Wrist and hand Flashcards
(100 cards)
1
Q
What is the wrist/carpus?
A
-Collection of bones and soft tissue structures that connects the hand to the forearm
2
Q
What are the wrist joints?
A
- Radiocarpal joint (mainly this one makes up the wrist)
- Ulnocarpal joint
- Distal radioulnar joint
3
Q
What is the radiocarpal joint? What kind of joint? Which carpal bones are involved?
A
-Synovial joint formed between radius and 3 carpal bones: scaphoid, lunate and triquetrum
4
Q
What is the ulnarcarpal joint? What type of joint? What carpal bones?
A
-Synovial joint between ulnar and carpal bones (lunate and triquetrum)
5
Q
What is the distal radioulnar joint? What kind of joint is it?
A
- Synovial joint
- Head of ulna articulates with ulnar notch of radius
6
Q
How does the wrist function kinematically? How does it function kinetically?
A
- 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
7
Q
Why is wrist stability important? What does wrist position affect?
A
- For the proper function of digital flexors and extensors
- Wrist position affects the ability of fingers to flex and extend maximally and grasp effectively
8
Q
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?
A
- 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
9
Q
Why is the mobility and stability of the shoulder, elbow and wrist operating in different planes important?
A
-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
10
Q
Why is the arrangement of bones and joints of the hand important?
A
-Provides a structural foundation of hands adaptability
11
Q
What does the wrist joint complex consists?
A
-Multiple articulations between the 8 carpals, distal radius, structures of the ulnocarpal space and metacarpals
12
Q
What are the soft tissue structures surrounding the carpal bone?
A
- Tendons that cross or attach to the carpus
- Ligamentous structures connecting carpal bones to each other and the bony hand and forearm
13
Q
What are the 8 carpals?
A
- Proximal row: scaphoid, lunate, triquetrum, pisiform
- Distal row: trapezium, trapezoid, capitate, hamate
14
Q
Which row of carpal bones is more mobile?
A
- Proximal row is mobile
- Distal row is immobile
15
Q
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?
A
- 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
16
Q
A
17
Q
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?
A
- 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
18
Q
Learn this picture
A
19
Q
What does the scaphoid bone span? What does it exclusively articulate with?
A
- It spans the distal and proximal row
- Anatomically and functionally
- It articulates exclusively with radius
20
Q
What is in the ulnar articulate disc (within distal radioulnar joint)?
A
-Lunate
21
Q
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
- 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
22
Q
What joint is found between the distal and proximal rows of carpals?
A
-Intercarpal joints
23
Q
What shape is the palmar surface of the carpus?
A
-Concave
24
Q
What bones articulate with the ulna? Through which complex?
A
- Distal radius
- Triquetrum and lunate
- Through ulnocarpal (ulnar triangular) fibrocartilage complex (ligamentous and cartilaginous structure)
25
What is each finger composed of?
- A metacarpal
- 3 phalanges (except thumb - thumb has 2)
26
What are the roman numerals for digits?
I= thumb
V= pinkie
27
What does each digit articulate with? To form what joint?
-Each digit articulates with a particular carpal bone to form carpometacarpal joint
28
What is the metacarpophalangeal joint?
Between the metacarpal and proximal phalanx
29
What is interphalangeal joint (proximal and distal)?
Between the phalanges
30
How many interphalangeal joint does the thumb have?
What about the rest of the digits?
- 1
- 2
31
Where is the thenar eminence?
-Intrinsic muscles found at the palmar side of 1st metacarpal
32
What is the hypothenar eminence?
-Created by muscles of the little finger and an overlying fat pad
33
What are the arches of the hand?
- 2 transverse arches (proximal and distal)
- 1 longitudinal arch
34
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)
35
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
36
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
37
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
38
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
39
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
40
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
41
What nerves innervate the wrist and hand (motor and sensory)?
- Median
- Radial
- Ulnar
42
What does sensory degradation of radial nerve do?
Has minimal impact on hand function
43
44
Which nerve is regarded as hand's power source for grasping?
Ulnar nerve
45
What are the roots of the median nerve? What cords is it derived from? Where does it originate? What is it lateral to initially? How does it enter the anterior forearm? What muscles does it pass between? Which branches does it give off? What do they supply? What happens to the remaining median nerve after these branches are given off?
