Movement Science: Lecture 7 - the elbow complex Flashcards
what joints makes up the elbow complex
elbow joint: humeroulnar and humeroradial joints
Proximal radioulnar joint (PRUJ) and distal radioulnar joint (DRUJ)
the elbow joint is a ____ joint with ___ DOF
hinge
1 (flex/ext)
what plane does the elbow joint move in and around what axis
sagitall and coronal
the proximal radioulnar joint and distal radioulnar joint what type of joint and how many DOF
diarthrodial pviot joint and 1 DOF (sup/pro)
what is medially located on the humeroulnar articulation
trochlea
the trochelar groove divides into ___ and ___ portions
medial and lateral
what receives the coronoid process of ulnar at the end of elbow FLX
coronoid fossa
what is the proximal humeroradial articulation
capitulum
what does the capitulotrochlear groove separate
the capitulum from the trochlea
what receives the head of the radius in full elbow flex
radial fossa
what receives the olecranon process of ulna in full elbow extension
olecranon fossa
the trochlear , coronoid fossa, capitulum , radial fossa and olecranon fossa are apart of what joint structure
proximal joint structure of the elbow joint
the distal joint surface of the elbow joint is made up of what
radius and ulna
what part of the distal joint surface of the elbow has a concave surface called the trochlear notch with trochlear ridge
ulna
what process is at the proximal end of the trochlear notch of the ulna ? distal end?
olecranon process
coronoid process
what notch is lateral to the coronoid process of the ulna and what does it articulate with
radial notch and articulates with the radial head
what part of the distal joint surface of the elbow has a cup shaped concave surface called fovea
radius
the radius is surrounded by a ___ rim that fits into the ____ grooove
convex
Capitulotrochlear
in the humeroulnar joint what slides on what
trochlear notch slides on trochlea
in full flexion of the elbow joint at the humeroulnar joint , what process enter the coronoid fossa ?
coronoid process
during full extension of the elbow joint at the humeroulnar joint the olecranon process enters what
the olecranon fossa
at the humeroradial joint of the elbow what slides over what
the concave radial head slides over the convex capitulum
in full flexion of the elbow joint at the humeroradial joint , the rim of the radial head slides into what
radial fossa
in full extension of the elbow joint at the humeroradial joint , what happens between the head and the capitulum
there is no contact
what kind of joint capsule is the elbow
large , loose and weak
the joint capsule of the elbow is continuous with and reiinforced by what
collateral ligaments
what lines the coronoid , radial and olecranon fossa of the elbow
synovial layer
what type of fold is there between the proximal radius and ulna
triangular synoival fold
hypertrophy of triangular synovial fold between the proximal radius and humerus can causes what
lateral epicondylalgia ,inflammation or degenerative changes
the triangular synovial fold can be aggravated by what kind of activities
repetitive such as reptitive gripping , wrist extension , pushups
hypertrophy of triangular synovial fold between the proximal radius and humerus can be improved how
distraction of humeroradial joint
the triangular synovial fold between the proximal radius and humerus is located on which side of the elbow
lateral
how many bundles for the MCL/ UCL have
3 ( ant, post , transverse )
the anterior bundle of the MCL is primary restraining to what
valgus stress ( arm going out )
20-120° of elbow flex
what bundle of the MCL limits elbow ext and less restraint to valgus stability
posterior
what bundle of the MCL may help keep joint surfaces in approximation
transverse
what does the LCL complex do
reinforces humeroradial articulation
the LCL provides some protection against what kind of stress
varus
what ligaments are secondary restraint to combined forced varus and supination forces
Lateral ulnar collateral lig and annular lig
what are the primary flexors of the elbow joint
brachialis
biceps brachii
brachiorad secondary
what are primary extensors of the elbow joint
triceps
anconeus
What is a normal carrying angle?
15°
if someone has a carrying angle > 15° what is that called? what about < 5°
cubitus valgus
cubitus varus
how much AROM is there at the elbow joint for flexion ? PROM?
AROM: 135-145
PROM: 150-160
do you have more flexion of the elbow joint in sup or pronation
supination
during full extension of the elbow joint where is the stability at
50% from the bone and 50% from LCL
during 90° of elbow flexion where is the stability coming from
anterior part of MCL , resist valgus and distraction stress
during full flexion of the elbow joint where is the stability coming from
coronoid process with fossa and rim of radial head
what muscle is for mobility due to insertion being close to elbow?
brachialis
When is brachialis MA greatest?
greatest slightly more at 100 degrees of elbow flexion
is brachialis affected by elbow or shoulder position?
no
which muscle is a mobility muscle and has MA greatest at 80-100 degrees of elbow flexion?
biceps brachii
When is biceps brachii a less effective elbow flexor?
less effective as an elbow flexor when in full extension
when is biceps brachii most active?
during elbow flexion with forearm supination
What is a compressing muscle
brachioradialis
when is brachioradialis peak moment arm?
