Upper limb Osteology Flashcards
What is the sternoclavicular joint?
Articulation between medial clavicle and manubrium of the sternum
Which end of the clavicle is enlarged and triangular?
-Sternal end
Which part clavicle is concave and which part convex?
- Medial two thirds convex
- Lateral third concave
What is the acromioclavicular joint?
-Articulation between acromium and clavicle
Which end of the clavicle is flat?
-Lateral end which articulates with acromium
What is the main function of the clavicle?
-Keep the upper limb away from the trunk
How does the spine of scapula divide it?
- Small supraspinous fossa
- Large infraspinous fossa
What is the concave anterior surface of scapula called?
-Subscapular fossa
Name the borders of the scapular
- Medial border
- Lateral border
- Superior border
What is a continuation of the spine of scapula?
-Acromion
What articulation occurs at the gleno-humeral joint?
-Between glenoid cavity on lateral surface of scapula and head of humerus
What articulations does the humerus have at the elbow?
- Capitulum with radial head
- Trochlea with trochlear notch of ulna
What defines the anatomical neck of the humerus?
-The groove around the head of humerus
What is a common site of fracture for the humerus?
-The surgical neck
What tendon passes in intertubecular groove?
-Long head of biceps brachii
What are the two prominent features of the humeral shaft?
- Deltoid tuberosity
- Radial Groove
What lies within the radial groove?
- Radial Nerve
- Profunda Brachii
What are the prominent features of the distal humerus?
- Medial and Lateral epicondyles
- Olecronon fossa
- trochlea
- Capitulum
- Radial and coronoid fossa
When does the coronoid fossa receive the coronoid process?
-During full flexion of the elbow
When does the olecronon fossa receive the olecronon?
-During full extension of the forearm
When does the radial fossa receive the radial head?
-When the elbow is fully flexed
Which bone is the longest and medial in the forearm?
-Ulna
What muscle tendon attaches to the ulnar tuberosity?
-Brachialis
What ligament surrounds the radial head?
-Annular ligament
Which styloid process is larger, radial or ulnar?
-Radial
Which styloid process lies most distally?
-Radial
In what direction do the fibres of the interosseous membrane run?
-An oblique course passing inferiorly from radius to ulna
Which bones make the wrist joint?
- Scaphoid
- Lunate
- Triquitrum
- Radius
What are the three areas of a metacarpal?
- Base
- Shaft
- Head
How can the clavicle vary in manual workers?
-Thicker and more curved, with sites of muscular attachment more marked
What is the most common cause of a clavicular fracture?
- Falling onto outstretched hands in children
- Fall directly onto the shoulder
What is the weakest point of the clavicle?
-The point between the medial two thirds and the lateral third
How does a broken clavicle present physically?
- The shoulder will be dropped with the superior end of medial two third fragment prominent
- Patient will be supporting sagging limb with other limb
Why does a fractured clavicle present with a dropped shoulder?
-Trapezius is unable to hold lateral fragment up, due to the weight of the upper limb and the shoulder drops
Why is the medial two thirds of a fracture clavicle become prominent?
-Sternocleidomastoid muscle elevates the medial fragment of bone
How come the acromioclavicular joint is not disrupted in a clavicular fracture?
-Coracoclavicular ligament is strong and prevents dislocation
What is a green-stick fracture?
-A fracture in which only one side of the bone is broken, the other side is bent
Why can ossification of the clavicle complicate fracture diagnosis?
- Clavicle does not finish fusion of epiphysis, results in a bony defect between lateral and medial thirds which can be mistaken for a fracture
- Epiphysis can occur at acromial end of clavicle which can sometimes be mistaken for a fracture
When would a scapula fracture occur?
-Severe trauma eg pedestrian-vehicle accident
What is also likely to fracture if the scapula has fractured?
-Ribs
Why do fracture of scapula require little treatment?
-Both sides covered by muscles
Where is the most commonly fractured site of humerus?
-Surgical neck
Who are fractures of surgical neck of humerus common in?
-Elderly with osteoporosis
What is an impacted fracture?
-One fragment is driven into the spongy bone of another fragment
Why is it possible for some humeral neck fractures to be only a little painful?
-Often impacted fracture which means the fracture site is stable and movement is possible with little pain
What is an avulsion fracture of the greater tubercle of the humerus?
-A small part of the greater tubercle is torn away from the main mass
When do avulsion fractures of the greater tubercle normally occur?
-From a direct fall onto the acromion
What is the main cause of a transverse fracture of shaft of humerus?
-Direct blow to the arm
When would an intercondylar fracture of the humerus occur?
-Severe fall on flexed elbow -> olecranon forced between medial and lateral part of condyle
What nerve is possibly damaged during surgical neck fracture?
-Axillary
What nerve is possibly damaged during mid-shaft humeral fracture?
-Radial nerve
What nerves are at possible risk of damage from fracture of distal humerus?
- Median nerve
- Ulnar nerve
What is a colles fracture?
-Complete transverse fracture of the distal 2cm of the radius
Who do distal radial fractures usually occur in?
-People over 50 years, especially women
Why does a dinner fork deformity occur in a colles fracture?
-Fragment of distal radius is posteriorly displaced
What is the main cause of colles fracture?
-Falling on pronated outstretched hands
What is the most frequently fractured carpal bone?
-Scaphoid
Why can avascular necrosis occur in scaphoid fractures?
-Blood supply comes distally, fracturing the scaphoid can disrupt the blood supply and result in avascular necrosis of the proximal fragment
How is fracture of scaphoid examined?
-Pain in anatomical snuff box
What is a boxers fracture and when does it occur?
- Fracture of the 5th metacarpal
- Unskilled person punches someone with a closed hand and abducted fist
