Nerve Plexi Flashcards
Blocks
What two nerves are part of the Cervical Plexus?
Supraclavicular nerve
Phrenic Nerve
What does the Supraclavicular nerve block?
It blocks the shoulder via the interscalene groove
What does the Phrenic nerve control?
Breathing via the diaphragm
Where is the Cervical Plexus located in the neck?
Posterior triangle of the neck, halfway up the sternocleidomastoid muscle and within the prevertebral layer of the cervical fascia
The Cervical plexus is formed by the _____ ______ (divisions) of cervical spinal nerves _____-_____.
The Cervical plexus is formed by the anterior rami (divisions) of cervical spinal nerves C1-C4.
What is a complication if you are off on your block of the supraclavicular nerve?
You can hit the phrenic nerve and cause hemi-diaphragmatic paralysis.
Not good for patients with COPD or breathing issues
Where is the Stellate Ganglion located?
C-7 and comes off the front side of the neck, above the FIRST rib.
What does the Stellate Ganglion have to do with the Cervical Plexus?
It is not part of the Cervical Plexus, however it comes off of and is adjacent to a cervical vertebrae.
What does the Stellate Ganglion do to the body? What are its branches?
It is a collection of sympathetic nerves and increases SNS transmission via multiple branches in the body.
Somatic branches - gray rami communicantes to C7, C8 and T1
Visceral branches - via the inferior cardiac nerve and contributes to cardiac plexus in the thorax
SNS branches to the brachial plexus, subclavian, vertebral arteries and brachiocephalic trunk
If you block the Stellate Ganglion what can you end up treating? (5 things he mentioned in class, but there is a long list.)
- Chest pain
- Scleroderma
- Long Covid symptoms (return smell/taste)
- Chronic pain
- Craniofacial hyperhidrosis (excessive sweating)
- Refractory angina
- Atypical angina
- Postherpetic neuralgia
- Phantom limb pain
- Chronic post-surgicalpain
- Post-traumatic stress disorder
- Neuropathic pain syndromes in cancer pain
- Vascular headaches including cluster headache and migraine headache
- Raynaud syndrome
- Upper extremity embolism
- Meniere syndrome
- Refractory cardiac arrhythmias including Roman/Ward syndrome and Jervell/Lang/Nielson syndrome
- To diagnosesympathetically mediated pain
- Quinine poisoning
- Sudden loss of hearing accompanied by tinnitus
- Accidental intraarterial injection of intravenous medications
What type of syndrome and symptoms do you see when you block the stellate ganglion?
Horners syndrome
Partial ptosis ( eyelid drooping)
Miosis ( constricted pupil)
Facial anhidrosis (absence of sweating)
Does blocking the phrenic nerve cause Horner’s syndrome?
No. It is the blockade of the stellate ganglion that causes Horner’s syndrome
*Phrenic nerve blockade can be associated because of how close it is to the stellate ganglion. - this causes respiratory problems
Interscalene blocks are associated with which spinal vertebrae nerve roots?
C5-C7
Which nerve plexus is the interscalene block associated with and what structures does it block?
Brachial Plexus - shoulder structures
When blocking the Interscalene what other structures could you block around it accidentally?
Stellate Ganglion, Phrenic nerve
What plexus innervates the upper extremities and what spinal root vertebrae does it come off of it?
The brachial plexus - C5-T1
It exits the cervical spine and traces between the anterior and middle scalene muscles and around the axillary artery.
What are the five parts that the Brachial Plexus is divided into?
Roots
Trunks
Divisions
Cords
Branches
There are no functional difference between these divisions, they are simply used to aid explanation of the brachial plexus
Mnemonic - Read That Damn Cadaver Book.
What four types of blocks can you do in the brachial plexus area?
Interscalene
Supraclavicular
Infraclavicular
Axillary
What area do you block when you put local anesthetic in the Axillary Nerve? What spinal root vertebrae is this associated with?
Primarily blocks the sensory functions of the upper lateral cutaneous nerve aka the skin over the lower deltoid (“regimental badge area”)
Blocks the motor functions of the teres minor and deltoid muscles
Spinal roots from C5-C6
Why would you block the Axillary Nerve?
Posterior shoulder pain
Tourniquet pain
Where are the spinal nerve roots located for the Musculocutaneous Nerve? What areas does this block?
C5-C7
Blocks the motor functions high in the biceps of the anterior compartment of the arm (coracobrachialis, biceps brachii and the brachialis)
Blocks the sensory down low to the lateral cutaneous nerve of the FOREARM.
Median nerve is innervated by which spinal nerve roots? What areas does it block?
