Wrist and Hand

How many degrees of freedom does the MP joint of the thumb have?

Hinge joint with 1 degree of freedom - only has flexion and extension

What movements occur at the interphalengeal joints?

Just flexion and extension - they are hinge joints with 1 degree of freedom

What muscle doesn't attach to bone?

Lumbricals - primarily MP flexors - Origin is on FDP tendon (the one that goes out to the finger) - Inserts on extensor mechanism - on the back of fingers (from volar surface to the back

The ______ has a split in it so that the _____ can pass and insert on the distal phalanx. This is called ______ chiasm

The flexor digitorum superficialis has a split in it so that the flexor digitorum produndus can insert onto the distal phalanx. This is called campers chiasm. -- the FDP bends the DIP joint --- the FDS inserts on the middle phalanx

What side of the hand has the most ligaments? Why is this?

The volar (palmar) side - it prevents major dislocations from occurring and protects the hand with more "squishy" or "shock absorbing" structures

Is the collateral ligament loose or tight when MP's are in flexion?

Tight! -- it is stretched out - two components are the cord and fan - located above the axis of rotation

Which carpal bone articles with the first metacarpal and is the source of the thumbs unique movements?

Trapezium

What is tenodesis?

Wrist extension or hand grasp is when your knuckles are higher than your wrist. When your wrist is extended, your fingers naturally curl or grip. When the wrist is extended, the tendons along the fingers shorten and pull the finger joints into flexion. - strongest in extension

What bone does the lunate articulate with?

capitate - center of location for flexion and extension and radial/ulnar deviation

Is the extensor carpi ulnaris stronger in flexion or extension?

flexion

What movements occur at the midcarpal joint?

flexion/extension and radial and ulnar deviation

what pinch is used for key turning?

lateral (key) - twist and rip

Ulnar deviation mostly occurs at what joint?

radiocarpal joint

Is there greater radial deviation or ulnar deviation at the wrist?

ulnar deviation - occurs in the frontal plane and its axis of rotation is anterior to posterior

Tendons in the first compartment of extensor retinaculum

· Abductor pollicis longus (APL) · EPB (extensor pollicis brevis)

What does the pulley system in the extrinsic flexors do?

- Flexor tendons - volar surface ---->Pulleys are holding tendon close to the bone o Prevents bowstringing ---->A2 is the biggest and most important - Annular and cruciate ---->Describes how they look ---->Cruciate - cross

What are the five zones of the hand?

- Zone 1 is tip of finger - Zone 5 is wrist - Zone 2s are the worst - no man's land for flexor tendon injuries · FDS and FDP run in sheath together o Cut one, cut the other o Forms a lot of scar tissue as it heals o Tendons are stuck and cannot move - T2 is the thumb

What is the cascade sign?

- fingers in full flexion, tips all point towards scaphoid - index and middle stay close to the thumb (important for prehension) - prehension from radial side - grip strength comes from ulnar side

What does the transverse carpal ligament do to support the hand?

- forms the roof of the carpal tunnel - prevents bowstringing of the flexor tendons

What does the extensor retinaculum do?

- forms the roof over 6 dorsal compartments for extensor tendons

What brakes in a boxer's fracture?

- fracture of the 5th metacarpal - comes from punching someone - problems with strength but prehension might be okay

What are and where are the check rein ligaments located?

- only at PIP and DIP joints - continuation or fold into part of volar plate -between P1 and P2 - adds extra support to volar plate

What does the palmar aponeurosis do?

- protects underlying neurovascular structures and tendons - soft tissue fascial complex in palm of hand

How does the Triangular fibrocartilage complex support joint stability and what is it comprised of?

- shock absorber between the wrist and ulna - Triangular fibrocarticlage which is a disc between the radius and ulna - Ulnocarpal ligament - Dorsal and volar raidal ligaments - Extensor carpi ulnaris sheath - ulnolunate and ulnotriquetral ligaments

What structures protect the hand and provide stability?

- transverse carpal ligament - palmar aponeurosis - extensor retinaculum

What type of pinch is important for picking up coins or pens?

2 point pinch (tip to tip) - thumb and pointer

What type of pinch is used for playing cards?

3 point (tripod) - thumb, pointer, middle finger

How many metacarpals are there?

5 in flat palm of hand

What muscle is located between the pisiform and the base of the fifth finger?

Abductor digiti minimi

What are the hypothenar muscles? *ball of little finger

Abductor digiti minimi Flexor digiti minimi Opponens digiti minimi

The distal tendons of which three muscles form the "anatomical snuffbox"

Abductor pollicis Extensor pollicis brevis Extensor pollicis longus

What muscles are responsible for thumb carpometacarpal abduction?

Abductor pollicis longus Abductor pollicis brevis

Which muscle is stronger - extensor carpi radialis breivs or extensor carpi radialis longus?

