Forearm Flashcards
1
Q
What compartments is the forearm divided into?
A
Anterior and posterior compartment
2
Q
What splits the forearm into the anterior and posterior compartments and joins the radius and the ulna?
A
interosseus membrane
3
Q
What does the anterior compartment of the forearm contain?
A
flexor muscles
4
Q
What are the muscles of the anterior forearm innervated by?
A
median and ulnar nerves
5
Q
What does the posterior compartment of the forearm contain?
A
extensor muscles
6
Q
What are the muscles of the posterior forearm innervated by?
A
radial nerve
7
Q
What is the role of the forearm movement?
A
assist the shoulder in the application of force and in controlling the placement of the hand in space
8
Q
The anterior compartment actions are what?
A
flexion and pronation
9
Q
What posterior compartment actions are what?
A
extension and supination
10
Q
What is the fibrous tissue with an oblique orientation from the radius to the ulna?
A
Interosseus membrane
11
Q
What maintains the interosseus space between the radius and ulna through forearm rotation and actively transfers forces from the radius to the ulna?
A
interosseus membrane
12
Q
What helps the interosseus membrane hold the radius and ulna together, particularly when upward thrusts are transmitted through the wrist (during a fall on the hand)
A
pronator quadratus
13
Q
What keeps the radius and ulna together?
A
interosseus membrane and pronator quadratus
14
Q
What are the common attachments (origins) of the anterior compartment of the forearm?
A
medial epicondyle of the humerus (superficial and intermediate; only 5 muscles)
15
Q
What is the common innervation of the anterior forearm compartment?
A
median nerve with some contribution from the ulnar nerve
16
Q
What muscle(s) in the forearm are innervated by the ulnar nerve?
A
1/2 flexor carpi ulnaris
flexor digitorum profundus
17
Q
What is the common action of the anterior compartment of the forearm?
A
flexion
18
Q
What the the 3 groups that the anterior forearm compartment divided into?
A
- superficial
- intermediate
- deep
19
Q
What do the 5 superficial and intermediate muscles cross that the 3 deep muscles do not?
A
elbow joint
20
Q
What muscles are included in the superficial layer of the anterior forearm compartment?
A
- pronator teres
- flexor carpi radialis
- palmaris longus
- flexor carpi ulnaris
21
Q
The 4 superficial anterior forearm muscles are all attached proximally by a _______________ to the medial epicondyle of the humerus, the ____________
A
common flexor tendon
common flexor origin
22
Q
What is the origin of the pronator teres, flexor carpi radialis, and palmaris longus?
A
medial epicondyle of the humerus
23
Q
What is the origin of the flexor carpi ulnaris?
A
humeral head- medial epicondyle
ulnar head- olecranon and posterior border of ulna
24
Q
What does the pronator teres insert onto?
A
middle lateral surface of the radius
25
What does the flexor carpi radialis insert onto?
Base of the metacarpals 2 and 3
26
What does the palmaris longus muscle insert onto?
distal 1/2 of flexor retinaculum and palmar aponeurosis
27
What does the flexor carpi ulnaris insert onto?
pisiform bone, hook of hamate, and base of metacarpal 5
28
What is the pronator teres, flexor carpi radialis, and palmaris longus muscles innervated by?
median nerve
29
What is the flexor carpi ulnaris muscle innervated by?
ulnar nerve
30
What are the actions of the pronator teres muscle?
forearm pronation and flexion
31
What are the actions of the flexor carpi radialis muscle?
flexes hand at wrist and assists in wrist abduction
32
What are the actions of the palmaris longus muscle?
flexes hand and tenses palmar fascia
33
What are the actions of the flexor carpi ulnaris muscle?
flexes hand at wrist and assists in wrist adduction
34
What is the blood supply of the pronator teres muscle?
anterior ulnar recurrent artery
35
What is the blood supply of the flexor carpi radialis muscle?
radial artery
36
What is the blood supply of the palmaris longus and flexor carpi ulnaris muscles ?
posterior ulnar recurrent artery
37
What is the only muscle included in the intermediate layer of the anterior forearm compartment?
