MSK Flashcards
what is potts disease
TB of intervertebral discs
what is a Jefferson fracture
fracture of anterior and posterior arches of C1
the olecranon process is a feature of what bone
ulna
how does a anterior dislocation of the shoulder occur
ABduction, arm is externally rotated/hyperextended or blow to the posterior shoulder
how does an anterior shoulder dislocation clinically present
loss of symmetry with loss of roundness of the shoulder and arm held in an ADDucted position supported by the patients other arm
what do teres minor and infraspinatus do
external rotation
the common extensor mechanism arises from where
the lateral epicondyle
what is a swan neck deformity
hyperextension at the PIP and flexion at the DIP
boutenniere deformity
hyperflexion at the pip and extension at the DIP
what is ulnar drift
fingers all move towards the pinky
z shape deformity
hyperextension of the interphalangeal joints and fixed flexion and subluxation of the metacarpal phalangeal joint
what does ustekinumab do
inhibits IL12 and IL23
what is usekinumab good for
psoriatic arthritis
what is secukinimab used for
psoriatic arthritis and ankylosing spondylitis
what does secukinimab do
inhibits IL17
what is celecoxib
a COX 2 inhibitor NSAID
when would you not use celecoxib
not used in people with increased risk of cardiovascular events
side effects of leflunomide
similar efficacy to methotrexate, similar side effects to methotrexate, thrombocytopaenia, leucopaenia hepatitis, cirrhosis, pneumonitis, nausea/diarrhoea
also tetarogenic needs to stop 2 years before conception
side effects of sulfasalazine
NEUTROPAENIA, reversible oligozoospermia
nausea, rash, mouth ulcers, can also rarely cuase a paraticularly nasty rash which stops when dtop taking drug
side effects of hydroxychoroquine
no effect on joint damage
used in connective tissue damage eg in SLE helps skin joints, and general malaise, sjogrens and RA
can rarely cause IRREVERSIBLE RETINOPATHY
side effects of TNFa
risk of infection-TB
potentially increased risk of cancer specially skin cancer
contraindicated in pulmonary fibrosis and heart failure
what side effect can allopurinol cause
can precipitate an acute attack of gout
can cause a rash-vasculitis in the elderly, more common in elderly and in renal impairment-so use lower doses in these patients
what would you no co presecrible with azithoprine
allopurinol
why is allopurinol and azathioprine contraindicated
as you can cause marrow aplasia
HLA in RA
HLA DR4
what is good for looking at joints in early RA
ultrasound
what level on DAS28 indicates active disease
greater than 5.1
what does an increase PV mean
inflammation or tissue damage
what are the MRI findings of early Ankylosing spondylitis
bone barrow oedema, Romanus lesions and enthesittis
can you take live vaccines while you are on DMARDS
no
how does Febuxostat work
it is a XO inhibitor
how do uricosuric agents work
they don’t affect production of uric acid but they increase the clearance of uric acid
when are uricosuric agents contraindicated
in renal impairment
what is the capitellum a bony feature of
the humerus
what is the elbow joint formed of
the radio-capitellar joint and the humero-ulnar joint
what does the radio-capitellar joint do
supination and pronation
what does the humero-ulnar joint do
flexion and extension
what muscles do pronation
pronator teres proximally and pronator quadratus distally
what is supination performed by
the biceps and supinator muscles
what is chronic regional pain syndrome
characteristics are variable but include constant burning or throbbing sensation, sensitivity to stimuli not normally painful cold, light touch, chronic swelling, paniful movement and skin changes
more common in patients with chronic pain issues
need specialist pain services
pharmacological agents include analgesics, antidepressants, anticonvulsants and steroids
which muscle tears can be treated conservatively
Achilles tendon, rotator cuff, longhead biceps brachii, distal biceps
what part fo the vertebral body is involved in a wedge fracture
the anterior part
does a wedge fracture require surgical intervention
no
where are the flexors located
on the volar aspect of the forearm
what mechanism helps prevent against muscle fatigue
asynchronous motor units, recruitmenet during submaximal contractions
how is summation of twitches possible
the duration of action potential is much shorter than the duration of resulting twitch
it is therefore possible to summate twitches to bring about a stronger contraction through repetitive fast stimulation of skeletal muscle
if a muscle fibre is stimulated so rapidly that it doesn’t have an opportunity to relax at all between stimuli this is called
tetanus
can cardiac muscle be tetansied
no because the long refractory period prevents against generation of tetanic contraction
if the skeletal muscle is stimulated once a what is produced
a twitch
what does a twitch produce
produces little tension, and it is not useful in bringing about meaningful skeletal muscle activity
what happens if skeletal muscel receives a second stimulation before it had time to completely relax
the second response add to the first and a greater muscle tension is developed
how does the tension of a skeletal muscle increase
it increases with increasing frequency of stimulation
when can maximal tetanic contraction be achieved
when the muscle is at its optimum length
when is optimum length achieved
when the point of optimal overlap lf thick and thin filament cross bridges
at this point maximal tetanic tension can be achieved
when is the optimal length achieved in the body
the resting length of a skeletal muscle is approximately its optimal length
what is isotonic contraction used for
body movements and for moving objects
what does changing muscle length do to tension in isotonic contraction
muscle tension remains constant as the muscle length changes
what is isometric contraction used for
