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Thursday, October 09, 2008

Which is not involved in Low Radial Nerve Palsy

Question 11
Which is not involved in Low Radial Nerve Palsy
a)      Brachoradialis
b)      Loss of Nerve Supply to Extensor Carpi Radialis Brevis
c)      Loss of Nerve Extensor pollicis brevis.
d)      Loss of Sensation over first dorsal web spave
Answer
A)    Brachoradialis
Reference
Snell's,6th,Pg-493,
AKDutta,Pg-66
BDC Vol 1 Page 90
Gray's Anatomy 38th Edition Page 1274
Quality
Reader
Status
Repeat
QTDF
All books
Discussion
BDC describe the branches of Radial Nerve only under the following headings
  • Before Spiral Groove
    • Long Head of Triceps
    • Medial Head of Triceps
  • In Spiral Groove
    • Long Head of Triceps
    • Lateral Head of Triceps
    • Medial Head of Triceps
    • Ancomeus
  • After Spiral Groove
    • Brachialis
    • Brachoradialis
    • Extensor Carpi Radialis
Gray describes the muscular branches as below
These supply the triceps, anconeus, brachioradialis, extensor carpi radialis longus and brachialis in medial, posterior and lateral groups.
  • Medial muscular branches
    • Arise from the radial nerve on the medial side of the arm.
    • They supply the
      • Medial head of Triceps -the branch to the medial being a long, slender filament which, lying close to the ulnar nerve as far as the distal third of the arm, is often termed the ulnar collateral nerve.
      • Long heads of the triceps,
  • A large posterior muscular branch
    • Arises from the nerve as it lies in the humeral groove.
    • It divides to supply the
      • Medial and
      • Lateral heads of the triceps and the
      • Anconeus, that for the latter being a long nerve which descends in the medial head of the triceps and partially supplies it; it is accompanied by the middle collateral branch of the arteria profunda brachii and passes behind the elbow joint to end in the anconeus.
  • Lateral muscular branches
    • Arise in front of the lateral intermuscular septum;
    • Supply the
      • Lateral part of the brachialis,
      • Brachioradialis and
      • Extensor carpi radialis longus.
Explanation
Lesions of Radial Nerve
At Axilla
Loss of Elbow Extension
Loss of Sensation in the lateral and posterior Part of Arm
Loss of Wrist Extension - Wrist Drop
Loss of Thumb Extension - Thumb drop
Loss of Finger Extension - Finger drop
Loss of Sensation in the first dorsal web space
At the lower end of Spiral Groove
Loss of Wrist Extension - Wrist Drop
Loss of Thumb Extension - Thumb drop
Loss of Finger Extension - Finger drop
Loss of Sensation in the first dorsal web space
Question 11
Which is not involved in Low Radial Nerve Palsy
a)      Brachoradialis
b)      Loss of Nerve Supply to Extensor Carpi Radialis Brevis
c)      Loss of Nerve Extensor pollicis brevis.
d)      Loss of Sensation over first dorsal web spave
Answer
A)    Brachoradialis
Reference
Snell's,6th,Pg-493,
AKDutta,Pg-66
BDC Vol 1 Page 90
Gray's Anatomy 38th Edition Page 1274
Quality
Reader
Status
Repeat
QTDF
All books
Discussion
BDC describe the branches of Radial Nerve only under the following headings
  • Before Spiral Groove
    • Long Head of Triceps
    • Medial Head of Triceps
  • In Spiral Groove
    • Long Head of Triceps
    • Lateral Head of Triceps
    • Medial Head of Triceps
    • Ancomeus
  • After Spiral Groove
    • Brachialis
    • Brachoradialis
    • Extensor Carpi Radialis
Gray describes the muscular branches as below
These supply the triceps, anconeus, brachioradialis, extensor carpi radialis longus and brachialis in medial, posterior and lateral groups.
  • Medial muscular branches
    • Arise from the radial nerve on the medial side of the arm.
    • They supply the
      • Medial head of Triceps -the branch to the medial being a long, slender filament which, lying close to the ulnar nerve as far as the distal third of the arm, is often termed the ulnar collateral nerve.
      • Long heads of the triceps,
  • A large posterior muscular branch
    • Arises from the nerve as it lies in the humeral groove.
    • It divides to supply the
      • Medial and
      • Lateral heads of the triceps and the
      • Anconeus, that for the latter being a long nerve which descends in the medial head of the triceps and partially supplies it; it is accompanied by the middle collateral branch of the arteria profunda brachii and passes behind the elbow joint to end in the anconeus.
  • Lateral muscular branches
    • Arise in front of the lateral intermuscular septum;
    • Supply the
      • Lateral part of the brachialis,
      • Brachioradialis and
      • Extensor carpi radialis longus.
Explanation
Lesions of Radial Nerve
At Axilla
Loss of Elbow Extension
Loss of Sensation in the lateral and posterior Part of Arm
Loss of Wrist Extension - Wrist Drop
Loss of Thumb Extension - Thumb drop
Loss of Finger Extension - Finger drop
Loss of Sensation in the first dorsal web space
At the lower end of Spiral Groove
Loss of Wrist Extension - Wrist Drop
Loss of Thumb Extension - Thumb drop
Loss of Finger Extension - Finger drop
Loss of Sensation in the first dorsal web space
Question 11
Which is not involved in Low Radial Nerve Palsy
a)      Brachoradialis
b)      Loss of Nerve Supply to Extensor Carpi Radialis Brevis
c)      Loss of Nerve Extensor pollicis brevis.
d)      Loss of Sensation over first dorsal web spave
Answer
A)    Brachoradialis
Reference
Snell's,6th,Pg-493,
AKDutta,Pg-66
BDC Vol 1 Page 90
Gray's Anatomy 38th Edition Page 1274
Quality
Reader
Status
Repeat
QTDF
All books
Discussion
BDC describe the branches of Radial Nerve only under the following headings
  • Before Spiral Groove
    • Long Head of Triceps
    • Medial Head of Triceps
  • In Spiral Groove
    • Long Head of Triceps
    • Lateral Head of Triceps
    • Medial Head of Triceps
    • Ancomeus
  • After Spiral Groove
    • Brachialis
    • Brachoradialis
    • Extensor Carpi Radialis
Gray describes the muscular branches as below
These supply the triceps, anconeus, brachioradialis, extensor carpi radialis longus and brachialis in medial, posterior and lateral groups.
  • Medial muscular branches
    • Arise from the radial nerve on the medial side of the arm.
    • They supply the
      • Medial head of Triceps -the branch to the medial being a long, slender filament which, lying close to the ulnar nerve as far as the distal third of the arm, is often termed the ulnar collateral nerve.
      • Long heads of the triceps,
  • A large posterior muscular branch
    • Arises from the nerve as it lies in the humeral groove.
    • It divides to supply the
      • Medial and
      • Lateral heads of the triceps and the
      • Anconeus, that for the latter being a long nerve which descends in the medial head of the triceps and partially supplies it; it is accompanied by the middle collateral branch of the arteria profunda brachii and passes behind the elbow joint to end in the anconeus.
  • Lateral muscular branches
    • Arise in front of the lateral intermuscular septum;
    • Supply the
      • Lateral part of the brachialis,
      • Brachioradialis and
      • Extensor carpi radialis longus.
Explanation
Lesions of Radial Nerve
At Axilla
Loss of Elbow Extension
Loss of Sensation in the lateral and posterior Part of Arm
Loss of Wrist Extension - Wrist Drop
Loss of Thumb Extension - Thumb drop
Loss of Finger Extension - Finger drop
Loss of Sensation in the first dorsal web space
At the lower end of Spiral Groove
Loss of Wrist Extension - Wrist Drop
Loss of Thumb Extension - Thumb drop
Loss of Finger Extension - Finger drop
Loss of Sensation in the first dorsal web space
After Spiral Groove Before Piercing the Supinator and before the origin of sensory branch
Diminished Wrist Extension - Wrist Deviates radially when extended
Loss of Thumb Extension - Thumb drop
Loss of Finger Extension - Finger drop
Loss of Sensation in the first dorsal web space
After Piercing the Supinator (Posterior Interosseus Nerve)
Loss of Thumb Extension - Thumb drop
Loss of Finger Extension - Finger drop
Superficial Branch
It lies superficially and relatively unprotected overlying the lateral aspect of the radius, where it is easily compressed by tight bracelets, watch straps and handcuffs, Called as Cheralgia Paraesthetica (compare with Meralgia Paraesthetica)
Loss of Sensation in the first dorsal web space
If the lesion is proximal in this nerve, sensation may be impaired over a variable area of skin over the lateral side of the dorsum of the hand.
Comments
Radial Nerve Extends, Flexes (by supplying Bracho Radialis, which is morphologically a extensor and functionally a flexor and Brachialis which has a dual nerve Supply along with Musculocutaneous Nerve) and also Supinatesbut it does not supply pronation
Tips
Other nerve Injuries
Lesions of the Median Nerve
Median nerve lesions occur at two sites,
In the forearm (Pronator Syndrome) and
At the wrist. (Carpal Tunnel Syndrome)

