MSK Flashcards
What are the articulating surfaces of the shoulder joint?
glenoid fossa
head of the humerus
What acts to increase the joint surface area>
glenoid labrum
fibrocartilage rim
where does the glenohumeral joint capsule extend from
from the anatomical neck of the humerus to the border of the glenoid fossa
name the synovial bursae of the shoulder
subacromial
subscapular
subcoracoid
Where is the subacromial bursa found?
inferiorly to the deltoid and acromion,
superiorly to the supraspinatus tendon and the joint capsule.
Where is the subscapular bursa found?
Located between the subscapularis tendon and the scapula.
What is the purpose of the coracoacromial ligament of the shoulder
prevents superior displacement of humerus
What is the purpose of the coracohumeral ligament of the shoulder
supports joint superiorly
What is the purpose of the glenohumeral ligament of the shoulder
stabilises joint anteriorly
What is painful arc syndrome?
inflammation of supraspinatus tendon and subacromial bursa beneath coracoacromial tendon
What gives the shoulder joint mobility
ball and socket
lax joint capsule
shallow glenoid cavity, large head of humerus
What gives the shoulder joint stability
ligaments - reinforce joint capsule
glenoid labrum - increases surface area
rotator cuff muscles - pull humeral head into glenoid cavity
What is the most common dislocation of the shoulder
anterior
What causes anterior dislocation of the shoulder
extension
external rotation
name the rotator cuff muscles
supraspinatus
infraspinatus
teres minor
subscapularis
What is the function of the rotator cuff muscles as a group?
pull humeral head into the glenoid cavity
name the origin and insertion of the supraspinatus
supraspinous fossa
greater tubercle of humerus
name the origin and insertion of the infraspinatus
infraspinous fossa
greater tubercle of humerus
name the origin and insertion of the teres minor
lateral posterior surface of scapula
greater tubercle of humerus
name the origin and insertion of the subscapularis
subscapular fossa
lesser tubercle of the humerus
Which rotator cuff muscles are innervated by the suprascapular nerve
supraspinatus
infraspinatus
Which rotator cuff muscles are innervated by the upper and lower subscapular nerves
subscapularis
Which rotator cuff muscles are innervated by the axillary nerve
teres minor
Which rotator cuff muscles act to laterally rotate the arm
teres minor
infraspinatus
Which rotator cuff muscles act to medially rotate the arm
subscapularis
Which rotator cuff muscles act to abduct the arm
supraspinatus
State the boundaries of the cubital fossa
medial = pronator teres lateral = brachioradialis superior = line between epicondyles of humerus
what are the contents of the cubital fossa
biceps tendon
brachial artery
median nerve
What makes up the floor of the cubital fossa
brachialis
supinator
What can a supracondylar fracture of the humerus lead to?
damage to the brachial artery
Volkmann’s contracture
How does Volkmann’s contracture present?
permanent shortening of forearm muscles
gives rise to a clawlike deformity of the hand, fingers, and wrist.
due to ischaemia
What nerve roots contribute to the brachial plexus?
C5-T1
State the dermatomes that correspond to C5-T1
C5 - lateral elbow C6 - posterior thumb C7 - posterior middle finger C8 - posterior little finger T1 - medial elbow
State the myotomes that correspond to C5-T1
C5 - elbow flexion, biceps and brachialis
C6 - wrist extension, extensor carpi radialis longus and brevis
C7 - elbow extension, triceps brachii
C8 - middle finger flexion, flexor digitorum profundus
T1 - little finger abduction, abductor digiti minimi
State the nerve roots of the median nerve
C5-T1
State the course of the median nerve
axilla lateral then medial to brachial artery cubital fossa between flexor digitorum profundus and superficialis carpal tunnel
What branches of the median nerve leave in the forearm
anterior interosseus
palmar cutaneous
What does the anterior interosseus nerve innervate?
deep flexors of the forearm
- pronator quadratus
- flexor digitorum profundus (lateral half)
- flexor pollicis longus
What does the palmar cutaneous branch of the median nerve innervate
sensory innervation to the lateral palm of the hand
What branches of the median nerve originate in the hand
recurrent branch
palmar digital
What does the recurrent branch of the median nerve innervate
thenar muscles
What does the palmar digital branch of the median nerve innervate
sensory lateral fingers
lateral lumbricals
How could the median nerve be damaged at the elbow?
