Elbow, Forearm, Humerus and Shoulder Flashcards
What is a Monteggia fracture-dislocation?
A proximal third ulna fracture with dislocation of the radial head.
What is the most common type of Monteggia fracture-dislocation?
Anterior dislocation of the radial head (occurs in 70% of cases).
What is another possible type of Monteggia fracture-dislocation?
Lateral dislocation of the radial head (25% of cases).
What is a Galeazzi fracture-dislocation?
A distal third radius fracture with dislocation of the distal radioulnar joint (DRUJ).
How are Galeazzi fractures classified?
By the position of the ulna:
- Palmar (volar) dislocation of the ulna
- Dorsal dislocation of the ulna
How common are Galeazzi fractures?
They account for 3-7% of forearm fractures and are rare in children.
What is the prevalence of Monteggia fractures among forearm fractures?
Uncommon, occurring in 1-3% of forearm fractures.
What is the prevalence of Galeazzi fractures among forearm fractures?
Uncommon, occurring in 3-7% of forearm fractures.
Why is it important to consider that the radius and ulna form a ‘bony ring’?
Because disruption at one site (e.g., a fracture) often results in injury at another site, making associated dislocations or fractures likely.
What bones make up the elbow joint?
The humerus, radius, and ulna form the elbow, which acts as a hinge joint.
What structures are found in the distal humerus?
Trochlea, Capitellum, Coronoid fossa, Olecranon fossa, Radial fossa, Medial epicondyle, Lateral epicondyle.
What are the key parts of the proximal radius?
Radial head, Radial neck, Radial tuberosity.
What are the key parts of the proximal ulna?
Olecranon process, Coronoid process, Radial notch, Trochlear notch, Elbow Fat Pads.
What are the 2 fat pads of the elbow?
Anterior fat pad, Posterior fat pad.
What does a visible posterior fat pad on an X-ray indicate?
A posterior fat pad sign suggests a possible occult fracture, often a radial head fracture in adults or a supracondylar fracture in children.
What are the three key fat pads in the elbow?
Anterior fat pad, Posterior fat pad, Supinator fat pad.
What is the radiological significance of a visible posterior fat pad?
A posterior fat pad sign suggests an occult fracture, commonly a radial head fracture in adults or a supracondylar fracture in children.
Where is the supinator fat pad located?
Adjacent to the proximal radius, near the supinator muscle. A displaced supinator fat pad can indicate a radial head fracture.
What is the anterior humeral line (AHL), and what does it indicate?
A line drawn along the anterior margin of the humerus, which should bisect the capitellum. If disrupted, it indicates a supracondylar fracture. Used in the lateral view only.
What is the radiocapitellar line (RCL), and what does it indicate?
A line drawn along the neck of the radius, which should bisect the capitellum in all views. If misaligned, it suggests a radial head dislocation.
What percentage of elbow fractures involve the radial head and neck in adults?
50% of elbow fractures involve the radial head and neck, making it the most common site.
What is the second most common elbow fracture site in adults?
The olecranon, accounting for 20% of elbow fractures.
What is a supracondylar fracture?
A fracture of the distal humerus just above the elbow joint, common in children.
What is the most common cause of supracondylar fractures in children?
Fall on an outstretched hand (FOOSH).
What are the two types of supracondylar fractures?
Extension-type (95%) – Distal fragment displaced posteriorly.
Flexion-type (5%) – Distal fragment displaced anteriorly.
What radiological sign helps diagnose a supracondylar fracture?
Disruption of the anterior humeral line (AHL) on a lateral X-ray.
What is the significance of a posterior fat pad sign in children?
Indicates an occult supracondylar fracture, even if the fracture is not clearly visible.
What is a major complication of supracondylar fractures?
Volkmann’s ischemic contracture due to brachial artery injury, leading to compartment syndrome.
What nerve injuries are associated with supracondylar fractures?
Median nerve injury (most common) → Weak grip, loss of sensation in lateral palm.
Radial nerve injury → Wrist drop.
Ulnar nerve injury → Claw hand.
How are supracondylar fractures managed?
