Radial Nerve Flashcards
Radial Nerve Formed in the
Axilla
Branches of Radial Nerve in the Axilla
Branches to Medial and Long Head of Triceps
In the Axilla
From Axilla, Radial nerve enters Posterior compartment of Arm by passing through
Lower Triangular Interval
In the Posterior Compartment of Arm, Radial nerve get accompanied by
Profunda brachii artery
In the Posterior Compartment of Arm Radial nerve passes through
Spiral Groove
Branches of Radial nerve in the posterior compartment of arm
Branches to Medial and Lateral head of Triceps
Branch to medial head also supplies Anconeus muscle
Injury at lower aspect of Spiral Groove;
Intact muscles -
Intact movements -
Intact muscles -
- Triceps muscle
- Anconeus muscle
Intact movements - extention of elbow
Action of Triceps
Triceps attached to Olecranon process of Ulna -
Extension of Elbow (assisted by Anconeus muscle)
Radial nerve in the lower part of arm present between
Brachialis and Brachioradialis
Radial Nerve Branches in Elbow
Motor Branches to -
Brachialis (hybrid muscle)
Brachioradialis
ECRL
Radial nerve below the Elbow Joint divides into
Superficial (sensory) Branch
Deep (motor) Branch
Deep (motor) branch of Radial Nerve is also known as
Posterior interosseous nerve
Posterior interosseous nerve reaches posterior compartment of forearm after piercing the
Supinator muscle
Posterior interosseous nerve supplies all the muscles of posterior compartment of forearm
Except;
Anconeus
Brachioradialis
ECRL - extensor carpi radialis longus
Low radial nerve palsy means
Injury to radial nerve -
Below the elbow before its division into superficial and deep
Low radial nerve palsy;
Intact muscles -
Intact movement -
Low radial nerve injury;
Intact muscles -
- triceps
- anconeus
- brachialis
- brachioradialis
- ECRL
Intact movement -
- extension of elbow
- extension of wrist
Why wrist drop is not seen in Low Radial Nerve Palsy
Because ECRL is intact
It supplied by Radial Nerve above the Elbow Joint
Function lost in Low Radial Nerve Palsy;
Loss of Extension of MetacarpoPhangeal Joint ~ deep branch affected
Sensory Loss ~ superficial branch affected
Posterior interosseous nerve palsy;
Normal action and Muscles intact
Extension of Elbow - Normal
(Triceps, Anconeus- Intact)
Extension of wrist - Normal
(ECRL-Intact)
Wrist drop not seen
No sensory loss
Posterior interosseous nerve palsy;
Lost function -
Extension of MCP Joint - Lost
Finger drop
(wrist drop not seen)
(no sensory loss)
Superficial branch of radial nerve is passing under the cover of
Brachioradialis muscle
Compression of Superficial branch of radial nerve during its course under brachioradialis results into
Wartenberg’s Syndrome
C/F of Wartenberg’s Syndrome
Loss of sensation in lateral 3 1/2 digits
Difference between Wartenberg Syndrome & Wartenberg Sign;
Wartenberg sign;
The little finger - unable to adduct towards ring finger
Due to Ulnar nerve injury - affects Palmar interosseous interossei
Extensor tendons reach upto Distal Phalanx by
DDE - Dorsal Digital Expansion
Dorsal Digital Expansion Trifurcates into
One medial band
Two lateral bands
One medial band inserted to
Action -
One mecial band,
Crossing Interphalangeal joint posteriorly and inserted to Middle Phalanx
Action - Extension of Proximal IP Joint
Two lateral bands inserted to
Action -
Two lateral bands unite and cross the Distal IP - Joint Posteriorly and inserted to distal phalanx
Action - Extension of Distal IP Joint
Tendons attached to DDE
Lumbricals
Palmar interossei
Dorsal interossei
Are Wing tendons - attaches DDE like a wing
Feature of Mallet Finger and is due to
Flexion of Distal IP - Joint;
Due to Lateral band avulsion results in Mallet Finger
Distal IP-Joint Flexion + Hyperextended Proximal IP-Joint
Is _________
Swan - Neck Deformity
Swan - Neck Deformity seen in
In Rheumatoid conditions
Difference between Mallet Finger and Swan-Neck Deformity
In Mallet Finger → Only Distal IP-Joint Flexion
In Swan-Neck Deformity →
Distal IP-Joint Flexion + Hyperextended Proximal IP-Joint
What is Boutonniere Deformity?
Flexion of Proximal IP-Joint
Due to Avulsion of Medial Band
What is Extensor Retinaculum?
The extensor tendons enter the dorsum through Externsor retinaculum
Has 6 Compartments from Lateral to Medial
Muscles (tendons) passing through 1st Compartment
Abductor pollicis longus
Extensor pollicis brevis
De Quervain’s Synovitis is due to
Involvement of
Abductor pollicis longus and Extensor pollicis brevis
Finkelstein Test Positive
Finkelstein Test is used for;
To check De Quervain’s Synovitis
Ask Patient to;
- To make Fist
- To give Ulnar Deviation
If patient has severe pain over the lower end of Radius, then test is Positive
Space between 1st and 3rd Compartment;
Anatomical Snuff Box
Boundaries of Anatomical Snuff Box;
Medial -
Lateral -
Medial - 3rd compartment
Lateral - 1st Compartment
Floor of Anatomical Snuff Box
Radius, Scaphoid, Trapezium, Base of 1st Metacarpal bone, ECRL, ECRB
Roof of Anatomical Snuff Box,
Skin,
Superficial fascia,
Cephalic vein,
Superficial branch of radial nerve
Content of Anatomical Snuff Box;
Radial Artery
Muscle(Tendon) passing through 2nd Compartment;
ECRL
ECRB
Muscle(Tendon) passing through 3rd Compartment;
Extensor pollicis longus
Structures passing through 4th Compartment;
Extensor digitorum
Extensor indicis
Posterior interosseous nerve
Anterior interosseous artery
Structures passing through 5th Compartment;
Extensor digiti minimi
Structures passing through 6th Compartment;
Extensor carpi ulnaris
Intersection Syndrome is due to
Crossing of 1st and 2nd Compartments → 4-6 cm proximal to wrist joint
This leads to Friction of ECRL, ECRB
