neuro500 (class 2 cervical/brachial plexuses & pathologies) Flashcards
parotid gland
para – beside
ot – ear
a salivary gland
lesser occipital – origin and distribution
c2
posteroinferior head – posterior to ear
greater auricular – origin & distribution
C2-C3
anterior/inferior to ear, over parotid gland (OVER SKIN NOT THE GLAND ITSELF)
transverse cervical – origin, and distribution
C2-C3
anterior neck
supraclavicular – origin, and distribution
over the clavicle to shoulder – superior to chest
ansa etymology
handle
e.g.
ansa cervicalis (cervical handle)
ansa cervicalis, superior root – origin & distribution
C1
infrahyoids
ansa cervicalis, inferior root – origin & distribution
C2-3
infrahyoids
phrenic nerve – origin & distribution
C3-C5
diaphragm
segmental branches (of cervical plexus) – origin & distribution
C1-C5
prevertebrals
(longus capitis/colli, rectus capitis anterior/lateralis)
also lev scap + middle scalenes
segmental branches leave off of ____
every level of spinal nerves
WHAT ABOUT SENSORY FEEDBACK FROM BACK OF NECK?
POSTERIOR RAMI
dorsal scapular nerve — distribution (innervates…)
rhombs
lev scap
C5
long thoracic
serratus anterior
C5-7
nerve to subclavius
subclavius
C5-6
suprascapular nerve
C5-6
supraspin
infraspin
lateral pecotral nn
pec MAJOR
C5-C7
medial pectoral nn
pec major AND MINOR
C8-T1
UPPER SUBSCAPULAR
subscapular
C5-C6
LOWER SUBSCAPULAR
SUBSCAP
+
TERES MINOR
C5-C6
THORACODORSAL
latissimus dorsi
UNIQUELY –> C6-C8
medial cutaneous n of ARM
C8-T1
MEDIAL, DISTAL arm
medial cutaneous n of FOREARM
C8-T1
MEDIAL FOREARM (not just distal)
THE MIXED NERVES (cutaneous, and muscle)
FIVE nerves – “TERMINAL BRANCHES”
these are also the “ENDS” of the brachial plexus
—> “these FIVE nerves innervate the entire upper extremity”
MUSCULOCUTANEOUS
AXILLARY
MEDIAN
RADIAL
ULNAR
MUSCULOCUTANEOUS
C5-C7
—> anterior arm mm
—> also sensory portion (not covered)
AXILLARY
C5-C6
—> delts
—> teres minor
—> SKIN (over the mm innervated)
MEDIAN
C5-T1
—> forearm flexors (not FCU)
—> thenar mm
—> central compartment of hand
—> SKIN (palm, digits 1-3.5, & posterior distal phalanges of digits 1-3.5)
RADIAL
C5-T1
—> posterior arm & forearm
—> brachioradialis
—> SKIN of posterior arm/forearm & dorsal hand + dorsal surfaces of digits 1-3.5 (except distal portion)
ULNAR
FCU,
hypothenar mass,
central compartment (certain mm?), ABDUCTOR POLLICIS
which nerves are commonly implicated in peripheral nerve issues
medial, ulnar, radial
COMPRESSION SYNDROMES OF PERIPHERAL NERVES
..
motor nerve compression
weakness
PAIN
sensory nerve compression
numbness, tingling
PAIN
SSx of nn compresison is D/t
impaired oxygenation (ischemia)
—> PAIN
IMPAIRED local nerve conduction
—> numbness/weakness
where do SSx show up when nn compressed?
DISTAL
classificaiton of neuropathy
mononeuropathy
polyneuropathy
radiculoneuropathy
polyradiculitis
mononeuropathy
-when a single peripheral nerve is affected
polyneuropathy
-when several peripheral nerves are involved
radiculoneuropathy
-involvement of the nerve root as it emerges from the spinal cord
polyradiculitis
-involvement of several nerve roots and occurs when infections create an inflammatory response
Erb-Duchenne palsy
-injury to the superior roots of the brachial plexus
Eerb Duchenne –> which roots?
(C5-C6)
Erb Duchenne cause/type
TRACTION INJURY
pulling
-forceful pulling away of head from shoulder
Erb Duchenne – Description (what happens?)
