MSK/movement Flashcards
how do you not cut off circulation in your knee when flexion of your knee?
peri-articular arterial anastomoses - anastamoses help supply blood at front of knee even when blood supply cut off
what is an articular surface?
surface forming the joint
where do arteries supplying joints come from?
large named arteries located near the joint - articular branches
what sensations are detected by sensory receptors of the joints nerves?
-pain
-touch
-temperature
-pro-prioception (being able to know the position of your joint without looking at it)
does joint have nerve & arterial supply?
yes- excellent sensory nerve supply
what are the classifications of joints?
- synovial
- cartilaginous
- fibrous
*each is a comprimise between mobility & stability e.g. more mobility = less stable and vice versa
what is mobility/stability balance of fibrous joints?
more stable - don’t move much
what are the types of fibrous joint?
- syndesmoses
= unite bones with a fibrous sheet (membrane)
= partially moveable - sutures
= between bones of skull e.g. coronal suture
= highly stable
what is interosseous membrane?
example of fibrous sheet between fibula & tibia - syndesmoses fibrous joint example
what are fontanelles?
they’re wide sutures in neonatal skull (anterior, posterior & lateral) that allow growing skull bones to “slide” over each and make babies head smaller for birth canal (called moulding)
- explains babies “soft spot” because it’s gaps between bones made of fibrous fluid that allow bones to move, a bit like tectonic plates
what are 2 types of cartilaginous joint?
primary or synchondroses
and
secondary or symphyses
what is description of primary/synchondroses cartilaginous joint?
joint where bones joined by hyaline cartilage
e.g. cartilage connecting rib to sternum or cartilage connecting diaphysis to epiphysis
- when it’s cartilage joining diaphysis to epiphysis the hyaline cartilage ossifies and fuses the 2 bone parts together
what is cartilaginous joint mobility/stability balance?
limited mobility but relatively stable
what is description of secondary/symphyses cartilaginous joint?
joint where body of one bone meets body of another
- strong & slightly moveable
- fibrocartilage
example = intervertebral discs and pelvic bone (pubis for birth)
what is problem with cartilaginous joints?
both types can “slip”
- slipped disc in vertebrae can compress spinal cord
describe appearance of fibrocartilage in symphyses cartilaginous joint intervertebral disc
outer fibrous annulus fibrosus (fibrous ring)
inner soft nucleus pulposus (soft centre- 90% water in newborns)
what is a synovial joint?
a joint that joins bone or cartilage with a fibrous joint capsule that is continuous with the periosteum of joined bones
what is structure of synovial joint?
-articular surfaces covered by hyaline cartilage
-capsule that wraps around joint (external fibrous layer and internal synovial layer)
-inner synovial fluid which cushions, nourishes and lubricates
- joint is supported by ligament (fibrous band connecting bone-bone)
general structure associated with: skeletal muscles & their tendons, bursae (fluid filled sac that prevents friction - can be extension of joint cavity or close sac from joint cavity)
tendon and ligament difference?
tendon = supports bone to muscle
ligament = supports bone to bone
what are the 5 types of synovial joints?
- ball & socket = good range of movement - less stable
- hinge = movement in 1 direction
- pivot = rotation (like head radio-ulna joint)
- plane = movement in 1 direction but more limited than hinge - gliding joint (wrist)
- bia-axial = movement in 2 planes, 1 plane less than the other(for example = knuckle)
what is order of joint types in order of decreasing mobility in an adult?
synovial - cartilaginous - fibrous
ball and socket in hip vs in shoulder
hip = tighter fit so more stable but less mobility
shoulder = looser fit so more mobility but less stable therefore shoulder has more dislocations
*some people have hyper mobility - like people able to dislocate & pop back
what determines possible movement at each joint?
shape of articular surface
what does subluxation mean?
reduced area of contact between articular surfaces (not complete dislocation)
what does dislocation mean?
complete loss of contact between articular surfaces
what are common joints of dislocation?
- shoulder
-hip - pubic symphysis (softens under influence of placental hormone relaxin in pregnancy)
- knee
- ankle
- interphalangeal joints
- craniovertebral joint (skull to vertebrae)
- temperomandibular joints
-acromioclavicular joint
where is temperomandibular joint?
it’s the synovial articulation between mandibular fossa (cavity) & articular tubercle of temporal bone superiorly & the head of condylar process of the mandible inferiorly
where are skeletal muscles usually found?
deep to deep fascia with tough fibrous connective tissue covering
what do longer muscle fibres mean?
greater potential range for shortening so greater potential range of movement produced at joint
what is an example of circular muscle?
orbicularis oculi (around eye)
what is an example of pennate muscle?
deltoid (across shoulder & chest)
what is an example of quadrate muscle?
rectus abdominus (abs)
what is an example of fusiform muscle?
biceps brachii (biceps over humerus)
what is an example of flat aponeurosis muscle?
external oblique (side of abdomen)
what are the features involved in naming muscles?
shape (latin/greek name)
location (body region)
size (relative size e.g. major/minor)
bony attachement (main one)
action/movement (main one)
what is an aponeurosis?
flattened tendon - commonly associated with flat muscles and attach muscle to soft tissue rather than bone
do tendons contract?
no - non contractile
where do muscles attach?
2 points of attachment:
- origin on 1 side of the joint
- insertion on other side
what is function of skeletal muscle?
to move origin & insertion closer together during contraction
during contraction - muscle fibres shorten along x-axis between origin & insertion
how can you work out the action of any muscle? i.e. which direction it moves
- which joint it spans
- long axis of muscle fibres (tells you what direction it will contract)
- aspect of joint that’s spanned
- shapes of articular surfaces of the joint
what is flexion withdrawal reflex?
like touching something hot, Nerve connections are at spinal cord level the brain is not involved
= automatic response
what is stretch reflex?
like bicep jerk, knee jerk, ankle jerk reflexes
- a tendon hammer used to apply brief sudden stretch to muscle via tendon and reflex contractions result in brief twitch of muscle belly or movement in normal direction
= this is protective response against overstretching
what are 2 main types of skeletal muscle flexes?
stretch reflex and flexion withdrawal reflex
describe process of deep tendon reflex?
type of stretch reflex - example hammer light on tendon of knee
- sensory nerve from muscle detects the stretch & tells the spinal cord
- synapse in the spinal cord between the sensory & motor nerves
- motor nerve from spinal cord passes message to muscle to contract
- the neuromuscular junction is the synapse where the motor nerve communicates with the skeletal muscle
- the whole route taken by the action potentials is called the reflex arc
- brain prevents reflex from being overly brisk
what does a normal stretch reflex indicate?
the following are working:
- the muscle
- its sensory nerve fibres
- its motor nerve fibres
- the spinal cord connections between the two
- the neuromuscular junction
- “descending controls”from the brain
what is muscle paralysis?
no functioning nerve supply, reduced tone (floppy) if were to test the muscle, muscle can’t contract
what is muscle spasticity?
muscle contracting, controls from brain not working properly, tone increased (tighter), has intact and functioning motor nerve
what is muscle atrophy?
wasting = becomes smaller, reducing muscles bulk e.g. after cast on = develops after inactivity
what is muscle hypertrophy?
individual muscle cells get bigger, not same thing as hyperplasia (when you get increase in number of cells)
