Week 6 Upper nerve injuries Flashcards
what is nerve injury
a nerve is no longer able to transmit an action potential
peripheral nerve injury
- stretch related, lacerations 撕裂伤, compression (external or internal)
- associated with # of UL (95%)
- male:female - 2.2:1
- dominant hand injury 慣用手受傷 > non dominant hand
three types of nerve injury seddon
classification of peripheral nerve injury
neurapraxia (sunderland I)
axonotmesis (sunderland II, III, IV)
neurotmesis (sunderland V)
pathophysiological basis of sunderland I, II, III, IV, V
I:
- local myelin damage
- axons preserved 保留
- no degeneration
II:
- axon degeneration
- endoneural tube preserved
III:
- axon degeneration
- loss of endoneural tube continuity
- perineurium intact
IV:
- axon degeneration
- endoneural tube and perineurium disrupted 保留
- epineurium intact
V:
- complete loss of neural continuity
diagnosis of a peripheral nerve injury
- physical assessment findings of nerve disruption (motor, sensory, reflex loss)
- imaging (MRI, CT)
- Peripherial nerve system:
–> pain, often burning or crutching
–> hyperaesthesia or anaesthesia
感覺過敏或麻醉
causes of brachial plexus - upper trunk injury - children
- most common neurapraxia in childbirth –> traction on neck
- damage to C5, 6 roots
- Erb’s palsy
treatment of brachial plexus - upper trunk injury - children
- Priority to maintain PROM abduction and ER
- may consider surgery if no change over 3 months
- In infants 在嬰兒中
- Healing occurs 1-2 mm per day
- Wide range of degree of damage – 80-90% regain full functioning upper
limb 損傷程度範圍廣泛 – 80-90% 恢復全功能
causes of brachial plexus - upper trunk injury - adults
trauma 創傷
inflammation
tumor 瘤
radiation
what loss of sensation to expect in brachial plexus - upper trunk injury?
sensation think about dermatomes
C5/6 ventral rami - affect lateral upper arm and forearm and thumb
what muscles will be affected by brachial plexus - upper trunk injury?
muscles think about myotomes
C5/6 ventral rami
- shoulder abduction and ER (C5)
- elbow flexion, wrist extension, forearm supination (C6)
what peripheral nerves affected in brachial plexus - upper trunk injury? (contains C5,C6 fibres)
dorsal scapular (C5)
suprascapular (C5, 6)
axillary (C5,6)
musculocutaneous (C5, 6, 7)
what typical presentation due to unopposed muscle action of the UL? (brachial plexus in upper trunk injury)
loss of shoulder Abd, ER, elbow F, wrist E, scapular retraction
= rests in Add, IR, elbow E, +/- wrist flexion
(waiter tip)
just opposite
causes of brachial plexus - lower trunk injury (C8-T1)
- fall, arm forced into extreme abduction
- Klumpke’s palsy (rare)
- C8 and T1 nerve roots are not well secured
-
rare injury
.
what is the sensory deficit in brachial plexus - lower trunk injury? (dermatomes C8, T1)
ulnar border of arm, forearm and hand
what is the motor loss in brachial plexus - lower trunk injury? (myotomes)
- mainly control in fingers and wrist
- may develop ‘claw hand’
- Horner’s syndrome - disruption of T1 sympathetic fibers on ventral ramus
brachial plexus - complete lesion
- rare
- loss of all sensation and motor control
- varying global areas of loss if less severe 如果不那麼嚴重的話，損失的範圍也不同
- tendon transfer surgery used to recover some function if possible 如果可能的話，肌腱轉移手術用於恢復部分功能
- assessment for phrenic nerve function (as it may affect diaphragm)
what is thoracic outlet syndrome (TOS)
a group of distinct disorders that affect neurovascular structures between the base of the neck and axilla
TOS can result from injury, disease, or a congenital abnormality:
- more common in women than in men
-
soft tissue (70%):
–> hypertrophy of scalenes
–> ligamentous/ fibromuscular bands - osseous
–> cervical rib
–> poor healing # clavicle
–> AC/SC joint dislocation/ injury - other features:
–> poor posture
–> obesity
–> chronic lung disease
–> fluid retention
symptoms of thoracic outlet syndrome (TOS)
- aching pain 酸痛 lateral neck, shoulder, occiput, axilla, medial forearm and hand
- hands may feel ‘clumsy’ 手可能會感覺“笨拙”
- pain aggravated by driving, carrying heavy objects and overhead activities
- unilateral/ bilateral
- burning, pins and needles 針刺症狀 common symptom
- symptoms may start distally or proximally
- may present overnight as well as with activity
- venous - feeling of heaviness and stiffness, swelling
- arterial involvement: coolness and cold sensitivity even numbness
diagnosis of thoracic outlet syndrome
- nerve conduction tests (eg: test dermatomes, myotomes)
- detailed assessment - cervical spine, shoulder, thoracic spine, detailed neurological, vascular assessment
- X-ray may be recommended
- MRI
- ultrasound
treatment of thoracic outlet syndrome
- pain management
- postural re-education
- strengthening neck, shoulder, scapular muscles
causes of axillary nerve injury (C5, 6)
- badly adjusted crutch
- downward displacement of humeral head
-
#SNOH
.
