MSK Flashcards
Where are skeletal muscle cells nuclei
at the periphery just under the cell membrane (sarcolemma)
the membrane around one fibre
around a group of fibres
around a muscle
endomysium
perimysium
epimysium
what is a sarcomere
unit of contraction - smallest contractile elements in a striated muscle cell
what is a motor unit
one motor unit and the muscle fibres it innervates
the fewer the number of muscle fibres it innervates the preciser the movement
Type 1 fibres
red lots of mitochondria dont fatigue less force produced slowly contracting aerobic respiration
intermediate fibres
relatively resistant to fatigue
fast contracting
type 2 fibres
white fast contracting high force produced not a lot of mitochondria anaerobic resp fatigue easily
chondobasts become what
chondrocytes which are cartilage cells and live in the extracellular matrix in lacuna
what does the extracellular matrix consist of and that broken down is what
75% water
20% - 60% type 3 collagen - finer and 3D meshwork and 40% proteoglycan aggregates made up of GAGs
hyaline cartilage
elastic
fibrocartilage
blue/white. translucent. commonest
hello
white. type 2 collagen
haemopeisis occurs where
in bone marrow
from 20s only in axial and limb girdle
what is the outer bone called
what are the ends of the bone called
cortical
cancellous/trabecullar bone (mashed network)
lines surrounding osteons called what
cement lines
osteoproginater cells
osteoblasts
osteoclasts
osteocytes
surface of cells. reserve for osteoblasts
surface of bone. bone forming
large multinucleate. surface. bone reabsorption
within bone matrix
why type of drugs are COX2 inhibitors
what does the COX enzyme do
lead to a decrease in what
NSAIDs
responsible for inflam and pain
peptic ulcers
synarthrosis joint
amphyathrosis joint
diathrosis joint
fibrous
cartilaginous
synovial
nociceptive pain
inflam pain
pathological pain
adaptive - early warning system
adaptive - activation of immune system
maladaptive - abnormal nervous system function
polymyositis has what kind of infiltration
Derm?
endomysial lymphatic infiltration. CD8. segmental fibre necrosis
immune complex and complement deposit within and around capillaries in muscle, perifasicular muscle fibre injury, B and CD4 cells
actin myosin H zone A band I band
thin - light thick - dark just myosin all of myosin and overlapping actin the actin that isn't in A
what happens when muscle is not given a chance to relax and is continuously stimulated
tetanus
isotonic contractions
isometric contractions
body movements and movement of objects - muscle tension is constant but muscle length increases
supporting objects in fixed position, maintaining body posture - muscle length is constant but tension increases
Knee jerk Ankle jerk biceps jerk brachioradialis triceps jerk
L3, L4 femoral nerve S1, S2 tibial nerve C5-C6 musculocutaneous nerve C5-C6 radial nerve C5-C6 radial nerve
what is renal dystrophy
bone changes due to CKD
less phosphate excretion and inactive Vit D - secondary hyperparathyroidism
what is a BMU
bone multicellular unit - location of osteoclasts and osteoblasts at sire or remodelling
difference between a benign and a malignant soft tissue swelling
benign - soft, fluctuation in size, well defined, fluid filled cyst
malignant - larger, rapid growth, solid, ill defined, irregular surface, assoc LD and systemic upset
what is a lipoma
neoplastic proliferation of fat
what is a sarcoma
who does it occur in
ix
treatment
malignant soft tissue tumour arising from connective tissue
50-70s
biopsy
surgical reaction and adjacent chemo/radio
what is osteopaenia
intermediate stage of osteoporosis
3 points for cartilage
3 for bone
semi rigid deformable, permeable, avascular
rigid, non permeable, cell surrounded by vessels
whats an osteon
functional unit of bone composed of lamella
what are harverson canals
carry vessels through bone
bone mineralisation involves what kind of crystals
what do osteoblasts secrete
calcium phosphate
osteoid
what bone is laid down after a break and what bone replaces it
woven
lamellar
CK levels 200-300x BL
20-30 x BL
2-5x BL
dystrophies like DMD, BMD, myotonic dystrophy
inflam mypoathies - polymysitis, dermatomyositis
neurogenic disorders
what are the changed in DMD at a cellular level
alterations in anchorage of acting cytoskeleton to basement membrane leading to uncontrolled calcium entry into cells which triggers the apatotic pathway
Signs of myotonic dystrophy
myotonia - inability to relax muscles after exercise cataracts frontal balding weakness in muscles obv ptosis - drooping of eyelids hatchet like face low intelligence atrophy of mostly type 1 fibres
neurogenic muscle disorders at a cellular level
small angulated muscle fibres
small round muscle fibres
adults
children
what happens in motor neurone disease and what does it lead to
progressive degeneration of anterior horn cells
uncontrollable twitching of muscles
why does myasthenia gravis occur
dysfunction of acetylcholinesterase - affects neuromuscular transmission
what are some of the signs of myasthenia gravis
drooping eyelids difficulty swallowing fatigue weakness thyoma or thymix hyperplasia muscle activity gets worse with activity and gets better with rest
what muscle does froments tests and what is it done in
adductor pollicus
cubital tunnel syndrome
what are the three causes of intoeing and investigations
femoral neck antiversion - hip rotational angle
internal tibial torsion - foot shape, thigh-foot angle
metatarsal adductus - banana shaped feet
What does the intermalleolar distance have to be at 11 year old to be referred
over 8cm
what are the symptoms of 0-3 months early post and causes
fever, drainage, warmth, effusion
SA, strep, enterococci
what are the symptoms at 3-24 months delayed low grade and the causes
persistent pain, device loosening, fistula
coag neg staph
> 24 months have spread causes
SA, e.coli
what is the procedure of prophylaxis for prosthetic joint replacement
1st dose given 60 minutes before start of op
2 doses given within 24 hours after the surgery
1.2g of co-amoxiclav (PA co trimoxazole)
what is pseudo locking and when does it occur
stiffness after sitting
patellar dysfunction
what should not be given in medial epicondylitis and why
steroid injection - risk of injury to ulnar nerve
what does tibialis posterior tendon dysfunction lead to
where does it insert and what does it support
acquired flat foot
medial navicular
medial arch
what two things does hallux valgus cause and what is the treatment
bunion over first metacarpal joint
rubbing of great and 2nd to a leads to ulcers and skin breakdown
wider and deeper shoes
spacer between the great toe and the 2nd toe
what is hallux rigidus and what is the treatment
OA of the 1st metatarsal joint
arthrodesis
neuroproxia
axohotemesis
neurotemesis
temp conduction block/demeylination resolves within 2 days
nerve cell axon dies distally from point of injury - regenerates at 1mm/day
nerve transected - surgery