flexor digitorum superficialis
38
What is the origin of the flexor digitorum superficialis muscle?
humeral head: medial epicondyle
ulnar head: coronoid process
radial head: anterior border of radius
39
What does the flexor digitorum superficialis muscle insert onto?
bodies of the middle phalanges of digits 2-5
40
What is the innervation of the flexor digitorum superficialis muscle?
median nerve
41
What are the actions of the flexor digitorum superficialis muscle?
flexes middle and proximal phalanges of digits 2-5
assists in hand flexion
42
What is the blood supply of the flexor digitorum superficialis?
ulnar and radial arteries
43
What are the 3 muscles included in the deep layer of the anterior forearm compartment?
flexor digitorum profundus
flexor pollicis longus
pronator quadratus
44
What nerve travels right on top of the flexor digitorum profundus muscle?
median nerve
45
What is the origin of the flexor digitorum profundus muscle?
proximal 3 quarters of medial and anterior surfaces of ulna and interosseus membrane
46
What is the origin of the flexor pollicis longus muscle?
anterior surface of radius and interosseus membrane
47
What is the origin of the pronator quadratus muscle?
distal quarter of the anterior surface of ulna
48
What does the flexor digitorum profundus insert onto?
bases of distal phalanges 2-5
49
What does the flexor pollicis longus muscle insert onto?
base of distal phalanx of thumb
50
What does the pronator quadratus muscle insert onto?
distal quarter of anterior surface of radius
51
What is the innervation of the flexor carpi profundus muscle?
digits 2 and 3: median nerve
digits 4 and 5: ulnar nerve
52
What is the innervation of the flexor pollicis longus muscle?
anterior interosseus nerve from median nerve
53
What are the actions of the flexor digitorum profundus muscle?
-flexes wrist joint and carpometacarpal (CMC) joints
-flexes distal interphalangeal (DIP) joints of digits 2-5
-assists with wrist flexion
54
What are the actions of the flexor pollicis longus muscle?
-flexes wrist joint and CMC joints
-flexes metacarpophalangeal (MCP) and interphalangeal joints of thumb
55
What are the actions of the pronator quadratus muscle?
pronates forearm
56
What muscle flexes the fingers in slow action?
Flexor digitorum profundus
57
What muscle reinforces the slow action of finger flexion when speed and flexion against resistance are required?
flexor digitorum superficialis
58
What are the long flexors of the digits?
flexor digitorum superficialis
flexor digitorum profundus
59
When the wrist is flexed, the contraction of the digits into the flexed position is ______. why?
weaker; the FDS and FDP are operating over a shortened distance between attachments
60
When the wrist is extended, the contraction of the digits into the flexed position is ______. Why?
stronger (strong grip); the FDS and FDP has a longer operating distance when the wrist is extended
61
What muscle is in the posterior compartment of the forearm but is the exception to the rule that the forearm flexor muscles are innervated by the median n.?
brachioradialis
62
What muscle is a relatively weak elbow flexor but is strongest when the forearm is in mid-pronated position?
brachioradialis
63
What muscle is important in arm wrestling?
brachioradialis
64
What are the common attachments (origins) of the posterior forearm muscles?
lateral epicondyle of the humerus
65
What is the common innervation of the posterior forearm muscles?
radial nerve
66
What is the common action of the posterior forearm muscles?
extension
67
What are the 2 groups that the posterior compartment of the forearm is divided into?
superficial
deep
68
What are the 3 functional groups of the posterior compartment of the forearm?
