How many bones in elbow complex?
3: humerus, ulna, radius
How many joint categories in the elbow?
Elbow joint:
1. humeroulnar
2. humeroradial
Radioulnar joints:
1. Superior
2. middle
3. inferior
radioulnar
So why does the medial part of trochlea project further distally down than lateral?
The carrying angle help lift, clearing the hips, not banging our sides to the legs
Ulna is relative to the humerus at what angle?
15 for women
10 for male
What is cubitus varus and valgus?
Malalignment of distal humerus
Increase carry angle: Cubitus valgus
Decreased carrying angle: cubitis varus
Complications of cubitis valgus and varus?
change in carrying angle, ulnar nerve neuritis and osteoarthritis
wears down hyaline cartilage
Pain further down forearm
Three fossae of the distal humerus?
Olecranon fossa posterior view
- for olecranon process for ulna
Radial (above capitilum) and coronoid (trochlea) anterior
- head of radius and coronoid process of ulna
Proximal ulna
2 processes:
- olecranon process: for triceps and anconeus
- coronoid process: Brachilias
Radioulnar joints action is
Pronation and supination
Radioulnar joints involve what three joints
- Superior radioulnar (major movement)
- synovial pivot
- between radial head and radial notch - Middle radioulnar:
- fibrous syndesmosis
- oblique downward fibres, weight trasnfer from radius to ulnar - Inferior radioulnar:
- synovial pivot
- ulna head and ulnar notch of radius
- triangular fibrocartilage complex: intraarticular disc, radioulnar lig, supportive cushioning for weight bear
Elbow movemetns
flex, extend:
- head of humerus and capitulum of humerus
- trochlea notch of ulna and trochlea of humerus
pronation and supination:
- head of radius and radial notch of ulna
What does pronation and supination involve?
Radius swings over ulna, bones not parallel
supination is original position
Do the superior radioulnar joint act alone during pronation?
No, always accompanied by inferior radioulnar joint
acts as a functional unit together
Elbow joint capsule
- fibrous capsule around proximal margin of trochlea and capitlum
do not attach to radius so it can still move
What is the elbow joint capsule stabilised by
medial/ulnar collateral lig (valgus forces)
Lateral/radial collateral lig (varus forces)
Annular lig; wrap around top of radius attach to radial notch of ulna
Brachialis muscle
Further accesorries to elbow capsule?
- fatpads between synovial mem and fibrous capsule:
- shock absorb
- cornoid, radial and olecranono fossa - Bursae:
- friction
- between olecranon fossa and fat
Arm flexor compartment anterior
Long head biceps brachii: Supraglenoid tubercle on humerus
Short head:
coracoid process
long and short ends at radius tuberosity
brachialis attach to humerus body end at coronoid process of ulna
Coracobrachialis: Start at coracoid on scapula, end at humerus body
Actions of biceps brachii
flex elbow and shoulder, supinate
Actions of coracobrachialis
flex, internal rotate, adduction shoulder joint only
Action of brachilis
Flexion
What innervates the anterior arm flexor muscles?
muscultaneous
arm extensor posterior
- triceps brachii:
- long, lateral, remove long for medial
- long attach to infraglenoid tubercle
- lateral and medial attachto superior and inferior radial groove respectively
- only LONG cross shoulder joint
- all heads attach to olecranon process
What innervates the triceps?
radial nerve
Extensor of elbow posterior of the arm (forearm):
Anconeus: Short muscle
- origin at humerus (lateral epicondyle, posterior aspect)
- insert at ulna olecranon process
Extends elbow joint, stabilise
assist triceps
