Wrist and hand Flashcards
What is the wrist/carpus?
-Collection of bones and soft tissue structures that connects the hand to the forearm
What are the wrist joints?
- Radiocarpal joint (mainly this one makes up the wrist)
- Ulnocarpal joint
- Distal radioulnar joint
What is the radiocarpal joint? What kind of joint? Which carpal bones are involved?
-Synovial joint formed between radius and 3 carpal bones: scaphoid, lunate and triquetrum
What is the ulnarcarpal joint? What type of joint? What carpal bones?
-Synovial joint between ulnar and carpal bones (lunate and triquetrum)
What is the distal radioulnar joint? What kind of joint is it?
- Synovial joint
- Head of ulna articulates with ulnar notch of radius
How does the wrist function kinematically? How does it function kinetically?
- By allowing changes in location and orientation of hand relative to the forearm
- It functions kinetically by transferring loads from the hand to the forearm and vice versa
Why is wrist stability important? What does wrist position affect?
- For the proper function of digital flexors and extensors
- Wrist position affects the ability of fingers to flex and extend maximally and grasp effectively
How would you describe the hand? What does it emphasise? What is it the final link in? What is the importance of the wrist, elbow and shoulder operating in different planes?
- Mobile and adaptable as it conforms to the shape of objects to be grasped
- Emphasises gestures
- The hand is the final link in the mechanical chain of levers beginning at the shoulder
- The mobility and stability of shoulder, elbow and wrist all operating in different planes allows the hand to move within a large volume of space and reach all parts of the body with relative ease
Why is the mobility and stability of the shoulder, elbow and wrist operating in different planes important?
-The mobility and stability of shoulder, elbow and wrist all operating in different planes allows the hand to move within a large volume of space and reach all parts of the body with relative ease
Why is the arrangement of bones and joints of the hand important?
-Provides a structural foundation of hands adaptability
What does the wrist joint complex consists?
-Multiple articulations between the 8 carpals, distal radius, structures of the ulnocarpal space and metacarpals
What are the soft tissue structures surrounding the carpal bone?
- Tendons that cross or attach to the carpus
- Ligamentous structures connecting carpal bones to each other and the bony hand and forearm
What are the 8 carpals?
- Proximal row: scaphoid, lunate, triquetrum, pisiform
- Distal row: trapezium, trapezoid, capitate, hamate
Which row of carpal bones is more mobile?
- Proximal row is mobile
- Distal row is immobile
Describe the proximal row of carpals. What does it articulate with? And what joint is formed? What are the distal components here? What happens during extreme ulnar deviation?
- The proximal row (scaphoid, lunate and triquetrum) articulates with the distal radius and triangular fibrocartilage to form the radiocarpal joint (RCJ).
- The distal components are the convex surfaces of the scaphoid and lunate
- During extreme ulnar deviation, the convex surface of triquetrum joins
What does the distal row of carpals articulate with? What joint is form?
How do the 4 bones fit together? And what ligaments hold them together?
- They articulate with metacarpals to form carpometacarpal joints (5 of them)
- All 4 bones fit tightly against each other and are held together by stout interosseous ligaments
Learn this picture
What does the scaphoid bone span? What does it exclusively articulate with?
- It spans the distal and proximal row
- Anatomically and functionally
- It articulates exclusively with radius
What is in the ulnar articulate disc (within distal radioulnar joint)?
-Lunate
What is pisiform? What does it articulate with? What tendon will it sit within? What the presence of pisiform do to the tendon and how?
- A sesamoid bone that forms a small articulation with the triquetrum
- It sits within the flexor carpi ulnaris (FCU) tendon
- Presence of pisiform mechanically enhances flexor carpi ulnaris by acting as the pulley that provides a smooth surface for the flexor carpi ulnaris tendon to glide over
What joint is found between the distal and proximal rows of carpals?
-Intercarpal joints
What shape is the palmar surface of the carpus?
-Concave
What bones articulate with the ulna? Through which complex?
- Distal radius
- Triquetrum and lunate
- Through ulnocarpal (ulnar triangular) fibrocartilage complex (ligamentous and cartilaginous structure)
What is each finger composed of?
- A metacarpal
- 3 phalanges (except thumb - thumb has 2)
What are the roman numerals for digits?
I= thumb
V= pinkie
What does each digit articulate with? To form what joint?
-Each digit articulates with a particular carpal bone to form carpometacarpal joint
What is the metacarpophalangeal joint?
Between the metacarpal and proximal phalanx
What is interphalangeal joint (proximal and distal)?
Between the phalanges
How many interphalangeal joint does the thumb have?
What about the rest of the digits?
- 1
- 2
Where is the thenar eminence?
-Intrinsic muscles found at the palmar side of 1st metacarpal
What is the hypothenar eminence?
-Created by muscles of the little finger and an overlying fat pad
What are the arches of the hand?
- 2 transverse arches (proximal and distal)
- 1 longitudinal arch
What are the transverse arches of the hand? Where do the proximal and distal transverse arches lie?
- Proximal and distal arches
- The proximal transverse arch lies at the level of distal carpals (relatively fixed and capitate is keystone)
- The distal transverse arch passes through all the metacarpals (more mobile and metacarpal III is its keystone)
What muscles maintain the configuration of the 3 arches of the hand? What are the extrinsic and extensor muscles responsible for?
- Intrinsic muscles
- Extrinsic and extensor muscles are largely responsible for changing shape of the working hand
What are the flexors of the wrist?
- Flexor carpi ulnaris = wrist flexion and ulnar deviaton
- Flexor carpi radialis = wrist flexion and radial deviation
- Palmaris longus = tenses palmar fasica
What are the extensors of the wrist?
- Extensor carpi radialis longus = wrist extension and radial deviation
- Extensor carpi radialis brevis = wrist extension and radial deivation
- Extensor carpi ulnaris = wrist extension and ulnar deviation
What are the pronators and supinators of the wrist?
- Pronator teres = pronation
- Pronator quadratus = pronation
- Supinator = supination
- Brachioradialis = pronation or supination depending on position of foreaem
What are the extrinsic flexors of the hand?
- Flexor digitorum superficialis = proximal interphalangeal joints and metacarpophalangeal joint flexion
- Flexor digitorum profundus = distal interphalangeal joints and metacarpophalangeal joint flexion
- Flexor pollicus longus = interphanageal joint and metacarpophalangeal joint flexion of thumb
What is the difference between dorsum and palmar surface of hand?
- Dorsal skin is thin, mobile and flexible
- Palmar skin is thick and hairless and inelastic