100-120 degree of elbow flexion
brachioradialis moderate activity when in what forearm postion
neutral
what muscle has dual action for returning to neutral FA position?
brachioradialis
is the triceps brachii affected by position of forearm?
no doesnt matter if pro or sup either
When is triceps brachii active insufficency?
elbow extension when shoulder is hyperrextended- avoided during pushups
how is force production of triceps brachii based on shoulder position?
variable
What muscle acts as a synergist to prevent elbow flexion
triceps brachii
what muscle assist with forearm extension
anconeus
what is part of the proximal radioulnar joint (PRUJ)
radial notch or ulna
annular lig
radial head
radial fovea
humeral capitulum
what is part of the distal radioulnar joint (DRUJ)
ulnar notch of radius
radioulnar disc (triangular fibrocartilage complex )
head of ulna
what ligaments are apart of the PRUJ
annular lig
quadrate lig
oblique cord
both the ulna and radius (fovea) are ___ surfaces moving on ____ humerus during ____ chain
concave; convex; open
what ligament encircles the radial head
annular lig
does the annular lig limit anything?
no just adds stability
the quadrate ligaments reinforces the ….
inferior aspect of the joint capsule
what lig helps maintain radial head to radial notch
quadrate
what does the quadrate lig limit
spin of radial head in sup and pro
how do the fibers of the oblique cord run
fibers run at right angle to fibers of interosseous membrane
what may the oblique cord do
may assist in preventing speration of radius and ulna
the dorsal and palmar ligaments of the DRUJ extend along which margins
margins of the TFCC
where does the dorsal and palmar ligaments of the DRUJ insert into
ulnar fovea and base of ulnar styloid
the TFCC and DRUJ capsule can also provide what
stability
after injury the DRUJ can limit what ? and what can build up
ROM and scar tissue
what stabilizes both the PRUJ and DRUJ
interosseous membrane
how is the interosseous membrane during rotation of the radius and ulna
taut to keep radius and ulna from splaying
what are the radioulnar muscles?
-PT
-PQ
-BB
-Supinator
Function of PT
-humeral and ulnar heads
-2 joint muscle
-stabilizes proximal joint
-pronation and elbow flexion
is PT a two or one joint muscle?
two
is PQ a two or one joint muscle?
one
what muscle is the dynamic stabilizer of the distal joint?
PQ
what muscle is the radioulnar supination and elbow flexor?
BB
when is supinator active?
active in all positions
wraps around radius in pronation to perform uncoiling/spinning
supinator
the radioulnar axis of motion is linked by a ____ longtitundinalaxis from radial head to ulnar head
single
how is the radius and ulna aligned during supination
parallel
what is supination limited by
tension in palmar radioulnar lig and oblique cord
when is torque generation the greatest for supination? when the arm is in pronation or supination
when forearm is in pronation
during pronation how does the radius and ulna move
radius rotates around ulna
what is limiting pronation
bone on bone
dorsal radioulnar lig
posterior fibers of MCL
when is torque generation the greatest for pronation? when the arm is in pronation or supination
forearm in supinated position
what is the ROM of radioulnar joint
150° (measure in elbow flx not ext due to shld IR and ER)
pronator teres role in elbow flexion?
slight role
PT stablizes what joints?
-proximal radioulnar
-humeroradial joints
is PQ affected by changes in elbow f/e?
no
is PQ a static or dynamic stabilizer and maintains compression at what joint?
dynamic; distal radioulnar joint
is supinator restisted or unresisted with and without elbow flexion? what muscle kicks in with resistance?
unresisted; biceps
when does supinator have greatest torque
75% pronation compared to neutral pro/sup
what muscle may act as a pronator when FA in supination? And a supinator when FA in pronation?
brachioradialis
when is brachioradialis most active
rapid alterations of sup/pro with elbow at 90 degrees
the radioulnar stability comes from muscular support of DRUJ from what muscles
pronator quadtrus and extensor carpi ulnaris tendon
the radioulnar forearm is stabilized by what muscle in pro/sup and gripping activites
extensor carpi radialis brevis
the dorsal radioulnar lig is taut in what position
pro
the palmar radioulnar lig is taut in what position
sup
the interosseous lig supports what
force transmissions esp thru WB
the TFCC transmits ___ and ____ forces and stabilizes what
compression and tension
carpals
in weight bearing the interosseous has greater ground reaction force thru what
radial head due to size
during weight bearing the interosseus between the radius and ulnar becomes ____
taut
in weight bearing , the interosseus transmits forces from where to where
radial head to head of ulna (proximal FA)
functional total ROM required for most activities soo there is how many degrees of elbow flexion and how many degrees of forearm rotation
~100° of elbow flexion (30-130°)
~ 100° of forearm rotation (50° each sup/pro)
does PRUJ have cascading consequences at DRUJ?
yes
T/F: hand and wrist muscles that cross the elbow help to stabilize the elbow during function ?
yes
ex: FCU reinforces MCL during throwing
CRITOE Growth plates ossification centers
C: capitelllum 1
R: radial head 3
I: internal (medial) epicondyle 5
T: trochlea 7
O: olecranon 9
E: external (lateral) epicondyle 11
what is the MOI of bony compression injuries at the elbow
FOOSH with elbow in extension
what is the results of a FOOSH with elbow extension
fx of proximal ulna and anterior dislocation of radial head
what is the MOI of muscle compression injuries at the elbow
repetitive contraction of FCU may compress ulnar nerve (pitching)
nursemaid elbow is an example of what type of injury
distraction
what is it called if the radis is pulled inferiorly from annular lig
nursemaids elbow
what type of injury is UCL and medial joint instability secondary to repetitive valgus stress with pitching
varus/valgus injuries
during varus/valgus injuries one side is ___ while the other is ___
compressed
distracted
UCL instability can causes (increased/decreased ) carrying angle and radial head compression on ____ and can lead to asvascualr necrosis of ____
increased
capitulum 2x
ulnar neuritis and medial/lateral epicondylitis is an example of what type of injury
varus/valgus injuries
varus force creates valgus stress what is distracted what is compressed?
lateral: compression
medial: distraction
where is the highest incidences of peripheral neuropathies in the body
elbow joint
why is the elbow join the highest incidences of peripheral neuropathies in the body
due to superfical positioning of nerves and mechanical/repepitive stresses on elbow
