L9 - Wrist and Hand Flashcards
1
Q
Name the carpal bones of the hand.
A
“So long to pinky, here come the thumb”
–> medial inferior, counter clockwise
Proximal Row:
Scaphoid, Lunate, Triquetrum, Pisiform
Distal Row:
Trapezium, Trapezoid, Capitate, Hamate
See NDC p.4 for illustration
2
Q
Carpal Bones
Describe the scaphoid.
- 3 regions
- vascularization
How do we palpate it?
A
3 Regions: distal pole, proximal pole and waist
Proximal pole poorly vascularized (avascular necrosis)
Palpation: Palpate in snuff box
See NDC p.5-6 for illustration
3
Q
How is the scaphoid frequently fractured?
A
Fractured frequently by fall on hyperextended radially deviated wrist.
4
Q
Carpal Bones
Describe the lunate.
- function
- movement
- vascular?
How do we palpate it?
A
Important stabilizer of the carpus
Very little movement
Also vulnerable to avascular necrosis
Palpation: Start in snuff box and go lateral.
See NDC p.7-8 for illustration
5
Q
Carpal Bones
What is Kienbock’s disease?
A
Avascular necrosis of the lunate.
(Kienbock’s disease)
6
Q
Carpal Bones
Describe the hamate.
- location
- 2 parts
- attachment of…
How can we palpate it?
A
Proximal pole
Hook and body
Site of attachment of the flexor retinaculum
Palpation: base of hypothenar eminence
See NDC p.9 for illustration
7
Q
Carpal Bones
Describe the trapezium
- shape
- location
- role for thumb
A
Saddle shaped bone
At the base of thumb
Position together with the scaphoid contributes to the
anterior orientation of the thumb
Palpation: follow thumb down shaft
See NDC p.10 for illustration
8
Q
Carpal Bones
Describe the capitate.
- size
- location
A
Largest carpal bone
Oriented at base of long finger
See NDC p.11 for illustration
9
Q
Carpal Bones
Describe the trapezoid.
- what
- function
A
Stable base for the index finger
Important for pinch
See NDC p.11 for illustration
10
Q
Carpal Bones
Describe the triquetrum.
- articulates with…
A
Articulates with fibro-cartilagenous disc and pisiform (sesamoid bone)
See NDC p.11 for illustration
11
Q
Name the joints of the wrist. (3)
What forms each?
A
- Distal radioulnar joint (DRUJ): radius-ulna
- Radiocarpal joint: radius-proximal carpals
- Mid-carpal joint: proximal-distal carpals
See NDC p.12 for illustration
12
Q
NEED TO KNOW
What is the force transmission of the radio-carpal joint during radial deviation?
A
Radial deviation: 87%
13
Q
NEED TO KNOW
What is the force transmission of the ulna-carpal joint during rotation?
A
Rotation: 37%
14
Q
NEED TO KNOW
What is the force transmission of the midcarpal joint between the scapho-trapezium-trapezoid?
A
Scapho-trapezium-trapezoid: 31%
15
Q
Describe the radiocarpal joint.
- between
- functions (3)
A
Between radius and proximal carpal row.
–> Radius articulates with scaphoid (1) and lunate (2).
Contributes to:
1. Flexion
2 Extension
3. Radial-ulnar deviation
See NDC p.14 for illustration
16
Q
Describe the distal radioulnar joint.
A
Between distal radius and distal ulna.
Functions:
1. Primary function: forearm pronation-supination
2. Facilitates load transmission between radius-hand and ulna
See NDC p.15 for illustration
17
Q
What 2 joints are essential for good wrist rotation (pronation-supination)?
A
Proximal and distal radio-ulnar joints.
18
Q
What is the difference between extrinsic and intrinsic ligaments of the hand?
A
Extrinsic ligaments: from carpal bones to radius/ulna
Intrinsic ligaments: between carpal bones
See NDC p.16 for illustration
19
Q
Describe the extrinsic ligaments of the wrist/hand.
- orientation
- 2 groups
A
Ligaments are oriented towards the midline.
- Volar ligaments (palmar)
- Dorsal ligaments
See NDC p.16 for illustration
20
Q
Describe the volar ligaments of the extrinsic ligaments of the wrist/hand.
- strength
- function
A
Volar ligaments stronger than dorsal ligaments.
