Nerve palsies in the limbs Flashcards
What is found in the dorsal root ganglia
the cell bodies of sensory nerves
what dermatome gives sensory innervation to the thumb
C6
what dermatome gives sensory innervation to the middle finger
C7
what dermatome gives sensory innervation of the little finger
C8
what dermatome gives sensory innervation for the big tow
L4
what dermatome gives sensory innervation for the little toe
S1
what dermatome gives sensory innervation for the middle 3 toes
L5
what myotome extends the wrists
C6
what myotome flexes the elbows
C5
what myotome extends the elbow
C7
what myotomes innervates the intrinsic muscles of the hand
T1
what myotome innervates the muscles that flex the hip
L2
what myotome is responsible for extending the knee joint
L3
what myotome extends the toes
L5
what myotome is responsible for plantar flexing the ankle joints
S1
what myotome is responsible for dorsiflexing the ankle
L4
Name 5 upper limb nerve palsies
- Erb’s
- Klumpke’s
- Total brachial nerve palsy
- Axillary nerve palsy
- Carpal Tunnel
- Cubital Tunnel
what is Erb’s palsy
a palsy that arises as a result of damage to the upper trunk of the brachial plexus.
It results in a waiter’s tip position (the elbow is extended and pronated) and the wrist is flexed
what is Klumpke’s palsy
damage to the lower trunk of the brachial plexus that results in claw hand
what cord does the musculocutaneous nerve come off of
the lateral cord
what does the musculocutaneous nerve supplies
the bicep muscles in the arm
what muscle does the musculocutanous nerve pierce through
the coracobrachialis
what is meant by Hilton’s law
a sensory nerve supplying a joint also supplies the muscles that move that joint and the skin overlying that joint
name two muscles that are innervated by the axillary nerve
the deltoid and the trees minor
what area of skin does the axillary nerve supply
the area of skin over the badge area on the arm
what can result in damage to the axillary nerve
a fracture in the surgical neck of the humerus or a dislocated shoulder
name some clinical signs of an axillary nerve palsy
- deltoid atrophy
- loss of sensation over the badge area of the arm
- unable to raise the arm at the shoulder
- weakness of the deltoid muscle
what does the radial nerve innervates
the triceps of the arm
what cord of the brachial plexus does the radial nerve branch from
the posterior cord
what does the radial nerve supply in the hand
the majority of the skin overs the dorsal of the hand and the area of skin over the thenar muscles
what is a term used to describe compression of the radial nerve
Saturday night palsy
what does the median nerve innervate
all of the flexors of the forearm (except the flexor carpi ulnas and the medial half of the FDP)
it provides sensory innervation to the majority of the palm of the hand and the tips of the first 3 fingers
what is compression of the median nerve known as
carpal tunnel syndrome
what are the contents of the carpal tunnel
9 tendons and one nerve
what forms the roof of the carpal tunnel
the flexor retinaculum
what forms the floor of the carpal tunnel
the carpal bones
name some causes of carpal tunnel
trauma, pregnancy, swellings (e.g. lipoma), hypothyroidism, TB, gout
what are some of the clinical signs of carpal tunnel
nocturnal pain, parasthesia is the area of median nerve distribution and wasting of the thenar muscles
there may be a deformity from a previous fracture, scars from previous carpal tunnel release
a positive Tinel’s and Phalens test
describe the Tinel’s test
this is when you tap over the nerve to elicit a sensation of pins and needles
describe the Phalen’s test
this is when you place the dorsal aspect of both hands together for at least 60 seconds. If there is numbness, pain or tingling, the patient could have carpal tunnel
what nerve fibres are found in the median nerve
the median nerve contains fibres from C5-T1 as it is a branch of the posterior cord of the brachial plexus
what cord does the ulnar nerve come from
the medial cord of the brachial plexus
what is the role of the ulnar nerve
the ulnar nerve has no branches in the arm and it is responsible for innervating the flexor carpi ulnaris and the medial half of the FDP
the ulnar nerve also innervates all of the intrinsic muscles of the hand and sensation to the medial 1.5 digits
where is the cubital tunnel located
between the olecranon process and the medial epicondyle - if this space narrows, this is when you get compression of the ulnar nerve/cubital tunnel syndrome
name some clinical signs of cubital tunnel syndrome
pain, disordered sensation over the ulnar aspect of the hand, wasting of the hypothenar muscles, guttering of the fingers and wasting of the first web space (this is usually one of the most marked signs)
what shape will the hand take in an ulnar nerve lesion
you may get claw hand there will be hyperextension at the metacarpal-phalangeal joint and flexion at the inter-phalangeal joints
what test is used to assess ulnar nerve palsy
Froment’s test - pulling on a sheet of paper - if they cannot do it with a flat thumb they have ulnar nerve palsy
what test is used to assess median nerve palsy
Phalen’s and Tinnel’s test
name the two main nerve plexuses int he lower limb
the sacral and the lumbar plexus
what is the sacral plexus made up of
the ventral rami of spinal nerves L4-S4
what are the main branches of the sacral plexus
the sciatic nerve, the superior gluteal nerve and the inferior gluteal nerve
what is the role of the sciatic nerve
innervates the posterior thigh muscle, the muscles of the leg and the foot
what makes up the sciatic nerve
L4-S3 ventral rami of spinal nerves
what is the role of the superior gluteal nerve
to innervate the gluteus medius and minimus
what is the role of the inferior gluteal nerve
to innervate the gluteus Maximus muscle
what is the main branch of the sacral plexus
the sciatic nerve
what are the main branches of the sciatic nerve
the tibial nerve and the common fibular/peroneal nerve
what are the branches of the common peroneal nerve and what is the role of each
the main branches are the superficial and deep peroneal nerves
the superficial nerve supplies the lateral compartment of the leg and the deep peroneal nerve supplies the anterior compartment of the leg
what could cause a common peroneal nerve palsy
a fracture in the head of the fibula
what is the main branch of the lumbar plexus
the femoral nerve
what are the branches of the lumbar plexus
the femoral nerve, the obturator and the lateral cutaneous nerve
what is neuralgia parasthetica
this I the compression of the lateral cutaneous nerve of the lumbar plexus. the compression occurs at the lateral border of the inguinal ligament where the nerve passes under it