motor and sensory changes of axillary nerve injury (C5, 6)
motor:
paralysis 麻痺 of deltoid and teres minor –> damaged to shoulder abduction (+ER)
(deltoid wasting after injury)
sensory:
loss of skin sensation over the lower half of deltoid
what is radial nerve (C5-T1)?
- passes posteriorly, along the spiral groove of humerus
- continuation of posterior cord
- supplies triceps, extensor muscles of wrist, skin over posterior aspect arm and forearm
what are the two disorders 疾病 of radial nerve injury?
crutch palsy
‘saturday night’ palsy
crutch palsy vs saturday night palsy
crutch palsy:
- compression in axilla
- all motor and sensory branches lost (triceps, wrist extensors)
saturday night palsy:
- compression in the spiral (radial) groove
- not all triceps lost
- sensation lost over posterior arm
- usually transient 短暫的
radial nerve injury
- # SHAFT of humerus
- most common peripheral nerve injury associated with # in the UL
- varying loss of tricpes
- ‘wrist drop’
- return muscular function often within 4-8 months (depending on degree of damage)
- With each injury lose motor control of wrist extensors +/- sensation dorsum hand 1st web space (每次受傷都會loss of motor control of wrist extensors)
what is median nerve (C6-T1)?
- motor supply to most muscles in anterior forearm
- passes under flexor retinaculum at wrist to supply most muscles of the thumb and some intrinsics of hand
what are the two disorders of medial nerve injury of elbow?
- supracondylar humeral #
- pronator syndrome
what is supracondylar humeral fracture
displaced #s and other vascular structures at risk
- 有骨折移位的風險
- 其他有風險的血管結構
what is pronator syndrome
- compression between pronator teres
- motor: loss finger F (1st and 2nd), weak wrist F, loss most thumb movements
- sensory: loss lateral 3.5 digits and palm (base of thumb)
what is the disorder of medial nerve injury - wrist?
carpal tunnel syndrome
what is carpal tunnel syndrome
- 10% population: repetitive occupational strain, pregnancy, RA
- sensation loss lateral 3.5 digits (sensation over thumb often preserved)
- wasted thenar muscles if severe
what is ulnar nerve (C8, T1)?
- wraps directly behind medial epicondyle of humerus
- main nerve for intrinsic muscles of the hand
- cutaneous supply medial 1.5 digits
some risks of ulnar nerve injury
- # medial epicondyle / # ulna
- Cubital tunnel syndrome (b/w 2 heads FCU)
- Guyon’s/ulnar canal syndrome (wrist)
- Sensation to dorsum hand spared 倖免於難
- When intrinsic muscles in the hand are lost “claw hand” 爪手
management of neural injuries
- young age have better sensory recovery
- often ‘pins and needles’ and sensation recovers
- less severe damage –> conservative management
physiotherapy management of neural injuries
- detailed assessment
- consider pre or post surgery - goals will differ
- protect joints and capsule
- education (managing affected area especially if sensation lost)
- aware of post-surgical complications: failure of nerve repair, neuroma, infection, scarring, joint contractures
- regular re-assessment and outcome measures
physiotherapy management of neural injury (aim)
- reduce pain
- reduce oedema
- maintain passive joint ROM/ muscle length
- maintain strength unaffected muscles
