Hand and Wrist Flashcards
What are the common causes of injury to the phalanges?
Crushing (commonly affects distal phalanx)
Twisting
Hyperextension and hyperflexion, leading to avulsion fractures that affect finger functionality
What are the types of injuries that can affect the phalanges?
Crush, split, vertical, transverse fractures
Volar plate injury (often an avulsion fracture)
Mallet finger
Boutonnière deformity
Distal Phalanx Fractures
What are the types of fractures that can occur in the distal phalanx?
Vertical split fractures
Shaft fractures (either vertical or transverse with angulation, visible on lateral views)
Crush fractures (common, especially in 50% of distal phalanx fractures)
Mallet finger deformity (a condition caused by an avulsion injury affecting the extensor tendon)
What is a Boutonnière deformity?
A Boutonnière deformity is a finger injury that occurs when the central slip tendon over the proximal interphalangeal (PIP) joint ruptures, leading to a deformity in the finger.
How does a Boutonnière deformity affect the finger?
A Boutonnière deformity causes:
PIP joint flexion (the middle joint of the finger bends)
DIP joint hyperextension (the fingertip bends backward).
What are the common causes of a Boutonnière deformity?
Trauma, including cuts or lacerations
Sprains or forceful blows to the PIP joint.
What are the symptoms of a Boutonnière deformity?
Pain and swelling over the PIP joint
Inability to straighten the PIP joint
Visible deformity: PIP joint flexion and DIP joint hyperextension.
How is a Boutonnière deformity treated?
Splinting the PIP joint in extension for several weeks.
Surgery may be required for severe cases, especially with fractures or complex injuries.
What is a common injury to the Middle Phalanx?
Volar plate injury due to hyperextension.
Volar plate injury results in avulsion fractures at the insertion point of the volar plate.
What imaging is needed to assess a Middle Phalanx injury?
Lateral and oblique X-rays of the affected finger are necessary to demonstrate small bone fragments from a volar plate injury.
What type of fractures are commonly seen in the Proximal Phalanx of children?
Spiral or transverse fractures are common, especially in pediatric patients.
These fractures are best seen on lateral and oblique X-rays.
What are the clinical signs of a Proximal Phalanx fracture?
The digit appears shortened and rotated.
What causes Mallet Finger Deformity?
Direct blow to an extended finger or laceration to the dorsal aspect of the DIP joint, causing rupture of the extensor tendon.
What are the clinical features of Mallet Finger Deformity?
The fingertip is flexed with an inability to straighten it due to ruptured extensor tendon.
What is the cause of Boutonnière Deformity?
Forced flexion of the proximal interphalangeal joint (PIPJ). This causes a rupture of the central slip of the extensor ligament and migration of the lateral bands downwards. This leads to flexion of the PIPJ and extension at the DIPJ.
What is a common condition associated with Boutonnière Deformity?
Rheumatoid arthritis (RA) is commonly associated with Boutonnière Deformity.
What is a Metacarpal Fracture often caused by?
A direct blow to the hand, punch-like injuries, or hyperextension.
What are the common clinical signs of a Metacarpal Fracture?
Soft-tissue swelling, tenderness, deformity, and usually wounds at the site of injury.
How are Metacarpal Fractures classified?
Fractures are described by their position: neck, shaft, or base of the metacarpal.
What is a Bennett’s Fracture?
An oblique intra-articular fracture at the base of the first metacarpal. Typically caused by a fall or punch-like mechanism that forces abduction of the 1st MC. Clinically, it presents with swelling, tenderness, and reduced range of movement.
How is a Rolando Fracture different from a Bennett’s Fracture?
A Rolando Fracture is comminuted (3-part fracture) and the fracture pattern is a T or Y shape. Like Bennett’s Fracture, it affects the base of the first metacarpal but is more complex. Caused by a fall or punch-like mechanism with the thumb in extension. Clinically, it presents with swelling, tenderness, and reduced range of movement.
What causes Skiers/Gamekeeper’s Thumb?
Hyperabduction of the first metacarpal phalangeal joint (MCPJ). This leads to the rupture of the ulnar collateral ligament of the thumb’s MCPJ or an avulsion fracture.
What are the clinical signs of Skiers/Gamekeeper’s Thumb?
Swelling and pain around the thumb joint.
What is a Boxer’s Fracture?
A fracture of the metacarpal neck with volar (palmar) angulation of the distal fragment. Typically occurs during a punch with a closed fist. Most often involves the 5th metacarpal, but the 4th metacarpal can also be involved.
What is the common cause of Boxer’s Fracture?
It commonly occurs during a punch with a closed fist.
What is the typical mechanism of injury for dislocations of the fingers?
Hyperextension injuries, most commonly affecting the PIP joints.
Which type of dislocation is most commonly seen in hyperextension injuries?
Dorsal dislocation is most commonly seen in PIP joints.
What is the most common injury mechanism for wrist trauma?
Fall onto outstretched hand (FOOSH).
What type of wrist fractures are common for different age groups after a fall onto outstretched hand (FOOSH)?
4–10 years: Torus fracture of the distal radius.
11–16 years: Salter-Harris type II fracture.
17–40 years: Scaphoid fracture.
Over 40 years: Colles’ type fracture.
What is the normal finding in a PA X-ray of the wrist?
The medial aspect of the radius articulates with the ulna notch.
The ulna is marginally shorter than the radius.
The carpal arcs should remain uniform throughout.
What is the normal finding in a lateral X-ray of the wrist?
The distal articular surface should be angled 10°–15°.
Flattening of this angle may indicate a fracture.
