L11: Functional anatomy of the hand and wrist

Question 1

What forms the wrist joint?

Answer 1

Distal radius, triangular fibrocartilage complex (TFCC), the scaphoid and lunate
Ulna not part of wrist

Question 2

What type of joint is the wrist joint?

Answer 2

Ellipsoid type of synovial joint

Between convex surface or carpal bones and concave surface of radius and triangular fibrocartilage

Question 3

What types of movement are there at the wrist?

Answer 3

Two axes
Flexion and extension
Abduction (radial deviation) and adduction (ulna deviation)
Circumduction–> all four movements together- move hand in a circle

Question 4

What stabilises the wrist joint?

Answer 4

Stabilised by ligaments
Dorsal and palmar radiocarpal ligaments
Ulnar and radial collateral ligaments

Question 5

What do the radiocarpal ligaments ensure?

Answer 5

The hand follows the hand follows the radius during pronation and supination of the forearm

Question 6

What are the main muscles responsible for flexion of the wrist?

Answer 6

Flexor carpi ulnaris (inserts onto pisiform, hook of hamate and base of 5th metacarpal)
Flexor carpi radialis (inserts onto base of 2nd and 3rd metacarpal)
Palmaris longus (Inserts onto palmar aponeurosis)

Question 7

What other muscles assist in flexion?

Answer 7

Flexor digitorum superficialis (Base of middle phalanx of 4 fingers)
Flexor digitorum profundus (base of distal phalanx of four fingers)
Flexor pollicis longus (base of distal phalanx of thumb)

Question 8

What are the main extensors?

Answer 8

Extensor carpi radialis longus (dorsal surface of 2nd metacarpal bone)
Extensor carpi radialis brevis (dorsal surface of 3rd metacarpal bone)
Extensor carpi ulnaris (Base of 5th metacarpal)

Question 9

What muscles assists extension?

Answer 9

Extensor digitorum (Extensor hood of the 4 fingers)
Extensor indicies (extensor hood of index finger, ulnar side of extensor digitorum)
Extensor digit minimi (extensor hood of little finger)
Extensor pollicis longus (distal phalanx of thumb)
Extensor pollicis brevis (proximal phalanx of thumb)
Abductor pollicis longus (radial side of base of first metacarpal)

Question 10

What muscles produce ulnar deviation (adduction)?

Answer 10

Flexor carpi ulnaris

Extensor carpi ulnaris

Question 11

What muscles produce radial deviation (abduction)?

Answer 11

Flexor carpi radialis

Extensor carpi radialis longus and brevis

Question 12

What is the innervation to the wrist?

Answer 12

3 nerves that supply the hand from the radial, ulnar and median nerves

Question 13

How many bones are there in the hand?

Answer 13

8 carpal
5 metacarpal
14 phalanges

Question 14

What are the 8 carpal bones? How are they arranaged?

Answer 14

'Straight Line To Pinky, Here Comes The Thumb!'
Proximal row 
-Scaphoid
-Lunate 
-Triquetrum  
-Pisiform
Distal row 
-Hamate
-Capitate
-Trapezoid 
-Trapezium

Question 15

Which bones articulate with the radius?

Answer 15

Scaphoid and lunate

Question 16

Which bones articulate with the metacarpal bones?

Answer 16

Distal row

Hamate, Capitate, Trapezoid and Trapezium

Question 17

What is significant about the hamate bone?

Answer 17

Hamate has a hook on it
Forms ulna border of carpal tunnel
Radial border of Guyons canal
Attachment site for flexor retinaculum and tendon of flexor ulnaris carpi

Question 18

What is unusal about the scaphoid?

Answer 18

Unusual blood supply- retrograde flow
Via dorsal carpal branch of the radial artery
Enters dorsal surface of scaphoid distally, supplies proximal 80% of scaphoid by retrograde flow (flow back towards the wrist)
Important to understanding why scaphoid fracture have a high rate of non-union

Question 19

What do each of the metacarpal bones articulate with?

