elbow Flashcards
What is the elbow joint comprised of?
distal humerus, proximal radius and ulna
is surrounded by a fibrous capsule
What part of the distal humerus articulates with the trochlear notch of the ulna?
trochlea
anterior/medial projection
What part of the distal humerus does the radial head articulate with?
capitulum
lateral projection
What is the coronoid fossa for and what is it above?
small depression above the trochlea for the coronoid process of the ulna to fit
what is the olecranon fossa and where is it?
large depression for the olecranon on the posterior surface of the distal humerus
What part of the proximal ulna articulates with the olecranon fossa?
olecranon process, hook shaped projection
What does the radial notch of the ulna articulate with and when?
with the radial head when the patient is supinating or pronating the forearm
What is the attachment site for the distal biceps?
radial tuberosity (on the medial radius)
What is the anterior elbow also called?
antecubital fossa/crease
Where does the median nerve run in the elbow joint?
medial to the brachial artery and biceps tendon
how should you scan the distal biceps insertion in LAX?
with the arm hyper-supinated
What area of the elbow is commonly scanned for joint effusions?
(anterior elbow)
radial and coronoid fossa
Where are anterior fat pads found in the elbow joint?
what is the function?
at the bottom of both the radial and coronoid fossas
it cushions the bones and protects against hyper extension
What can you see when excessive fluid is present in the joint recess?
anterior fat pad will be elevated, creates the sail sign on XR
What is the medial elbow responsible for?
flexing the elbow
flexors run through the medial elbow and down to the palmar side of the hand
What is the common flexor tendon comprised of and where do they attach?
pronator teres
flexor digitorum
flexor carpi radialis
- attach on the medial epicondyle
(is a dynamic stabilizer of the elbow)
What is the UCL comprised of? (3 pieces)
anterior bundle: largest and most important**
posterior bundle
transverse bundle (or Coopers ligament)
What is valgus stress and what ligament of the elbow protects against it?
valgus stress is when you hold your arm stable and pulling it laterally - problems are seen when it is painful
UCL
Where is the most common location for ulnar nerve entrapment and what is it called?
elbow joint is most common place, called cubital tunnel syndrome
Where does the ulnar nerve run?
runs under and around the medial epicondyle of the humerus
What forms the roof of the cubital tunnel?
(what is the name of the retinaculum)
Osborne ligament
What is the primary function of the triceps tendon?
are tears of the triceps common or rare?
extension of the elbow, composed of 3 muscle bellies that come together in a common insertion
rare
what is the lateral elbow responsible for?
extension of the elbow
What does the common extensor tendon attach?
the forearm extensor muscles to the lateral epicondyle of the humerus
What are the group of muscles that make up the common extensor tendon?
extensor digitorum
extensor digit minimi
extensor carpi ulnaris
extensor carpi radialis
what is the most common tendon affected in lateral epicondylitis?
extensor carpi radialis
What ligament connects the radius to the ulna in the radiocapitular joint?
annular ligament
holds radius against the ulna
What is affected with medial epicondylitis? what is it caused by?
common flexor tendon
caused by excess or repeated stress
which tendons are commonly affected by medial epicondylitis?
superficial flexor tendon and pronator teres at the insertion to medial epicondyle
What is most commonly affected in common extensor tendinopathy? (what tendon)
what is it caused by
extensor carpi radialis brevis
repetitive supination of wrist or arm
What pathology is uncommon with the biceps tendon but happens due to weight lifting?
rupture of the biceps tendon
is a popping sensation, painful and palpable with muscle retraction
how does a partial thickness tear of the distal biceps tendon appear?
thick, wavy and echogenic where it is still attached
What is the measurement that demonstrates UCL injury/disruption?
> .5mm of the humeral-ulnar joint when opening under valgus stress
What is olecranon bursitis composed of?
increased fluid in the bursa and edema in the surrounding tissue
What causes olecranon bursitis?
trauma, autoimmune, gout, rh arthritis, pressure or infection
What usually causes a triceps tendon rupture?
what can it cause in the cubital tunnel?
FOOSH injuries
ulnar nerve compression due to excess fluid pressure
the elbow is the second most common site for what?
loose bodies
- can accumulate in presence of degenerative path and trauma
- migrate to the olecranon fossa
What can compress the ulnar nerve in the cubital tunnel?
thickened Osborne’s ligament/retinaculum
ganglion cyst
bony spur
fluid effusions
What are the symptoms of ulnar nerve compression?
medial elbow pain and sensory loss in the 4th and 5th fingers
What pathology of the ulnar nerve occurs in 20% of normal elbows?
medial dislocation of the nerve
repeated friction can cause neuritis
