Peripheral nerve entrapment syndromes

Question 1

Median Nerve

Answer 1

○ Provides motor and sensory innervation to a portion of the hand.
○ Sensory- Thumb, index, middle, and lateral half of ring finger.
○ Motor- Thumb opposition and thumb abduction.

Question 2

Ulnar Nerve

Answer 2

○ Provides motor and sensory
innervation to a portion of the hand.
Nerves in the Upper Extremities
○ Motor- Flexor carpi ulnaris, flexor
digitorum profundus, opponens
digiti minimi, abductor digiti minimi,
interossei muscles, etc.
○ Sensory- Medial half of the hand,
including small finger and medial
half of the ring finger, both the
palmar and dorsal sides

Question 3

Carpal Tunnel Syndrome

Answer 3

● Compression of the Median Nerve at the wrist is the most common of the
mononeuropathies, with about a 14% lifetime prevalence

Question 4

Carpal tunnel syndrom etiology & epidemiology

Answer 4

● Although it can occur at any age, diagnosis
has a bimodal distribution peak at early
50s and 75-84 years.
● Three times as common in females, and
frequently occurs during pregnancy.
● Can be significantly debilitating, especially
if severe and bilateral.
● Often associated with repetitive
movements or vibrations (occupational).

Question 5

Carpal Tunnel Syndrome pathophysiology

Answer 5

○ Median nerve compression occurs due to
increased pressure within the carpal
tunnel, a passageway for the median nerve
and 9 flexor tendons, covered by the
Transverse Carpal Ligament
○ Tenosynovitis of the flexor tendons
is the most common cause

Question 6

Other causes of compression (carpal tunnel) include

Answer 6

■ Fractures (current or previous)
■ Mass lesions (like a synovial cyst
or tumor)
■ Infection
■ Edema (common in pregnancy)
■ Systemic illness such as
rheumatoid arthritis

Question 7

Carpal Tunnel Syndrome signs and symptoms

Answer 7

○ Paresthesias (often painful) in the
distribution of the median nerve is classic.
○ Can develop weakness of thumb abduction
and thumb opposition.
Carpal Tunnel Syndrome
○ Severe cases can have continual
numbness and/or atrophy of the
thumb musculature.
○ Being woken in the night by painful paresthesias of
the hand is very characteristic.

Question 8

Carpal Tunnel Syndrome diagnosis

Answer 8

○ Tinel’s Sign (firm tapping) may be positive
over the Transverse Carpal Ligament.
Carpal Tunnel Syndrome
○ Phalen’s Maneuver can be positive, with
reproduction of the patient’s symptoms while
holding in wrist flexion.
○ Electrodiagnostic studies (especially the nerve conduction study) are diagnostic and will
grade severity of disease
○ CTS-6 is a valid and reliable diagnostic tool for CTS as well
○ Ultrasound of the Median Nerve with measurement of its
diameter is occasionally performed
○ In uncommon situations, an MRI of the
wrist may be ordered if a mass lesion is
suspected as the cause of the median
nerve compression at the wrist

Question 9

Carpal Tunnel Syndrome management - conservative

Answer 9

○ Conservative measures are focused on reducing,
eliminating, or modifying exacerbating activities.
Carpal Tunnel Syndrome
○ Nocturnal wrist splinting in the neutral position
can be very helpful. Palmar or flexor support is
used. Daytime use may or may not be feasible or
helpful.
○ Local corticosteroid injection into the carpal tunnel may be very beneficial
for patients.

Question 10

Carpal Tunnel Syndrome management - severe

Answer 10

○ If 1-2 months of conservative treatment fails, and symptoms are still significantly bothersome, surgical referral can be made.
○ Significant motor deficit or
NCS/EMG results revealing severe
disease are also indications for surgical intervention.
○ Endoscopic and open
decompression surgeries are
available (surgeon preference)

Question 11

Cubital Tunnel Syndrome

Answer 11

● Also known as Ulnar Neuropathy at the elbow or Ulnar Neuritis,
Cubital Tunnel Syndrome is the second most common of the
mononeuropathies or peripheral nerve entrapment syndromes.