supracondylar humeral fracture
What functions would be lost if the median nerve was damaged at the elbow
loss pronation loss flexion of wrist loss abduction of wrist loss of thumb movement loss of flexion at lateral MCP loss of sensory innervation to lateral hand
What position would the arm be in if median nerve is damaged at the elbow
supination
extension
adduction
hand of benediction
What causes the hand of benediction
loss of median nerve innervation to lateral two lumbricals (palmar digital)
when tries to make a fist, only medial two fingers can flex at MCP
How would the median nerve be damaged at the wrist
laceration proximal to flexor retinaculum
What functions are lost if the median nerve is damaged at the wrist
loss of thumb movement
loss of flexion at lateral MCP
loss of sensory innervation to lateral hand
Name the thenar muscles
flexor pollicis brevis
abductor pollicis brevis
opponens pollicis
State the nerve roots of the ulnar nerve
C8-T1
Describe the course of the ulnar nerve
axilla medial arm posterior to medial epicondyle of humerus alongside ulna above flexor retinaculum ulnar (Guyon's) canal terminates in hand
What branches of the ulnar nerve originate in the forearm
muscular
palmar cutaneous
dorsal cutaneuous
What does the muscular branch of the ulnar nerve innervate
medial flexor digitorum profundus
flexor carpi ulnaris
What does the palmar cutaneous branch of the ulnar nerve innervate
sensory medial palm
What does the dorsal cuteneous branch of the ulnar nerve innervate
dorsal medial palm and fingers
What branches of the ulnar nerve originate in the hand
deep branch
superficial branch
What does the deep branch of the ulnar nerve innervate
hypothenar eminence interossei medial lumbricals adductor pollicis palmaris brevis
What is the action of the lumbricals
DAB PAD
dorsal - abdcution
palmar - adduction
What does the superficial branch of the ulnar nerve innervate
sensory palmar surface medial 1.5 fingers
How is the ulnar nerve damaged at the elbow
fracture of medial epicondyle
What functions are lost if the ulnar nerve is damaged at the elbow
weakened flexion, accompanied by abduction
loss of adduction
loss of adduction and abduction of fingers
reduced MCP flexion of medial fingers
loss of sensation of medial hand
What is the characteristic sign of ulnar nerve damage at the elbow
patient cannot grip paper between fingers
due to loss of innervation to interossei
How is the ulnar nerve damaged at the wrist
lacerations to wrist
What functions are lost if the ulnar nerve is damaged at the wrist
loss of adduction and abduction fingers
reduced MCP flexion of medial fingers
loss of sensation to medial palmar surface of hand
Which sensory branch of the ulnar nerve is usually maintained in a laceration to the wrist
dorsal cutaneous branch
so dorsal sensory function is maintained
What is the sign of long term damage to the ulnar nerve at the wrist
ulnar claw
Hyper-extension of the medial MCP due to paralysis of the medial two lumbricals,
Flexion at the interphalangeal joints
What is the ulnar paradox?
If the ulnar nerve is damaged at the elbow, the ulnar claw is less pronounced
this is because the medial half of the flexor digitorum profundus is paralysed, which would usually act to flex DIP
so there is no flexion at distal IP joints
There is only hyperextension at the MCP and flexion at PIP which is less noticeable!
State the nerve roots of the radial nerve
C5-T1
State the course of the radial nerve
axilla
posterior to axillary artery
radial groove
anterior to lateral epicondyle of humerus
cubital fossa
splits into superficial and deep branches
What muscles does the radial nerve innervate before it reaches the forearm?
triceps brachii
brachioradialis
extensor carpi radialis longus
Name the three sensory branches of the radial nerve that arise proximal to the elbow
lateral cutaneous nerve of the arm
posterior cutaneous nerve of the arm
posterior cutaneous nerve of the forearm
What area does the lateral cutaneous nerve of the arm, originating from the radial nerve, innervate
sensory innervation to the lateral arm, inferior to the area supplied by the axillary nerve
What area does the posterior cutaneous nerve of the arm, originating from the radial nerve, innervate
posterior arm
What area does the lateral cutaneous nerve of the forearm, originating from the radial nerve, innervate
strip of skin posteriorly on the forearm
What is the function of the deep branch of the radial nerve
innervates the posterior muscles of the forearm
What does the deep branch of the radial nerve become when it penetrates through the supinator?