Pronator Syndrome
This is an uncommon entrapment neuropathy of the median nerve
Sites
The nerve may be involved at any of these sites.
1. As it passes alongside the fibrous band connecting the biceps tendon to the forearm fascia,
2. As it passes down between the two heads of pronator teres
3. As it passes through a fibrous arch formed by flexor digitorum superficialis.
Symtoms and Signs
Motor
There is weakness of all the muscles innervated by the median nerve, including abductor pollicis brevis and the long finger flexors.
Sensory
There is also sensory impairment on the palm of the hand(spared in the carpal tunnel syndrome because the palmar cutaneous branch
of the median nerve arises above the carpal tunnel and lies superficial to it.)
Anterior interosseous nerve palsy
The anterior interosseous nerve usually arises from the median nerve proximal to the site of compression in the pronator syndrome; it may be affected with the median nerve or by itself.
Causes
1. Due to external pressure(a form of Saturday night palsy),
2. Sometimes by tight grip in association with pronation without obvious cause.
3. May be a manifestation of neuralgic amyotrophy and tends to resolve spontaneously over several months.
Motor:
An anterior interosseous nerve palsy causes weakness of pinch grip due to involvement of flexor pollicis longus and flexor digitorum profundus to the index finger.
Please note that
Innervation of flexor digitorum profundus to the middle finger is rather variable,(also by Ulnar Nerve) therefore this muscle may or may not be weak.
The branches to these three muscles (FDP,FPL,PQ)may arise separately from the median nerve, so that isolated weakness of the terminal phalanx to the thumb or index finger may occur. The pronator quadratus is also involved but is not clinically significant.
Carpal Tunnel Syndrome
This is the most common entrapment mononeuropathy caused by the compression of the median nerve as it passes through the fibro-osseous tunnel beneath the flexor retinaculum.
Causes
The carpal tunnel may be narrowed by
1. Arthritic changes in the wrist joint, particularly rheumatoid arthritis;
2. Soft tissue thickening as may occur in myxoedema and acromegaly;
3. Edema and obesity including pregnancy.
Pathology
Normally the nerve slides smoothly in and out of the carpal tunnel with flexion and extension of the wrist; when the nerve is compressed there is an additional damage to the nerve with flexion and extension.
The dominant hand is usually affected first, probably because this hand is used more frequently and more vigorously.
Motor
There is wasting and weakness of abductor pollicis brevis
Sensory
Impairment of sensation in the
1. Thumb,
2. Index Finger,
3. Middle Fingerand
4. Median side of the Ring finger,
(the palmar branch of the median nerve is spared since it does not pass through the carpal tunnel.)
Lesions of the Ulnar Nerve
Ulnar nerve lesions occur at four sites,
Behind the medial epicondyle,
In the cubital tunnel,
At the wrist and
In the hand.