1. muscles that extend and abduct/adduct the hand at the wrist joint
2. muscles that extend the medial 4 digits
3. muscles that extend or abduct the thumb
69
What muscles are in the functional group of muscles that extend/abduct/adduct the hand at the wrist joint?
extensor carpi radialis longus
extensor carpi radialis brevis
extensor carpi ulnaris
70
What muscles are in the functional group of muscles that extend the medial 4 digits?
extensor digitorum
extensor indicis
extensor digiti minimi
71
What muscles are in the functional group of muscles that extend or abduct the thumb?
abductor pollicis longus
extensor pollicis brevis
extensor pollicis longus
72
What are the extensor tendons in the posterior forearm compartment held in place in the wrist region by?
extensor retinaculum
73
What does the extensor retinaculum do?
prevents bowstringing of the tendons when the hand is extended at the wrist joint
74
What reduces friction for the extensor tendons as they traverse the osseofibrous tunnels formed by the attachment of the extensor retinaculum to the distal radius and ulna?
synovial tendon sheaths
75
What are the superficial layers of the posterior forearm compartment?
-brachioradialis
-extensor carpi radialis longus
-extensor carpi radialis brevis
-extensor digitorum
-extensor digiti minimi
-extensor carpi ulnaris
76
The superficial extensors (ECRB, extensor digitorum, EDM, and ECU) are attached proximally by a _____________ to the lateral epicondyle?
common extensor tendon
77
What is the origin of the brachioradialis muscle?
proximal 2/3 of lateral supra-epicondylar ridge of the humerus
78
What is the origin of the extensor carpi radialis longus muscle?
lateral supra-epicondylar ridge of the humerus
79
What is the origin of the extensor carpi radialis brevis muscle?
lateral epicondyle of the humerus
80
What does the brachioradialis insert onto?
lateral surface of distal end of radius proximal to styloid process
81
What does the extensor carpi radialis longus muscle insert onto?
dorsal aspect of base of 2nd metacarpal
82
What does the extensor carpi radialis brevis muscle insert onto?
dorsal aspect of base of 3rd metacarpal
83
What innervates the brachioradialis muscle?
radial nerve (C5, C6, C7)
84
What innervates the extensor carpi radialis longus muscle?
radial nerve (C6,C7)
85
What is the extensor carpi radialis brevis innervated by?
deep branch of the radial nerve
86
What are the actions of the brachioradialis muscle?
relatively weak elbow flexion; maximal when forearm is in midpronated position
87
What are the actions of the extensor carpi radialis longus and extensor carpi radialis brevis muscle?
Extends and abducts wrist joint
extends carpometacarpal (CMC) joints
88
What muscle is active during fist clenching?
extensor carpi radialis brevis
89
What is the origin of the extensor digitorum and extensor digiti minimi muscles?
lateral epicondyle of the humerus
90
What is the origin of the extensor carpi ulnaris muscle?
lateral epicondyle; posterior border of ulna, shared aponeurosis
91
What does the extensor digitorum muscle insert onto?
extensor expansions of medial 4 digits
92
What does the extensor digiti minimi insert onto?
extensor expansion of digit 5
93
What does the extensor carpi ulnaris muscle insert onto?
dorsal aspect of base of 5th metacarpal
94
What innervates the extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris muscle?
posterior interosseus nerve, continuation of deep branch of the radial nerve
95
What are the actions of the extensor digitorum muscle?
-extends wrist and CMC joints
-extends medial 4 digits primarily at the MCP joints, secondarily at the interphalangeal joints
96
What are the actions of the extensor digiti minimi muscle?
-extends wrist and CMC joints
-extends digit 5 primarily at the MCP joint, secondarily at the interphalangeal joint
97
What are the actions of the extensor carpi ulnaris muscle?
extends and adducts wrist joint and CMC joints
98
Besides the extensor carpi radialis brevis muscle, what other muscle is also active during fist clenching?
extensor carpi ulnaris
99
What muscles are included in the deep layer of the posterior forearm compartment?
abductor pollicis longus
extensor pollicis longus
extensor pollicis brevis
supinator
100
The 3 muscles acting on the thumb (APL, EPL, EPB) are what to the superficial extensors?
deep
101
The 3 muscles acting on the thumb (APL, EPL, EPB) emerge ("crop out") from a furrow in the lateral part of the forearm that divides the extensors. Because of this, they are referred to as what?
the outcropping muscles
102
What is the origin of the abductor pollicis longus?
posterior surface of proximal 1/2 of ulna, radius, and interosseus membrane
103
What is the origin of the extensor pollicis longus?