posterior interosseous nerve
What is the function of the superficial branch of the radial nerve
sensory innervation to dorsum of lateral 3.5 digits
How can the radial nerve be damaged in the axilla
shoulder dislocation
fracture of proximal humerus
Describe the presentation of radial nerve damage at the axillla
wrist drop! - unopposed flexion
unable to extend elbow
unable to extend wrist
unable to extend at MCP
loss of sensation at lateral and posterior arm, posterior forarm and lateral dorsum of hand
How can the radial nerve be damaged in the arm
fracture of the shaft of the humerus
radial nerve lies in radial groove
Describe the presentation of radial nerve damage in the radial groove
wrist drop = unopposed flexion at wrist and fingers
weakened extension at elbow
unable to extend wrist
unable to extend fingers
loss of sensation to lateral dorsum of hand
Which muscles are innervated by the radial nerve before it enters the radial groove
long and medial heads of the triceps brachii
Which sensory branches of the radial nerve arise before it enters the radial groove
lateral cutaneous nerve of the arm
posterior cutaneous nerve of the arm
posterior cutaneous nerve of the forearm
How can the superficial branch of the radial nerve be damaged?
stabbing or laceration of forearm
Describe the presentation of damage to the superficial branch of the radial nerve
loss of sensation to lateral dorsum of hand
How can the deep branch of the radial nerve be damaged?
posterior dislocation of radius
fracture of radial head
Describe the presentation of damage to the deep branch of the radial nerve
weakened extension of the wrist
NO WRIST DROP
the extensor carpi radialis is not innervated by the deep branch, and maintains some innervation
no loss of sensation
State the nerve roots of the femoral nerve
L2-L4
Describe the course of the femoral nerve
lumbar plexus through psoas major behind iliac fascia under inguinal ligament - midpoint of inguinal ligament femoral triangle adductor canal
Which branches of the femoral nerve leave in the femoral triangle
anterior division
posterior division
What is the function of the anterior division of the femoral nerve
innervates hip flexors
- sartorius
- pectineus
- iliacus
sensory to anteromedial thigh
What is the function of the posterior division of the femoral nerve
knee extensors
- vastus medialis
- vastus intermedius
- vastus lateralis
- rectus femoris
saphenous nerve - sensory to medial leg and foot
What nerve does the femoral nerve transition into?
saphenous
Which area of the leg does the saphenous nerve provide sensory innervation to?
medial leg and foot
Which vessel lies closely to the saphenous nerve?
long saphenous vein
What problems can damage to the saphenous nerve cause?
pain, paresthesia or loss of sensation to medial leg and foot
How is the saphenous nerve often damaged?
stripping of the long saphenous vein eg. varicose vein op
State the nerve roots of the sciatic nerve
L4-S3
Describe the course of the sciatic nerve
lumbosacral plexus greater sciatic foramen inferior to piriformis deep to long head of the biceps femoris popliteal fossa splits to form tibial and common fibular nerves
What structures does the sciatic nerve innervate in the thigh
hamstring portion of adductor magus
biceps femoris - long head and short head
semimembranosus
semitendinosus
Which muscles are most medial in the posterior thigh
semimembranosus
semitendinosus
What is the relevance of the sciatic nerve in terms of giving IM injections in the gluteal region
you don’t want to hit it!
divide into quadrants
- one line between horizontal halfway between ischial tuberosity and highest point iliac crest
- one line vertically from highest point iliac crest
go in lateral upper quadrant
State the nerve roots of the tibial nerve
L4-S3
Describe the course of the tibial nerve
sciatic nerve popliteal fossa deep to soleus posterior to tibia posterior to medial malleolus beneath flexor retinaculum (tarsal tunnel) splits into terminal branches
Name the terminal branches of the tibial nerve
medial calcaneal
medial plantar
lateral plantar
Which branch of the tibial nerve leaves in the popliteal fossa
sural nerve
What area does the sural nerve provide sensory innervation to?
posterolateral leg
lateral foot
Which muscles does the tibial nerve provide innervation to?
deep
- flexor digitorum longus
- flexor hallucis longus
- popliteus
- tibialis posterior
superficial
- soleus
- gastrocnemius
- plantaris
What area does the medial calcaneal nerve provide sensory innervation to?
