Forearm and Wrist SDL Flashcards

(120 cards)

1
Q

The forearm bones are the radius and ulna. What do these bones articulate with?

A

Proximally with the humerus at the elbow joint

Proximally with each other at the proximal radioulnar joint

Distally with with each other at the distal radioulnar joint

Radius - distally with the carpal bones to form the radiocarpal/wrist joint

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2
Q

In life, a tough, fibrous membrane lies between the radius and ulna. What is this membrane called?

A

Interosseous membrane

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3
Q

Bony landmarks of radius and ulna

A
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4
Q

What muscles is supination of the arm achieved by?

A
  • Supinator (a deep posterior forearm muscle)
  • Biceps brachii (an anterior arm muscle) acts as powerful supinator especially when the elbow is flexed
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5
Q

What muscle is pronation of the forearm achieved by?

A

2 anterior forearm muscles:

  • Pronator teres (superficial)
  • Pronator quadratus (deep)
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6
Q

What type of joints are the joints within the hand?

A

Synovial

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7
Q

The human thumb is opposable. What benefit is this?

A

Allows us to manipulate all manner of objects with great dexterity, and form various grips, including a precision grip.

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8
Q

How are the 8 carpal bones arranged?

A

In 2 rows; proximal and distal

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9
Q

What bones makes up the proximal carpal row?

A
  • Scaphoid, lunate, triquetral, pisiform (from radial to ulnar side)
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10
Q

What bones make up the distal carpal row?

A
  • Hamate, capitate, trapezoid, trapezium (from ulnar to radial side)
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11
Q

Which carpal bones articulate with the radius to form the wrist (radiocarpal) joint?

A

Scaphoid and lunate

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12
Q

The scaphoid bone is the most commonly fractured carpal bone. What can happen as a result of a missing a scaphoid fracture?

A

Arthritis, wrist fusion, death of bone tissue, non union

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13
Q

What bones does the first carpometacarpal joint involve?

A

The first metacarpal and the trapezium

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14
Q

What movements is the thumb capable of?

A
  • Abduction
  • Adduction
  • Flexion
  • Extension
  • Opposition
  • Reposition
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15
Q

What movements is the wrist capable of?

A
  • Flexion
  • Extension
  • Abduction
  • Adduction

All 4: circumduction

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16
Q

What movements are the fingers capable of?

A
  • Abduction
  • Adduction
  • Flexion
  • Extension
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17
Q

Why is the (ante)cubital fossa important in clinical practice?

A
  • Contains several important neurovascular structures
  • Superficial veins that overlie the cubital fossa are routinely accessed for venepuncture and intravenous cannulation.
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18
Q

What is the superior boundary of the cubital fossa?

A

An imaginary line between the medial and lateral epicondyle of the humerus

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19
Q

What makes up the floor of the cubital fossa?

A

Brachialis

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20
Q

What makes up the medial and lateral borders of the cubital fossa?

A

2 forearm muscles: pronator teres and brachioradialis

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21
Q

If the skin that overlies the cubital fossa is removed, what do we see?

A

Fascia and superficial veins overlying the cubital fossa

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22
Q

When accessing the superficial veins in the cubital fossa, why must care be taken to keep the needle superficial?

A

The brachial artery and median nerve lie deeper in the cubital fossa

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23
Q

How many layers of muscles are there in the anterior forearm?

A

3; superficial, middle, deep

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24
Q

What muscles make up the superficial layer of the anterior forearm?

