134 - Joints of Upper Limb 3. Wrist Complex & Joints of Hand Flashcards
Rows of phalanges in hand
1
2
3
Proximal, middle, distal
Orientation of metacarpal of the thumb
At right angle to other digits
Two nodular bones on thumb metacarpal
Sesamoid bones
Number of phalanges in thumb
Two
Bones forming the proximal row of carpal wrist
(Radius) Scaphoid, lunate, triquetrum, pisiform (last to ossify) (Ulna)
Bones forming the distal row of carpal wrist
Trapezium, trapezoid, capitate (largest & 1st to ossify), hamate (with hook)
Bone forming the floor of the anatomical snuffbox
Scaphoid bone
Example of a sesamoid bone of the wrist
Trapezoid bone
Proximal border of the flexor retinaculum
Corresponds to location of distal wrist crease
Which wrist bone does the ulna sit across from?
Triquetral bone
Largest bone in the wrist
Capitate
Bone likely to break when falling on an outstretched hand
Radius most likely.
Force passes through the capitate, as it is the largest, into radius.
When do carpal bones commence ossification?
After birth
First bone in wrist to ossify?
Capitate
Order of ossification of carpal bones
Starts at capitate, goes in a counterclockwise direction
capitate->hamate->etc
Age at which pisiform ossifies?
~10-13 years.
Last carpal bone to ossify
Pisiform
Orientation of base and head of metacarpals
Base is proximal, head is distal
When do ossification centres of metacarpals fuse?
Early teens
Bones areticular at the wrist
Scaphoid, lunate, radius.
Triquetral bone slides across, articulates with ulan when hand is bent laterally
Midcarpal joint
Where carpal bones articulate with one another.
Joints in the wrist complex
1
2
•2 joints:
- Radiocarpal - ellipsoid
- Intercarpal (midcarpal) - condylar
Movements at the wrist complex 1 2 3 4
•Biaxial movements -flexion/extension -radial/ulnar deviation Circumduction -flexion > extension (F/E) -ulnar deviation > radial (UD/ RD)
Type of joint that radiocarpal joint is
Synovial ellipsoid joint