C6 - T1 (also contains fibers from C5 in some individuals)
Blocks motor functions of the flexor and pronator muscles in the anterior compartment of the forearm. Thenar muscles and lateral two lumbricals in the hand
Blocks sensory functions in the palmar cutaneous branch, lateral aspect of the palm, and the digital cutaneous branch, which innervates the lateral three and a half fingers on the anterior palmar surface of the hand
What spinal nerve root innervates the Radial nerve? What areas does this block?
C5-T1
Blocks sensory to most of the skin of the posterior forearm, lateral aspect of the dorsum of the hand, and the dorsal surface of the lateral three and half digits
Blocks motor functions of the triceps brachii and the extensor muscles in the forearm.
Where is the Radial Nerve easiest to find?
You can find it easily next to the radial artery. It can also be found in the axilla.
The radial nerve is a spiral Nerve that wraps around the bone several times, not easy to find.
What spinal nerve root is associated with the Ulnar nerve? What does it block?
C8 - T1
Block of motor function to the two muscles of the anterior forearm - flexor carpi ulnaris and medial half of flexor digitorum profundus. Intrinsic muscles of the hand.
Blocks sensory functions - Medial one and half fingers and the associate palm area
Where do you expect to see the motor response if you stimulated the Ulnar nerve?
Pinky finger!!
What spinal nerve roots make up the Lumbar Plexus? What are the six major peripheral nerves of this plexus?
L1-L4
These nerves descend down the posterior abdominal wall to reach the lower limbs
Iliohypogastric - abdomen
Ilioinguinal
Genitofemoral
Lateral cutaneousnerve of the thigh
Obturator
Femoral
Mneumonic
I, I GetLeftoversOnFridays.
Which spinal nerve roots innervate the Iliohypogastric nerve? What does blocking this nerve do?
L1 (some T12)
Blocks motor function of the internal oblique and transverse abdominis muscle
Blocks sensory - posterolateral gluteal skin in the pubic region.
What surgery did Cornelius mention for blocking the Iliohypogastric nerve?
Inguinal hernia repair
What spinal nerve root innervates the Ilioinguinal nerve? What does blocking it do?
L1
After innervating the muscles of the anterior abdominal wall, it passes through the superficial inguinal ring to innervate the skin of the genitalia and middle thigh.
Blocks motorfunctions of the internal oblique and transversus abdominis.
Blocks sensoryfunctions of the skin on the superior antero-medial thigh.
Why do you need to warn males and females about when blocking the Ilioinguinal nerve?
In males, it also supplies the skin over the root of the penis and anterior scrotum.
In females, it supplies the skin over mons pubis and labia majora.
Which spinal nerve roots innervate the Lateral Femoral Cutaneous nerve? What happens when you block this nerve?
L2, L3
Lateral thigh
This nerve has a purely sensory function. It enters the thigh at the lateral aspect of the inguinal ligament, where it provides cutaneous innervation to the skin there.
Blocks sensory Functions in the anterior and lateral thigh down to the level of the knee.
What patients would you do a Lateral Femoral Cutaneous nerve block on?
Femoral fractures
Which spinal nerve roots innervate the Obturator nerve? What happens when you block this nerve?
L2, L3, L4
Medial Thigh
Blocks motor functions in the obturator externus, adductor longus, adductor brevis, adductor magnus and gracilis.
Blocks sensory functions of the skin over the medial thigh.
Which spinal nerve roots innervate the femoral nerve? What happens when you block this nerve?
L2, L3, L4
Anterior thigh
“Catch-all for the thigh”
Large nerve
Blocks motor functions in the muscles of the anterior thigh – the illiacus, pectineus, sartorius and quadriceps femoris (can’t walk d/t weakness).
Blocks sensory functions in the skin on the anterior thigh and the medial leg.
What spinal nerve roots innervate the Sacral plexus? What happens when you block this nerve?
L4-S4
Thesacral plexusis a network of nerve fibers that supplies the skin and muscles of the pelvis and lower limb.
Deep in the pelvis there is the internal pudendal nerve
It is located on the surface of the posterior pelvic wall, anterior to the piriformis muscle.
What spinal nerve roots innervate the Sciatic nerve? What happens when you block this nerve?
L4-S3
Thesciatic nerveis a major nerve of the lower limb. It is a thick flat band, approximately 2cm wide – the largest nerve in the body.
Higher up is mostly motor functions - Directly the posterior thigh (biceps femoris, semimembranosus and semitendinosus) and the hamstring portion of the adductor magnus (remaining portion of which is supplied by the obturator nerve).
Indirectly all the muscles of the leg and foot.
Distal down the leg is more sensory - Indirectly innervates (via its terminal branches) the skin of the lateral leg, heel, and both the dorsal and plantar surfaces of the foot.