heel
What area does the medial plantar nerve provide sensory innervation to?
medial 3.5 toes and sole
What area does the lateral plantar nerve provide sensory innervation to?
lateral 1.5 toes and sole
Describe tarsal tunnel syndrome
tibial nerve compressed posteriorly to medial malleolus in tarsal tunnel
causing paresthesia in sole of foot, worsened by exercise
Name the contents of the tarsal tunnel
Tibialis posterior tendon flexor Digitorum longus tendon posterior tibial Artery posterior tibial Vein tibial Nerve flexor Hallucis longus tendon
What can cause tarsal tunnel syndrome
ostetoarthritis
RA
post trauma ankle deformities
What is the surgical management of tarsal tunnel syndrome?
flexor retinaculum cut
How can the tibial nerve be damaged
entrapment
direct trauma
compression over long period of time
What are the problems caused by damage to the tibial nerve
loss of plantar flexion
loss of sensation to sole of foot
loss of toe flexion
weakened inversion (tibialis posterior lost)
State the nerve roots of the common fibular nerve
L4-S2
Describe the course of the common fibular nerve
popliteal fossa
medial border of biceps femoris
superficial to lateral head gastrocnemius
around the neck of the fibula
between attachments of fibularis longus muscle
splits into terminal branches
What branches does the common fibular nerve split into?
deep fibular
superficial fibular
What muscles does the common fibular nerve innervate in the thigh
short head of the biceps femoris
name the branches of the common fibular nerve that originate over the lateral head of the gastrocnemius
sural communicating branch
lateral sural cutaneous
Which area does the sural communicating branch of the common fibular nerve provide sensory innervation to?
posterolateral leg (as sural nerve)
Which area does the lateral sural cutaneous branch of the common fibular nerve provide sensory innervation to?
upper lateral leg
above sural area
State the nerve roots of the superficial fibular nerve
L4-S1
Describe the course of the superficial fibular nerve
head of the fibula
between fibularis musles, lateral to extensor digitorum longus
pierces deep crural fasia
enters foot
Which muscles does the superficial fibular nerve innervate?
fibularis longus
fibularis brevis
What are the terminal cutaenous branches of the superficial fibular nerve
medial dorsal cutaneous nerve
intermedial dorsal cutaenous nerve
What area do the medial and intermedial cutaneous branches of the superficial fibular nerve provide sensory innervation to?
dorsum of the foot
What area does the superficial fibular nerve provide sensory innervation to?
anterolateral leg
Describe how superficial fibular nerve entrapment presents
pain and paresthesia over anterolateral leg and dorsum of foot
What causes superficial fibular nerve entrapment
twisting/spraining ankle - stretches nerve in lower leg
nerve entrapment in deep crural fascia
What causes superficial fibular nerve damage
fracture of the fibula, or by a perforating wound to the lateral side of the leg.
Describe how superficial fibular nerve damage presents
loss of eversion.
loss of sensation over the majority of the dorsum of the foot and the anterolateral aspect of the lower leg
State the nerve roots of the deep fibular nerve
L4-L5
Describe the course of the deep fibular nerve
common fibular nerve
alongside anterior tibial artery
superiorly: between tibialis anterior and extensor digitorum longsus
inferiorly: between tibialis anterior and extensor hallucis longus
anterior to distal tibia, beneath extensor retinaculum
What muscles does the deep fibular nerve innervate?
tibialis anterior
extensor hallucis longus
extensor digitorum longus
fibularis tertius
State the terminal branches of the deep fibular nerve
medial terminal branch
lateral terminal branch
What is the function of the medial terminal branch of the deep fibular nerve
sensory to skin between 1st and 2nd toes
What is the function of the lateral terminal branch of the deep fibular nerve
motor to
extensor digitorum brevis
extensor hallucis brevis
What nerve is damaged in foot drop?
common fibular
or deep fibular
How is the deep fibular nerve damaged?
anterior leg muscles have been excessively used and so are compressing the nerve within the anterior compartment. The patient will experience pain in the anterior leg.
tight-fitting shoes, compressing the nerve beneath the extensor retinaculum. The patient will also experience pain in the dorsum of the foot
How does damaged to the deep fibular nerve present?
pain in anterior leg or dorsum of foot
loses the ability to dorsiflex the foot, so with unopposed plantarflexion, their foot drops.