Brevis - inserts into base of 3rd metacarpal, base of wrist, centrally located

The radial and ulnar artery form what two structures?

Deep and superficial palmar arches

What muscles are involved in wrist radial deviation?

Extensor carpi radialis longus Extensor carpi radialis brevis Flexor carpi radialis Abductor pollicis longus

True or False - there is movement between the distal row and metacarpals

False - no movement here

What is Dupuytren's disease?

Fascia tightens, familial disease Treatment: - inject fascia with collagenase and breaks up the fascia

What are the extrinsic muscles? *bellies in forearm

Finger flexors - flexor digitorum superficialis - flexor digitorum profundus - flexor pollicis longus Finger extensors - extensor digitorum comunis - extensor indicis - extensor digiti minimi

What are the intrinsic muscles? *bellies in hand

Hypothenar muscles (muscles for 5th finger) Thenar muscles (thumb muscles) Adductor pollicis Interossei (4 dorsal abduct, 3 volar adduct) Lumbricals (no attachment to bone)

The actions of the intrinsic muscles are influenced by the different positions of what?

MCP, DIP, and DIP joints

Proper name of the "knuckle" joint

Metacarpalphalengeal joint

There is 1.5x more extension at the ________joint than at the ________ joint

Midcarpal joint - distal carpal glides on proximal row

What muscle is responsible for thumb carpometacarpal oppostition?

Opponens pollicis

Which muscle creates opposition of the thumb?

Opponens pollicis

Which four carpals serve as attachment sites for the flexor retinaculum?

Pisiform Hook Hamate Trapezium tubercle Scaphoid tubercle

What are the four types of grip?

Power Hook Spherical Cylindrical

What grip is most commonly tested and measured in adults?

Power grip

Mnemonic for carpal bones

Proximal Row She (scaphoid) Likes (lunate) To (triquetrum) Play (pisiform) --------------- Distal Row Try (trapezium) To (trapezoid) Catch (capitate) Her (hamate)

where is the CMC joint of the thumb?

between carpals and base of metacarpal

The supeficial palmar arch forms what structure?

common palmar digital arteries

P3 of finger is called what

distal phalanx

Are the extensor carpi radialis longus and brevis stronger in flexion or extension?

extension

The common extensor tendon in made up of what muscles?

extensor carpi radialis brevis (ECRB) and longus, extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris come together to form the common extensor tendon.

What bone does the triquetrum articulate with?

hamate

Radial deviation mostly occurs at what joint?

midcarpal joint

P2 of finger is called what

middle phalanx

What row moves ulnarly on the radius and radioulnar disc during radial deviation?

proximal

P1 of the finger is called what

proximal phalanx

Tendons in the second compartment of extensor retinaculum

· Extensor carpi radialis brevis and longus (wrist extensors)

Tendons in the fifth compartment of extensor retinaculum

· Extensor digiti minimi (little finger extensor)

Midcarpal joint mobility occurs between the scaphoid and what 3 bones?

trapezium, trapezoid, capitate

What is the extensor retinaculum?

- A thickening of the deep fascia on the extensor aspect of the wrist - holds tendons down and in place - 6 tunnels (compartments) the extensor tendons travel through

What structures provide stability to the wrist?

- articulations (8 bones interconnected) - ligaments (more on palmar surface) ---->Extrinsic ligaments (RCL, UCL, dorsal and palmar radiocarpal, TFCC) ---->Intrinsic ligaments - muscles (PQ, ECU, FCU)

What does the extensor digitorum do?

- extensor of the MP joints - crosses wrist on way to the fingers (belly in forearm) - helps wrist ONLY if something goes wrong with wrist extensors

What is the purpose of the palmar ligament and volar plate?

- stops hyperextension and dislocation on palmar side

What are the bones of the wrist?

-Ulna (40% load) - Radius (60% load)

What muscles are responsible for flexion at the wrist?

Flexor carpi radialis Fexor carpi ulnaris Palmaris longus

What muscle is the primary wrist flexor?

Flexor carpi radialis (60% of work) - FCU comes in only if person needs additional support

What muscle is responsible for thumb carpometacarpal flexion?

Flexor pollicis brevis

What muscle is responsible for thumb metacarpophalengeal flexion?

Flexor pollicis brevis

How many muscles act on the thumb? How many of those are located at the thenar eminence?

- Eight - Four of the eight

What movements occur at the carpometacarpal joint of the thumb?

Flexion/extension Abduction/adduction Opposition/repositon

What band of tissue forms the "roof" of the carpal tunnel?

Flexor Retinaculum

The _____ eminence is located at the thumbs base, while the ______ eminence is located along the ulnar side of the palm

- Thenar (fleshy mass) - Hypothenar

How many phalanges are there?

14 phalanges - each finger except thumb has 3

How many planes of motion does the Radiocarpal joint have?

2 - flex/ext and rd/ud

What are the three types of pinch patterns?

