Hand and wrist Flashcards
What are the carpal bones?
scaphoid
lunate
triquetrum
pisiform
hamate
capitate
trapezoid
trapezium
How many metacarpals are there?
5
How many phalanges are there?
14
The wrist joint is a ______?
radiocarpal synovial joint
What is the radiocarpal synovial joint between?
between the radius and an articular disc covering the distal ulna, and the proximal articular surfaces of the scaphoid, lunate, and triquetrum?
What does the radiocarpal synovial joint permit?
a wide range of movements
What are the movements that the radiocarpal synovial joint allows for?
flexion
extension
abduction
adduction
circumduction
The carpal bones themselves (intercarpal and midcarpal) provide for what?
gliding movements and significant wrist extension and flexion
What do the carpometacarpal (CMC) joints allow?
some gliding
Why is the 1st CMC joint unique?
it is the thumb joint- allows for flexion, extension, abduction, adduction, and circumduction
What is the first CMC joint a common site for?
arthritis
What do the metacarpophalangeal (MCP) joints allow for?
flexion, extension, abduction, adduction, and circumduction at the metacarpals
What do the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints do?
complete the joints of the hand- allows flexion and extension
How many PIP and DIP joints are on the hand?
5 PIP joints
4 DIP joints
The palmar fascia is a continuation of the forearm fascia that will thicken centrally to form what?
the palmar aponeurosis
What attaches distally to the palmar aponeurosis?
palmaris longus muscle
What is the proximal attachment of the palmaris longus muscle?
flexor common tendon at the medial epicondyle
What structures are associated with the flexor common tendon?
- pronator teres
- flexor carpi radialis
- palmaris longus
- flexor carpi ulnaris
Where can you find the fibrous digital sheath?
palmar aspect of each digit
What does the palmar aponeurosis protect against?
infection and invaders
The palmar fascia is a continuation of what?
antebrachial/forearm fascia
What are the characteristics of the palmar aponeurosis?
-part of the deep fascia
-thick and strong, continuous with forearm and dorsal surface
-contains palmar branch of the median n
Where is the fibrous digital sheath located?
on the palmar aspect of each digit
What occurs in Dupuytren’s contracture?
the medial longitudinal aponeurotic digital bands shorten, thicken and become fibrotic, causing the degeneration of the medial longitudinal digital bands of the aponeurosis on the medial side of the 4th and 5th digits
What increases your risk of developing Dupuytren’s contracture?
if you are:
-male
-between 40 and 60 years old
-northern european descent
-have a family history of the condition
-smoke or drink alcohol
-have diabetes
The thenar muscles are innervated by what nerve except for what muscle(s)?
recurrent branch of the median nerve
flexor pollicis brevis deep head and adductor pollicis
What is the flexor pollicis brevis deep head and adductor pollicis muscle innervated by?
deep branch of the ulnar nerve
What are the 2 clinically relevant fascial potential spaces on the palmar aspect of the hand?
- deep to the thenar muscle compartment (thenar space)
- deep to the central mm compartment: FDS, FDP, FPL; (midpalmar space)
What is the mid palmar space communicated with?
carpal tunnel
What is the clinical significance of the potential spaces such as the thenar and mid palmar space?
-if they become infected, it can show direction of spreading and how extensive the infection is (spread of pus formed in infected areas)
-depending on the site, puss with accumulate in the thenar, hypothenar, or adductor compartments
What sheath creates the thenar space?
index finger synovial sheath
What sheath created the midpalmar space?
3-5 digits synovial sheath and carpal tunnel
What are the characteristics of the dorsum/dorsal fascia?
thinner than the palmar fascia, thus, infectious swellings usually appear on the dorsum of the hand
Why do infections usually track to the back of the hand?
the dorsal fascia is thinner than the palmar fascia so the infectious swellings usually appear on the dorsum of the hand
What should snuffbox tenderness be equated with?
scaphoid fractures unless radiographs prove otherwise
What is the most commonly fractured carpal bone?
scaphoid
What are scaphoid fractures often misdiagnosed as?
severely sprained wrist
How does a scaphoid fracture usually occur?
falling with an outstretched hand
A patient fell with an outstretched hand and comes in complaining of pain and tenderness over the snuff box, what has likely occured?
scaphoid fracture
Optimal healing of a scaphoid fracture depends on adequate blood supply from what?
palmar carpal branch of the radial artery
Disruption of the blood supply to the proximal portion of the scaphoid in a fracture can result in what?
-avascular necrosis
-arthritis
What is the lateral border of the anatomical snuff box?
-abductor pollicis longus tendon
-extensor pollicis brevis tendon
What is the medial border of the anatomical snuff box?
extensor pollicis longus tendon
What makes up the floor of the anatomical snuffbox?
-radial artery
-scaphoid and trapezium
What makes up the roof of the anatomical snuffbox?
superficial radial nerve
What is the anatomical snuffbox clinically correlated with?
scaphoid fracture
What is the most important nerve in the hand?
ulnar nerve
The intrinsic muscles of the hand are located in how many compartments?
5
What are the 5 compartments that contain the intrinsic hand muscles?
- thenar compartment
- hypothenar compartment
- adductor compartment
- central compartment
- interosseus compartment
What are the thenar muscles are in the thenar compartment?
- adbuctor pollicis brevis
- flexor pollicis brevis
- opponens pollicis
What are the hypothenar muscles are in the hypothenar compartment?
- adbuctor digiti minimi
- flexor digiti minimi brevis
- opponens digiti minimi
What the the adductor muscles in the adductor compartment of the hand?
adductor pollicis
What are considered the short muscles of the hand?
lumbricals
What muscles are in the central compartment of the hand?
lumbricals and long flexor tendons
What is found in separate interosseous compartments between the metacarpals?
the interossei
What muscles in the hand allow for thumb abduction?
Abductor pollicis longus and abductor pollicis brevis
What muscles in the hand allow for adduction of the thumb?
adductor pollicis and 1st dorsal interosseous