At the Elbow
The ulnar nerve is in a vulnerable position as it lies between the median epicondyle and the olecranon: it lies on bone covered only by a thin layer of skin.
It is easily damaged if the ulnar groove is shallow and the nerve may become more prominent than the medial epicondyle or the olecranon when the elbow is fully flexed.
Sometimes the nerve may override the medial epicondyle in full flexion. Loss of the ulnar groove may be associated with arthritis of the elbow joint, often due to an old fracture, in which case there may be incomplete extension of the elbow with a wide carrying angle.
The nerve is easily palpable and is often thickened.
Motor
There is usually weakness of flexor digitorum profundus to the ring and little fingers, and if these muscles are involved the lesion must be at the elbow.
Sensory
Sensation Impaired in
Palmar Aspect
Medial palmar skin,
Medial side of the little finger,
Adjoining sides of little and ring fingers
Dorsum
Medial side of the little finger,
Adjacent sides of the little and ring,
Adjoining sides of the ring and middle finger
Cubital Tunnel Syndrome
This is an entrapment neuropathy of the ulnar nerve in the tunnel formed by the tendinous arch connecting the two heads of flexor carpi ulnaris at their humeral and ulnar attachments. The clinical features are precisely the same as a lesion in the ulnar groove and again, involvement of flexor digitorum profundus to the ring and little fingers is variable.
Lesions at these two sites cannot be reliably distinguished neurophysiologically, but in the cubital tunnel syndrome the elbow joint is usually normal: elbow movements are full with a normal carrying angle; the ulnar nerve feels normal in the ulnar groove; it does not sublux; nor does it become superficial on elbow flexion.
At the Wrist
Site
The ulnar nerve may be compressed in Guyon's canal by a ganglion.
Motor
All the small hand muscles innervated by the ulnar nerve are involved.
Preservation of flexor digitorum profundus to the ring and little fingers
The dorsal cutaneous branch and the palmar branch of the ulnar nerve are both spared since the lesion is distal to their origin from the main trunk of the ulnar nerve in midforearm.
In the Hand
The deep motor branch of the ulnar nerve may be compressed against the pisiform and hamate bones when the hand is used as a mallet, or if a vibrating tool or motorcycle handlebar is held in such a way that the hypothenar eminence is off the edge of the handle. The sensory branches are always spared and involvement of the hypothenar muscles is variable depending on the level at which branches to these muscles arise.

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