A
  • Flexor carpi radialis
  • Flexor carpi ulnaris
  • Palmaris longus
  • Pronator teres
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25
What muscles make up the middle layer of the anterior forearm?
Flexor digitorum superficialis
26
What muscles make up the deep layer of the anterior forearm?
* Flexor digitorum profundus * Flexor pollicis longus * Prontor quadratus
27
Where do the superficial flexors of the anterior forearm arise from?
The medial epicondyle - 'common flexor origin'
28
Location of superficial flexors
29
Which superficial anterior forearm muscle is found most laterally? What is its action?
Pronator teres - pronator (and weak flexor) of the forearm
30
Where does palmaris longus lie?
Between the flexor carpi ulnaris and radialis
31
Where does palmaris longus arise from? Where does it insert?
Arises from 'common flexor origin' and inserts into palmar aponeuorsis
32
What is palmar aponeurosis?
A thick band of connective tissue in the palm
33
Action of palmaris longus?
Flexes the wrist
34
Distal insertion of pronator teres?
Lateral surface of radial midshaft
35
Distal insertion of flexor carpi radialis?
Metacarpals of 2nd and 3rd digits
36
Distal insertion of flexor carpi ulnaris?
Base of metacarpal 5
37
Distal insertion of palmaris longus?
Palmar aponeurosis
38
Insertions of superficial anterior forearm muscles
39
Other than flexion, what actions do FCR and FCU have at the wrist?
* Flexor carpi ulnaris **adducts** * Flexor carpi radialis **abducts**
40
Which nerves innervate the superficial flexors of the wrist?
Median nerve - innervates flexor carpi radialis, palmaris longus and pronator teres Ulnar nerve - innervates flexor carpi ulnaris
41
How many tendons does flexor digitorum superficialis give rise to? Where do these travel?
4 - these travel under the **flexor retinaculum** to digits 2-5
42
Onto which phalanges of digits 2-5 do the FDS tendons insert?
Each tendon of FDS then splits into 2, inserting either side of the **middle phalanx** of digitis 2-5
43
What happens to the FDS tendons just before they insert upon these bones?
They split into 2
44
What is the action of FDS and what is its innervation?
Actions: * Flexor of digits at PIPJ, MCPJ and wrist Innervation: * Median nerve
45
Diagram of origin and insertion of FDS
46
Where do the ulnar and radial neurovascular bundles lie in relation to FDS?
Ulnar neurovascular bundle - lies medial Radial neurovascular bundle - lies lateral
47
Where does the median nerve lie in relation to FDS?
Deep to FDS
48
Where do the deep flexors of the anterior forearm arise from?
The shaft of the radius and ulna and the interosseous membrane
49
What are the deep flexors of the anterior forearm?
* Flexor digitorum profundus * Flexor pollicis longus * Pronator quadratus
50
What are the deep muscles of the forearm innervated by?
A branch of the median nerve called the **anterior interosseous nerve**
51
Describe the innervation of FDP?
Dual innervation: * Lateral part (which sends tendons to the index and middle fingers) is innervated by the anterior interosseous nerve * Medial part (part (which sends tendons to the ring and little fingers) is innervated by the ulnar nerve
52
How many tendons does FDP give rise to?
4
53
Where do the tendons of flexor digitorum profundus insert? How are they related to the tendons of FDS?
* Insert on the distal phalanges of digits 2-5 * Run deep to FDS * The 4 tendons of FDS then split into 2 and FDP tendons travel between this split
54
What is the action of FDP?
Flexes digits 2-5: at the DIPJ, PIPJ, MCPJ
55
Where does **FPL** insert, and what action does it have?
Flexor pollicis longus inserts on the distal phalanx of the thumb Action: flexes the thumb
56
What is the action of pronator quadratus?
Pronates the forearm at the distal radioulnar joint
57
What is the carpal tunnel?
A space or ‘channel’ on the anterior aspect of the wrist through which some of the long flexor tendons of the forearm and the median nerve travel to reach the hand.
58
What forms the roof of the carpal tunnel?
The transverse carpal ligament