-no sensation over lateral arm
(sensory loss C5 & C6 dermatomes)
Erb Duchenne – What about effect on motor component of C5-6 (MYOTOME)
(Think abduction of GH, & flexion @ HU, & extension @ RC)
Therefore…
-arm is adducted
-medial rotation
-elbow extended
-forearm pronated
-wrist and fingers flexed
(AKA WAITER’S TIP POSITION)
possible MOI for Erb Duchenne’s
baby delivery headfirst
(head is pulled too hard by delivering doctor/nurse)
or
E.g.
Intense Whiplash
how long does it take for arm/limb to go into new position (E.g. Erb Duchenne)
takes some time (E.g. as mm atrophy)
Klumpke’s paralysis
TRACTION INJURY
Klumpke’s which roots?
Lower Brachial PLexus
C8-T1
Klumpke’s possible causes
-poor positioning at birth (breech), or pulled by forceps
-falling from height & grabbing something to break fall
Klumpke’s results in lesions where?
-results in median and ulnar lesions
(ulnar = C8-T1
median = C5-T1)
Klumpke’s where is sensory loss
(DERMATOMES C8-T1)
posteiror arm/forearm
Klumpke’s where is motor issues?
(MYOTOME C8-T1)
C8 myotome = thumb extension (ulnar deviation?) & FINGER FLEXION (CNS notes)
ALSO THINK, C8-T1 ULNAR NERVE = FLEXOR DIGITORUM PROFUNDUS & FCU
THEREFORE…
Claw hand
Klumpkes – Can cause ____
Horner’s syndrome
Horner’s Syndrome
“a condition marked by a contracted pupil, drooping upper eyelid, and local inability to sweat on one side of the face, caused by damage to sympathetic nerves on that side of the neck.”
Horner’s syndrome on affected side (of Klumpke’s)
miosis
= constriction of pupil
ptosis
= drooping of eyelid
anhydrosis
= loss of sweating to face and neck
enophthalmos
= recession of eyeball into orbit
enophthalmos ETYMOLOGY
“The “en” refers to “in” and “ophthalmos” means eye. The opposite of enophthalmos is exophthalmos (proptosis) of the eyes, also called bulging eyes. Sunken eyes, or enophthalmos, can be something that you’re born with (congenital), or something that happens to you sometime after birth (acquired).”
THORACIC OUTLET SYNDROME
-Compression of brachial plexus from structures in the
thoracic outlet
trophic changes in skin d/t b/v blockage (e.g. TOS)
e.g. stop growing hair in area
e.g. shiny skin
e.g. fingernails brittle/pitted/break easily
e.g. thicker skin
I.e.
integumentary changes
Via
arterial /bv blockage/compression
trophic change sof skin – where usually?
ankles
thoracic outlet
thoracic outlet runs from interscalene triangle
to inferior border of axilla
tos what other strucures
-Subclavian artery and vein may also be compressed
anterior scalene syndrome – which strucure not affected?
subclavian vein
3 tos
anterior scalene syndorme
(interscalene triangle)
costoclavicular syndrome
(costoclavicular space)
pec minor syndrome
(subcoracoid space)
subclavian vein joints after
The subclavian vein joins in after the scalenes and the whole neurovascular bundle goes below the clavicle and under the pec minor insertion and down the arm
between scalenes are …
The brachial plexus travels with the subclavian artery between the anterior and medial scalene
tos causes
trauma
repetitive use
anatomic irregularities
posture
tumour
tos SSx
-pain, numbness, weakness, tingling in arm or
across upper thoracic area or over scapula
-trophic changes in tissue with blood vessel
compression
( see above)
trophic changes
“Trophic changes is a term used to describe abnormalities in the area of pain that include primarily wasting away of the skin, tissues, or muscle, thinning of the bones, and changes in how the hair or nails grow, including thickening or thinning of hair or brittle nails. [”
note cervical rib vs tos
Presence of cervical rib
-additional rib at C7
Anterior Scalene Syndrome
Compression between anterior and middle scalene
Interscalene triangle
- anterior scalene
- middle scalene
- rib 1
- brachial plexus and subclavian artery pass
through only (subclavian vein is anterior)
Costoclavicular Syndrome
Compression between the clavicle and rib1
Pectoralis Minor Syndrome
Compression between coracoid process and
pec minor
Radial nerve
Continuation of the brachial plexus
Travels along the spiral groove of the humerus
radial nn supply
Triceps, anconeus, brachioradialis, ECRL, ECRB, supinator, ED, ECU, EDM, APL, EPB, EPL, EI
NOTE STRUCTURES
radial nerve splits @ around elbow
–> SUPERFICIAL BRANCH
–> DEEP BRANCH (VIA ARCADE OF FROHSE TO —> POSTERIOR ANTEBRACHIAL INTEROSSEOUS NERVE)
uperficial branch - travels down the posterior forearm
to the hand
..