2 point (tip to tip) 3 point (tripod - playing cards) Lateral (key or spoon)

What are the thenar muscles? *ball of thumb

Abductor pollicis brevis Flexor pollicis brevis Opponens pollicis

What muscle is responsible for thumb carpometacarpal adduction?

Adductor pollicis

What is the acronyum for remembering the intrinsic muscles? *not discussed in lecture but good to reference*

All For One, And One For All A- abductor pollicis brevis f- flexor pollicis brevis o- opponens pollicis A- adductor pollicis o- opponens digiti minimi f- flexor digiti minimi brevis A- adductor digiti minimi

What joint of the hand is typically fractured, irritated, etc?

CMC

If the extensor pollicis brevis gets irritated what syndrome can occur?

De Quervain's Syndrome

What is De Quervain's tenosynovitis

De Quervain's tenosynovitis involves the tendons of the extensor pollicis brevis and abductor pollicis longus. - inflammation of the tendons within the first extensor compartment of the wrist, resulting in wrist pain and swelling. - It is most common in women between the ages of 30-50, especially in those with occupations or hobbies involving repetitive movements of the wrist

What muscles are responsible for extension at the wrist?

Extensor carpi radialis longus Extensor carpi radialis brevis Extensor carpi ulnaris

What muscles are involved in wrist ulnar devation?

Extensor carpi ulnaris Flexor carpi ulnaris

What muscles are responsible for extension of the fingers?

Extensor digitorum communis Extensor digiti minimi (extends little finger) Extensor indicis (extends index)

What muscle is responsible for thumb carpometacarpal extension?

Extensor pollicis brevis

What muscle is responsible for thumb metacarpophalengeal extension?

Extensor pollicis brevis

What muscle is responsible for thumb interphalangeal extension?

Extensor pollicis longus

What muscle extends the distal tip of the thumb? *hint* the tendon wraps around listers tubercle as it goes out to the thumb

Extensor pollicus longus (ELP)

The pisiform acts as an attachment site for what muscle?

Flexor carpi ulnaris

The lumbricals sprout from the sides of the tendons of which muscle?

Flexor digitorum profundus

What muscle bends the tips of the fingers (DIP joints)?

Flexor digitorum profundus

This muscle flexes the PIP joints and has tendons that pass through the carpal tunnel to attach to the phalanges

Flexor digitorum superficialis

What muscles are responsible for flexion at the fingers?

Flexor digitorum superficialis (PIP flexion) Flexor digitorum profundus (DIP flexion) Flexor digiti minimi brevis

What muscle is responsible for thumb interphalangeal flexion?

Flexor pollicis longus

What is the name of a common type of injury that occurs on the volar side of an outstretched hand?

Foosh injury

What movements occur at the metacarpophalangel joint "knuckle"

It is a condyloid joint - flexion/extension -abduction/adduction

What movements occur at the distal interphalangeal joint "DIP"

It is a hinge joint - flexion/extension (lumbricals/interossei)

What movements occur at the proximal interphalangeal joint "PIP"

It is a hinge joint - flexion/extension (lumbricals/interossei)

Extensors of the wrist originate on what side?

Lateral

Flexors of the wrist originate on what side?

Medial

What types of joints are CMC joints 2-5

Plane joints with very little movement if any at all

What main arteries supply blood to the hand?

Radial artery Ulnar artery

There is 1.5x more flexion at the ________joint than at the ________ joint

Radiocarpal joint - proximal row of carpal slides dorsally onto the radius and disc

True or False - there is movement between the proximal and distal rows of the carpals

True - this is where the midcarpal joint is located

What ruptures when skiers thumb occurs?

Ulnar collateral ligament

Which two structures pass through the Tunnel of Guyon?

Ulnar nerve Ulnar artery

The common palmar digital arteries turn into what structure that supplies blood to the flexor tendons?

Vinculars

Is there a lot of mobility at the CMC joint?

Yes - fibrous joint capsule

Where is the midcarpal joint located?

between proximal and distal rows of carpal bones

What two bones have the most mobility at the midcarpal joint?

scaphoid and triquetrum

The actions of the extrinsic muscles are influenced by the position of what?

the wrist

Tendons in the third compartment of extensor retinaculum

· EPL - goes around listers tubercule on the way out to the distal thumb

Tendons in the sixth compartment of extensor retinaculum

· Extensor carpi ulnarus

Tendons in the fourth compartment of extensor retinaculum

· Extensor digitorum (NP extensors) · Extensor indicis (index finger extension)

What is ulna variance?

· Ulna positive - tip creates problems at the wrist for clients (styloid process is more distal - we do not want this) o Ulna shortened to bring styloid process more proximal · Ulna negative o Styloid process of ulna more proximal, lower o most people have this · Ulna neutral o Everything is where it should be o Axis for pivot joint is in line

Which carpal forms the floor of the "anatomical snuffbox"?

Scaphoid