general knowledge of the elbow
blood supply to the elbow joint
brachial artery
what type of joint is the elbow
hinge synovial joint
what forms ligaments
- joint capsule is strong and fibrous it strengthens the joint
- the capsule is thickened medially and laterally to form collateral ligaments
what does bone growth and maintaince require
vitamins = A C D
minerals = calcium, phosphorus and magnesium
hormones = parathyroid, growth and calcitonin
what population do 95% of supracondylar fractures occur in
what is the peak incidence age range (bonus 100)
kids
during a fall onto the outstretched hand in a child
5-7 years old
innervation to the elbow joint
-medial
- muscultaneous
- radial
- ulnar
what 3 synovial joints make up the elbow joint
- humeroulnar (trochlear) joint = between humeral trochlea and ulnar trochlear notch
- humeroradial joint = between the capitulum of the humerus and radial head
- proximal radioulnar joint = between head of radius and radial notch of the ulna
(only the first 2 are included in the elbow joint, the proximal radioulnar joint is a separate articulation within the elbow joint capsule)
how may a fracture effect the antecubiotal fossa
The displaced fracture fragments may impinge and damage the contents of the cubital fossa such as the median and radial nerve
what happens in stage 1 of bone repair
Hematoma formation
- blood vessels in broken bone tear and haemorrhage results in formation of clotted blood or a hematoma at site of break
- severed blood vessels at the broken ends are sealed by the clotting process
- bone cells deprirved of nutrients begin to die
what type of fracture is typically a supracondylar
transverse between the 2 epicondyles framed by the olecramon fossa and coronoid fossa which lie opposite each other in the distal humerus
what muscles flex the elbow joint
- brachialais
- biceps brachii
- brachioradilais
define bursa and the function
bursa = sac like structure containing small amount of synovial fluid
- the fluid is to decrease the friction between the tendons, bone and skin during movement, many bursa in elbow but only few have clinical importance
what are the 3 borders of the cubital fossa
- epicondylar line
laterally = brachioradiallis
medially = pronator teres
what happens in stage 2 of bone repair
bone generation
- within days of fracture capillaries grow into hematoma
- phagocytic cells begin to clear away the dead cells
- fragments of blood clot main remain
- fibroblasts and osteoblasts enter the area and begin to reform bone
- osteoblasts grow spongy bone
- repair tissue between the broken bone ends, the fibrocartilaginous callus is composed of both hyaline and fibrocartillage
- some bone spicules may also appear a this point
what would be the clinical symptoms of an acute interrupted blood supply
pale
pulseless limb
needs emergency surgery
what muscles extend the elbow joint
- triceps brachii
- anconeus
what is the function of the bicep tendon and tricep tendon
what are the 4 ligaments in the elbow joint
- radial collateral ligament = found on lateral side, extends from lateral epicondyle (ligament from the proximal radioulnar joint)
- ulnar collateral ligament = originate from the medial epicondyle and attaches to the coronoid process and olecranon of the ulnar
- annular ligament = holds the radius tight against the ulnar through a strong band of fibres around radius head
- quadrate ligament = another connection between ulna and radius
what happens in stage 3 of bone repair
Bony callous formation
- fibrocartilaginous callus converted into a bony callus of spongy bone
- takes about 2 months for broken bone ends to be firmly joined together after a fracture
- similar to endochondral formation of bone when cartillage becomes ossified, osteoblasts, osteoclasts and bone matrix are present
with a supracondylar fracture, the swelling can cause interference with the blood supply
what may result
ischaemia can lead to volkmanns ischaemic contracture = uncontrolled flexion of the hand as the flexors muscles become fibriotic and short
also can be damage to the ulnar medial and radial nerves
label the muscles surrounding the elbow joint
go onto notes
what are the 3 bursa with clinical importance
- intratendinous olecranon = located within the tendons of the triceps brachii, also to reduce friction
- subtendinous olecranon = between the olecranon and the tendon of the triceps brachii, reduce the frictio between the 2 structures during extension and flexion of the arm
- subcutaneous olecranon bursa = between the olecranon and overlying connective tissue this is implicated in olecranon bursitis
what are the contents of the antecubiotal fossa
My Brother Throws Rad Parties
M = median nerve
B = brachial artery
T = tendon of biceps
R = radial nerve
P = posterior interossesous branch of the radial nerve
(from medial to lateral)
what happens in stage 4 of bone repair
bone remodelling
- bony callus then remodelled by osteoclasts and osteoblasts
- excess material on exterior of the bone and within the medullary cavity being removed
- compact bone is added to create bone tissue similar to the orginal unbroken bone
- remodelling can take many months and the bone may remain uneven for years
what is the gartland classification of supracondylar fractures
type 1 = undisplaced
type 2 = displaced with an intact posterior cortex
type 3 = displaced in 2 or 3 planes
type 4 = displaced with a complete periosteal disruption