posterior surface of middle third of ulna and interosseus membrane
104
What is the origin of the extensor pollicis brevis?
posterior surface of distal third of radius and interosseus membrane
105
What does the abductor pollicis longus insert onto?
base of 1st metacarpal
106
What does the extensor pollicis longus insert onto?
dorsal aspect of base of distal phalanx of thumb
107
What does the extensor pollicis brevis insert onto?
dorsal aspect of base of proximal phalanx of thumb
108
What innervates the abductor pollicis longus, extensor pollicis longus, and extensor pollicis brevis?
posterior interosseus nerve, continuation of deep branch of radial nerve
109
What are the actions of the abductor pollicis longus muscle?
-abducts thumb and extends it at the CMC joint (MAIN ACTION)
-extends wrist joint and CMC joints
110
What are the actions of the extensor pollicis longus muscle?
-extends distal phalanx of thumb at interphalangeal joint; extends MCP and CMC joints
-extends wrist joint, CMC joints
111
What are the actions of the extensor pollicis brevis?
-extends proximal phalanx of thumb at MCP joint; extends CMC joint
-extends wrist joint, CMC joints
112
What is the origin of the supinator muscle?
lateral epicondyle of humerus, radial collateral and annular ligaments, supinator fossa and crest of ulna
113
What does the supinator muscle insert onto?
lateral, posterior, and anterior surface of proximal 3rd of radius
114
What is the innervation of the supinator muscle?
deep branch of the radial nerve
115
What is the main action of the supinator muscle?
supinates forearm, rotates radius to turn palm anteriorly or superiorly (if elbow is flexed)
116
What are the borders of the anatomical snuffbox?
Laterally: tendons of the Abductor pollicis longus and extensor pollicis brevis
medially: tendon of the extensor pollicis longus
117
What is visible as a hollow on the lateral aspect of the wrist when the thumb is extended fully?
the anatomical snuff box
118
What lies on the floor of the snuff box?
radial artery
119
What can be palpated proximally of the snuff box?
radial styloid process
120
What can be palpated distally in the stuff box?
base of the 1st metacarpal
121
What can be felt in the floor of the snuff box between the radial styloid process and the 1st metacarpal?
scaphoid and trapezium
122
What are the major nerves of the forearm?
median, ulnar, and radial nerve
123
Even the the radial nerve appears in the cubital region, it soon enters what?
posterior compartment of the forearm
124
Besides the cutaneous branches, there are only 2 nerves of the anterior aspect of the forearm, what are they?
median and ulnar nerves
125
What is the principal nerve of the anterior compartment of the forearm?
median nerve
126
What is the passage way of the median nerve?
-enters forearm with brachial a. and lies medial to it
-median n. leaves cubital fossa by passing between the heads of the pronator teres, supplying branches to them
-passes deep to the FDS, continuing distally through the middle of the forearm, between the FDS and FDP
127
What is the major branch of the median nerve?
anterior interosseous nerve
128
What does the median nerve do as a motor nerve to the anterior forearm compartment?
-flexes wrist and fingers except for FCU and 1/2 FDP
-forearm pronation
129
What does the median nerve do as a sensory nerve to the anterior forearm compartment?
sensory supply to:
-3 1/2 digits
-tip of index finger
130
What are common etiologies of a median nerve lesion in the elbow region?
-supracondylar fracture/elbow dislocation
-supracondylar process
-tight bicipital aponeurosis
-pronator teres m
131
If you have a median nerve lesion in the elbow region, where will you have motor and sensory deficits?
below the elbow
132
What are the clinical presentation motor deficits shown in the median nerve lesion of the elbow region?
-mean fist "hand of benediction" : still have flexion of digits 4 and 5
-"Ape's Hand" thenar eminence wasting : can't oppose thumb
133
What is the passage of the ulnar nerve?