Function: Stabilize carpus during extension
See NDC p.16 for illustration
21
Q
Name the extrinsic wrist ligament (that we need to know).
A
Triangular fibrocartilage complex (TFCC)
–> commonly injured
22
Q
What forms the triangularfibrocartilage complex (TFCC)? (4)
What is the orientation of these components?
A
- Dorsal radioulnar ligament (DRUL)
- Palmar radioulnar ligament (PRUL)
- Extensor carpi ulnaris (ECU)
- Articular disc
Form a triangle.
See NDC p.18-19 for illustration
23
Q
What are the functions of the triangularfibrocartilage complex (TFCC)? (4)
A
- Stabilization of distal radio-ulnar joint (DRUJ) and ulnar side of carpus
- Cushions ulna on carpus
- Allows axial loading of ulna on forearm
- Increases articular surface of carpus
24
Q
What provides dynamic stabilization to the distal radio-ulnar joint (DRUJ)? (4)
A
- Extensor Carpi Ulnaris (ECU) Tendon
- Tendon sheath (6th dorsal compartment)
- Pronator Quadratus
- Interosseous membrane of forearm
25
RECAP - Distal Radio-Ulnar Joint (DRUJ)
What provides static stabilization? (3)
1. Triangularfibrocartilage complex (TFCC)
2. Extensor carpi ulnaris (ECU) + sheath
3. Interosseous Membrane
26
RECAP - Distal Radio-Ulnar Joint (DRUJ)
What provides dynamic stabilization? (4)
1. Pronator Quadratus
2. Pronator Teres
3. Biceps brachii
--> insertion: tuberosity of the radius and deep fascia of FA
4. Supinator
--> insertion: lateral, proximal shaft of radius
27
Describe the midcarpal joint.
- between
- function
Formed between two carpal rows
Function: Contributes to flexion, extension, radial-ulnar
deviation
28
How is the midcarpal joint stabilized?
Stabilization via ligaments and capsule
29
Why is the midcarpal joint more important than the radiocarpal joint? (3)
1. Proximal row has no tendinous insertions
2. Wrist movement starts at distal row of carpus
3. Movement pulls midcarpal ligaments taut, creates a
compressive load and moves proximal row
30
Describe the intrinsic wrist ligaments (that we need to know).
- orientation
- the 2 we need to know
Transverse orientation
1. Scapholunate (interosseous) ligament
2. Lunotriquetral interosseous ligament
See NDC p.25-26 for illustration
31
What is the most common wrist ligament injury?
During which action?
What does it cause?
Scapholunate ligament rupture: Most common wrist ligament injury.
A common cause of carpal instability
Falling on an outstretched hand: Higher S-L ligament tensile force in extension.
32
What is the sign of a scapholunate ligament tear?
Describe it. (xray)
Terry Thomas Sign
A big space between the scaphoid and lunate indicates a rupture of the scapholunate ligament.
See NDC p.27-29 for illustration
33
What are the 2 types of midcarpal joint instability?
1. Volar intercalary segment instability (VISI)
2. Dorsal intercalary segment instability (DISI)
--> rupture of ligament causes dissociation between the movements of the bones
34
Midcarpal Joint Instability
Describe normal intrinsic ligament action.
Good alignment between radius, lunate, capitate and base of metacarpal.
The horizontal line passes in the middle of the lunate, in the middle.
See NDC p.30 for illustration
35
Midcarpal Joint Instability
Describe volar intercalary segment instability (VISI).
What is the cause?
The lunate points in a volar (palmar) direction.
Lunotriquetrial ligament rupture (plus dorsal radiocarpal + volar radiocarpal)
See NDC p.30 for illustration
36
Midcarpal Joint Instability
Describe dorsal intercalary segment instability (DISI).
What is the cause?
The lunate points a dorsal direction.
Scapholunate ligament rupture (plus scaphotrapeziumtrapezoid or dorsal intercarpal)
See NDC p.30 for illustration
37
What is the incidence of carpal instability 2 years after fall on outstretched hand
44% had clinical evidence of carpal instability
Of the 44%, 24% had scapho-lunate dissociation.
38
What is slac wrist?
What is seen?