Answer 19

I- trapezium proximally, proximal phalanx of the thumb distally
II- trapexoid proximally, proximal phalanx of index finger distally
III- capitate proximally, proximal phalanx of middle finger distally
IV- Hamate proximally, proximal phalanx of ring finger distally
V- Hamate proximally, proximal phalanx of little finger distally

Question 20

What is the structure of the metacarpal bones?

Answer 20

Base, shaft and head

Medial and lateral surfaces are concave (accomodate interossei muscles)

Question 21

What movements are possible at the thumb?

Answer 21

Flexion*
Extension* 
Radial abduction* 
Radial adduction
Palmar abduction 
Palmar adduction 
Opposition 
Reposition 
Retropulsion 
Circumduction 

*in coronal plane

Question 22

What is flexion of the thumb?

Answer 22

Bending of the thumb

Bend at metacarpophalangeal joint and interphalangeal joint

Question 23

What is extension of the thumb?

Answer 23

Returns flexed thumb to anatomical position

Question 24

What is radial abduction?

Answer 24

Contunation of extension beyond the anatomical plane
In coronal plane

(if you were to spread your fingers out your thumb would be radially abducted)

Question 25

What is opposition?

Answer 25

Rotatory movement of the thumb over the palm | Enables the thumb to touch the tips of the fingers

Question 26

What is reposition?

Answer 26

Returning the thumb to the anatomical position from the position of opposition

Question 27

What is palmar abduction?

Answer 27

Raising the thumb in the sagittal plane Perpendicular to the palm (perpendicular plane to radial abduction)

Question 28

What is adduction?

Answer 28

Opposite of both palmar abduction and radial adduction

Question 29

What is retropulsion?

Answer 29

Extending the thumb posteriorly beyond the coronal plane

Question 30

What is circumduction?

Answer 30

Winding your thumb round in circles

Question 31

What movement are possible with the fingers?

Answer 31

``` Flexion Extension Abduction Adduction Circumduction ```

Question 32

What is the difference between the intrinsic and extrinsic muscles of the hand?

Answer 32

Intrinsic--> originate within the hand and insert within the hand Extrinsic--> originate the forearm and insert within the hand

Question 33

How can the intrinsic muscles of the hand be divided?

Answer 33

``` Four compartments Thenar compartment Adductor compartment (adductor pollicis) Hypothenar compartment Central compartment ```

Question 34

What muscles are in the thenar compartment?

Answer 34

Form the thenar eminence Abductor pollicis brevis Flexor pollicis brevis Opponens pollicis --> largest, lies deepest

Question 35

What muscles are in the hypothnar compartment?

Answer 35

Abductor digit minimi Flexor digiti minimi Opponens digiti minimi--> deepest

Question 36

What muscles are in the central compartment?

Answer 36

Lumbricals Interossei Palamaris Brevis

Question 37

What is the origin, insertion, innervation and function of the opponens pollicis?

Answer 37

Largest lies deepest O: Trapezium and flexor retinaculum I: Lateral border of 1st metacarpal F: Opposes thumb (by medially rotating and flexing 1st metacarpal) Innervation: Median nerve

Question 38

What is the origin, insertion, innervation and function of the abductor pollicis brevis?

Answer 38

O: Scaphoid, trapezium and flexor retinaculum I: Lateral border of proximal phalanx of thumb F: Palmar abducts the thumb Innervation: Median nerve

Question 39

What is the origin, insertion, innervation and function the flexor pollicis brevis?

Answer 39

O: Superficial head: trapezium and flexor retinaculum Deep head: Trapezoid and capitate I: Ulnar aspect of base of proximal phalanx of thumb (with adductor pollicis) F: Flexes metacarpophalangeal joint of thumb Innervation: SH: Median nerve DH: Ulnar nerve

Question 40

What is the origin, insertion, innervation and function of the adductor pollicis?

Answer 40

O: Transverse head: shaft of 3rd metacarpal Oblique head: capitate and base of 2nd and 3rd metacarpal I: Ulnar aspect of base of proximal phalanx F: Adductor of the thumb both the palmar adduction and radial adduction Innervation: Ulnar nerve

Question 41

What is the origin, insertion, innervation and function of the opponens digiti minimi?