Non-displaced (Type I) → Immobilization with a long-arm cast.
Displaced (Type II/III) → Closed reduction + percutaneous pinning (CRPP) or open reduction if needed.
What is the most common type of shoulder dislocation?
Anterior Shoulder Dislocation (95%)
How is the humeral head displaced in an anterior shoulder dislocation?
Anteriorly, inferiorly, and medially, below the coracoid process
What injuries commonly accompany an anterior shoulder dislocation?
Bankart lesion (15%) and Hill-Sachs deformity (80%)
What happens in a posterior shoulder dislocation?
The humeral head is displaced posteriorly, losing articulation with the glenoid fossa
What is a classic radiographic sign of a posterior shoulder dislocation?
Lightbulb sign – the humeral head appears more rounded
What condition is a posterior dislocation often associated with?
Seizures
How common are posterior shoulder dislocations?
2-4% of all shoulder dislocations
What is Luxatio Erecta?
A rare form of inferior shoulder dislocation, caused by forced hyperabduction and extension of the arm
How common is inferior shoulder dislocation (Luxatio Erecta)?
0.5-1% of all shoulder dislocations
What is a Hill-Sachs lesion?
A depression-type fracture of the posterolateral articular surface of the humeral head caused by anterior shoulder dislocation.
How does a Hill-Sachs lesion occur?
It is created when the humeral head passes over the edge of the anterior glenoid fossa during an anterior dislocation.
Why are Hill-Sachs lesions clinically significant?
They predispose the patient to recurrent anterior dislocations.
What is a Bankart lesion?
An injury to the anteroinferior glenoid labrum that occurs with an anterior glenohumeral dislocation.
What imaging modality may be needed to assess the full extent of a Bankart lesion?
MRI
How common is a Bankart lesion after an anterior shoulder dislocation?
Present in 15% of patients after dislocation.
What are common causes of AC joint injuries?
Contact sports, FOOSH (fall on outstretched hand), or a fall onto the apex of the shoulder.
What are the normal measurements for the AC and CC joints?
AC joint: 0.3-0.8 cm
CC joint: 1.0-1.3 cm
What is a key finding in rotator cuff tears (old injuries)?
Superior migration of the humeral head and flattening of the undersurface of the acromion.
What does supraspinatus tendon calcification look like on imaging?
Amorphous, lobular calcification, often more pronounced than commonly seen.
Where is supraspinatus tendon calcification typically located?
Just superior to the greater tuberosity of the humerus, where the tendon inserts.
What is the most common site for clavicle fractures?
The middle third (approx. 75-80% of cases).
How do the fragments of a clavicle fracture typically displace?
Medial fragment: Displaces upward due to the sternocleidomastoid muscle.
Lateral fragment: Pulled downward by the weight of the limb.
What are common causes of clavicle fractures?
Falls onto the lateral aspect of the shoulder or contact sports.
In which population are proximal humerus fractures most common?
Elderly patients, often due to FOOSH (fall on outstretched hand) or direct trauma.
What percentage of proximal humerus fractures are non-displaced?
85%.
What are the four main fracture fragments in a proximal humerus fracture?
Greater tuberosity
Lesser tuberosity
Humeral head
Humeral shaft
How does CT help in assessing radial head fractures?
CT improves fracture detection, evaluates displacement and fragmentation, and helps identify associated injuries.
What are the advantages of CT over X-rays in radial head fractures?
CT offers better visualization of subtle fractures, precise measurement of displacement, and detection of associated injuries.
How does CT assist in surgical planning for radial head fractures?
CT, especially with 3D reconstruction, helps in understanding fracture patterns and planning fixation or arthroplasty.
What associated injuries can CT help identify in radial head fractures?
CT can reveal coronoid fractures, ligamentous injuries (LCL complex), and Essex-Lopresti injuries.
What is calcification of the supraspinatus tendon?
It is the deposition of calcium hydroxyapatite crystals within the tendon.
What are the consequences of calcification of the supraspinatus tendon?
It leads to pain, inflammation, and restricted shoulder movement.