Untreated Scapholunate Ligament Injury
--> Scapholunate advanced collapse
1. Scapholunate dissociation (Terry Thomas Sign)
2. Capitate crashes down into the space
See NDC p.32 for illustration
39
Are ligaments the only wrist stabilizers?
No!
Many activities are able to surpass the tensile strength of wrist ligaments without rupture.
--> proprioception plays a role
40
Name an example of how proprioception acts as wrist stabilizer.
At the very beginning of flexion, the first muscle to activate was the extensor!
Proprioception = protective action
Also occurs during extension: flexor fires first
See NDC p.35-338 for graphs/illustration
41
What is the role of ligaments in proprioception?
Scapholunate ligament = more than just a passive restraint
Mechanoreceptors in ligaments signal joint perturbation and influence surrounding muscles. Reactions are protective.
42
What is the center of rotation of the wrist?
The capitate.
See NDC p.40 for illustration
43
What is the joint contribution in flexion-extension?
Flexion: greater contribution form midcarpal joint
Extension: greater contribution form radiocarpal joint
Distal radius fracture = more difficulty gaining back extension
See NDC p.41 for illustration
44
Describe the movement of the rows of carpal bones during flexion.
Distal and proximal carpal rows both move into flexion.
--> carpal rows act like 2 cylinders rolling in same direction
See NDC p.42 for illustration
45
Describe the movement of the rows of carpal bones during extension.
Distal and proximal carpal rows both move into extension.
--> carpal rows act like 2 cylinders rolling in same direction
See NDC p.42 for illustration
46
Describe the carpal kinematics in radial deviation. (3)
1. Proximal row flexes, and translates ulnarly
2. Lunate pronates
3. Triquetrum rides proximally and dorsally on hamate
See NDC p.43 for illustration
47
Describe the carpal kinematics in ulnar deviation. (3)
1. Proximal row extends and translates radially
2. Lunate supinates
3. Triquetrum rides distally and volarly on hamate
See NDC p.43 for illustration
48
What bones form the fingers?
Metacarpal, proximal phalanx, middle phalanx and distal phalanx.
--> exception: thumb has no middle phalanx
49
Describe the mobility of finger metacarpals.
What does this facilitate?
Greater mobility with ring and little finger metacarpals.
--> middle finger metacarpal less mobile
This permits us to cup our hand into a good position to pick objects up = prehension
See NDC p.47 for illustration
50
Describe the different lengths of finger metacarpals.
What is the function?
Different metacarpal lengths = cascade/convergence.
In a fist, fingers are angled towards thumb side
--> convergence of arch of movement toward thumb
See NDC p.47 for illustration
51
Name the arches of the hand. (3)
Describe each.
1. Fixed proximal transverse arch: midpoint = capitate
2. Mobile distal transverse arch: midpoint = 3rd
metacarpal
3. Longitudinal arch: 3rd metacarpal
See NDC p.48 for illustration
52
Name the joints of the fingers. (3)
1. Metacarpophalangeal (MCP)
2. Proximal interphalangeal (PIP)
3. Distal interphalangeal (DIP)
53
Finger Joints Review
Describe the metacarpophalangeal (MCP) joints.
- classification
- degrees of freedom
- movement
Condylar
2 degrees of freedom
- flexion-extension
- abduction-adduction
--> synovial joint
See NDC p.49 for illustration
54
Finger Joints Review
Describe the proximal and distal interphalangeal (PIP and DIP) joints.
- classification
- degrees of freedom
- movement
Ginglymus Hinge
1 degree of freedom: Flexion-extension
--> synovial joint
See NDC p.49 for illustration
55
Name the finger ligaments.
1. Ulnar and Radial Collateral Ligaments
(cord and accessory)
2. Volar (Palmar) Plate
See NDC p.50 for illustration
56
In which position are the collateral ligaments taut?
- metacarpophalangeal (MCP)
- proximal and distal interphalangeal (DIP, PIP)
MCP: flexion
PIP and DIP: extension
--> these are the closed pack position for each
See NDC p.50 for illustration
57
What is the normal finger AROM for flexion/extension of:
- metacarpophalangeal (MCP)
- proximal interphalangeal (PIP)
- distal interphalangeal (DIP)
MCP: 0°-90°
PIP: 0°-100°
DIP: 0°-80° / 70° (Evans)
See NDC p.51 for illustration
58
What percentage of hand function is the thumb responsible for?