Answer 41

Deepest O: Hook of hamate, flexor retinaculum I: Ulnar margin of 5th metacarpal F: Rotates the 5th metacarpal towards the palm, enabling opposition against the thumb Innervation: ulnar nerve

Question 42

What is the origin, insertion, innervation and function of the abductor digiti minimi?

Answer 42

O: Pisiform and tendon of flexor carpi ulnaris I: Base of proximal phalanx of little finger F: Abduct the little finger (only in coronal plane) Innervation: Ulnar nerve

Question 43

What is the origin, insertion, innervation and function of flexor digiti minimi brevis?

Answer 43

O: Hook of hamate and flexor retinaculum I: Base of proximal phalanx of little finger F: Flexion of metacarpophalangeal joint of little finger Innervation: Ulnar nerve

Question 44

What is the origin, insertion, innervation and function of palmaris brevis?

Answer 44

O: Palmar aponeurosis and flexor retinaculum I: Dermis of skin on medial margin of hand F: Wrinkles the skin of hypothenar eminence, deepens the curvature of the palm, improving grip Innervation: Ulnar nerve

Question 45

What is the function of the lumbrical muscles?

Answer 45

Link the flexor digitorum tendon to the extensor digitorum tendon Contract--> flex fingers at the metacarpophalangeal joint and extend at the interphalangeal joints

Question 46

What is the muscles structure of the lumbircals?

Answer 46

Unipennate--> muscle fibres originate on same side of tendon --> index and middle finger Bipennate--> muscle fibres originate on opposite sides of the tendon --> ring finger and little finger

Question 47

What is the origin, insertion, innervation and function of each of the lumbricals?

Answer 47

I--> FDP to index finger --> Extensor digitorum (ED) to index finger II--> FDP to middle finger --> ED to middle finger III--> FDP to middle and ring finger --> ED to ring finger IV--> FDP to ring and little finger --> ED to little finger F: Extend the interphalageal joints, flex the metacarpophalangeal joints Innervation: I and II--> Median nerve, III and IV--> ulnar nerve

Question 48

What are the interossei muscles?

Answer 48

``` Located between the metacarpal bones PADs and DABs Palmar interossei--> adduct Dorsal interossei--> abduct All innervated by the ulnar nerve ```

Question 49

What are the dorsal interossei?

Answer 49

Abduct away from the midline Bipennate muscles Originate from own metacarpal and adjacent metacarpal bones

Question 50

What is the origin, insertion, innervation and function of dorsal interossei muscles?

Answer 50

I--> between thumb and first finger O: Shaft of first and second metacarpals I: Radial aspect of base of proximal phalanx of index finger and extensor expansion II--> O: Shaft of 2nd and 3rd metacarpals I: Radial surface of base of proximal phalanx of middle finger and extensor expanion III--> O: Shaft of 3rd and 4th metacarpals I: Ulnar surface of base of proximal phalanx of middle finger and extensor expansion IV--> O: Shaft of 4th and 5th metacarpal I: Ulnar surface of base of proximal phalanx of ring finger and extensor expansion F: Abduction away from the midline assist in flexing the metacarpophalangeal joint and extending the interphalangeal joint Innervation: Ulnar nerve

Question 51

What are the palmar interossei? Why is there less?

Answer 51

Adduct towards the midline Unipennate muscles Only three muscles Thumb adduction carried out adductor pollicis Middle finger is moved side to side by DABs

Question 52

What is the origin, insertion, innervation and function of the palmar interossei?

Answer 52

O and I: Shaft of second metacarpal--> Ulnar side of base of proximal phalanx of index finger and extensor expansion Shaft of fourth metacarpal--> Radial side of base of proximal phalanx of ring finger and extensor expanson Shaft of fifth metacarpal--> Radial side of base of proximal phalanx of little finger and extensor expansion F: Adduction Innervation: Ulnar nerve

Question 53

What are the extrinsic muscles of the hand that insert onto the digits?

Answer 53

Extensor digitorum Flexor digitroum profundus Flexor digitorum superficialis

Question 54

What is the origin, insertion, innervation and function of extensor digitroum?

Answer 54

Posterior forearm muscle O: Lateral epicondyle I: Extensor expansion --> Four tendons onto the phalanges --> Divided into a central slip and two lateral slips --> Central slip-->base of middle phalanx --> Lateral slips--> converge to insert onto base of distal phalanx F: Extension at the interphalangal joints and metacarpophalangeal joints Innervation: Radial nerve

Question 55

What is the origin, insertion, innervation and function of flexor digitorum profundus?

Answer 55

Anterior forearm muscle (deep) O: Proximal 2/3rds of shaft of ulna and adjacent interosseous membrane on anterior forearm I: Base of distal phalanx of 4 fingers F: Flexion of the fingers Innervation: medial half --> ulnar, radial half--> median nerve

Question 56

What is the origin, insertion, innervation and function of flexor digitorum superficialis?

Answer 56

Anterior forearm muscle (superificial/ intermediate) O: -Humeroulnar head--> medial epicondyle of humerus, ulnar collateral ligament, coronoid process of ulnar - Radial head--> superior half of radius I: Base of middle phalanx of four fingers F: Flexion of the metacarpophalangeal joint Innervation: Medial

Question 57

How are the tendons of the FDP and FDS arranged?

Answer 57

FDS tendon splits into two slips at the proximal phalanx | FDP tendon passes in between

Question 58

What is the carpal tunnel?

Answer 58

Narrow passageway on anterior surface of the wrist | Entrance for tendons and median nerve

Question 59

What are the borders of the carpal tunnel?

Answer 59

