What nerve controls the index, middle and thumb?
Median Nerve
If you are considering a median nerve injury and need to distinguish between wrist and neck injury: what can you look at?
C7 dermatomes (Middle finger and part of the index and ring) and myotomes (elbow extension-triceps). If it does not get worse with neck motion.
What is a positive Phalen Sign?
Tests for carpal tunnel: have patient flex wrists together at 90 degrees. If they have a positive test, they will experience tingling and numbness in hand/wrist. This is again, testing median nerve injury in the wrist.
Describe three areas on the neuron that could result in injury and dysfunction.
Cell body. Axon. Schwann cell.
Give two examples of an axonal issue.
Wallerian Degeneration and Axon Degeneration
Give an example of a shwann cell issue
segmental demyelination
Give examples of physical forces that could affect neuron health
Compression, penetration, traction. Note: ischemia causes compression and axon damage.
Give two examples of an endogenous disturbance of structural maintenance of a nerve
Renal failure and Diabetes
Give three examples of an exogenous disturbance of structural maintenance of a nerve
alcohol, toxins, and chemotherapy
Give an example of a genetic disturbance of structural maintenance of a nerve
Charcot Marie Tooth Disease
Give an example of an idiopathic disturbance of structural maintenance
Amyotrophic Lateral Sclerosis
Give me an example of an inflammatory syndrome having autoimmune cells against shwann cells
Guillain Barre Syndrome
Give an example of an inflammatory attack involving cancer
paraneoplastic-> antibodies against cancer cross react with nueronal proteins
Give two examples of a motor neuron infection
West Nile and Polio
Give an example of a sensory neuron infection
Herpes Zoster (shingles)
Give an example of a shwann cell infection
Leprosy
Describe elbow ulnar neurapraxia
This can occur when the ulnar is stuck in the cubital tunnel and causes a nerve block. The amplitude at proximal arm will be much lower than at wrist. Recovery takes about two months as shwann cells remyelinate the area of lesion. Axonal transport is reserved so there is little muscle atrophy, the axon distal to lesion still responds to stimuli.
Describe the neuronal changes, action potential conduction changes, and axon structural changes in wallerian degeneration.
Cut the nerve. So in a few days following lesion you will see cell bodies swelling and an increased synthesis of RNA. Conduciton- immediate loss of electrical potential across lesion and in 5-10 days once reserves run out, you'll see lack of electrical responsiveness in distal. Structure: myelin degeneration and axon atrophy
What does "reinnervation" entail?
Axon regeneration or sprouting from local UNinjured axons (recovery is months to 2 years)
Define Neuronopathy
Dysfunction in the motor (ALS, SMA), sensory (sensory loss, atxia), or auntonomic system (orthostatic hypertension) ALONE
Define radiculopathy
Dysfunction at root, affecting doral and ventral roots and spinal nerve. caused by herniated nucleus pulpus (soft) or osteophyte herniation (hard). Symptoms are signs correspond to motor MYOTOME, sensory DERMATOME, and deep tissue/joint sensory of spinal nerve SCLERATOME.
Define plexopathy
dysfunction too great to be attributed to a single nerve root. This can happen at the brachial or lumbosacral plexus. Usually caused by trauma or birth canal trauma.
Define Mononeuropathy
Dysfunction with a single peripheral nerve
Name these mononeuropathies in order: 1.)Facial nerve constricted at stylomastoid 2.)Median nerve at wrist 3.) Ulnar nerve at elbow 4.) Radial nerve at spiral groove 5.) Lateral cutaneous nerve at thigh 6.) Peroneal nerve at the fibular head
1.) Bells Palsy 2.) Carpal Tunnel Syndrome 3.) Cubital Tunnel Syndrome 4.) Saturday noght palsy 5.) meralgia paresthetica 6.) cross leg palsy
Describe the Hallmarks of polyneuropathy
occurs BILATERALLY/ SYMMETRICALLY and DISTALLY first. More than single nerve root-> populations of axons. Reflexes reduced distal then proximal.
Name the 5 etiologies of polyneuopathy
Hereditary (Charcot Marie Tooth Disease), idiotpathic, metabolic (RF and Diabetes), toxins (chemo and alcohol), and autoimmune (gillain barre)