Posterior motor branch “Posterior interosseous nerve”
-it enters supinator and travels down
the lateral radius to the wrist
..
radial nerve leisons Etiology
Fractures – at spiral/ radial groove
Dislocations – of head of radius, humeroradial or radioulnar joints
Post-surgical complications
Compression
Radial nerve lesions Ssx
-altered sensation at posterior arm and hand (digits 1,
2, 3 and lateral half of 4)
radial nn lesions & WRIST DROP
-wrist drop (can’t extend wrist and fingers)
IS SENSORY OR MOTOR AFFECTED?
DEPENDS on where radial nerve is injured (relative to elbow)
-if injury is proximal to elbow, both sensory & motor affected,
if injury distal to elbow, only sensory OR motor is affected
Radial nn LESIONS — TYPICAL LOCATIONS
Crutch Palsy
Saturday Night Palsy
Posterior Interosseous Syndrome
Cheiralgia paresthetica
Crutch Palsy
Crutch Palsy
—> -at axilla
Saturday Night Palsy
Saturday Night Palsy
—> -at spiral groove of humerus
-from direct pressure against a firm
object
-deep sleep on arm (passed out on
hard surface)
Posterior Interosseous Syndrome
Posterior Interosseous Syndrome
-Posterior Interosseous Nerve comes off in front of the lateral epicondyle of the humerus
-motor nerve
-get wrist drop
-compression occurs in the arcade of Frohse
Cheiralgia paresthetica
Cheiralgia paresthetica
-compression of the superficial branch of the radial nerve as it passes under the tendon of brachioradialis
-sensory
-pain at dorsum of wrist, thumb, webspace
-cause: trauma, tight cast, swelling
arcade/canal of frohse
-fibrous arch in supinator
-btw the 2 heads of supinator
-occurs in 30% of people
cheir- algia
cheir- = hand
E.g.
Chiro-practor
does biceps mm hypertonicity ever compress median nerve
not really
SSx
NUMBNESS
TINGLING
WEAKNESS
PAIN
median nn lesion etiology
-fractures at elbow, wrist and carpals
-dislocations at elbow, wrist, carpals
-compressions
-trauma
Median Nerve and APE HAND
-thumb in same plane as rest of hand since
there is no opposition (wasting of thenar
eminence)
Median Nerve and OATH HAND
-you see when you go to make a fist
only digit 4 & 5 can be flexed
Can you usually see oath hand when hand is at rest
no
have to ask patient to attempt to contract (flex) fingers
individuals with median nerve lesions have difficulty _____
GRASPING OBJECTS
Median nn lesions SSx
-can’t grasp objects
-can’t pronate forearm, flex PIPs, flex DIPS of digit #2, 3
(can’t do air quotes)
-weak wrist flexion, weak thumb movements
-altered sensation on digit 1, 2, 3 and half of 4 (palmer surface)
median nerve lesions & Ligament of Struthers
..
Ligament of Struthers
-runs from an abnormal spur on the shaft of the humerus to the medial epicondyle
what perentage does ligament of struthers occur?
“In the lower mammals, the tunnel of osteo-fibrous tissue formed by the humerus, the supracondylar process and Struthers’ ligament protects the nerves and blood vessels that extend to the forearm. Its occurrence in humans is very rare, in only 0.7-2.5% of the population.”
more about ligament of struthers
-runs from an abnormal spur on the shaft of the humerus to the medial epicondyle
-median nerve can be compressed above the elbow as it passes under
-only in 1% of the population
List of potential locations for median nn lesions
Ligament of Struthers
Pronator Teres Syndrome
anterior interosseous syndrome
Carpal Tunnel Syndrome
Pronator Teres Syndrome
-compressed at proximal attachment of pronator teres
-aching in anterior forearm
-numbness in thumb and index finger
-some weakness in thenar mm
I.e.