``` Superficial border: Flexor retinaculum (transverse carpal ligament) Deep border: carpal bones form concavity Lateral (radial): scaphoid, trapezium Medial (ulnar): pisiform, hook of hamate Proximal border: Distal wrist crease ```

Question 60

What structures pass through the carpal tunnel?

Answer 60

Flexor pollicis longus tendon Flexor digitorum superficialis tendon (x4) (tendons of middle and ring finger pass superficial to the index and little finger tendon) Flexor digitroum profundus tendon (x4) Median nerve--> lateral to FDS tendons

Question 61

Which nerve branches off superficial to the carpal tunnel? Why is this important?

Answer 61

Palmar cutaneous branch of the median nerve | Compression of medial nerve in carpal tunnel syndrome doesn't affect sensation to the palmar surface

Question 62

What is Guyon's canal?

Answer 62

Semi-rigid longitudinal canal in the wrist | Allows passage of the ulnar nerve and artery into the hand

Question 63

Where is Guyon's canal located?

Answer 63

Superficial to flexor retinaculum Radial to pisiform bone Between pisiform bone and hook of hamate Roof--> palmar carpal ligament (distinct from the transverse carpal ligament (flexor retinaculum))

Question 64

Why is Guyon's canal important?

Answer 64

Site of ulnar nerve compression | Ulnar nerve not involved in carpal tunnel syndrome

Question 65

What is the anatomical snuffbox?

Answer 65

Triangular depression on the radial surface of dorsum of the hand Level of carpal bones

Question 66

What are the borders of the anatomical snuffbox?

Answer 66

Radial (lateral) border--> tendon of abductor pollicis longus and extensor pollicis brevi Ulnar (medial) border--> tendon of extensor pollicis longus Proximal border--> styloid process of the radius Floor--> Scaphoid and trapezium Roof--> skin

Question 67

What are the contents of the anatomical snuffbox?

Answer 67

Radial artery Superficial branch of radial nerve Cephalic vein

Question 68

What is the arterial supply to the hand?

Answer 68

Radial and ulnar artery supply the hand via deep and superficial palmar arches

Question 69

Where does the ulnar artery pass?

Answer 69

Crosses anterior to the flexor retinaculum with the ulnar nerve in Guyon's canal Lies radial to pisiform bone and ulnar nerve In hand divides into superficial and deep branches Anastomose with corresponding branches of radial artery to form superficial and deep palmar arches Superficial palmar arch--> common palmar digital arteries that supply the fingers

Question 70

Where does the radial artery pass?

