Peripheral nerve injuries/palsies Flashcards
What is Erb-Duchenne paralysis?
Damage to C5,6 roots, characterized by winged scapula.
May be caused by a breech presentation.
What is Klumpke’s paralysis?
Damage to T1, resulting in loss of intrinsic hand muscles due to traction.
What is carpal tunnel syndrome?
Carpal tunnel syndrome is caused by compression of the median nerve in the carpal tunnel.
What are the common symptoms of carpal tunnel syndrome?
Pain and pins and needles in the thumb, index, and middle finger. Unusually, the symptoms may ‘ascend’ proximally. Patients often shake their hand to obtain relief, classically at night.
What are the examination findings in carpal tunnel syndrome?
Weakness of thumb abduction (abductor pollicis brevis), wasting of the thenar eminence (NOT hypothenar), Tinel’s sign (tapping causes paraesthesia), and Phalen’s sign (flexion of wrist causes symptoms).
What are the causes of carpal tunnel syndrome?
Causes include idiopathic reasons, pregnancy, oedema (e.g., heart failure), lunate fracture, and rheumatoid arthritis.
What are the electrophysiological findings in carpal tunnel syndrome?
Motor and sensory prolongation of the action potential.
What is the recommended treatment for mild-moderate carpal tunnel syndrome?
NICE recommends a 6-week trial of conservative treatments.
What conservative treatments are suggested for carpal tunnel syndrome?
Corticosteroid injection and wrist splints at night, particularly useful if transient factors are present (e.g., pregnancy).
What is the surgical treatment for severe carpal tunnel syndrome?
Surgical decompression (flexor retinaculum division) if there are severe symptoms or if symptoms persist with conservative management.
What are the two nerves that the sciatic nerve divides into?
The sciatic nerve divides into the tibial and common peroneal nerves.
Where does injury to the common peroneal nerve often occur?
Injury often occurs at the neck of the fibula.
What is the most characteristic feature of a common peroneal nerve lesion?
The most characteristic feature is foot drop.
What are the other features of a common peroneal nerve lesion?
Other features include:
- weakness of foot dorsiflexion
- weakness of foot eversion
- weakness of extensor hallucis longus
- sensory loss over the dorsum of the foot and the lower lateral part of the leg
- wasting of the anterior tibial and peroneal muscles.
What is the radial nerve a continuation of?
The posterior cord of the brachial plexus (root values C5 to T1).
Where does the radial nerve lie in the axilla?
It lies posterior to the axillary artery on subscapularis, latissimus dorsi, and teres major.
How does the radial nerve enter the arm?
It enters between the brachial artery and the long head of triceps (medial to humerus).
What path does the radial nerve take around the humerus?
It spirals around the posterior surface of the humerus in the groove for the radial nerve.
What happens at the distal third of the lateral border of the humerus?
The radial nerve pierces the intermuscular septum and descends in front of the lateral epicondyle.
Where does the radial nerve divide into branches?
At the lateral epicondyle, it lies deeply between brachialis and brachioradialis where it divides into a superficial and deep terminal branch.
What does the deep branch of the radial nerve become?
It crosses the supinator to become the posterior interosseous nerve.
What muscles are innervated by the radial nerve (motor)?
Triceps, Anconeus, Brachioradialis, Extensor carpi radialis.
What muscles are innervated by the posterior interosseous branch?
Supinator, Extensor carpi ulnaris, Extensor digitorum, Extensor indicis, Extensor digiti minimi, Extensor pollicis longus and brevis, Abductor pollicis longus.
What sensory area does the radial nerve supply?
The area of skin supplying the proximal phalanges on the dorsal aspect of the hand (excluding the little finger and part of the ring finger).
What is the effect of paralysis of the long head of triceps?
Minor effects on shoulder stability in abduction.
What is the effect of paralysis of the triceps?
Loss of elbow extension.
What muscles are affected by radial nerve paralysis in the forearm?
Supinator, Brachioradialis, Extensor carpi radialis longus and brevis.
What is the effect of paralysis on forearm muscles?
Weakening of supination of prone hand and elbow flexion in mid prone position.
What are the patterns of damage associated with radial nerve injury?
Wrist drop and sensory loss to a small area between the dorsal aspect of the 1st and 2nd metacarpals.
What happens with axillary damage to the radial nerve?
Paralysis of triceps and the same effects as above.
What is thoracic outlet syndrome (TOS)?
TOS is a disorder involving compression of the brachial plexus, subclavian artery, or vein at the thoracic outlet. It can be neurogenic or vascular; neurogenic cases account for 90%.