The articular surfaces of the radius, lunate, and capitate should be aligned.
What is the Pronator quadratus fat pad and what is its significance in a lateral wrist X-ray?
It appears as a dark line within the anterior soft tissues at the distal radius.
Normally parallel to the anterior cortex of the radius.
Anterior displacement, bowing, or obliteration of this line is indicative of a fracture.
What is the Pronator quadratus fat stripe, and how is it affected by fractures of the distal radius?
Pronator quadratus fat stripe: A dark line seen on lateral wrist X-rays.
Fractures of the distal radius: Blood from the fracture raises the pronator quadratus muscle, causing the fat pad/stripe to bulge.
About 80% reliability for detecting fractures.
What is a Colles’ fracture, and how does it occur?
Colles’ fracture: The most common fracture of the distal forearm, usually from a FOOSH (fall onto outstretched hand).
Common in patients over 50 years.
Extra-articular radial fracture.
Distal fracture fragments show dorsal (posterior) displacement/angulation.
Avulsion fractures of the ulna styloid process often seen.
What is a Smith’s fracture, and what causes it?
Smith’s fracture: Caused by a fall onto the back of the hand or a direct blow causing forced palmar flexion.
Fracture of the distal radius with possible intra-articular involvement.
Distal fracture fragments show palmar (anterior) displacement/angulation.
What are the key points to remember about Carpometacarpal (CMC) dislocations, specifically the fifth CMC joint?
The fifth CMCJ is the most commonly dislocated (50%).
Usually dorsal dislocation (66%).
Can be easily missed due to overlapping anatomy on a lateral wrist X-ray.
Check for loss of alignment:
CMCJ should show clear joint spaces.
Loss of normal alignment is most visible on the lateral view.
What are the key points to remember about Carpal Arcs and their assessment on a DP X-ray?
The carpal joint spaces should be equal and parallel. The carpal arcs are three lines used to assess carpal alignment on the DP X-ray. Each arc should be smooth and continuous, with no steps or breaks. Arc 1: Runs from the proximal scaphoid -> proximal lunate -> proximal triquetral. Arc 2: Runs from the distal scaphoid -> distal lunate -> distal triquetral. Arc 3: Runs around the proximal capitate -> proximal hamate.
What are the common causes and clinical signs of a scaphoid fracture?
Common causes: FOOSH, MVA, or sporting injury. Clinical signs: Pain and tenderness over the anatomical snuff box (ASB). Pain and tenderness when force is applied to the thumb metacarpal (scaphoid compression test). Most fractures are un-displaced and involve the waist of the scaphoid. Occult fractures may be hard to detect on initial X-ray. Follow-up imaging is required (10–14 days).
Why is blood supply to the scaphoid crucial for healing?
The distal pole of the scaphoid has its own blood supply, enabling quicker healing. The proximal pole receives blood through the waist region. Fractures at the waist disrupt blood supply, increasing the risk of non-union or avascular necrosis. The risk of non-union increases as the fracture gets closer to the proximal pole, as blood supply is only from one direction.
What are the common causes and clinical signs of carpal dislocations?
Causes: Uncommon, most involve the lunate. Usually caused by extended or ulnar deviated hand. Often associated with a fall from height or MVA. Clinical signs: Pain and swelling in the wrist. Increased pain when attempting to extend the fingers. The patient may prefer to keep the hand in flexion.
How does a lunate dislocation appear on X-ray?
Lateral X-ray: The lunate slips to the palmar (anterior) aspect of the wrist. The concave surface of the lunate tilts anteriorly and is empty. The lunate should articulate with the radius proximally and the capitate distally. The convex aspect of the lunate should face upwards with the capitate fitting into it. DP X-ray: The lunate appears triangular and the scapholunate joint appears widened.
What is a perilunate dislocation and how does it appear on X-ray?
Perilunate dislocation is less common and often associated with other injuries. Lateral X-ray: The lunate stays in its normal position. The capitate and metacarpals are dorsally displaced but still aligned with each other.
What is a mid-carpal dislocation?
In a mid-carpal dislocation, the lunate tilts anteriorly and subluxes from the radius. There is an associated dorsal dislocation of the capitate from the lunate. The dislocation is not as severe as a true perilunate dislocation.
What is the normal joint space of the scapholunate joint in adults?
The scapholunate joint space is about 2 mm in adults.
What does widening of the scapholunate joint space indicate?
Widening of the joint space indicates injury to the scapholunate ligament, which is indicative of scapholunate dissociation.
What type of wrist fracture is common in children (4–10 years) after a FOOSH?
Torus (buckle) fracture of the distal radius due to soft, flexible bones.
What type of wrist fracture is common in adolescents (11–16 years) after a FOOSH?
Salter-Harris type II fracture involving the growth plate and metaphysis.
What type of wrist fracture is common in young adults (17–40 years) after a FOOSH?
Scaphoid fracture, often due to high-energy falls, risk of avascular necrosis.
What type of wrist fracture is common in adults over 40 years after a FOOSH?
Colles’ fracture – distal radius fracture with dorsal angulation, common in osteoporosis.
What is the difference between a midcarpal dislocation and a lunate dislocation?
Lunate Dislocation: The lunate displaces anteriorly (palmar); seen as a “spilled teacup” sign on lateral X-ray.
Midcarpal Dislocation: Disruption at the midcarpal joint, often with perilunate dislocation (lunate stays aligned with radius, other carpal bones displace dorsally).
Lunate dislocation = isolated lunate injury.
Midcarpal dislocation = multiple ligament injuries and widespread carpal disruption.