Answer 70

Enters between the tendons of brachioradialis and flexor carpi radialis GIve off superificial branch that anastomoses with the superficial palmar arch, then passes dorsally to cross the floor of the anatomical snuffbox on dorsum of the hand Re-enters palm passing between the two heads of adductor pollicis Radial artery anastomoses with the deep artery to form deep palmar arch

Question 71

Where do the ulnar and radial artery mainly supply?

Answer 71

Ulnar artery--> mainly superficial palmar arch--> blood supply to fingers Radial artery--> deep palmar arch--> blood supply to thumb and radial side of index finger

Question 72

What is the nerve supply to the hand?

Answer 72

Radial, ulnar and medial nerve Radial--> posterior forearm Ulnar and median--> anterior forearm and muscles of the hand

Question 73

What is the motor supply to the muscles of the hand?

Answer 73

All ulnar expect 1/2 LOAF--> (1/2 lumbricals (radial side), Opponens pollicis, abductor pollicis brevis and flexor pollicis brevis (superficial head))--> median nerve

Question 74

What is the sensory innervation to the palmar surface of the hand?

Answer 74

Fingertip originate on palmar surface of the hand in development Dragged over to dorsal aspect--> take nerve supply with them Nerve supply to palmar surface--> palmar cutanous branch of median nerve (Carpal tunnel), palmar cutanous branch of ulnar nerve (Guyon's canal)

Question 75

What is the sensory innervation to the fingers?

Answer 75

Palmar digital branches from the median and ulnar nerves in the palm Palmar digital branch of the median nerve--> thumb, index finger, middle finger and radial border of ring finger Palmar digitial branch of ulnar nerve--> ulnar border of ring finger and little finger Innervate the dorsum of these digits over the distal phalanx and nail bed

Question 76

What is the sensory innervation to the dorsal surface of the hand?

Answer 76

Dorsal cutaneous branch of ulnar nerve --> main forearm --> Skin over dorsal aspect of ulnar border of hand --> Skin over dorsum of ulnar 1.5 digits as far as the distal interphalangeal joint Superficial branch of the radial nerve --> Lateral side of dorsal hand and lateral 3.5 digits except the tips (palmar digital branches of the median nerve)

Question 77

Where would you test the sensory innervation of each of these nerves?

Answer 77

Radial nerve: Dorsum of the first webspace Median nerve: Palmar surface of the tip of the index finger Ulnar nerve: Ulnar border of the hand

Question 78

What are the different fractures that can occur at the wrist?

Answer 78

Scaphoid fracture Colles’ fracture --> extra articular fracture of the distal radial metaphysis, with dorsal angulation and impaction -(dorsiflexed hand) Smith fractures--> Fracture of distal radius with volar (palmar) angulation of the distal fracture fragments -(palmar flexed hand)

Question 79

Which fractures commonly occur due to falling on an outstretched hand? (FOOSH) What does FOOSH cause?

Answer 79

Scaphoid fracture Colles fracture Hyperextension and impaction of scaphoid against rim of radius or direct axial compression of scaphoid

Question 80

What is the typical presentation of a patient with a scaphoid fracture?

Answer 80

Occur at any age—> most common among adolescent and young adults following FOOSH Pain in anatomical snuffbox Made worse by movement Passive range of movement reduced—> not dramatically Swelling around radial and posterior aspect of the wrist is common

Question 81

What are the different types of fracture to the scaphoid?

Answer 81

Fracture to the waist (70-80%) Fracture to proximal pole (20%) Fracture to distal pole (10%)—> scaphoid tubercle fracture

Question 82

What would you see on an X-ray of a fractured scaphoid?

Answer 82

X-ray may not reveal anything 10-14days fracture maybe visible after some bone reabsorption has occurred MRI, CT scans maybe required

Question 83

Why are fractures to the scaphoid quite severe?

Answer 83

Retrograde blood supply (distal to proximal supply) Blood supply to proximal pole tenuous Fractures to waist of the scaphoid—> avascular necrosis Displaced fractures through the waist lead to higher risk of non union, malunion, avascular necrosis and late complications of carpal instability and secondary osteoarthritis Osteaoarthritis more common if there has been non union, malunion or avascular necrosis

Question 84

What is a Colles’ fracture?