What is the epidemiology of thoracic outlet syndrome?
The epidemiology of TOS is not well documented due to a lack of widely agreed diagnostic criteria. Patients are typically young, thin women with long necks and drooping shoulders, with peak onset in the 4th decade.
What are the aetiological factors for thoracic outlet syndrome?
TOS develops from neck trauma in individuals with anatomical predispositions. This trauma can be a single acute incident or repeated stresses, with anatomical anomalies in soft tissue (70%) or osseous structures (30%).
What is a well-known osseous anomaly associated with TOS?
The presence of a cervical rib is a well-known osseous anomaly associated with TOS.
What are examples of soft tissue causes of TOS?
Examples include scalene muscle hypertrophy and anomalous bands.
What are the clinical presentations of neurogenic TOS?
Clinical presentations include painless muscle wasting of hand muscles, hand weakness, and sensory symptoms like numbness and tingling. If autonomic nerves are involved, symptoms may include cold hands, blanching, or swelling.
What are the clinical presentations of vascular TOS?
Subclavian vein compression leads to painful diffuse arm swelling with distended veins, while subclavian artery compression causes painful arm claudication and, in severe cases, ulceration and gangrene.
What examinations are necessary for TOS?
Neurological and musculoskeletal examinations are necessary. Stress manoeuvres like Adson’s manoeuvre may be attempted, though they have limited utility.
What investigations are used for TOS?
Investigations include chest and cervical spine plain radiographs to check for osseous abnormalities, CT or MRI to rule out cervical root lesions, and venography or angiography for vascular TOS.
What is the first-line management for neurogenic TOS?
Conservative management with education, rehabilitation, physiotherapy, or taping is typically the first-line management.
When is surgical decompression warranted in TOS?
Surgical decompression is warranted when conservative management has failed, especially if there is a physical anomaly. Early intervention may prevent brachial plexus degeneration.
What treatment may be preferred for vascular TOS?
Surgical treatment may be preferred for vascular TOS.
What other therapies are being investigated for TOS?
Other therapies being investigated include botox injection.
What is the origin of the ulnar nerve?
The ulnar nerve arises from the medial cord of the brachial plexus (C8, T1).
What muscles does the ulnar nerve provide motor innervation to?
The ulnar nerve provides motor innervation to the medial two lumbricals, adductor pollicis, interossei, and the hypothenar muscles: abductor digiti minimi, flexor digiti minimi, and flexor carpi ulnaris.
What is the sensory distribution of the ulnar nerve?
The ulnar nerve is sensory to the medial 1 1/2 fingers (palmar and dorsal aspects).
Describe the path of the ulnar nerve.
The ulnar nerve travels through the posteromedial aspect of the upper arm to the flexor compartment of the forearm, then enters the palm of the hand via Guyon’s canal, superficial to the flexor retinaculum and lateral to the pisiform bone.
What does the muscular branch of the ulnar nerve supply?
The muscular branch supplies the flexor carpi ulnaris and the medial half of the flexor digitorum profundus.
What does the palmar cutaneous branch of the ulnar nerve supply?
The palmar cutaneous branch supplies the skin on the medial part of the palm.
What does the dorsal cutaneous branch of the ulnar nerve supply?
The dorsal cutaneous branch supplies the dorsal surface of the medial part of the hand.
What does the superficial branch of the ulnar nerve supply?
The superficial branch provides cutaneous fibers to the anterior surfaces of the medial one and one-half digits.
What does the deep branch of the ulnar nerve supply?
The deep branch supplies the hypothenar muscles, all the interosseous muscles, the third and fourth lumbricals, the adductor pollicis, and the medial head of the flexor pollicis brevis.
What are the effects of ulnar nerve damage at the wrist?
‘Claw hand’ occurs, characterized by hyperextension of the metacarpophalangeal joints and flexion at the distal and proximal interphalangeal joints of the 4th and 5th digits, along with wasting and paralysis of intrinsic hand muscles (except lateral two lumbricals), wasting and paralysis of hypothenar muscles, and sensory loss to the medial 1 1/2 fingers (palmar and dorsal aspects).
What are the effects of ulnar nerve damage at the elbow?
The effects are similar to those at the wrist; however, there is an ulnar paradox where clawing is more severe in distal lesions, along with radial deviation of the wrist.
Radial Nerve Position
The cutaneous sensation of the upper limb- illustrating the contribution of the radial nerve
Radial nerve - regions innervated
Muscular innervation and effect of denervation - shoulder, arm, forearm - muscle affected& effect on paralysis