60% of hand function
59
Name the joints of the thumb.
1. Carpometacarpal (CMC)
2. Metacarpophalangeal (MCP)
3. Interphalangeal (IP)
60
Thumb Joints Review
Describe the carpometacarpal (CMC) joint.
- classification
- degrees of freedom
- movement
Saddle joint
3 degrees of movement
- flexion-extension
- abduction-adduction
- circumduction
- opposition
See NDC p.52 for illustration
61
Thumb Joints Review
Describe the metacarpophalangeal (MCP) joint.
- classification
- degrees of freedom
- movement
Biaxial joint
2 degrees of movement
- flexion-extension,
- abduction-adduction
See NDC p.52 for illustration
62
Thumb Joints Review
Describe the interphalangeal (IP) joint.
- classification
- degrees of freedom
- movement
Ginglymus hinge joint
1 degree of movement
- flexion-extension
See NDC p.52 for illustration
63
What is the normal thumb ROM for:
- metacarpophalangeal (MCP)
- interphalangeal (PIP)
- palmar abduction
MCP: 55° flexion and 10° hyperextension
IP: 80° flexion and 0°of extension
Palmar abduction: 45°
See NDC p.53 for illustration
64
Name the dynamic stabilizers of the thumb carpometacarpal (CMC) joint. (8)
1. Adductor (ADD)
2. Abductor Pollicis Brevis (APB)
3. Opponens Pollicis (OPP)
4. Flexor Pollicis Brevis (FPB)
5. Abductor Pollicis Longus (APL)
6. Flexor Pollicis Longus (FPL)
7. Extensor Pollicis Brevis (EPB)
8. Extensor Pollicis Longus (EPL)
See NDC p.54 for illustration
65
What is responsible for the static stabilization of the thumb carpometacarpal (CMC) joint.
Name the 2 most important.
16 ligaments.
Most important are:
1. palmar oblique (beak) ligament
2. dorsoradial ligament
See NDC p.54 for illustration
66
Describe the thumb CMC joint contact force.
What does this cause?
1kg pinch force = 1.9kg CMC joint contact force
Regular activity contributes to erosive changes to the stabilizing ligament
Can lead to dorsal-radial subluxation of proximal aspect of metacarpal
--> CMC subluxation
See NDC p.55-56 for illustration
67
What is a shoulder sign?
Pump visible with CMC subluxation.
See NDC p.56 for illustration
68
Common Thumb Instability
Describe gamekeeper's thumb.
- movement
- injury
Excessive abduction at thumb CMC = torn ulnar collateral ligament (at CMC)
Gamekeeper = break animal neck
Falling onto pole = pulling back on thumb
See NDC p.57 for illustration
69
Name the extrinsic flexor musculotendinous structures of the wrist. (4)
--> extrinsic = crosses wrist joint
1. Flexor digitorum superficialis (sublimis) (FDS)
2. Flexor digitorum profundus (FDP)
3. Flexor Pollicis Longus (FPL)
4. Palmaris Longus (PL)
See NDC p.58 for illustration
70
What is the excursion / glide of a muscle tendon?
When a muscle contracts, the tendon glides = excursion / glide
71
Flexor Tendons - Excursion
What is the optimal excursion for a hook fist?
Hook fist: extended MCP, flexed IPs
Optimal differential glide of flexor digitorum superficialis (FDS) and flexor digitorum profundis (FDP)
--> optimize gliding of one one top of the other
See NDC p.59 for illustration
72
Flexor Tendons - Excursion
What is the optimal excursion for a straight fist?
Straight fist: flexed MCP and PIP, extended DIP
Optimal glide of flexor digitorum superficialis (FDS).
See NDC p.59 for illustration
73
Flexor Tendons - Excursion
What is the optimal excursion for a full fist?
Full fist: flexed MCP, PIP and DIP
Optimal glide of flexor digitorum profundis (FDP).
See NDC p.59 for illustration
74
Name the extrinsic extensor/adductor musculotendinous structures of the wrist. (6)
--> extrinsic = crosses wrist joint
1. Extensor Digitorum
2. Communis (EDC)
3. Index Proprius
4. Extensor digiti quinti
5. Extensor pollicis longus/brevis
6. Abductor pollicis longus
index extensor and pinky extensor = easy to extend this fingers solo
See NDCp.60-61 for illustration
75
What are the Juncturae Tendinae?