Answer 84

Extra-articular fracture Fracture of distal radial metaphysis, with dorsal angulation and impaction Associated ulnar fracture present in 50% of cases Fall on dorsiflexed hand

Question 85

Who is most likely to present with a Colles’ fracture what is the mechanism of fracture?

Answer 85

Common in patients with osteoporosis (reduced bone density)--> post menopausal women (young patients usually involved in high trauma accidents) Most common fracture--> FOOSH Forearm pronated and wrist in dorsiflexion Energy transmitted from the carpal to the radius in dorsal direction and along the long axis of radius--> Dorsally angulated and impacted

Question 86

What is the clinical presentation of Colles' fracture?

Answer 86

Painful, swollen, deformed wrist --> dinner fork shapped

Question 87

What would you see on an x-ray of Colles' fracture?

Answer 87

Fracture line clearly visible | Angulation and impaction visible

Question 88

How are Colles' fractures treated?

Answer 88

Reduction and immobilisation in cast

Question 89

What are some of the complications associated with Colles' fracture?

Answer 89

Malunion--> dinner fork deformity Median nerve palsy and post traumatic carpal tunnel syndrome Secondary osteoarthritis Tear of extensor pollicis longus tendon- as tendon moves over sharp bone

Question 90

What is Smith's fracture?

Answer 90

Fractures of distal radius with volar (palmar) angulation of the distal fracture fragment Extra-articular--> opposite of Colles' fracture Fall onto plantarflexed wrist

Question 91

How do Smith's fractures occur?

Answer 91

(Less than 3% fractures) Young males or elderly females Fall onto dorsum of flexed wrist or direct blow to back of the wrist

Question 92

What does a Smith's fracture usually resemble? What is a complication of this deformity?

Answer 92

Garden spade deformity Residual volar displacement results in cosmetic deformity Narrows carpal tunnel--> carpal tunnel syndrome

Question 93

How does rheumatoid arthritis of the MCPJ and IPJs occur?

Answer 93

Autoimmune disease Autoantibodies attack the synovial membrane Inflammed synovial cells proliferate to form a pannus (abnormal layer of granulation tissue) Penetrates through the cartilage and adjacent bone--> bone erosion and deformity

Question 94

Why is rheumatoid arthritis of the hand difficult to diagnoses?

Answer 94

Affects multiple joint--> symmetrical distribution | Difficult as no 'normal' hand to make a comparison

Question 95

How does a patient with rheumatoid arthritis of the hands normally present?

Answer 95

Pain and swelling of PIPJs and MCPJs of the fingers Erythema (redness) overlying joints Stiffness--> worse in the morning or after periods of inactivity --> difficult to carry out some tasks- doing up buttons Carpal tunnel syndrome--> compression of median nerve Fatigue and flu like symptoms--> systemic nature of disease

Question 96

What are the late features of rheumatoid arthritis?

Answer 96

Nodules over the fingers and elbows | Deformities--> Swan neck and Boutonniere deformity

Question 97

What are the features of rheumatoid arthritis on an x-ray?

