Nerve Palsies in the Limbs Flashcards
What is a dermatome?
Sensory area of skin supplied by a single spinal nerve
What are the S’s of Sacral dermatomes?
Stand on S1
Sleep on S2
Sit on S3
Shit on S4
What is Hilton’s Law?
Nerves crossing a joint supply the muscles acting on it and the joint itself
What is the innervation of the hip joint?
OBTURATOR NERVE
Femoral nerve
Lateral femoral cutaneous nerve
What is a myotome?
Group of muscles supplied by 1 segment of spinal cord
What is the structure of the brachial plexus?
Roots Trunks Divisions Cords Branches
How do downward traction Brachial plexus lesions typically present?
Downward traction (fall onto shoulder)
C5, 6 damage
Waiter’s tip
How do upward traction Brachial plexus lesions typically present?
Upward traction (breech delivery) T1 damage (intrinsic muscles of hand) Clawed hand (Klumpke's paralysis)
Axillary Nerve injury is commonly due to what?
Humeral neck surgery
Shoulder dislocation
Saturday night palsy
How does axillary nerve injury present?
Motor deficit - loss of shoulder abduction
Sensory Deficit - badge area
What are the roots of the radial nerve?
C5 - T1
In the arm, the Radial nerve is closely associated with what?
Profunda brachii
Where does the radial nerve enter the forearm?
Pass between brachioradialis and brachialis
What is saturday night palsy?
Falling asleep with arm over chair - compression of the posterior cord of the brachial plexus
At what point is the radial nerve at risk?
Spiral groove of the humerus & lateral intermuscular septum
Radial nerve injury is a complication of?
Humeral shaft break
Saturday night palsy
What deficit is associated with radial nerve palsy?
Motor - wrist drop (extensors)
Sensory - 1st web space dorsally (space between thumb, 1st finger)
What are the root values of the median nerve?
C7, 8
T1
The median nerve is associated with what in the arm?
Brachial artery
Where does the median nerve enter the forearm?
Passes between the two heads of pronator teres
At which point is the median nerve at risk?
Volar aspect of the wrist
Cubital fossa
Median nerve damage is a complication of what?
Wrist lacerations
Carpal tunnel syndrome
What deficits are associated with median nerve injury?
Motor - thenar wasting, pointing finger
Sensory - volar aspect thumb
What structures traverse the carpal tunnel?
Transverse carpal ligament
Flexor tendons
Median nerve
What are the roots of the ulnar nerve?
C7, 8
T1
The ulnar nerve is associated with what?
Superior ulnar collateral artery
How does the ulnar nerve enter the forearm?
Passes between two heads of flexor carpi ulnaris
Which part of the ulnar nerve is at risk?
Area behind medial epicondyle of humerous
Ulnar nerve injury is a complication of what?
Break at humeral condyles
Wrist laceration
What deficit is associated with Ulnar nerve injury?
Motor - claw hand, hypothenar wasting, 1st dorsal interosseus wasting
Sensory - little finger
Where does the Lumbar Plexus lie?
Surface of quadratus lumborum
Within body of psoas major
Where do Lumbar Plexus nerves exit the pelvis?
Mostly - sciatic foramen
Which Lumbar Plexus nerves do not exit the pelvis via the sciatic foramen?
Genitofemoral & Ilioinguinal
Femoral
Lateral femoral cutaneous
Obturator nerves
What are the nerve roots of the femoral nerve?
L2 - 4
What is the largest branch of the lumbar plexus?
Femoral nerve
Where does the femoral nerve travel?
Through Psoas, exits under inguinal ligament
Lateral to fermoral artery, vein, lymphatics
(femoral triangle)
What does the femoral nerve supply?
Quadriceps muscles of thigh
How does the femoral nerve terminate?
Long fine sensory branch
Saphenous Nerve
What does the Saphenous Nerve travel with?
Femoral artery in thigh
Long saphenous vein in lower leg
Front medial malleolus
What does the Saphenous nerve supply?
Big toe
What are the nerve roots of the Lateral Femoral Cutaneous Nerve?
L2, 3
The Lateral Femoral Cutaneous Nerve lies where?
Surface of iliacus
Exits under lateral end of inguinal igament
What is the function of the Lateral Femoral Cutaneous Nerve?
Sensory - lateral thigh
Compression of the Lateral Femoral Cutaneous Nerve causes what?
Meralgia Paraesthetica
What are the nerve roots of the Sciatic Nerve?
L4 - S3
What does the Sciatic Nerve supply?
Hamstring muscles
Adductor magnus
Lower leg and foot muscles via branches
What can put the sciatic nerve at risk?
Hip dislocation
Intra-muscular injections
Surgery
What are the roots of the Common Fibular Nerve?
L4 - S3
The Common Fibular Nerve is a branch of what?
Lateral branch of the sciatic nerve
Where is the Common Fibular Nerve at risk?
Lateral aspect of fibula
The Common Fibular Nerve divides into what?
Superficial and Deep Fibular nerves
Common Fibular Nerve Deficit leads to what?
Slapping gait
Foot drop
