Where in the PNS Flashcards
(25 cards)
What does the Cauda Equina enTAIL lmaozedong
Whats Sciatic Nerve
L1-L5
S1-S5
L4-S3
Sciatic Plexus is L4-S4
Give the components of PNS after spinal cord exit
Roots - Plexus - Nerve
- NMJ
- Muscle
How to distinct between Nerve and NMJ-Muscle problem
If Nerve - Sensory impairments;
If Nerve - complete NO REFLEX
- Weak Reflex nia - BOTH NMJ-Muscle
NMJ vs Muscle lesion
- Presentation - Compare and Contrast
Note:
Fasciculations arise as a result of spontaneous depolarization of a lower motor neuron
Muscle Weakness
- WASTING, sometimes Pseudohypertrophy
NMJ
- NO wasting, NO fasciculations
- Ocular weakness in Myasthenia Gravis
- FATIGUE
- Both have Proximal Weakness, Weak Reflex, No sensory loss
Name a congenital Myopathy and describe pathogenesis and effects;
Duchenne Musculat Dystrophy
- XLR
- mutated dystrophin
- needed for membrane stability - sarcolemma;
- Ca2+ enters, muscle die, hypertrophy
Myasthenia Gravis
- pathogenesis
- all symptoms
- drugs
AchRAb against AchR - competitive inhibition
- Ach is exhausted + normal breakdown by AchE
Myasthenia gravis also affects eyes (special case);
- Fatigability is a symptom;
- Muscle wasting, pseudohypertrophy
(notes said no wasting, PH for NMJ but lecturer said yes)
– maybe for MG can
neostigmine and pyridostigmine - AE: diarrhoea
- AchE inhibitors
Peripheral Neuropathy
- presentation principal
- name some causes
Longer nerves more vulnerable to systemic insults
- all nerves beyond a certain point will be affected;
- Weakness distribution is called “glove and stocking”
- Fasciculations, No reflexes, Wasting, Hypotonia
- SENSORY LOSS;
- Diabetes
- Guillain Barre Syndrome
- think Campylobacter Jejuni, CMV
- Type II HS;
- B12 deficiency
- think Posterior Cord Syndrome
Nystagmus
Diplopia
- suspect where?
- Note Monocular is when close other eye still see it;
otherwise is Binocular Diplopia; Monocular is eye problem;
Nystagmus
- eyes make repetitive, uncontrolled movements
- think Cerebellum; Vestibulocerebellar
can have others - thiamine deficiency, Chiari Malformation
- BS also can; Multiple Sclerosis also can
Diplopia
- Double vision
- can be alot
- think CN346 eye problems; extraocular muscles hence CN nerves, or NMJ for Myasthenia Gravis
- BS can, Cerebellum can also cos of Vestibulocerebellar (googled);
- Myasthenia Gravis (for NMJ), ANTIPSYCHOTICS
- GBS, Multiple Sclerosis - Neuropathies
Cannot name pen or watch
Right hand weakness
Left hemisphere lesion
Broca’s Area - Left Frontal Cortex - speech production
- Wernicke’s at temporal/parietal (Left)
Weakness of climbing stairs
Double Vision
Assuming no sensory complain
- Think NMJ+Muscle
Double vision
- NMJ, Myasthenia Gravis possible
Numbness and weakness in hands and feet, Absent reflexes;
Sensory involvement
- Peripheral Neuropathy
Peripheral Neuropathy causes
- Categories by Systemic, Drugs
Systemic Diseases
- Diabetes
- B12 deficiency
- GBS Type II HS
DRUGS
- FQ, Metronidazole
- Isoniazid, Ethambutol
- Isoniazid treat w B6 Pyridoxine
Differentiate presentation of peripheral neuropathy and myopathy
Further differentiate between NMJ and Muscle problem
PN presents as
- sensation loss at Glove and Stocking distribution
Myopathy presents as
- proximal weakness, no sensory
- BOTH NMJ and MUSCLE
- no sensory loss, reflex weak/NORMAL
- muscle problem leads to wasting
NMJ no wasting but have fatigability and in Myasthenia Gravis ocular weakness
Mononeuropathy time!
Median Nerve time
- innervation motor, sensory
- lesion
Median Nerve - C5-T1
ALL wrist flexors, pronator teres
(except flexor carpi ulnaris)
Thenar eminence - OAF;
Lumbricals (2)
Sensory 3.5 fingers + fingertips;
Lesion - hand of benediction - cannot make a fist - loss of extension of IP - loss of flexion of IP Sensory Loss
Lesion - carpal tunnel syndrome
- Thenar wasting - LMN lesion
- cutaneous sparing of sensation - cutaneous sensory nerve
Ulnar Nerve time
- innervation motor, sensory
- lesion
Ulnar Nerve - C8 T1
- Hypothenar Eminence
- 2 Lumbricals
- Interossei
- ADDUCTOR pollicis
Sensory to 1.5 fingers on both sides
Lesion - Ulnar Claw
- cannot extend IP joints cos of Lumbricals
- MCP joint extended cos of Interossei cannot flex
Radial Nerve time
- innervation motor, sensory
- lesion
Radial Nerve - C5-T1
- Triceps Brachii
- Brachoradialis, Supinator, Wrist extensors
- Snuffbox sensation
Lesion - Wrist drops
Femoral N
Obturator N
L2 3 4
Femoral - anterior compartment of thigh
- Quads
Obturator - medial compartment of thigh
- adductors
Sciatic N
Lesion at Pelvis
Lesion at Head of fibula
L4-S3
Sciatic nerve innervates Hamstring for hip extension, knee flexion
Gives tibial nerve; and Common peroneal nerve;
Tibial: Posterior leg, plantar foot
CPN: Anterior and Lateral leg;
Pelvis:
Weak hip extension
Weak knee flexion
Weak dorsiflexion - foot drop AND Weak plantarflexion
Fibula; Common Peroneal Nerve gone Foot drop but Strong plantar flexion Strong hip extension Strong inversion - tibialis posterior Tibial N ok - inversion is sole face in;
Leg compartments
Anterior + Lateral by Common Peroneal Nerve
- Dorsifexion and eversion
Posterior by Tibial Nerve
- Plantar flex
Sensation nerves
Dermatome description
Thigh mostly femoral; medial is obturator
LEG and feet by Sciatic; medial is femoral Saphenous
L1 L2 L3 thigh;
L4 L5 S1 Leg
S2 rise up;
Brachial Cords to Nerves
Posterior - Axillary and Radial
Lateral - MLC
Medial - Ulnar
Medial Nerve - both Lateral and Medial cord
What does upper plexus supply
Lower plexus?
C5 C6
- MLC - BBC
+ ROTATOR CUFF
C8 T1
- Ulnar, Median, Radial
- More so muscles of HANDS;
Erb’s Palsy
C5-C6 gone
MLC - C567
Axillary - C5 C6
Suprascapular - Rotator Cuff - C5 C6
- Winging of scapula
- Radial nerve for wrist and finger extension gone too;
- Fingers and Wrist flexed - “waiter’s tip”
- Shoulder rotated forward - i think cos pec major pull;
- Note rotator cuff is for external rotation of shoulder
C8 T1
Klumpke’s Palsy
- nerves affected and presentations
Median
Ulnar
Horner syndrome from T1 sympathetic outflow
- Ptosis, Miosis, Sweating problems