Answer 97

``` Narrowing of joint space Periarticular osteopenia Juxta-articular bony erosions Subluxation and gross deformities Soft tissue swelling inferred from shadow ```

Question 98

What is Swan neck deformity?

Answer 98

PIPJ hyperextends and MCPJ and DIPJ are flexed PIPJ lax due to adjacent synovitis on volar surface Imbalance between muscle forces extension>flexion DIPJ elongation or rupture of insertion of extensor tendon--> flexion (mallet deformity)

Question 99

What is Boutonniere deformity?

Answer 99

PIPJ flexed and MCPJ and DIPJ hyperextended Inflammation at PIPJ--> lengthening or rupture of central slip of extensor digitorum as it insert into base of middle phalanx on dorsal surface--> lateral bands slips into side--> acts as flexor at PIPJ and hyperextend at DIPJ

Question 100

What is psoriatic arthropathy?

Answer 100

Psoriasis that develops into arthritis Involves small joints of the hand and feet Develops asymmetrically

Question 101

What is psoriasis?

Answer 101

Skin condition Red, flaky patches of skin covered with silvery scales Usually on knee, elbows, scalp and lower back

Question 102

Which joints are normally affected in psoriatic arthritis?

Answer 102

DIPJs | 80% have nail lesions also--> pitting and onycholysis

Question 103

Where in the hand does osteoarthritis normally affect?

Answer 103

1st CMC joint --> trapezium and 1st metacarpal | More common in women

Question 104

What do patients normally present with in osteoarthritis?

Answer 104

Pain in base of their thumb Exacerbated by movement, relieved by rest Stiffness follows periods of rest Swelling around base of thumb Later stages--> 1st metacarpal subluxes in ulnar direction Squaring of the hand Spreads to fingers in fifth or sixth decade of life --> DIPJs

Question 105

What are Heberden's nodes?

Answer 105

Classic sign of osteoarthritis and affects DIPJ of fingers Chronic swelling of affected joint--> sudden onset of pain, swelling and loss of manual dexterity Cystic swellings develop--> gelatinous hyalronic acid on dorsolateral apsect of DIPJ Initial pain and swelling eventually subsides--> osteophyte formation instead

Question 106

What are Heberden's nodes in the PIPJs called?

Answer 106

Bouchard's nodes

Question 107

What is carpal tunnel syndrome?

Answer 107

Compression of the median nerve as it passes through the carpal tunnel

Question 108

What are the risk factors for carpal tunnel syndrome?

Answer 108

Obesity, pregnancy, repetitive wrist work, rheumatoid arthritis and hypothyroidism

Question 109

What is the result of compression of the median nerve?

Answer 109

Paraesthesia in thumb, index finger, middle finger and radial half of ring finger Long standing--> thenar muscle weakness (Flexor Pollicis brevis (superficial head), Abductor Pollicis Brevis and Opponens pollicis)

Question 110

When does carpal tunnel syndrome become worse?

Answer 110

At night--> flexion of wrist when sleeping--> narrowing of carpal tunnel Worsen in daily activities such as driving, combing hair, holding a book or phone etc...

Question 111

What is diminished in patients with carpal tunnel syndrome?

Answer 111

Manual dexterity Unable to button clothes Pain in forearm, elbow, shoulder and neck (do not need to know why)

Question 112

Why is sensation to the palm spared in carpal tunnel syndrome spared?

Answer 112

Palmar cutaneous branch of median nerve branches proximal to carpal tunnel

Question 113

What is ulnar tunnel syndrome or Guyon's canal syndrome?

Answer 113

``` Compression of the ulnar nerve in Guyon's canal Passes radial (lateral) to the pisiform bone over the volar surface of flexor retinaculum ```

Question 114

What are the symptoms of Guyon's canal syndrome?

Answer 114

Paraesthesia in ring and little finger | Long term--> weakness of intrinsic muscles of the hand

Question 115

What is Dupuytren's contracture?

Answer 115

Localised thickening and contraction of palmar aponeurosis--> flexion deformity of the adjacent fingers

Question 116

What are the first signs of Dupuytren's contracture?

Answer 116

Thickening in palm (nodule)--> painful or painless Myofibroblast in nodule contract--> cords in palmar fascia--> overlying skin tightly adhered Progresses to involve the proximal fascia and skin of the fingers Fingers become stuck in flexed position and cannot be passively straightened

Question 117

Which fingers are most commonly involved? Who is it most commonly seen in?

Answer 117

Ring and little finger Males 40-60 years North European origin

Question 118

What is the genetics of Dupuytren's contracture?

Answer 118

Autosomal dominant 70% cases--> family history Remainder sporadic

Question 119

What increases the risk of Dupuytren's contracture?

Answer 119

Type 1 diabetes Having had adhesive capsulitis of the shoulder (frozen shoulder) Epilepsy--> drugs Liver disease and/or excessive alcohol consumption Smoking Hypercholersterolaemia Heart disease HIV Hypo-/ Hyper- thyroidism Trauma to hand or fingers Vibration-related hand injury (vibrating tools >10yrs) (LEARN FOUR EXAMPLES!)

Question 120

Why are fractures to the humerus in the midshaft dangerous?

Answer 120

At risk of damaging the radial nerve | Runs in the spinal groove

Question 121

Following midshaft humeral fracture will the patient still be able to extend their elbow?