- Roots: C6-T1
- Cords: Medial and lateral cords
- It originates at the axilla
- Initially lateral to the brachial artery
- In the forearm, it passes through flexor digitorum profundus and flexor digitorum superficialis
- The 2 major branches given off are: anterior interosseous nerve and palmar cutaneous nerve
- Anterior interosseous nerve supplies deep muscles of the forearm (e.g flexor pollicus longus)
- Palmar cutaneous nerve supplies the skin of the lateral palm
- After giving off these 2 branches, the median nerve continues through the carpal tunnel and terminates as the recurrent branch (supplies thenar muscles) and palmar digital branch (supplies lateral 3.5 digits palmar surface and fingertips and the lateral 2 lumbricals)
46
What are the branches of the median nerve? Which muscles does it pass between? What are the branches there? What are the branches before carpal tunnel?
- Enters the forearm and passes between flexor digitorum profundus and flexor digitorum superficialis
- Giving off 2 branches: anterior interosseous nerve (supplies deep flexor muscles) and palmar cutaneous nerve (supplies lateral part of palm)
- After passing through the carpal tunnel, it gives branches to recurrent branches (innervates thenar muscles) and palmar digital branch (innervates palmar surface and fingertips of 3.5 digits; 2 lumbricals)
47
What roots make up the radial nerve? What cord is it a terminal continuation of? Where does it arise? How does it exit? What muscle and what part of it does it off branches to? Where is it found in the humerus, along with what other structure? What part of the same muscle does it apply? Which epicondyle does it pass anterior to? How many branches does it divide into? What are the 2 branches?
- Roots: C5-T1
- Cord: termination of the posterior cord
- Arises at axilla
- Exits via triangular space (quadstrangular)
- Gives off branches to supply long and lateral heads of triceps brachii
- Then found within spiral groove alongside profunda brachii artery
- As the nerve wraps around the humerus, it supplies the medial head of the triceps
- It passes anterior to the lateral epicondyle
- The 2 branches are: deep branch and superficial branch
48
What does the deep branch of the radial nerve supply? What happens when it penetrates the supinator?
- Motor innervation to the posterior forearm
- When this penetrates supinator, it is called the posterior interosseous nerve for the remainder of its course
49
What does the superficial branch of the radial nerve supply?
-Sensation to the dorsum of hand and dorsal aspects of digits (3.5 digits)
50
How many branches of the radial nerve provide cutaneous innervation to the skin of the upper limb? What are they? What do they supply?
- 4 branches
- 3 of these branches arise in the upper limb
1. Lower lateral cutaneous nerve of the arm = innervates lateral aspect of arm
2. Posterior cutaneous nerve of the arm = innervates posterior surface of arm
3. Posterior cutaneous nerve of the forearm = innervates strip of skin down the middle of the posterior forearm
4. The superficial branch = terminal division of radial nerve. Innervates dorsal surface of the lateral 3.5 digits and the associated area on the dorsum of the hand
51
What are the roots of the ulnar nerve? What cord is it a continuation of? Where does it pass through in the humerus? What branch does it give rise to? Where is ulnar nerve vulnerable? What does it pierce through and alongside which bone? What are the 3 branches in the forearm? How does the ulnar nerve travel in the wrist? What does it enter the hand through? How does it terminate in the hand?
- Roots: C8-T1
- Continuation of medial cord
- Passes posterior to medial epicondyle
- Gives rise to the articular branch that supplies elbow joint
- Pierces through the 2 heads of the flexor carpi ulnaris, and travels deep to the muscle. alongside ulna
- The 3 branches in the forearm
1. Muscular branch
2. Palmar cutaneous branch
3. Dorsal cutaneous branch
- Ulnar nerve travels superficially to the flexor retinaculum
- It enters the hand through the ulna canal (Guyon's canal).
- It terminates in the hand by giving rise to deep and superficial branches
52
What does the deep branch of the ulnar nerve in the hand supply?
- Supplies hypothenar muscles
- Medial 2 lumbricals
- Adductor pollicis
- Interossei
- Palmaris brevis
53
What does the superficial branch of the ulnar nerve in the hand supply?
-Innervates surface of medial 1.5 fingers
54
What kind of organ is the hand? How many sensory receptors are there within the skin? How are they positioned and why?
- Organ for touch
- 10,000 receptors
- They are positioned uniquely within skin to provide the CNS with information about: finger motion, objects held within hand, environmental context (e.g temp)
55
What does macroscopic study of the palmar surface of hand show?
- Posesses highly specialised pilary ridges
- Types of sensory receptors (mechanoreceptors or encapsulated receptors)
- Nerve fibres
- There are more receptors than nerve fibres so each fibre is connected to several receptors
56
57
Where is there greater receptivity to stimulus in hand? Why is it important?
