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humeral-ulnar jt - what type?
saddle
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humeral-radial jt - what type?
ball and socket
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sup radio-ulnar jt - what type?
trochoid joint / pivot joint
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trochoid / pivot joint def
- a synovial joint in which one bone pivots within a bony or an osseoligamentous ring, allowing only rotary movement;
- ex: the joint between the first and second cervical vertebrae, and the sup radio-ulnar joint
- Called also rotary joint.
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inf radio-ulnar jt - what type?
trochoid/pivot
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the long joint between radius and ulna - tell me about it?
syndesmosis w interosseus membrane
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ginglymus jt def
- hinge joint
- articular surfaces are molded to each other in such a manner as to permit motion only in one plane
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elbow jt is arguably ginglymus, but functions as tho __
saddle joint - it has too much mvmnt to be hinge or uniaxial
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what kind of joint is the elbow?
compound (not complex bc no disk)
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3 joints that make up the elbow
- humero-ulnar (saddle jt)
- humero-radial (ball n socket)
- sup radio-ulnar (trochoid)
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at the elbow, flex/ext abd/add, sup/pron happen at which joints?
- flex/ext: hum-uln
- abd/add: hum-uln
- sup/pron: hum-rad
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trochlea capitulum - which is where?
- troch is medial w ulna
- capitulum is lat w radius
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how is the trochlea angled? why?
45 degrees ant to promote flexion
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contours fo trochlea
- ant post it's convex
- med to lat it's concave
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end feel of elbow extension/flexion?
- ext: bony bc of olecranon hitting olecranon fossa
- flex: muscular, - only bone on bone if there's no muscle mass
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contour of radial head?
rel of radius to capitulum?
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prox rel of radius to ulna contours
- convex on concave (the radial notch of the ulna is concave)
- radial head spins in this notch
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annular lig
- attaches only to the ulna, not at all to radius
- attaches ant and post to ulna and surrounds the radius, protects it, keeps it close to ulna
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distal radio ulnar jt contours
- radius to ulna: concave to conves
- the ulnar notch of the radius is concave, and the ulnar head is convex
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where do the ulna and radius see a disk?
- at the distal radio-ulnar joint
- there's a triangular disc there
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tell me about the triangular disc at the distal radio-ulnar joint?
- it reinforces the joint
- fills the gap btwn distal ulna & prox carpals
- gets reinforced by ant & post RU ligs
- it's a space filler
- stabilizes wrist
- shock absorber
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if the disc at the distal radio-ulnar jt is present, what's the wt distribution? if it's not?
- w disk: radius bears 60% ulna 40%
- if disc is disrupted: radius gets 95% of load
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TFCC
- triangular fibroartilagionous complex
- it's housed with the disc at the distal radio-ulnar jt
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distal ulna concave/convex?
- convex where it meets the radius
- concave for the carpals
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when is there rolling at the humero-ulnar jt?
going in and out of terminal ext/flex
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which way does the ulna roll on the humerus going from terminal ext into flex?
5 degrees IR
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fwhich way does the ulna roll on the humerus going into terminal flexion
5 degrees ER
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how does the ulna move during sup and pro?
- sup: forward and medially
- pro: post and lat
- it's as if it's trying to join the radius
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three fibers of the medial/ulnar collateral ligament of the elbow
- anterior
- intermediate
- posterior
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the anterior fibers of the medial/ulnar colateral lig do what?
- valgus stability
- strengthen anular lig
- couple w flexor carpi ulnaris to create cubital tunnel for ulnar nerve
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the intermediate fibers of the medial/ulnar colateral lig do what?
most helpful in valgus stability
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the posterior fibers of the medial/ulnar colateral lig do what?
not as distinct or powerful as rest of fibers in this lig
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Tardy Ulnar Plsy
a stretch injury on the ulnar nerve
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3 lateral ligs of the elbow
- the lateral/radial collateral ligaments:
- lateral ulnar collateral lig
- radial collateral lig
- accessory lateral collateral lig
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where's the lat ulnar collateral lig
when is it most stretched?
- attaches hum to ulna
- lat epicondyle --> supinator crest
- flexion
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tell me about the 3 parts of the radial collateral lig at the elbow - gen shap and where are they taut?
- it's fan shaped
- ant is taut in ext
- middle is taut thru both
- post is taut in flex
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pic of lat collateral ligs
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tell me about the 3 parts of the radial collateral lig at the elbow - gen shap and where are they taut?
attaches radius to ulna
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when is the interosseous lig of the forearm most taut?
5 degrees sup
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tell me about the annular lig
- fibrocartilage
- very strong
- makes a ring around the radius, but only attaches to the ulna (it's continuous to radius, not attached)
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quadrate lig
- from radius to ulna
- at radial notch/neck of radius on ant side, going to supinator fossa of ulna
- sits right below anular lig
- it's tiny, just connecting the two bones for stability and to limit spin
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oblique ligament/cord
- proximal to interosseous lig
- it run from medial radius to lateral ulna, more proximally
- kinda twists in pronation
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zero starting position aka anatomical position for elbow
upper arm and forearm in frontal plane w forear sup and elbow straight
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how's the synovium in the elbow?
- there's lots
- bursa over olecranon can get big as a baseball
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resting pos of humero-ulnar joint?
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resting pos of humero radial joint?
fully ext and sup
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resting pos of prox RU joint?
flex 70 sup 35
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resting pos of distal RU joint?
sup 10
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close-packed pos for humero-ulnar jt?
fully ext and sup
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close packed for humero-radial jt?
flex 90 sup 5
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close packed for prox and dist RU jts?
sup 5
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capsular pattern of elbow
- flex limited > ext
- (roughly 90:10)
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capsular pattern of forearm?
- sup = pro
- only occurs when there's significant restriction of flex and ext
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stretch elbows?
- NO! it'll give heterotropic bone formation
- but a controlled prolonged stretch in a DynaSplint is ok
- work on active ext to get ROM
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double crush injury
nerve impingement in cervical spine and in extremity (often in cubital fossa)
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triangle sign at elbow
epicondyles plus olecranon make a triangle when flexed, straight line in ext
(if not, sign of olecranon bursitis??)
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AROM and PROM for elbow
- flex: 140-150
- ext: 0 (or 5 hyperext is ok)
- pro: 80-90
- sup: 90
and for PROM, add abotu 10-15
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end feels of elbow flex ext
- ext - boney
- flex - soft tissue
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end feels for sup/pro
- sup: abrupt and firm
- pro: hard, bone on bone
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