Flashcards in Session 1: Common Sites of Fracture Deck (14):
Especially common in children
Often caused by an indirect force transmitted from an outstretched hand through the bones of the forearm and arm to the shoulder during a fall.
May also result from a fall directly on the shoulder.
Weakest part of the clavicle is the junction of the medial 2/3 and lateral 1/3 - middle third.
What happens after a fracture of the clavicle?
The sternocleidomastoid muscle elevates the medial fragment of the bone.
The trapezius is unable to hold the lateral fragment up owing to the weight of the upper limb; thus shoulder drops.
Strong coracoclavicular ligament usually prevents dislocation of the acromioclavicular joint.
The lateral fragment may also be pulled medially by the adductor muscles e.g. Pec major.
Overriding of the bone fragments shortens the clavicle.
What is a greenstick fracture?
One side of a bone is broken and the other is bent.
The parts of the bone do not separate; the bone resembles a tree branch (greenstick) that has been sharply bent but not disconnected
Describe a Fracture of the Scapula
Usually the result of severe trauma as occurs in pedestrian-vehicle accidents.
Usually also fractured ribs.
Requires little treatment normally because the scapula is covered on both sides by muscles.
Most fractures involve the protruding subcutaneous acromion.
What kind of common fractures of the humerus may there be?
Surgical neck (axillary nerve and posterior and anterior humeral circumflex arteries)
Mid shaft fracture: radial nerve (and profunda brachii in radial groove)
Distal end of humerus (supraepicondylar fracture - transverse): median nerve, brachial artery
Medial epicondyle: ulnar nerve (posterior)
Describe how fractures of the surgical neck may occur
Especially common in elderly people with osteoporosis whose demineralised bones are brittle.
Humeral fractures often result in one fragment being driven into the spongy bone of the other fragment (impacted fracture).
Injuries usually result from a minor fall on the hand with the force being transmitted up the bones of the forearm of the extended limb,
Because of impaction of the fragments, the fracture site is sometimes stable and the person is able to move the arm passively with little pain.
Describe Fractures of the Radius and Ulna
Usually result of severe injury
Direct injury produces transverse fractures at the same level - usually in the middle third of the bones.
Isolates fractures of the radius or ulna also occur. Because the shafts of these bones are firmly bound together by the interosseous membrane, a fracture of one bone is likely to be associated with dislocation of the nearest joint.
What is a Colles Fracture?
A complete transverse fracture of the distal 2cm of the radius.
Most common fracture of the forearm.
Distal fragment is displaced posteriorly and is often comminuted (broken into pieces).
Usually results from forced extension of the hand, usually as a result of trying to ease a fall by out stretching the upper limb.
Dinner fork deformity - due to shortening of the radius
Often the ulnar stylus process is avulsion (broken off)
Because of the rich blood supply to the distal end of the radius, bony union is good
What might happen in radius fractures in children?
When the distal end of the radius fractures, the fracture line may extend through the distal epiphysial plate.
Epiphysial plate injuries are common in older children because of their frequent falls in which the forces are transmitted from the hand to the radius and ulna.
Healing process may result in malalignment of the epiphyseal plate and disturbance of radial growth.
Describe fracture of scaphoid
Most frequently fractured carpal bone.
Often results from a fall on the palm when the hand is abducted.
Tenderness in the anatomical snuffbox + pain during dorsiflexion and abduction of the hand especially,
Initial radiographs may not reveal a fracture - radiographs taken 10-14 days later reveal a fracture because of bone resorption
Due to poor blood supply to the proximal part of the scaphoid, union of fractured parts may take at least 3 months. Avascular necrosis could happen.
What could avascular necrosis of the proximal fragment of the scaphoid lead to?
Results from inadequate blood supply.
Could produce degenerative joint disease of the wrist. In some cases it is necessary to fuse the carpals surgically (arthrodesis)
Describe Fracture of Hamate
May result in non-union of the fractured bony parts because of the traction produced by the attached muscles.
Because the ulnar nerve is close to the hook of hamate, the nerve may be injured causing decreased grip strength of the hand.
Ulnar artery may also be damaged
Describe Fracture of Metacarpals
The metacarpals (except the 1st) are closely bound together hence isolated fractures tend to be stable.
Good blood supply so fractures usually heal rapidly.
Severe crushing injuries of the hand may produce multiple metacarpal fractures resulting in instability of the hand.
Fracture of the 5th metacarpal 'boxers fracture'. Punch with closed and abducted fist. Head of the bone rotates over the distal end of the shaft, producing a flexion deformity.