- Important for very fine motor prehension and restoration of hand function following injury
- Ulnar half of digital pulp of thumb
- Ulnar border of the little finger
- Radial half of digital pulp of both index and middle fingers
58
What is the hand and wrist dually supplied by? What do they do?
- Radial and ulnar arteries
- They anastomose after entering the hand
- They form the deep and superficial palmar arch
59
What is the skin of the hand supplied by (vascular)? Why is the circulation specialised? Why is there a dense capillary system?
- It is supplied by deep and superficial plexus
- Circulation is specialised as hand is distal to heart and is exposed to thermal and postural variations
- There is a dense capillary system allowing variation of capillary pressure
60
What does hand injury or disease that threatens the cycle of vasodilation and vasoconstriction cause?
- Progressive wrist and hand oedema
- This can cause stiffness and causalgia (burning pain)
61
What are the branches of the subclavian artery?
- Vertebral artery
- Internal thoracic artery
- Thyrocervical artery
- Dorsal scapular artery
- Costocervical
The subclavian artery continues as the axillary artery
62
When does the subclavian artery become the axillary artery?
Lateral border of the first rib
63
What is the axillary artery split into?
All in respect to pec minor:
- proximal
- posterior
- distal
64
What does the first part of the axillary artery give rise to?
-Superior thoracic artery
65
What does the second part of the axillary artery give rise to?
- Thoracoacromial artery
- Lateral thoracic artery
66
What does the 3rd part of the axillary artery give rise to?
- Subscapular artery
- Anterior circumflex humeral artery
- Posterior circumflex humeral artery
67
When does the axillary artery become the brachial artery? What branch does brachial artery give rise to? What does it supply?
- Lower border of teres minor
- Profunda brachii artery (found in the spiral groove, along with radial nerve). Supplies upper arm
68
What does the profunda brachii artery supply?
- Supply upper arm
- E.g help supply deltoid, triceps, biceps brachii
69
Where does the brachial artery bifurcate?
- Bifurcates at cubital fossa
- Ulnar and radial arteries are formed as a result
70
What does the radial artery supply?
- Posterolateral forearm
- supplies elbow, carpal tunnel bones, joints and thumb
71
What does the ulnar artery supply? And what branch does it give rise to?
- Anteromedial forearm
- Ulnar artery gives rise to an interosseous branch
72
What do the radial and ulnar arteries do?
-They anastomose to form superficial and deep palmar arches
73
What does the superficial palmar arch give rise to?
Digital branches
74
What is the venous drainage of the upper limb? Where do each of them arise from? What do they drain into?
- Main superficial veins: cephalic vein and basilic vein
- Both of them arise from the dorsal venous network of the hand
- They drain into the axillary vein
75
What is the median cubital vein?
- Union of basilic vein and cephalic vein
- Allows their communication
76
What are the major deep veins of the upper limb?
- Brachial veins
- They form the axillary vein
77
What artery supplies the arm?
Brachial artery
78
How is active control of wrist achieved? Why is this important?
- Through coordinated action of extrinsic muscles (originating in forearm) and intrinsic muscles (originating in wrist and hand)
- This allows mobility and stability during activities of wrist and hand
79
What are the 4 passive control mechanisms?
- Bony mechanisms
- Ligamentous ligaments
- Connective tissue restraints
- Tendinous expansion
80
How can the carpal bones collapse?
-Mobile proximal row and immobile distal row create an intercalated segment that is subject to 'zigzag' collapse under compression loads
81
How is the zigzag collapse of carpal bones counteracted to help with stability?
- Intricate ligamentous constraints
- Precise opposition of multifaceted articular surfaces
- Helps stability
82
What is the carpal tunnel?
What does it serve as?
The narrow passageway on the anterior part of the wrist.
It serves as an entrance to the palm for 9 tendons and the median nerve
83
What are the two layers of the carpal tunnel?
1) deep carpal arch
- It is concave and forms the base and sides of the carpal tunnel.
- Formed laterally by scaphoid and trapezium
- Formed medially by hook of hamate and pisiform
2) superficial flexor retinaculum
- Thick connective tissue that forms the roof of the carpal tunnel
- Spans hook of hamate and pisiform to scaphoid and trapeziun
84
What are the 9 tendons in the carpal tunnel?
- Flexor pollicus longus
- Flexor digitorum profundus (x4)
- Flexor digitorum superficialis (x4)
85
What are the sheaths surrounding the tendons in carpal tunnel?
