Basic mammalian form of upper limb
Limb girdle attached to axial skeleton
1 proximal bone 2 distal bones
Pentadactyl hand (thumb rotated 90 degrees in humans)
Role of scapula
Muscle attachments to shoulder joint
Role of clavicle
Attaches shoulder girdle to axial skeleton
Joints of clavicle
Common locations of clavicular fracture
Between lateral 1/3 and medial 2/3
Role of bicipital groove
Houses biceps tendon
What links the radius and ulna bones?
Main humeral fracture sites
Surgical neck, mid-shaft, suprachondylar
Fracture of distal radius. Often from falling onto outstretched hand.
Effect of broken scaphoid
Because of unusual blood supply, proximal scaphoid becomes ischaemic, necrotic.
Mid-shaft break of ulna
Features of stable joints
1) Congruent articular surfaces
2) Tight capsule, strong capsular ligaments
3) LImited range of motion
Features of unstable joints
1) Incongruent articular surfaces
2) Stability often reliant on fixator muscles
3) Prone to dislocation or subluxation
Features of sternoclavicular joint
1) Interosseus disc
2) Very strong capsule
3) Costoclavicular ligament (main limiter of movement)
Main features of acromioclavicular joint
1) Weak capsule
2) Main stabiliser is the coracoclavicular ligament (prevents upward rotation of clavicle)
Structures increasing stability of shoulder joint
1) Glenoid labrum
2) Long head of biceps
3) Rotator cuff muscles
Rotator cuff muscles
4) Teres minor
Location of subscromial bursa
Beneath acromial process. Prone to irritaiton during shoulder abduction.
Most common direction that shoulder dislocates in
Humerous pushed anteriorally, drops downwards
Place of shoulder joint instability
Little muscle inferior to shoulder joint.
Hence most common dislocation is anteriorally inferiorally
Endangered structures with shoulder dislocation
Where do elbow collateral ligaments join?
Medial and lateral epicondiles
Motions of a pivot joint
Joint around which forearm rotates
Proximal radio-ulnar joint (radius rotates around ulna)
What is the name of a break of the distal radius?
Often from falling onto an outstretched hand.