Wrist and Hand Biomechanics Flashcards
What is prehension
Grip
True or False:
You need proximal stability for distal mobility
True
True or False:
The UE is subservient to the wrist and hand
True
Is compensation proximally for lost hand function effective
Nope
How many degrees of freedom does the humeroulnar joint have
1
During CKC pronation and supination what is moving
Ulna rotates on a fixed radius
Fewer degrees of freedom means there is more mobility or stability
Stability
What is AOM
Analysis of Motion
How can the ulna rotate on the radius during CKC supination and pronation
The ulna has no articulation with the wrist
Where is the expansion of the radius
At the carpus
What is the purpose of the expansion of the radius and ulna
Attachment of muscles, tendons, and ligaments
Where is the ulnar expansion
At the humerus
The ulna at the carpus is modified for what
Radius and hand to rotate
The space at the distal end of the ulna is called what
Ulnocarpal space
What is in the ulnocarpal space
Triangular Firbrocartilage Complex (TFC)
Where does the stability of the hand come from
3rd metacarpal and somewhat the 2nd metacarpal
What is the 3rd metacarpal flanked by
Mobile segments
What is the thenar eminence
Thumb side muscularture
What is the hypothenar eminence
Pink side musculature
What muscles are present at the 2nd and 3rd metacarpals to provide stability at the wrist allowing for freedom of movement around the pillar (3)
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Flexor carpi radialis
Which carpal is most inportant
Capitate
What type of motion occurs at the wrist complex
Biaxial
What are the planes motion occurs in at the wrist complex
Frontal and sagittal
What are the sagittal plane motions
Flexion and extension
What is the range for flexion and extension at the wrist complex
Flexion: 80-90
Extension: 70-80
What are the frontal plane motions
Ulnar and radial deviation
What is the range for ulnar and radial deviation
Ulnar: 30-35
Radial: 20-25
Why is radial deviation less than ulnar deviation
Due to the size of the radial styloid
What makes up the proximal articulation of the radiocarpal joint
Radius and radioulnar disc (TFC)
What makes up the distal articulation of the radiocarpal joint
Scaphoid, lunate, triquetrium
What are the arthronkinematics of the radiocarpal joint
Convex scaphoid and lunate moving on a concave distal radius
What does the lateral radial facet articulate with and percent of the radiocarpal joint
Scaphoid, 46%
What does the medial radial facet articulate with and percent of the radiocarpal joint
Lunate, 43%
What does the inferior radioulnar disc articulate with and percent of the radiocarpal joint
Triquetrium, 11%
True or False:
There is no formal carpal articulation with the ulna
True
Is the pisiform included in the radiocarpal joint
No
What type of bone is the pisiform bone
Sesamoid bone
What does the pisiform do
Increase MA of the flexor carpi ulnaris
What does a sesamoid bone do
Enhances MA of muscles
True or False:
No muscles act directly on the RC joint
True
What is motion at the radiocarpal joint due to
Ligamentous forces distributed and muscles that insert at the distal carpals and metacarpals
What 2 motions does the radiocarpal joint contribute to most
Flexion and ulnar deviation
If someone has flexion and ulnar deviation problems what joint should you focus on
Radiocarpal joint
True or False:
The midcarpal joint has no isolated capsule
True
How would you describe the midcarpal joint
Interrupted multiarticular surface
True or False:
The scaphoid contributes to motion both at the radiocarpal and midcarpal joints
True
How many degrees of freedom does the midcarpal joint have
2
What 2 motions does the midcarpal joint contribute to most
Extension and radial deviation
True or False:
The intercarpal joints allow minimal movement to accomodate hand and wrist positioning
True
Which side of the intercarpal joints is more mobile
Ulnar side
What ligaments of the intercarpal joints are stronger palmar or dorsal ligaments
Palmar ligaments
True or False:
The palmar side of the lunate is reltively unstable
True
Which carpal is the most commonly dislocated
Lunate
Does the scaphoid have any ligament attachment dorsally near the proximal pole
No
What does the lack of ligament attachment on the proximal pole of the scaphoid potentially lead to
Ganglion cyst formation
True or False:
Ligaments are support structures and passive movers
True
What does the dorsal radiocarpal ligament contact
Lunate and radius
What is the dorsal radiocarpal ligament a check rein to
End range wrist flexion
What are the ulnar and radial collateral ligaments check reins to
Radial: Ulnar deviation
Ulnar: Radial deviation
True or False:
The volar radiocarpal ligament is the most important of all ligaments for stability and passive mobility contribution
True
How many bands does the volar radiocarpal ligament have
3
What is the coupled motion with flexion
Ulnar deviation
What is the coupled motion with extension
Radial deviation
What is the angle of the radial head called
Ulnar tilt
What is the angle of the radial head
25
During flexion at the radiocarpal joint what arthrokinematics occur
Palmar roll and dorsal glide
During extension at the radiocarpal joint what arthrokinematics occur
Dorsal roll and palmar glide
During radial deviation at the radiocarpal joint what arthrokinematics occur
Radial roll and ulnar glide
During ulnar deviation at the radiocarpal joint what arthrokinematics occur
Ulnar roll and radial glide