The 8 tendons are surrounded by a single synovial sheath
-Flexor pollicus longus has its own synovial sheath which allows free movement of the tendon
86
Tell me about the median nerve in the carpal tunnel
- Palmar cutaneous branch of the median nerve branches before the nerve enters carpal tunnel (so travels superficially). This nerve supplies central palm (sensory)
- After median nerve enters carpal tunnel, it gives rise to recurrent branches and palmar digital branches of the median nerve
87
What does the palmar digital branch of the median nerve supply?
- Sensory innervation to palmar skin (laterla 3.5 digits)
- sensory innervation to dorsal nail of lateral 3.5 digits
- Lateral 2 lumbricals
88
What do the recurrent branches of the median nerve supply?
Supplies the thenar muscles
89
What is carpal tunnel syndrome?
What is it caused by?
What does it cause on the thenar muscles?
What are the clinical features?
- Compression of median nerve within carpal tunnel
- mononeuropathy caused by thickened ligaments and tendon sheaths
- can cause weakness and atrophy of thenar muscles
- Clinical features: numbness, tingling, pain.
Worse in the mornings
90
How to test for carpal tunnel syndrome?
- Tinel's sign (tapping the nap in the carpal tunnel to elicit pain)
- Phalen's manoeuvre (holding the wrist in flexion for 30 seconds to elicit numbness/pain)
91
How do you treat carpal tunnel syndrome?
- Splint
- Corticosteroids to reduce swelling of connective tissue
- Surgical decompression in severe cases
92
What is a scaphoid fracture?
What is it caused by?
What are the clinical features?
- Fracture of scaphoid bone (most commonly fractured carpal bone)
- Normally caused by falling on an outstretched hand
- Clinical features = pain and tenderness of anatomical snuffbox
93
Why is the scaphoid at risk of avascular necrosis after fracture?
- It has a retrograde blood supply which means the blood flow enters from the distal end to the proximal end
- Hence, fracture to the middle/waist of this bone can interrupt blood flow to the proximal part of the scaphoid, rendering it avascular
94
What is the median nerve?
- C6-T1
- Initially lateral to brachial artery
- Anterior interosseous supplies deep muscles of anterior forearm and flexor pollicus longus
- Palmar cutaneous nerve supplies lateral palm
- After giving off these branches, the median nerve continues through the carpal tunnel before terminating as 2 more branches
- Recurrent branch supplies thenar muscles
- Palmar digital branch innervates the palmar surface and fingertips of the lateral 3.5 digits and the lateral 2 lumbricals
95
What does the radial nerve do for the hand and wrist?
- Deep branch provides motor innervation to the posterior forearm (after it reaches the supinator, it's known as posterior interosseous nerve)
- Superficial branch is terminal division of the radial nerve; it innervates the dorsal surface of the lateral 3.5 digits and the associated area on the dorsum of the hand
- Damage to fracture of humeral shaft (where radial nerve is present): triceps brachii and muscles in posterior compartment are affected; patient can't extend forearm. Wrist drop (unopposed wrist flexion). Loss of sensation over lateral and posterior arm, forearm and dorsal surface of the lateral 3.5 digits
96
What is the importance of the ulnar nerve?
- C8-T1
- Pierces through the 2 heads of the flexor carpi ulnaris
- Muscular branch innervates flexor carpi ulnaris and half of flexor digitorum profundus
- Palmar cutaneous branch innervates medial half of palm
- Dorsal cutaneous branch - innervates dorsal surface of medial 1.5 fingers
- Deep branch supplies hypothenar muscles, medial 2 lumbricals, adductor pollicis, interossei, palmaris brevis
97
What is De Quervain's Tenosynovitis?
* Inflammation of tendon sheaths in 1st extensor compartment (adductor pollicus longus and extensor pollicus brevis)
* Causes wrist pain and swelling
* Most common on women between 30 and 50
* Also affects those who do repetitive wrist and thumb movements (abduction and extension)
Pain near base of thumb
* Swelling over radial styloid
* Difficulty and pain grasping and pinching
* O/E palpable thickening of tendon sheath
* Finkelstein's test +ve • Passively flex thumb and ulnar deviate wrist
98
What is trigger finger?
Stenosing flexor tenosynovitis
* Joint locks in flexion preventing return to extension • Usually affects A1 pulley (over MCP joint)
* Most cases occur spontaneously
* Prevalence ~2 in 100
* May be associated with RA, amyloidosis and DM Pathophysiology:
* Repetitive movements inflame tendon and sheath • Localised nodes form distal to pulley (usually A1)
* Flexion pulls node proximal to pulley
* Can't then pass back under pulley to extend finger
* Joint locks in flexion
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