Answer 121

Extension normal or partially compromised Nerve supply to long and lateral head of triceps given off before the radial nerve enters the spiral groove Triceps still able to extend Anconeus--> paralysed but only had minor role in extension

Question 122

What is the clinical presentation following radial nerve damage?

Answer 122

'Wrist drop' --> Flexion of wrist and fingers Paralysis to extensor muscles (posterior forearm) Flexed when forearm is pronated due to unopposed flexor muscles and gravity Sensory innervation--> posterior cutaneous nerve branches before the spiral groove so unaffected Lower lateral and posterior cutaneous nerve unaffected Paraesthesia therefore usually in superficial branch of radial nerve--> lateral part of dorsum of the hand from thumb up to middle of ring finger, excluding the tips of all the fingers and thumb

Question 123

What is the result of a supracondylar fracture of the humerus?

Answer 123

Median nerve damage Paralysis to flexor muscles of the anterior forearm expect FCU and medial half of FDP Paralysis to thenar muscles and radial half of lumbricals Forearm supinated--> unapposed action of supinator (radial nerve) and biceps brachii (musculcutaneous nerve) Wrist adducted (FCU) Loss of sensation to radial side of palm up to middle of ring finger and tips of thumb, index and middle finger on dorsal surface Prolonged--> thenar muscle wasting

Question 124

What is the clinical test for median nerve damage?

Answer 124

Attempt to make a fist Ring and little finger will flex into palm normally (FDP and lumbricals intact) Index and middle finger will remain extended Thumb will be adducted, lateraly rotated, and extended (IPJ and MCPJ) Hand of Benediction --> only seen when patient attempts to make a fist

Question 125

What is the difference if the median nerve is only damaged at the wrist?

Answer 125

Penetrating injury or compression of carpal tunnel Only muscles paralysed are 1/2LOAF Ape Hand deformity - thenar eminence is flatterened and thumb us adducted and externally (laterally) rotated Palmar cutaneous branch of median nerve also spared--> skin over thenar eminence spared Prolonged--> thenar muscle wasting

Question 126

What happens if the ulnar nerve is damaged at the wrsit?

Answer 126

Laceration or compression of Guyon's canal Loss of function of all muscles of the hand except 1/2LOAF Claw hand--> little finger and ring finger only --> Hyperextension of the MCPJ --> Flexion of PIPJ and DIPJ Loss of sensation--> Palmar aspect of ulnar 1.5 digits and dorsum of hand over the distal phalanges only

Question 127

Why do you get hyperextension to the MCPJ and flexion of the PIPJ and DIPJ of the little finger and ring finger in ulnar wrist lesion?

Answer 127

Lumbrical muscles to ring and little finger paralysed Normally involved in flexion at the MCPJ--> hence hyperextension --> unopposed extensor digitiroum Extenion of PIPJ and DIPJ--> hence flexion --> unopposed FDS and FDP

Question 128

What happens to the other muscles of the hand with a ulnar nerve injury to the wrist?

Answer 128

Not involved in claw hand Interossei, hypothenar muscles, adductor pollicis Interossei wasting--> guttering between metacarpals AP and Hypothenar--> wasting of 1st webspace and hypothenar eminence

Question 129

What could cause an upper nerve lesion? What happens with a high ulnar nerve lesion?

Answer 129

Fracture to medial epicondyle, compression in cubital tunnel Paralysis of FCU and ulnar half of FDP as well as intrinsic muscles of the hand (except 1/2LOAF) Loss of sensation of dorsal and palmar cutaneous branch --> little finger and ulnar half of ring finger on palmar and dorsal surface

Question 130

What is the clinical presentation of a upper ulnar nerve lesion?

Answer 130

Claw hand will be less pronounced Why?--> FDP is paralysed so no flexion at DIPJ in ring and little finger Ulnar claw only consists of hyperextension of MCPJ and flexion of PIPJ

Question 131

What is the difference between upper and lower ulnar nerve lesions called?

Answer 131

Ulnar paradox | Would expect an upper nerve lesion to have more pronounced deformity but in this case it doesn't