supporting objects in fixed positions and for maintain body posture
how does muscle tension develop in isometric contraction
muscle tension develops at constant muscle length
how is muscle tension transmitted to bone
via the elastic components of the muscle
how does the velocity of muscle shortening change
velocity of muscle shortening decreases as the load increases
when maximum load is carried
zero velocity of shortening ie isometric contraction
are skeletal muscle fibres all the same
no
spinal segment and peripheral nerve in knee jerk
L3, L4
femoral nerve
spinal segment and peripheral nerve in ankle jerk
S1,S2 tibial nerve
biceps jerk
C5-C6 musculocutaneous nerve
brachioradioradialis
C5-C6 Radial nerve
triceps jerk
C6-C7 Radial nerve
what are the sensory receptors for the stretch reflex
muscle spindles are the sensory receptors for the stretch reflex
what are muscle spindles known as
intrafusal fibres
what are ordinary muscle fibres referred to
extrafusal fibres
where are muscel spindles found
within the belly of muscles
where do muscle spindle run in relation to ordinary muscle fibres
muscle spindles are found within the belly of muscles and run parallel to ordinary muscle fibres
what are the sensory nerve endings known as
annulospiral fibres
what happens as the muscle spindles are stretched
the discharge from the muscle spindle sensory endings increases as the muscle and hence the spindles are stretched
what is the nerve supply to the muscle spindles
muscle spindles have their own efferent (motor) nerve supply
what are the efferent neurons that supply the muscle spindles
gamma y motor neurons
how do the y motor neurons work
they adjust the level of tension in the muscle spindles to maintain their sensitivity when the muscle shorten during muscle contraction
delayed relaxation after voluntary contraction
myotonia
what does EMG do
electrodes detect the presence of muscular activity
records frequency and amplitude of muscle fibres action potentials
helps differentiate primary muscle disease from muscle weakness caused by neurological disease
what is a stretch reflex
serves as a negative feedback that resists passive change in muscle length to maintain optimal resting length of muscle
where is an enchondroma most commoly found
in the digits
what are multiple enchondromas associated with
a non inheritable condition Olliers syndrome
what are multiple enchondromas and haemangiomas associated with
Maffuccis syndrome
where do osteomas tend to be found
in the cranial bones
what are some of the features of an osteoid osteoma
tend to be sore at night
pain resolved by NSAIDS as tumour releases prostaglandins
features of osteosarcoma
tend to be in kinds
tend to be long bones
x ray shows codmans triangle
any malignant tumour that produces osteoid is osteosarcoma until proven otherwise
features of Ewings sarcoma
malignant tumour of unknown cell origin
small round blue cell tumours
specific genetic abnormlaity
what type of collagen is found in cartilage
type II
how does type II cartilage differ from type I cartilage
type II is finer and forms a 3D meshwork but type I is thicker and aggregates into linear bundles
what is the most common type of cartilage
hyaline cartilage
what are the three forms of cartilage
hyaline, elastic, fibrocartilage
what is fibrocartilage
a hybrid between tendon and hyaline cartilage, it has bands of densely packed type I collagen interleaved with rows of chondrocytes surrounded by small amounts of cartilaginous ECM
what is bone made up of
mineral-calcium hydroxapatit crystals, water, collagen and non collagen protiens
where is cancellous bone found
cancellous or trabecular bone is found at the ends of the bone the epiphyses
what type of bone is lamellar
both cortical and cancellous are lamellar
what are the living cells in bone
osteocytes
what are the lines surrounding the osteon called
cement lines
where and what are volkmanns canals
they are inside osteons, they transmit blood vessels from the periosteum into the bone and lie perpendicular to and communicate with the haversian canals
what does trabecular bone lack
it lacks haversian canals but because the struts are thin, the osteocytes can survive from contact with the marrow spaces
what is osteoid
collagen, glycosaminoglycans, proteoglycans and other organic components of the matrix which becomes mineralised over time in the extracellular space
where are osteoclasts derived from
macrophages, several of these will fuse to form a single giant cell
how is bone laid down after it is broken
the collagen fibres are laid down in a random fashion=woven bone
this is not as strong as lamellar bone and is subsequently remodelled into lamellar bone by being broken down by osteoclasts and reformed by new osteoblasts
what is the short head of biceps supplied by
common peroneal nerve
what is adductor magnus supplied by
tibial nerve
what is the nerve supply to the posterior thigh
tibial L5-S1
what are the nerve roots of the femoral nerve and obturator nerve
L2-L4
what is froments test for
palsy of the ulnar nerve associated with cubital tunnel syndrome
it specifically tests for the adductor pollicis
common extensor origin
lateral epicondyle
common flexor origin
medial epicondyle
what is a swan neck due to
volar plate rupture
what is a boutenniere deformity due to
torn central slip extensor
dislocation at lunate can cause what type of nerve injury
median-ie carpal tunnel syndrome
what tests can be used for carpal tunnel
Phalens test and Tinels test
what tests can be used for cubital tunnel and describe how they work
hold piece of paper, test the adductor pollis muscle usually thumb will be straight but with positive forments the thumb isn’t straight
can also get hyperextension of the thumb on the ok sign
what is finkelsteins test
grab the thumb and ulnar and deviate the hand sharply
check for tenosynovitis in the ABductor pollicis longus and the extensor pollicis brevis
