lecture 10: elbow and forearm Flashcards
which of the following is NOT a static GH joint stabilizer (deltoid, labrum, capsule, GH lgs)
deltoid
arm elevation in the plane of the scapula occurs why
beacuse the scapula sits on the curved surface of the thorax
what does the elbow do
controls the movement within the spheres (position of the arm and hand) to carry out functional activties
what are the movements of the elbow
flexion/extension
pronation/supination
define valgus at the elbow
lateral deviation of a distal segment with respect to proximal segment
define varus at the elvow
medial deviation of a distal segment with respect to proxima lsegment
what is normal ROM at the elbow for flexion/extension
flexion: 140-145
extension: 0
what is normal ROM for elbow for sup/pron
80-90
what is the arc of movement required for most ADLs at the elboe
30-130 (100 degrees) in flexion/extension
50 degrees of pronation and supination
what are the bones of the elvow
humerus
radius
ulna
the medial epicondyle of the hum is an attachment for what muscles
flexors and pronators
the lateral epicondule of the hum is an attachment for what muscles
extensors
supinators
the trochlea is located medially or lateral
medial
the capitellum is located medially or lateral
lateral
what part of the humerus articulates with the radius
capitellum
what bony parts lock to form stability at the elbow
coronoid fossa with coronoid
olecrannon fossa with olectronon
during flexion, what bony segments lock together
in flexion, coronoid with coronoid fossa anterior
during extension, what bony segments lock together
olecrannon with olecrannon fossa (posteriorly)
what nerve passes medially to the elbow and wh=y is that a problem
ulnar nrve passes medially and it can get injured/entrapped
cubital tunnel is located medially or laterally
medial
the distal humerus has a 30 degree anterior or posterior curve
anterior
the distal humerus has a BLANK degree anterior curve
30 degree
because of the anterior curve of the distal humerus favours movement in flexion or extension
flexion (greater contact area during flexio)
true or false: the distal humerus only has an anterior curve
false, also has a tilt
what degrees of tilt is there at the distal humerus
6 degrees of tilt
what is there 6 degrees of tilt at the distal humerus
beacuse of trochlea protruding
what are the important aspects of the proximal ulanr
trochlea notch
olecreannong
coronoid process
olecreannon locks with olecrannon fossa in flexion or extension
extension
olecreannon locks with blank in extension
olecreannon fossa
coronoid process locks with coronoid fossa fossa in flexion or extension
flexion
coronoid process locks with BLANK in flexion
coronoid fossa
what are the important aspects of the proximal radius
radial head
radial neck
radial tub
fovea
what bone is commonly fractured at the elbow
radius
what is the radial tuberosity an attachment for
biceps
the fovea of the radius articulars with what surface
the humerus
what are the joints of the elbow joint
humeroulnar
humeroradial
proximal radioulnar
what type of joint is the humeroulnar joint
ginglymus (hinge)
what are the movments of the humeroulnar joint
flexion/extension
explain the joint space of the humeroulnar jt
assymetrical
they boney shape of the humeroulnar joint favours what
favors flexion excursion vs extension excursion
what type of joint is the humeroradial joint
ginglymus (hinge)
what are the movements possible at the humeroradial jt
flexion/extension
in the humeroradial joint, there is greater contact with elbow during extension of flexion and why
during flexion beause of anterior rotation of humerus (distally)
what type of joint is the superior radioulnar
trocchoid (pivot)
what is the movements possible at the superior radioulnar joint
pronation/supination
true or false: the superior radioulnar joint has no support from bone structure-only soft tissues
true
what are the soft tissues that support the superior radioulnar jt
annular lig (around the radial head)
interosseus membrane
what is the function of the interosseus membrane
interosseus membrane an important static longitudinal stabilizer of the forearm (less contribution to forearm rotation)
the COR during flexion and extension goes where
oblique through the capitulum anfd trochlea
why is knowing the COR at the elbow important
for orthotic hinge alignment
hinge needs to allgin with anatomical COR
axis of orthosis needs to allign with axis of arm
the COR during pronation and supination
rotaiton about a longitudninal axis between the raidl head and the ulnar head
explain joint contact with an applies compressive force during extension
there is more humeroradial contact than humeroulnar
the medial trochlea extends farther where
distally
the medial aspect of trochlear notch of ulna ectrends further where
distally
true or false: there is medial deviation of ulna with respect to humerus
false, there is lateral
there is lateral deviation of ulna with respect of humerus known ask what
carrying angle
what is the valgus/carrying angle
men=women
valgus 10-15 degrees
what are the 3 primary static constraints of the elbow
ulnohumeral articulation
anterior bundle of the medial collateral ligaments
lateral collateral ligaments
what are the 4 secondary constraings
radiocapitellar articulation
common origin of the flexors
common origin of the extensiors
capsule
when are the secondary elbow constaints going to be able to support
muscles are additional support while in tension
radial head stabilizers with stress in waht direction
valgus
olecrannon stabilizes with stress in what direction
valgus
coronoid stabilies with stres on what direction
varus direction
what are the 3 bundles of the MCL at the elbow
anterior
posterior
and tranverse
which is the most important bundle of the medial collateral ligament
anterior
what ligament is an important stabilizer at the elbow of valgus stress
medial colalteral
MCL ligaments is an important stabilizer with what kind of stress
valgus (lateral)
what are the bundles of the lateral collateral lig
lateral ulnar collateral
accessory lateral collateral
radial collateral
annular
the LCL stabilies with what stress
varus (stops it from moving medially)
the MCL deficient elbow should be rehabilitation in what postion and why
in supination as the medial muscles are taut generating greater passive tension enhancing medial sided stability
the LCL deficient elbow should be rehabilitated in what position and why
in pronation as the lateral muscles are taut generating greater passive tension enhancing lateral sided stability
in pitching, is there high valgus or varus stress
valgus
what is the average valgus torque during pitching
64 NM
when is valgus force highest during pitching
highest at late coking and acceleration phases
professional pitchers have what newtons of valgus stress during pitching
290 of force across elbow joint
what are the consequences of the fact that professional pitchers pitch at 290 N and ligamentous tensile strength is 260 N
possible rupture of ligaments.
