ventral primary rami of C1-C4 the cervical plexus consists of motor nerve and cutaneous nerve branches |
What is the significance of C1 not having a dorsal root ganglion nor a dorsal root? | No C1 contribution to cutaneous portions of the cervical plexus ***Therefore, NO C1 DERMATOME*** |
The suboccipital nerve innervates the subocciptial muscles, but why is it NOT considered part of the cervical plexus? | The suboccipital nerve represents the dorsal primary ramus of C1 (therefore, not part of the cervical plexus(see prior card)) and is purely motor (see first card). *Important when considering origin of headaches. |
What the three other nerves anastomose with the cervical plexus? | CN XI: spinal accessory nerve CN XII: hypoglossal nerve branches for the sympathetic chain (postganglionic sympathetic axons) |
What do the three other nerves innervate? | CN XI ---->(GSE, only) sternocleidomastoid & upper part of trapezius (m.test: shoulder shrug) CN XII ---->(GSE, only) intrinsic mm. of tongue sympathetic chain (postganglionic sympathetic axons)---->smooth m. of vessels, sweat glands, erector pili m |
What are the motor portions of the cervical plexus distributed as? | branches of ansa cervicalis; nerves to scalenes, levator scapulae, trapezius, longus colli and longus capitus, and the phrenic nerve |
What (level/innervate) are the ansa cervicalis branches? | ansa cervicalis are C1-C3 geniohyoid and thyrohyoid are only innervated by C1 sternothyroid, sternohyoid, and omohyoid are innervated by all, C1-C3 Phrenic nerve innervates diaphragm |
Still motor portions of the cervical plexus, but not arising from the ansa cervicalis are the segmental branches. What (level/innervate) are these motor segmental branches? | C1-C4 (largely C3-C4) innervate anterior and middle scalene mm., trapezius, and levator scapulae (m. test: shoulder shrug). |
What (level/name) are the cutaneous portions of the cervical plexus? | C2: lesser occipital nerve C2-C3: great auricular nerve C2-C3: transverse cervical nerve C3-C4: supraclavicular nerves |
What (level/area of innervation) is the lesser occipital nerve? | C2: distributed to the lateral part of occipital region |
What (level/area of innervation) is the great auricular nerve? | C2-C3: distributed to the skin around the outer ear and the external acoustic meatus |
What (level/area of innervation) is the transverse cervical nerve? | C2-C3: distributed to the anterior region of neck |
What (level/area of innervation) are the supraclavicular nerves? | C3-C4: distributed to the region of supraspinatus, shoulder, and upper thoracic region |
Dr. T's FYI about the greater occipital nerve. I just copy/pasted. | greater occipital nerve: sensory portion of the medial branch of the dorsal primary ramus of C2, and transmits GSA and GVA input from the vertex of the head, back of the head, over the tops of the ears and anterior to the skin over the parotid glands. |
General function of C1 | Motor to head and neck extensors (subocciptal mm.), geniohyoid, thyrohyoid, rectus capitis anterior, rectus capitis lateral, and longus capitis. *No sensory component of C1 |
General function of C2 | Motor to longus colli in addition to those of C1 Sensory to lateral and posterior occiput and submandibular area |
General function of C3 | Motor to head and neck extensors: omohyoid, sternohyoid, longus capitus, longus colli, levator scapulae, anterior middle and posterior scaleni, trapezius, diaphragm Sensory to lateral occiput and lateral neck, overlapping C2 area |
General function of C4 | Motor to head and neck extensors: longus colli, levator scapulae, anterior middle and posterior scaleni, trapezius, and diaphragm Sensory to lower lateral neck and medial shoulder area |
segments and the rami that make up the cervical plexus; other nerves that anastomose with the cervical plexus; motor portions of the cervical plexus and the muscles innervated; cutaneous portions of the cervical plexus and the areas supplied. | Important points to recognize for Part I Boards Need to be able to name all of them |