-passes posteriorly to medial epicondyle
-enters forearm by passing between heads of FCU, giving them branches
-passes inferiorly between FCU and FDP, supplying the ulnar part of the muscle that sends tendons to digits 4 and 5
134
The ulnar nerve becomes ______ at the wrist, running on the medial side of the ulnar artery and lateral side of the FCU tendon
superficial
135
The ulnar nerve emerges from beneath the FCU tendon, proximal to the wrist and passes superficial to the flexor retinaculum to enter the hand, where it supplies what?
the skin on the medial side of the hand
136
What supplies all the sensory in the hand that the median nerve does not?
the ulnar nerve
137
If you have an ulnar nerve injury, it usually occurs in 1 of 4 places, what are those places?
1. posterior to medial epicondyle of humerus
2. cubital tunnel (formed by tendinous arch connecting the humerus and ulnar heads of the FCU)
3. at the wrist
4. in the hand
138
What is the most common place of injury of the ulnar nerve?
posterior to the medial epicondyle
139
What could ulnar nerve injury occurring at the elbow, wrist, or hand result in?
extensive motor and sensory loss to the hand
140
If you have an ulnar nerve injury shown in a posterior medial epicondyle clinical presentation, what actions can't you do?
can't move digits 4 and 5
141
What is the course of the radial nerve?
-leaves posterior compartment of the arm to cross the anterior aspect of the lateral epicondyle
-in the cubital region, the radial nerve divides into the deep and superficial branches
142
What branch of the radial nerve arises anterior to the lateral epicondyle and pierces the supinator?
deep branch of the radial nerve
143
What does the deep branch of the radial nerve continue as?
posterior interosseous nerve
144
What is the course of the deep branch of the radial nerve?
-winds around lateral aspect of the neck of the radius
-enters posterior compartment of the forearm
-continues as the posterior interosseous nerve
145
What branch of the radial nerve emerges in the distal part of the forearm and crosses the roof of the anatomical snuff box?
superficial branch of the radial nerve
146
What is the superficial branch of the radial nerve distributed to?
skin on dorsum of hand and to a number of joints in the hand
147
What are the clinical presentations to a radial nerve lesion in the forearm?
-wrist drop (unable to extend wrist/fingers; loss of all MP joints)
-no power grip
148
Where does the brachial artery end?
distal part of cubital fossa
149
What does the brachial artery divide into?
ulnar and radial artery
150
What travels through the cubital fossa, descends between the FCU and FDP muscles, and terminates in the hand?
Ulnar artery
151
What does the ulnar artery terminate in the hand as?
deep and superficial ulnar palmar arches
152
What does the ulnar artery give rise to?
1. superior ulnar recurrent artery
2. inferior ulnar recurrent artery
3. common interosseous artery
153
What artery courses in a superior direction anterior to the medial epicondyle and forms an anastomosis with the inferior ulnar collateral artery?
superior ulnar recurrent artery
154
What artery courses in a superior direction posterior to the medial epicondyle and forms an anastomosis with the superior ulnar collateral artery?
inferior ulnar recurrent artery
155
What artery courses toward the interosseous membrane and bifurcates into the anterior and posterior interosseous branches?
common interosseous artery
156
What does the common interosseous artery bifurcate into?
1. anterior interosseous artery
2. posterior interosseous artery
157
What travels along the anterior surface of the interosseous membrane, pierces the membrane, and supplies the deep extensor muscles?
anterior interosseous artery
158
What travels along the posterior surface of the interosseous membrane and supplies the superficial extensors and forms and anastomosis with the recurrent interosseous artery vascular network of the elbow?
posterior interosseous artery
159
What travels in a superior direction, posterior to the elbow complex, and forms and anastomosis with the middle collateral artery?
recurrent interosseous artery
160
What does the ulnar artery course with?
ulnar nerve
161
What travels through the cubital fossa along the lateral side of the forearm, deep to the brachioradialis along the FPL muscle?
radial artery
162
What is often felt on the lateral, palmar surface of the wrist?
pulse of the radial artery
163
The radial artery terminates in the hand as what?
the deep and superficial radial palmar arches
164
The radial artery gives rise to what?
radial recurrent artery
165
What courses anteriorly to the lateral epicondyle of the humerus to anastomose with the radial collateral artery?
radial recurrent artery