what are the muscles that crontol the elbow
flexors
extensiors
pronators
supinators
what are the elbow flexors
biceps brachii
brachialis
brachioradiualis
pronator teres
when are biceps less active
less active with arm in full pronation
what ar ethe elbow extensir muscles
triceps brachii
anconeus
what are the pronators and supinators
pronator teres
pronator quadratus
supinator
biceps
what is the fancy name for tennis elbow
lateral epicondilyis
what is the fancy name for golfers elbow
medial epicondylitis
lateral epicondylitis affects what muscles
wrist extensors
medial epicondylitus affecst what muscles
wrist flexors
what is the cause of lateral epicondylitis and what position
overuse of the ECRB and EDC
resistance with arm and wrist in extension
according to EMG, there is decreased exntsor activity in tennis for what position
for two handed back hand
what are the consdierations of lateral epicondylitis and tennis
arm position
grip diameter
weight of item help in hand
repetition
medial epicondylistis is overuse of what muscle
flexor pronator musculature
medial epicondulitis is caused by excess what
excess valgus force and medial tension
what are the considerations of medial epicondylitis in golfing
appropriate technique
lightweigth equipment
repetition
which is harder to correct, lateral or medial epicondylitis
medial
which muscle has the longest moment arm : biceps, brachialis, pronator teres and brachiiradialis
brachioradialis
place these muslces in order of longest to shortest moment arms : biceps, brachialis
pronator teres
brachioradialis
brachioradlis
biceps
brachioalis
pronator teres
the moment arms are at peaks when arm flexed between what degrees
100-120 degrees
maximum isometris elbow flexion forec as peaks when
midrange between 75-90 degrees of flexion
what is active insuffieciency
Active insufficiency is the decreased tension of a multiarticular muscle when it is shortened across one or more of its joints.
true or false: when muscle if at shortest length, it is at strongest length
false, weakest
what is the active insuffiecieny for biceps
shoulder flexion
elbow flexion
supination
what are the movements of the wrist
flexion/extension
radial/ulnar dev
circumduction
what is the functional axis of movement of the wrist
dart throw motion
“a plane in which functional oblique motion occurs, spefically from radial extension to ulnar flexion:
why is “dart throw motion important
less movment of the scaphoid and lunate compared to pure flexion/extension or ulnar/radial devaltion
=good for people who may have instabilities
=safe protected ROM
what is the common path of motion in many daily activities of the elbow
oblique plane of movement
dart through motion
what is the ROM for flexion/extension at wrist
70-80
what is the ROM for ulnar dev at wrist
30-50
what is the ROM for radial dev at wrist
20-30
what is the functional wrist ROM
40 degrees flexion and extension should be good
what are the 6 biomechanical requirements of distal UE function
adequate flexion and extension
adequate radial and ulnar dev
adequate forearm rotation
function oblique movement
adequate ligamentous contraint (translation, rotaiton, distrcation, compression)
independant wrist and finger movement
what are the main wrist flexors
flexor carpi radialus
flexor carpi ulnaris
what are the main wrist extensors
ECRB ECRL
ECU
the variable bone geometry of the wrist does what
accomodates movement
=multifaceted articulations accomodate movement and stability
distal radius is inclined 15 degrees palmarly or dorsally
palmarly
distal radius is inclined BLANK degrees palmarly
15
distal radius is inclined 15-20 degrees ulnarly or radially
ulnary
distal radius is inclined BLANK degrees ulnarly
15-20
what is the most common upper extremity fracture in people over 50
distal radius fracture
what is the MOI for distal radius fracture
fall on outstretched hand (bending and compressive force)
what is the common fracture of the distal radius fracture
compressed and dispalced
what are the important aspects of the distal ulna
stylod process
head of ulna
what does distal ulna articulate with
TFCC
what is the movment of the radius/ulna during pronation
radius crosses over ulna with anterior roll
what is the movment of the radius/ulna during supination
radius uncrosses from ulna with posterior roll
during supination, radius uncrosses from ulna with posterior or anterior roll
posterior
during pronation, radius crosses over ulna with anterior or posterior roll
anterior
the forearm supinates maximalyl with elbow is in what postiion
elbow flexed
the forearm pronates maximalyl with elbow is in what postiion
elbow extended
elbow extension increased or decreased the transmitted forces of the DRUJ and PRUJ
increases
normally, what percentage of load is taken by the distal radius
80%
true or false: there is normally alt of difference between radial height/ulnar variation
false, not a lot
in negative ulnar variance, does more of the load get transmissted to ulna or radius
radius
with 2-5 mm of ulnar variance (negative ulnar variance) explain the load transmission
95% load transmission via radius and 5% through ulna
with negative ulnar variance there is increased risk for what
lunate injury
explain load tranmission with positive ulnar variance
60% of load transmission via radius and 40% via ulna
in positive ulnar variance, does more of the load get transmissted to ulna or radius
still more radius, but decreased from 80 to only 60%
ulna
with positive ulnar variance there is increased risk for what
ligamentous tears
what do u need to be cautious for distal radius fractures
beware of excessive hand squeezing and forceful ROM if distal radiu. does not have solid fixation
during forearm pronation, the radius crosses the ulna or oppsite
radius over ulna