59
What forms the floor and sides of the carpal tunnel?
The carpal bones
60
Diagram of carpal tunnel
61
What structures run through the carpal tunnel?
* Median nerve * Long flexor tendons of the forearm (4 tendons of FDS + FDP, tendon of FPL)
62
What causes carpal tunnel syndrome?
Compression of the median nerve in the carpal tunnel
63
What specific areas of skin are affected in carpal tunnel syndrome?
Skin over lateral 3 1/2 digits (palm side) Skin over lateral 3 digits (dorsal side)
64
Which muscles in the hand are affected by carpal tunnel syndrome? What happens to these muscles over time if surgery is not performed?
* Thenar muscles: * Opponens pollicis * Abductor pollicis brevis * Flexor pollicis brevis * Lateral two lumbricals Lose control of the thumb
65
How many layers of muscle are there in posterior forearm?
2 - deep and superficial
66
What muscles make up the superficial layer of the posterior forearm?
* Extensor carpi radialis brevis * Extensor carpi radialis longus * Extensor carpi ulnaris * Extensor digitorum * Extensor digiti minimi * Brachioradilais
67
What muscles make up the deep layer of the posterior forearm?
* Extensor pollicis longus * Abductor pollicis longus * Extensor pollicis brevis * Supinator * Extensor indicis
68
What are all the muscles in the posterior forearm innervated by?
The radial nerve
69
Where do the superficial extensors of the posterior forearm originate from?
Lateral epicondyle of the humerus - 'common extensor origin'
70
What are the superficial extensors of the posterior forearm?
* Extensor radialis longus * Extensor radialis brevis * Extensor radialis ulnaris * Extensor digitorum * Extensor digiti minimi
71
What muscles are the principal wrist extensors?
Extensor carpi radialis (longus and brevis) and extensor carpi ulnaris
72
Where do ECRL, ECRB and ECU insert distally?
ECRL - inserts on 3rd metacarpal ECRB - inserts on 2nd metacarpal ECU - inserts on 5th metacarpal
73
Diagram of origin and insertion of superficial flexors
74
Where does ED lie in the forearm? How many tendons does it give rise to?
Lies centrally in the posterior forearm and gives rise to 4 tendons that travel to digits 2-5
75
What is EDM? How many tendons does it have?
Part of ED and its tendon travels to the 5th digit.
76
Where do the tendons of ED and EDM pass in relation to extensor retinaculum?
These tendons pass beneath the extensor retinaculum
77
Where do ED and EDM tendons insert?
On the extensor expansion or 'hood'
78
What is extensor expansion?
A fibrous band of tissue that overlies the dorsum of the digits
79
What is purpose of extensor expansion?
Helps to keep the extensor tendons in the **midline** of the digits and also serves as an **insertion point** for the tendons of some of the small muscles in the hand, thus allowing those muscles to move the fingers too
80
Where does brachioradialis lie?
It lies over the most lateral part of the posterior compartment, on the boundary with the anterior compartment
81
What is the action of brachioradialis? How is this unusual?
Contributes to **flexion** at the elbow joint and is also important for returning the forearm to the mid-prone position (i.e. like a racquet grip) from either full supination or pronation. Unusual as is a posterior forearm muscle
82
Where does brachioradialis originate from? Where does it insert?
The supracondylar ridge of the humerus (not the common extensor origin) and extends to the distal radius
83
What is anconeus?
A small muscle situated on the **posterior aspect** of the **elbow**. Some consider it part of the posterior compartment of the arm, others as part of the posterior compartment of the forearm.
84
What are the deep extensor muscles of the posterior forearm?
* Extensor pollicis longus * Extensor pollicis brevis * Abductor pollicis longus * Extensor indicis
85
Where do the deep extensor muscles of the posterior forearm arise? What movements are they involved in?
* From the shaft of the radius and ulna and the interosseous membrane * Involved in abduction and extension of the thumb and extension of the index finger