BOTH MOTOR & SENSORY
anterior interosseous syndrome
-branch of median nerve (anterior interosseous nerve)
-can be pinched or entrapped as it passes between the 2 heads of pronator teres
-pain and motor loss of flex pollicis long, lateral ½ FDP, and pronator quadratus
THEREFORE…
-paralysis of flexors in index finger & thumb
Carpal Tunnel Syndrome
-compression through the carpal tunnel at wrist
-most common entrapment condition in arm
carpal tunnel define
-carpal bones form the floor of the tunnel
-flexor retinaculum forms the roof
-structures that pass through carpal tunnel:
Median nerve
Flexor digit super (4 tendons)
Flex digit profundus (4 tendons)
Flex pollicis longus (1 tendon)
flexor retinaculum attachments
“On the ulnar side, the flexor retinaculum attaches to the pisiform bone and the hook of the hamate bone. On the radial side, it attaches to the tubercle of the scaphoid bone, and to the medial part of the palmar surface and the ridge of the trapezium bone.”
CTS SSx
-numbness and tingling in digit #1, 2, 3 and half of 4 (palmer surface)
-distinguishing feature = presence of nocturnal symptoms that wake person up
-muscle weakness and clumsiness of thumb and fingers
-later stages –> thenar muscle wasting
why CTS SSx common @ night
awkward posture/position of hand @ night
TWO ways median nn can get compressed in carpal tunnel
1) Size of the tunnel decreases
2) Size of the contents passing through increases
1) Size of the tunnel decreases
Bony callous, space occupying lesion, bony changes
E.g. RA
2) Size of the contents passing through increases
Repetitive actions -> edema and then fibrosis + tendon
thickening
Retinaculum thickening from scar tissue (repeated trauma)
Systemic conditions that cause edema + fluid retention
note pathology that can affect radial, median, AND ulnar nerves
Thoracic Outlet Syndrome
hypertoned FCU & ulnar nerve compression
possible
what about hypertoned FDP @ ulnar nerve compression?
Not typical
FDP hypertones/hypertrophies DOWNWARD —> AWAY FROM ulnar nerve
Guyon’s Canal (Tunnel of Guyon)
between pisiform & hook of hamate
this is where ulnar nerve travels over in hand, over flexor retinaculum
ulnar nerve lesions —> etiology
Fractures – at medial epicondyle, midforearm, wrist
Dislocations – of elbow
Post-surgical complications (badly positioned arm while under anesthetic)
Compression
- resting elbow on hard surface
- wearing tight wrist band
- cycling
Repetitive actions
- weightlifting (bench press)
Direct trauma
Ulnar nerve lesions & ULNAR CLAW HAND
LUMBRICAL ATROPHY
Lumbricals:
flex @ MCP & extend @ PIP/DIP
recall:
lumbricals via the ulnar nerve
if innervation interrupted
= lumbrical atrophy dysfunction
= OPPOSITE of lumbrical action
= CLAW HAND
ulnar claw hand
-baby finger is hyperextended and abducted at MCP and flexed at IP
-ring finger is hyperextended at MCP and flexed at IP
-atrophy of interosseous mm
other SSx of ulnar nerve lesions
Muscle wasting of hypothenar
Altered sensation in little finger + medial half of ring finger (palmar and dorsal)
Froment’s sign is positive
(ADDUCTOR POLLICIS weakness)
Paradoxical Ulnar Claw
“Ulnar paradox is a condition where a high ulnar nerve lesion at the elbow causes a milder clawing appearance than a low ulnar nerve lesion at the wrist. This is because the flexor digitorum profundus muscle (FDP) is weakened by a high lesion, which reduces the claw-like appearance of the hand.”
Froment’s sign
-hold paper between thumb + index finger
-you need adductor pollicis to hold the paper like the clinician (which in innervated by the ulnar nerve)
-so patients flex thumb to use flex pollicis longus
Tardy Ulnar Palsy
-ulnar nerve palsy is a common complication of fractures of the elbow
-it is a late (tardy) palsy that can occur years after a fracture
-it is associated with a callus formation or a valgus deformity of the elbow
—> it produces a gradual stretching of the nerve in the ulnar groove of the medial epicondyle
