Ulnar Neuropathy at the Elbow and Wrist Flashcards
Ulnar neuropathy at the elbow is the ___ most common focal neuropathy of the UE.
2nd
median nerve is most common (carpal tunnel)
The most common site of focal ulnar entrapment or compression is at the ____, followed by the ____.
elbow
wrist
What is the etiology of ulnar nerve lesions at the elbow?
- acute trauma (distal humeral fracture, nerve lacerations, perioperative injury)
- nerve compression
- traction
- friction from leaning on the elbow or from prolonged elbow flexion
- subluxation of the ulnar nerve laterally over the medial epicondyle
What are some intrinsic causes of ulnar neuropathy at the elbow?
- osteophytes
- arthritis
- synovitis
- anomalous muscles or fibrous bands
- ganglia
- other mass lesions
What are the 2 branches off of the distal trunk of the ulnar nerve that can be injured around the wrist?
- superficial sensory branch
- deep motor branch
What are the extrinsic causes of ulnar neuropathy at the wrist?
- bone fractures (eg, hook of hamate)
- lacerations
- direct, often repetitive trauma, such as repetitive use of tools in the workplace or propulsion of a manual wheelchair
_____ palsy is common in bicyclists
Handlebar
What are the intrinsic causes of ulnar neuropathy at the wrist?
- ganglia arising from the wrist joint
- intraneural ganglia
Many cases of ulnar neuropathy are ______.
idiopathic
Localization of entrapment is dependent upon what?
- the clinical scenario
- the presence of proximal pain or a mass pain
- the involvement of other nerves (median and radial)
What are 2 places distal to the elbow in which the ulnar nerve can become entrapped?
- within the body of flexor carpi ulnaris muscle
- where it exits through the deep flexor-pronator aponeurosis
The annual incidence of ulnar neuropathy is ___ per 100,000 people
24.7
The prevalence of ulnar neuropathy in ____ is double that in _____.
men
women
Ulnar neuropathy is positively associated with what?
smoking
Are gender, body mass index, alcohol consumption, elbow trauma, diabetes, and hypertension risk factors for ulnar neuropathy?
no
What are the clinical features of ulnar neuropathy at the elbow?
- numbness and tingling in the fourth and fifth digits
- medial elbow and forearm pain
- nocturnal numbness and paresthesia
- worsening of symptoms with elbow and/or repeated wrist flexion
What are the clinical features of ulnar neuropathy at the wrist?
- hand weakness and atrophy
- loss of dexterity
- variable sensory involvement
What characteristic of ulnar neuropathy is more pronounced with lesions at the wrist than at the elbow?
clawing of digits 4 and 5
Injury to the terminal branches of the ulnar nerve at the wrist can occur at 4 sites. What are they?
- the main trunk of the nerve proximal to or within Guyon’s canal
- the deep terminal motor branch of the ulnar nerve proximal to the branches supplying the hypothenar muscles
- the deep motor branch distal to the hypothenar muscles
- the superficial terminal branch supplying the superficial sensory branches
What are 5 provocative measures for ulnar neuropathy?
- Tinel’s test
- elbow flexion
- pressure
- combined elbow flexion with pressure
- palpation
How is Tinel’s test performed?
Firm percussion over the ulnar nerve in the ulnar groove and a bit further distally over the cubital tunnel
What 2 imaging techniques are useful in helping diagnose ulnar neuropathy?
Ultrasound and MRI
What are 2 differential diagnoses for UNE and UNW?
Proximal lesions of the C8 or T1 roots and the lower trunk/medial cord of the brachial plexus
When is conservative treatment suggested over surgery for ulnar neuropathy?
For patients with mild to moderate UNE or UNW, characterized by intermittent or persistent sensory loss and weakness without wasting, and no causative structural lesion. Also in those who have moderate to severe but stable ulnar neuropathy of less than six months duration.
To prevent excessive or prolonged elbow flexion, splints that limit flexion to __ to __ degrees can be used at night
45-90
What are the 2 main categories of operation performed for UNE?
- in situ decompression of the ulnar nerve
- ulnar transposition
What surgery approach is recommended for UNW?
decompression of the ulnar tunnel (Guyon’s canal)
