LECTURE 11A: ELBOW ANATOMY Flashcards
what are the 3 elbow complex joints?
- humero-ulnar
- humero-radial
- proximal radio-ulnar
humero-ulnar articulation
1. what is the medial side?
2. what is posterior articulation?
medial side: medial lip of trochlea and trochlear notch of ulna
olecranon: posterior articulation of humero-ulnar joint
Humero-radial articulation:
what is the lateral side?
lateral side: concave radial head, convex capitulum (humerus)
All three elbow joints share a ____
capsule! They are under one house
T or F: The humero-ulnar joint (the big one) is very stable
T, very stable! lots of bony congruency unlike the shoulder
At the humero-radial articulation, the radial head resists _____ stress at elbow
VALGUS stress (bc it is concave)
also ligaments to help out!
Proximal radio-ulnar joint is made of ____, ____, and _____
radial head, annular ligament ring, radial fossa of ulna
The proximal radio-ulnar articulation is held together by
interosseous membrane
what joint does mainly pronation and supination?
Proximal Radio-ulnar articulation
optimal motion consists of:
___ pronation
___ supination
70° pronation & 80° of supination
functionally, what ROM is needed at elbow?
30 degrees of extension, 130 degrees of flexion
Does the elbow heal well?
Yeah! good blood flow
Is the elbow good at compensating?
No! Since it is really strong and stable, it will not compensate/adjust well.
Tiny bad things can cause a lot of problems (small osteophyte = big problem)
Is the elbow prone to overuse injury?
HECK YEAH
capsular pattern of humero-ulnar joint
flex loss > ext loss
closed packed position of humero-ulnar joint
full ext, full forearm supination
The medial side is longer than the lateral side of the elbow. Why?
longer
Why do females have a larger carrying angle?
more lax = more hyperextension
medial ulna travels laterally during extension
open packed position of humero-ulnar joint
70° flex, 10° forearm supination
humero-radial joint is what type of joint and has what motions?
Uniaxial hinge joint (2 DOF)
Flex/ext
Spin
CPP of humeral radial joint
90° flex, 5° forearm supination
OPP position of humero radial joint
full ext, full forearm supination
capsular pattern of humero-radial joint
No real capsular pattern
Clinically, pronation loss = supination loss
proximal radio-ulnar joint: will you lose ROM when this is the issue?
not really, it is the end range pain
proximal radial-ulnar joint
greatest extensiblity and mob position of the elbow joint capsule
b/t 70-90° flex
If you injure the elbow, how easy is it to regain motion?
NOT THAT EASY:
does not respond well to injury
forms thick scar tissue = contractures due to less motion/WB
medial ligament complex/UCL
is the primary restrain to ____
valgus stress at elbow (the most common way to go is valgus in injury)
What part of the UCL gets hurt the most?
anterior: strongest and stiffest
radial-collateral ligament = lateral collateral ligament (LCL) is primary restraint to _____ at elbow
postero-lateral instability at elbow
fork, attaches to both radius and ulna
LCL is taut in ____
full supination
*provides some varus stabiltiy
What are 2 distinct components of the lateral ligament complex?
Radial collateral ligament
Lateral (ulnar) collateral ligament
less discrete, kinda look like capsule thickeniings
annular ligament does what?
very strong loop around radial head!
maintains proximal radial-ulnar joint relationship
*not likely to tear, more likely to pop out under
Internal circumference lined w/ cartilage to ↓ friction
main WB joint of the wrist?
of the elbow?
wrist: radial-carpal
elbow: humero-ulnar
*interosseous membrane assists in force transfer from radius to ulna
interosseous membrane fibers are directed away from teh radius in a _______ direction
oblique medial direction
The interosseous membrane is also called ________ , a collagen sheet that binds radius and ulna together
radioulnar syndesmosis
____ provides attachment sites for deep muscles of forearm
interosseous membrane
flexor pronator strain in baseball is common. Why?
They go together, and baseball is throwing motion (flexion + pronation)
What elbow muscles are anterior/flexor group
Biceps brachii
Brachialis
Brachioradialis
What elbow muscles are posterior/extensor group
Triceps brachii
Anconeus
fibro-osseous canal through which ulnar nerve passes through
cubital tunnel
SUPER SUPERFICIAL
What increases cubital tunnel volume?
elbow held in extension
What decreases cubital tunnel volume?
full elbow flexion, space occupying lesions, OA, RA, heterotopic bone formation, trauma to nerve
borders of the cubital tunnel
Floor – UCL
Roof – aponeurosis, arcuate lig
Posterior – medial head of triceps
Anterior – medial epicondyle
Lateral – olecranon
borders of the cubital fossa
Lateral – brachioradialis, ECRL
Medial – PT
Proximal – imaginary line that passes through humeral condyles
Floor – brachialis
cubital fossa contents
distal biceps tendon
median n.
brachial a.
radial n.
medial cubital cutaneous v.
Elbow has good blood and nerve supply! What are the arteries?
- brachial artery
- radial artery
- ulnar artery
- middle and radial collateral arteries
- superior and inferior ulnar collateral arteries
Posterior / extensor-supinator forearm group
Supinator
ECRL, ECRB, EDC, EDM, EI, ECU, APL
Anterior / flexor-pronator forearm group
Pronator teres
Pronator quadratus
FCR, FCU, FDS, FDP, PL
If you lose flexion/extension, will you lose supination/pronation?
YES, interdependent, esp at end ROM
they share a joint capsule