Question 12

Risk factors for Cubital tunnel syndrome

Answer 12

● Risk factors can include smoking,
repetitive movements involve the elbow
(such as occupational), or frequent and
repetitive direct pressure on the elbow

Question 13

Cubital Tunnel Syndrome pathophysiology

Answer 13

○ Ulnar nerve entrapment may be idiopathic, due to active compression of the nerve, or associated with ulnar nerve subluxation over the medial
epicondyle (w/ or w/o compression)
○ Results in demyelinating neuropathy
○ Repetitive blunt trauma to the area (“hitting your funny bone”)
can also result in an inflammatory tenosynovitis of the area, which
can compress the nerve (common in truck drivers)

Question 14

Cubital Tunnel Syndrome signs and symptoms

Answer 14

○ Patient will report paresthesias over
the 4th and 5th fingers.
○ They will also experience weakness
of the hand, especially with grip
strength.
Cubital Tunnel Syndrome
○ Certain movements of the arm can
sometimes make it worse.
○ Some experience an inflamed and
tender cubital tunnel (can have
positive Tinel’s at the elbow)

Question 15

Cubital Tunnel Syndrome diagnosis

Answer 15

○ Spurling Test and imaging can help rule out
a C8 spinal nerve compression
○ Assess the strength of the hands, including
flexor muscles of the fingers.
○ Electrodiagnostic studies (NCS/EMG) are diagnostic for Ulnar Nerve Entrapment.
○ Tinel’s Test
○ Assess for Wartenberg’s Sign,
○ Duchenne Sign (AKA Claw Sign)
○ Froment Sign

Question 16

Wartenberg’s Sign

Answer 16

the involuntary abduction of the small
finger with weakness noted with
adduction of that small finger
Seen in cubital tunnel syndrome

Question 17

Duchenne Sign (AKA Claw Sign)

Answer 17

the inability to fully extend the joints of the ring
and (especially) the small finger.

Question 18

Froment Sign

Answer 18

flexion of the thumb is required by the patient to
pinch and hold a piece of paper

Question 19

Cubital Tunnel Syndrome management

Answer 19

○ Conservative therapy may include one or all of the following:
■ Physical/Occupational Therapy
■ Padding or splinting of the elbow
■ Activity modification (all patients)
■ NSAIDs for the pain
■ Sometimes steroid injections
○ Simple elbow braces or splinting of the
elbow reduces ROM of the joint, and can
help an inflamed nerve heal
○ If motor weakness is present, or if the patient fails several weeks
of conservative therapy, surgical referral is warranted

Question 20

Patient education for cubital tunnel syndrome

Answer 20

■ Patients should avoid leaning on their elbows when sitting or
driving and should avoid prolonged elbow flexion.
■ Avoid sitting with arms crossed

Question 21

Peroneal Nerve (Fibular Nerve)

Answer 21

○ Provides motor and sensory innervation
to the lower leg (below the knee).
○ Motor- Peroneus longus and brevis,
anterior tibialis, extensor hallucis longus,
extensor digitorum longus, etc.
○ Sensory- Each branch innervates a
portion of the anterolateral shin/foot

Question 22

Peroneal Nerve Palsy

Answer 22

● Peroneal Mononeuropathy is the most common mononeuropathy in
the lower extremities, and the third most common overall.
● Dancers seem to have an increased prevalence, presumably due to
specific repetitive movements of the knee
● The Peroneal Nerve is also known as the
Fibular Nerve, so this condition is also called
Fibular Nerve Mononeuropathy or Palsy

Question 23

Peroneal Nerve Palsy pathophysiology

Answer 23

○ Compression or inflammation of the Peroneal Nerve can
○ One of the most common likely etiologies is
sitting with legs crossed, with pressure right on
the fibular head (can be idiopathic though)

Question 24

Peroneal Nerve Palsy signs and symptoms

Answer 24

○ Depending on the location of the nerve damage, distribution of the paresthesias are characteristic.
○ Weakness with ankle dorsiflexion/eversion and of the Extensor Hallucis Longus are common.
○ Severe disease can also produce a significant foot drop (frequently misdiagnosed as L4-5 HNP)
■ Pro Tip: A painless foot drop is more
likely to be peroneal nerve palsy than an
L5 radiculopathy

Question 25

Peroneal Nerve Palsy diagnosis

Answer 25

○ Because the symptoms often mimic those of an L4-5 herniated disc causing an L5 radiculopathy (which is much more common,
actually), providers often order an MRI Lumbar spine initially
○ Electrodiagnostic Studies (NCS/EMG) is
the diagnostic study of choice, however,
and can pinpoint exactly where the
compression is occurring (most commonly
at the head of the fibula / lateral knee)

Question 26

Peroneal Nerve Palsy management

Answer 26

○ Most peroneal nerve palsies will respond to conservative management with activity modification (ie. stop crossing legs)
○ Physical therapy can be beneficial for recovery of function (refer!).
○ If there is motor dysfunction, surgery needs to occur sooner rather than later, which simply involves decompressing the nerve at the site
of entrapment.
○ Because peripheral mononeuropathies often result in demyelination and sometimes axonal death, neurologic dysfunction can be permanent.
○ Patients with a significant foot drop can be
fitted for an Ankle Foot Orthosis (AFO),