What kind of gait does foot drop produce?
difficulty in clearing the ground during the swing phase of walking.
the foot will slap down on the floor when the patient walks, because it can’t be lowered in a controlled manner.
How is the common fibular nerve damaged?
fracture of fibula
a tight plaster cast.
How does damage to the common fibular nerve present?
lose the ability to dorsiflex the foot at the ankle joint. Hence the foot will appear permanently plantarflexed – known as footdrop.
loss of sensation over the dorsum of the foot, and lateral side of the leg.
State the definition of sciatica
symptoms of pain, tingling, and numbness
which arise from impingement of lumbosacral nerve roots as they emerge from the spinal canal,
and are felt in the distribution of the nerve root (dermatome).
There may be accompanying motor weakness in a corresponding myotomal distribution
What are some of the causes of lumbar radiculopathy
disc hernation
spinal stenosis
Spondylolisthesis
What is spondylolisthesis
proximal vertebra moves forward relative to a distal vertebra.
What is the characteristic nature of the pain in spinal stenosis?
relieved by forward flexion and worsened with extension
What are the signs of lumbar radiculopathy
+ve straight leg raise test
Numbness, paraesthesia, muscle weakness, or loss of tendon reflexes in the distribution a single nerve root.
Describe the presentation of L4 nerve root compression
loss of sensation over medial ankle and foot
weakened ankle dorsiflexion
loss of patellar reflex
Describe the presentation of L5 nerve root compression
loss of sensation in dorsal foot
weakened extension great toe
Describe the presentation of S1 nerve root compression
loss of sensation on sole and lateral ankle
weakened plantarflexion
loss of ankle reflex
What is the management for disc herniation
conservative: NSAIDs + PPI, drug for neuropathic pain,
exercise, physiotherapy
Keep active, resume normal activities, return to work. Should return to normal in 4-6wks
Spinal decompression - discectomy if pain and function have not resolved
What are the red flags for back pain?
>50y previous cancer or infection (TB, UTI) weight loss fever night sweats thoracic pain pain at night neurological problems incontinence saddle anaesthesia
What is cauda equina syndrome?
compression of the terminal spinal nerve roots of the cauda equina L2-S4
What can cause cauda equina syndrome
disc herniation
spinal stenosis (insidious onset)
cancer
trauma
What are the symptoms of cauda equina syndrome
back pain unilateral or bilateral leg pain saddle anaethesia sensorimotor loss painless urinary retention overflow incontinence
What are the signs of cauda equina syndrome?
palpable bladder sensorimotor loss in lower limbs decreased or absent reflexes loss of sensation in perianal area decreased/lost perianal tone / loss cough reflex contraction on DRE
What is the key investigation in cauda equina syndrome
spinal MRI
What is the management of cauda equina syndrome
emergency surgical decompression
What is spinal stenosis
narrowing of spinal canal or neural foramina leading to neurogenic claudication and root ischaemia
What can cause spinal stenosis
degeneration of discs
osteophytes
hypertrophic ligamentum flavum
spondylolisthesis
What are the symptoms of lumbar spinal stenosis
back pain
leg pain on walking or standing, relieved by flexion/sitting down
weakness
what investigations are needed in suspected spinal stenosis
lumbar xray
MRI
What is the treatment for spinal stenosis
NSAIDs, physio, steroid and anaethetic injections
surgical decompression
What spinal infections can you get?
discitiis
epidural abscess
osteomyelitis
What are the risk factors for a spinal infection
recent infection TB immunosupression IVDU diabetes
What are the symptoms of a spinal infection
severe localised back pain
fever
raised inflammatory markers
What investigations should be done in suspected spinal infection
Bedside:
Bloods: FBC, U+E, CRP, ESR,
Micro: blood cultures, cultures from potential primary infection sites
Imaging: MRI
What cancers can cause a spinal lesion
multiple myeloma
metastasis from breast, prostate, lung, thyroid and kidney
What are the symptoms of a spinal tumour?
thoracic pain pain worse at night localised pain weight loss malaise
What investigations should be done in suspected spinal cancer
Bloods: LFTs, Ca, Phos, alkaline phosphatase, ESR
Imaging: CTCAP, MRI
Special tests: Bence-Jones in urine (multiple myeloma)