Upper limb injuries are common, and orthopedic surgeons frequently treat these injuries. Knowledge of upper limb anatomy and orthopedics is essential to diagnose and manage such injuries.
In this blog we’ll cover sensory distribution of upper limb, seddon classification for nerve injuries, brachial plexus palsy, and compression neuropathy.
SENSORY DISTRIBUTION OF UPPER LIMB
Tip of index finger - Median nerve
Tip of little finger - Ulnar nerve
Over dorsum of hand, 1st web space -Radial nerve
SEDDON CLASSIFICATION FOR NERVE INJURIES
Neuropraxia
Physiological block in nerve conduction
100% recovery
One moment
Tinel sign negative
Axonotmesis
Damage to axon sheath
Recovery - Motor march (proximal to distal)
Tinel sign positive & progressive - marks recovery of nerve at the rate of 1 mm/day
Neurotmesis
Complete nerve transection
Tinel sign positive & static
Does not recover without surgical intervention
AXILLARY NERVE
Damaged by
Shoulder dislocation
Fracture of upper end of humerus
Injection into deltoid muscle
Clinical Features
Regimental badge area (area at upper end of humerus) - sensations are impaired
ULNAR NERVE
Interosseous muscles of hand
Palmar interossei – Adduction (PAD)
Dorsal interossei – Abduction (DAB)
They are supplied by Ulnar nerve
Tests for Ulnar Nerve Injury
Card Test
For Palmar Interossei
Holding card between the fingers (adduction) & trying to pull the card
If they are able to hold it, means palmar interossei is functioning
If not, it means ulnar nerve palsy
Book Test/Froment Sign
Ask the patient to hold book between his thumb & index finger
Adductor pollicis is supplied by ulnar nerve
If they hold the book by flexing thumb (Froment sign)
Flexion is due to flexor pollicis longus- supplied by AIN, branch of Median nerve (spared in ulnar nerve injury)
Wartenberg sign
Abducted 5th finger
Igawa test
Middle finger has only dorsal interossei, can move middle finger to either side (abduction)
MEDIAN NERVE
Tests for median nerve
Pointing index
If you ask the patient to make a fist, the first two fingers do not flex in median nerve palsy.
Index finger is not flexed at PIP & DIP
This is called as pointing index
Also known as Benediction test, Oschner clasp test
Benediction test or Pope's attitude
Oschner clasp test
Pen test
If you keep the pen above the palm and as the patient to touch the pen, it is called as pen test
To check abductor pollicis brevis
Ape thumb deformity
Loss of thenar eminence
Thumb in same plane as palm (Ideally it is anteriorly)
Kiloh-Nevin sign
Check for anterior interosseous nerve (AIN), branch of median nerve
Sign of Appreciation - WOW sign (created by flexion of index finger and thumb)
CLAW HAND
Lumbricals - 4 in no.
Makes a ‘L’ in hand
Medial 2 lumbricals - supplied by Ulnar nerve
Lateral 2 lumbricals - supplied by Median nerve
Action of lumbricals
Flexion of metacarpophalangeal joint
Extension of interphalangeal joint
Paralysis of lumbricals
Causes Claw Hand
Hyperextension of metacarpophalangeal joint
Flexion of interphalangeal joint
Management
Knuckle bender splint used for Ulnar nerve > Median nerve
RADIAL NERVE
Relation with Humerus
Travels along spiral groove
At lower 1/3rd level, it pierces lateral intermuscular septum & comes anteriorly (most common area of involvement)
Important Information
Holstein Lewis sign - Radial nerve injury in lower 1/3rd fracture of shaft of humerus
It divides into -
Posterior interosseous nerve (PIN)
Pure motor nerve
Supplies finger extensors
Injury - only finger drop, no sensory loss
Superficial radial nerve
Supplies dorsum of 1st web space
Clinical features
Wrist drop
Paralysis of ECRL & ECRB
Sensory loss over dorsum of 1st web space
Finger drop
Due to injury to PIN.
No sensory loss
Saturday night palsy/Crutch palsy/Honeymoon palsy
Radial nerve is compressed against bone d/t sustained pressure
Release radial artery palm will turn red if it is patent
Repeat the same process
Now release ulnar artery palm will turn red if it is patent
Practice Questions
Q. Identify the splint?
Cock up splint
Knuckle bender splint
Dynamic finger splint
Sugar tongs
Ans - A
Q.Middle finger extension test is useful for all except?
PIN palsy
Radial tunnel syndrome
Tennis elbow
Multifocal motor neuropathic disorder
Ans - D
Important Information
Middle finger extension test is painful in
* Radial tunnel syndrome * Tennis elbow
Q. A patient can't extend his wrist but he has no sensory loss, after he has met with an accident. Level at which the affected nerve got injured is?
Spiral groove of humerus
Head of radius
Near medial epicondyle
Surgical neck of humerus
Ans – A
Important Information
Head of radius - PIN involvement - only finger drop
Near medial epicondyle - Ulnar nerve
Surgical neck of humerus - Axillary nerve
Previous Year Question
Q.The Nerve related to medial epicondyle is?(FMGE -Dec - 2020)
A. Median Nerve
B. Ulnar nerve
C. AIN
D. PIN
Q.Hyperextension at MCP joint and flexion at IP joint occurs due to involvement of which muscle? (NEET - Jan - 2020)
A. Lumbricals
B. Palmar interossei
C. Dorsal interossei
D. Adductor pollicis
Q. Most specific test for Carpel tunnel syndrome? (AIIMS - June - 2020)
A. Cozen test
B Phalen test
C. Durkan test
D. Tourniquet test
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