Orthopedics - Hand Anatomy and Kinematics Flashcards
During flexion what occurs with the scaphoid
- The scaphoid will look shorter and you will be able to see the cortical ring.
During radial deviation what will happen to the scaphoid, lunate and triquetrum?
Scaphoid will get longer, the lunate and the triquetrum (which are attached to the scaphoid) flex also.
During extension what will happen to the scaphoid, and what will be more visible?
The scaphoid will look longer and the hook of the hamate will be more visible.
During ulnar deviation what will happen to the triquetrum, scaphoid and lunate?
- For ulnar deviation to occur the triquetrum needs to slide under the hammate to get out of the way of the ulnar. Due to ligaments the scaphoid and lunate will follow the triquetrum.
What will happenif the scapho-lunate ligament is severed?
The lunate will only be able to be pulled into extension by the triquetrum, so it will be displaced dorsally.
What will happen if the triquetro-lunate ligament is severed?
The lunate will follow the scaphoid into flexion and will be volarly displaced.
When the wrist goes into radial deviation what flexes?
The entire proximal row of carpal bones. And vice versa for ulnar deviation.
Does radial deviation or ulnar deviation cause the scaphoid to flex more?
Radial deviation will cause the scaphoid to flex more. Ulnar deviation will cause less flexion.
What is dorsal intercalated segment instability?
How would you identify this?
- Disruption of the dorsal portion of the scapho-lunate interosseous ligament and the radioscaphocapitate ligament.
- volar radial lip and a wider spacing
What is volar intercalated segment instability?
Disruption of the dorsal portion of the luno-triquetral interosseous ligament.
What would smaller spaces between carpal bones indicate?
- mineral density problems
What is the cortical ring sign?
When hamates hook is pointing toward the viewer.
What is carpial collition
- a fusion of the lunate and triquitrium (more common in african americans)
What is a
- Grade 1 sprain?
- Grade 2 sprain?
- Grade 3 sprain?
Grade 1 sprain: stretching of a ligament - no tearing
Grade 2 sprain: stretching of some ligaments and tearing of others
Grade 3 sprain: tearing of others
What motion is retroposition?
If the palm is flat and the thumb is raised upward.
What is the primary function of the extensor pollicus longus?
Primary function is to extend the IP joint when there is EPL pathology.
What is the primary supinator and adductor of the thumb?
Extensor pollicus longus.
What are the primary MP joint flexors and IP joint extensors?
- The intrinsics
What are the interosseous muscles?
What is there innervation?
Dorsal abductors (4) DAB Palmar Adductors (3) PAD - pinky finger does not get a adductor - The ulnar nerve
What is the Abductor digiti quinti muscle?
It is an abductor of the pinky.
What does the superficial head of the dorsal interossei do?
- Abducts the MPJ (flexes)
What does the deep head of the dorsal intersossei do?
Flexes the MPJ (abducts) and extends the IPJs
What are the primary flexors of the MP joints?
The intersossi muscles**
lumbricals have a much more minor role in flexion.
What muscles make up the Thenars?
Oppocins Pollicis
Abductor Pollicis Brevis
Flexor Pollicis Brevis
OAF
What muscles make up the Hypothenars?
Oppocins Digiti Minimi
Flexor Digiti minimi brevis
Abductor digiti minimi
OFA
What are the median nerve innervated intrinsics?
Lumbricals (index and middle)
Opponens Pollicis
Abductor Pollicis Brevis
Flexor Pollicis Brevis
What side of there respective digits are the lumbricals on?
The radial side
What group of muscles extend all joints of the fingers?
The extrinsics
What action does intrinsic muscles have?
Flex MP joints
Extend IP joints
Where doe the lumbrical muscles originate?
What do they join?
- Originates on the FDP tendon
- ## Joins radial lateral band
What is unique to the lumbrical muscles?
It will pull the flexor digitorum profundus tendon distally and the radial lateral band proximally.
How are lumbricals increase the dexterity of the fingers?
- They take away a little more tone from the antagonistic muscles to allow for smoother and faster contraction.
