Osteology of the Forearm, Wrist and Hand Flashcards
What is the primary role of the ulna in the forearm?
The ulna is the main stabilizing bone of the forearm.
How does the shape of the ulna change distally?
The ulna narrows distally.
Does the ulna articulate at the wrist joint?
No, the ulna does not articulate at the wrist joint.
What movement does the radius perform over the ulna?
The radius rotates over the stationary ulna
How does the shape of the radius change distally?
The radius becomes broader distally.
Where does the radius articulate?
The radius articulates at the radiocarpal (wrist) joint and the distal radioulnar joint
What is the function of the interosseous membrane between the radius and ulna?
The interosseous membrane connects the radius and ulna, helping in force transmission and stabilization.
What are the styloid processes of the radius and ulna?
The styloid process of the radius and the styloid process of the ulna are bony projections located at the distal ends of each bone.
What is the significance of the ulnar notch?
The ulnar notch on the distal radius articulates with the head of the ulna at the distal radioulnar joint.
Where is the head of the radius located?
The head of the radius is located at the proximal end of the radius, near the elbow.
How many carpal bones are there in the wrist?
8
What is the mnemonic for remembering the order of carpal bones?
“Straight Line To Pinky, Here Comes The Thumb”.
Name the bones in the proximal row of the carpus.
The bones in the proximal row are:
Scaphoid
Lunate
Triquetrum
Pisiform (a sesamoid bone).
Which carpal bone is most commonly fractured?
The scaphoid is the most commonly fractured carpal bone.
Name the bones in the distal row of the carpus.
Hamate (with a hook called the hook of hamate)
Capitate
Trapezoid
Trapezium.
How do the carpal bones in the proximal row participate in wrist movement?
The proximal row articulates at the wrist joint via the articular disc.
What type of joints are the intercarpal joints?
The intercarpal joints are synovial plane joints between the carpal bones.
Which carpal bones are involved in forming the carpal arch?
The carpal arch is formed by the scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, and hamate.
What is the hook of hamate, and why is it clinically significant?
The hook of hamate is a projection on the hamate bone and is important because it can be fractured or involved in compression of the ulnar nerve.
What is the most common carpal bone injury?
Scaphoid fractures are the most common carpal bone injury.
What is the usual mechanism of injury for scaphoid fractures?
The usual mechanism is a Fall on an Outstretched Hand (FOOSH).
Where is the most common location for a scaphoid fracture?
The most common location is at the waist of the scaphoid.
What is the significance of the blood supply to the scaphoid?
10% of the scaphoid receives its blood supply from the distal source, which makes the proximal scaphoid vulnerable to avascular necrosis.
What complication can occur if a scaphoid fracture is missed on X-rays?
If missed, the fracture can lead to delayed diagnosis, increasing the risk of avascular necrosis and eventual osteoarthritis of the wrist in later life.
What type of joint is the radiocarpal (wrist) joint?
The radiocarpal joint is a condyloid synovial joint.
What bones form the articulation of the radiocarpal joint?
The radiocarpal joint is formed by the distal radius and articular disc with the proximal row of carpal bones (except the pisiform).
What ligaments support the radiocarpal joint?
The ligaments supporting the joint include the ulnar collateral ligament, radial collateral ligament, and palmar and dorsal radiocarpal ligaments.
What is the distal radioulnar joint responsible for?
The distal radioulnar joint allows for pronation and supination of the forearm.
What is the function of the midcarpal and intercarpal joints?
The midcarpal joint and intercarpal joints allow for small gliding movements between the carpal bones.
What is the role of the carpometacarpal joints?
The carpometacarpal joints allow the metacarpals to articulate with the distal carpal row.
How many bones are there in the hand?
There are 19 bones in the hand.
How many metacarpals are there in the hand?
There are 5 metacarpal bones in the hand.
How are the phalanges divided in the fingers?
Each finger (except the thumb) has three phalanges: proximal, middle, and distal.
How many phalanges does the thumb have?
The thumb has 2 phalanges: proximal and distal.
What type of joint is the MCP joint?
The metacarpophalangeal (MCP) joint is a condyloid synovial joint.
What type of joint are the PIP and DIP joints?
The proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints are hinge synovial joints.
What is the function of the palmar plates in the hand?
The palmar plates join the head of one bone to the base of the adjacent bone, stabilizing the joints.
How are the palmar plates attached?
They are firmly attached to the deep transverse metacarpal ligament.
What does the deep transverse metacarpal ligament connect?
It connects the 2nd to 5th metacarpals.
What is the function of the deep transverse metacarpal ligament?
It resists separation of the metacarpals, stabilizing them during movement.
What do the collateral ligaments stabilize in the hand?
The collateral ligaments stabilize the MCP (metacarpophalangeal) joints and IP (interphalangeal) joints.
When are the collateral ligaments taut?
The collateral ligaments are taut in flexion.