What is their function? (2)
Longitudinal connective tissue between the extensor tendons.
1. Increase extension force to individual fingers
2. If one or two fingers passively flexed at MP, pulls EDC of other fingers along
See NDC p.62 for illustration
76
In rehab, why do we need to be mindful of the function of the juncturae tendinae?
It can act as a booster to hide a lesion.
If you have a cut of EDC for the middle finger, it may get compensated when extending index finger
--> movement will happen but involuntarily
See NDC p.62 for illustration
77
Name the intrinsic muscles of the thenar eminence (thumb). (3)
1. Flexor pollicis brevis
2. Opponens pollicis
3. Abductor pollicis brevis
See NDC p.63 for illustration
78
Name the intrinsic muscles of the hypothenar eminence (thumb). (4)
1. Flexor digiti minimi
2. Opponens digiti minimi
3. Abductor digiti minimi
4. Adductor pollicis
See NDC p.63 for illustration
79
Name the intrinsic muscles of the hand.
1. Lumbricals
2. Interroseous muscles
See NDC p.64 for illustration
80
Name the intrinsic supporting structures of the hand. (2)
1. Lateral band: along lateral finger
2. Central tendon: around finger at PIP
3. Terminal tendon
See NDC p.64 for illustration
81
Describe the lateral bands and Diamond of Stack during flexion and extension of PIP.
Flexion: lateral bands drift apart, Diamond of Stack gets wider
Extension: lateral bands come together, Diamond of Stack gets narrower
See NDC p.65 for illustration
82
Extensor Tendon Deformity
What occurs in a Boutonniere deformity?
Rupture central tendon
- lateral bands migrated in a volar direction
- overpull finger into PIP flexion and DIP extension
Excessive passive flexion
Excessive DIP hyperextension
See NDC p.66 for illustration
83
What is the function of the intrinsic muscles of the hand?
1. MCP flexion
2. PIP and DIP extension
See NDC p.67 for illustration
84
What is the finger movement sequence for digital flexion? (3)
1. Extrinsic FDS initiates flexion at PIP joint
2. Extrinsic FDP then flexes DIP joint
3. Intrinsics then flex MP joint
85
What is the finger movement sequence for digital extension? (2)
1. Extrinsic EDC extends MP joint
2. Intrinsic Lumbricals and interosseous muscles extend PIP and DIP joints
86
What is tenodesis?
What is it due to?
Wrist extension = finger flexion
Wrist flexion = finger extension
Due to the length-tension relationship of structures crossing the wrist.
See NDC p.69 for illustration
87
What are the components of the retinacular system of the wrist?
1. Flexor retinaculum
2. Extensor retinaculum
See NDC p.70-71 for illustration
88
What is the flexor retinaculum relative to the carpal tunnel?
Flexor retinaculum = roof of carpal tunnel.
It is cut open in carpal tunnel syndrome surgery
See NDC p.70 for illustration
89
What is the function of the flexor retinaculum?
1. Prevents bowstringing of flexor tendons,
2. Maintains carpal arch
3. Optimizes flexor forces
See NDC p.70 for illustration
90
What is the function of the extensor retinaculum?
1. Functions as a pulley for the extensor tendons
2. Maintains constant moment arm
We need 2/3 of the extensor retinaculum intact for normal digital extension
See NDC p.71 for illustration
91
What is DeQuervain's Tendonitis?
Inflammation at the 1st dorsal compartment of
extensor retinaculum.
Impacts the tendons of Abductor pollicis longus and Extensor pollicis brevis.
See NDC p.72 for illustration
92
What is a test used to diagnose DeQuervain's Tendonitis?
Finklestein’s Test:
Wrist ulnar deviation and thumb flexion = pain --> positive.
See NDC p.72 for illustration
93
What is the digital flexor tendon pulley system?
What is the function?
Retinacular system at the level of the digits.
Stops the tendon from bowstringing during movement
See NDC p.73-74 for illustration
94
What part of the digital retinacular system is most important?
1. 4 normal annular pullies facilitate normal flexion
2. Mechanically, the three most useful pullies to preserve are the A2, A4 and A3 pullies
See NDC p.73-74 for illustration