86
What are the deep extensor muscles of the posterior forarm innervated by?
A branch of the radial nerve called the **posterior interosseous nerve**
87
Distal insertion of: 1. EI 2. EPL 3. EPB 4. APL
1. EI - inserts on extensor expansion of index finger 2. EPL - inserts on distal phalanx of thumb 3. EPB - inserts on proximal phalanx of thumb 4. APL - inserts on lateral aspect of 1st metacarpal
88
Action of: 1. EI 2. EPL 3. EPB 4. APL
EI - extends index finger EPL - extends thumb EPB - extends thumb APL - abducts thumb and accessory extensor of thumb
89
What tendons are involved in forming the ASB?
APL, EPL, EPB
90
What carpal bone lies in the floor of the ASB?
Scaphoid bone
91
Which artery can be palpated in the snuffbox?
Radial artery
92
Which vein can be accessed in the snuffbox?
Cephalic vein
93
What is E?
Styloid process of the ulna
94
What forms the medial, lateral, superior, floor and roof of the cubital fossa?
Medial - pronator teres Lateral - brachioradialis Superior - An imaginary line between the humeral epicondyles Floor - Brachialis Roof - Antebrachial fascia, reinforced by the bicipital aponeurosis
95
What is C?
Flexor carpi radialis
96
What is B?
Brachioradialis
97
Name B-F
B - extensor carpi ulnaris C - extensor digitorum D - Abductor pollicis longus E - Extensor pollicis brevis F - Extensor digiti minimi
98
what is C?
Extensor pollicis longus
99
Which carpal bone articulates with the distal radius at region C
Lunate
100
Muscle B is innervated by which nerve?
Radial
101
What is E?
Flexor digitorum superficialis
102
Which bony landmark lies under region A?
Medial epicondyle - We can see the posterior forearm muscles and the dorsum of the hand, hence this is the posterior aspect of a right forearm. A is the medial epicondyle. The posterior forearm muscles can be seen origination form the region directly opposite region A - the lateral epicondyle.
103
Muscle B is capable of producing which of the the following actions?
Extension of the interphalangeal joints of the fingers Extension of the metacarpophalangeal joints of the hand Extension of the radiocarpal joint
104
Identify A and B.
A - Flexor pollicis longus B - Flexor digitorum profundus
105
Muscle A inserts on the:
distal phalanx of the thumb
106
Nerve E innervates which muscles in the anterior forearm?
Pronator teres Flexor carpi radialis Flexor digitorum superficialis Lateral half of flexor digitorum profundus
107
Muscle B is innervated by which nerve?
Posterior interosseous nerve
108
The red arrow indicates the:
Lateral epicondyle
109
What is B?
Flexor digitorum profundus
110
This image shows branches of which nerve innervating the skin of the region circled?
Superficial radial
111
What is artery A?
Radial artery
112
The tendons of which muscles travel through the carpal tunnel in the region circled B?
Flexor digitorum profundus Flexor digitorum superficialis Flexor pollicis longus
113
What is A-E?
A - ulnar nerve B - ulnar artery C - median nerve D - tendon of flexor pollicis longus E - radial arery
114
Muscle A is innervated by which nerve?
Anterior interosseous
115
Identify the tendon indicated by the letter C.
Extensor pollicis longus
116
Nerve G innervates which muscles in the forearm?
G is the ulnar nerve: * Flexor carpi ulnaris * Medial half of flexor digitorum profundus
117
Letter C indicates the common flexor origin. Is this true or false?
True
118
Identify the vein indicated by letter C.
Basilic
119
What is the anterior interosseous nerve a branch of? What does it innervate?
Branch of the median nerve - innervates the deep muscles of the anterior forearm
120
What is the posterior interosseous nerve a branch of? What does it innervate?
Branch of the radial nerve Innervates: * Extensor carpi radialis brevis * Extensor carpi ulnaris * Extensor digitorum * Extensor digiti minimi * Supinator * Extensor pollicis brevis * Extensor indicis * Extensor pollicis longus * Abductor pollicis longus Only exceptions are: extensor carpi radialis longus, brachioradiali which are innervated by the **radial nerve itself**