Chapter 56 Entrapment Neuropathies Flashcards

Question

Syndrome of Site of Entrapment of Median

Answer 1

Pronator syndrome, flexor digitorum sublimis syndrome Anterior interosseous syndrome, Kiloh-Nevin syndrome Carpal tunnel syndrome Intermetacarpal tunnel syndrome, “bowlers’ thumb”

Answer 2

Cubital tunnel syndrome “Tardy” ulnar palsy Ulnar tunnel syndrome, “cyclists’” palsy (Radfahrerlahung) Piso-hamate hiatus syndrome

Answer 3

Notalgia paresthetica

Answer 4

Lumbosacral tunnel syndrome

Answer 5

Meralgia paresthetica, Roth’s meralgy, Bernhardt’s syndrome

Answer 6

Iliacus tunnel syndrome Gonyalgia paresthetica, “housemaids’ knee”

Answer 7

Howship–Romberg syndrome

Answer 8

Pyriformis syndrome

Answer 9

“Cross leg” palsy (Anterior) tarsal tunnel syndrome

Answer 10

Canal calcaneen de Richet (ligamentum laciniatum) Medial plantar nerve Medial plantar proper digital nerve Transverse metatarsal ligament

Answer 11

(Posterior) tarsal tunnel syndrome “Joggers’ foot,” abductor hallucis tunnel syndrome Joplin’s neuroma Morton’s neuroma (metatarsalgia)

Answer 12

carpal tunnel is at the base of the hand. The carpal, or wrist bones, form the floor of the tunnel and the flexor retinaculum forms the roof. Nine flexor tendons also pass through the tunnel. Due to this crowded arrangement, any tenosynovial proliferation, fluid collection, or arthritic deformity can lead to carpal tunnel syndrome.

Answer 13

wrist extension or flexion. In those with carpal tunnel syndrome, pressures can reach over 100 mmHg in flexion or extension, pressures high enough to impede flow to the arteries supplying the nerve, causing epineural ischemia. At somewhat lower pressures, venous return can be reduced, resulting in venous stasis and intraneural edema.

Answer 14

Classically, patients report numbness on the palmar surface of the thumb and index, middle, and half of the ring finger. fifth finger is spared

Answer 15

The pain can be both distal and proximal to the site of compression. Patients can report pain in the hand, wrist, elbow, and shoulder. Pain and numbness may increase when the wrist is flexed or extended.

Answer 16

patients often report symptoms at night when they awake after sleeping with their wrists in flexion. Many patients will report needing to shake their hand on waking to relieve their numbness

Answer 17

They may report dropping things or having difficulty with certain motor activities like doing up buttons or opening a jar. These complaints are probably the result of a combination of mild thenar weakness and sensory loss.

Answer 18

The median nerve after it exits the carpal tunnel supplies sensation to the palmar surface of the thumb and index, middle, and half the ring finger. It also supplies the dorsal tips of these same fingers. Also the median nerve after exiting the carpal tunnel innervates a number of intrinsic hand muscles

Answer 19

supplies sensation to the proximal portion of the palm and thenar eminence, does not go through the carpal tunnel, and is therefore

Answer 20

sensory deficits in parts of the median sensory territory.

Answer 21

the patient should place the thumb perpendicular to the plane of the hand and then resist as the examiner attempts to push the thumb into the plane of the hand. In most patients, weakness will only be appreciated when compared to the unaffected hand or to the flexor pollicis longus muscle of the affected side

Answer 22

increases pressure by putting the patient’s wrist in hyperextension or hyperflexion. Most patients with carpal tunnel syndrome will report numbness, tingling, or pain within 60 sec of the wrist being placed in extension or flexion.

Answer 23

involves tapping over the carpal tunnel to elicit brief symptoms. It should be noted that brief symptoms can be elicited in anyone if the tapping is vigorous enough.

Answer 24

Electrodiagnostic testing. The hallmark of electrodiagnosis is a delay in the distal latency of median nerve conduction. This suggests a conduction delay through the carpal tunnel.

Answer 25

splinting to maintain the wrist in a neutral position and thereby minimize the pressure in the carpal tunnel. Splints should be worn both day and night. Anti-inflammatory treatments including steroid injection benefit some select patients. Should conservative measures fail, then surgical decompression is indicated

Answer 26

repetitive stress injuries that occur with computer use. any occupation that requires repeated flexion and extension at the wrist Others: obesity, arthritis, diabetes, and hypothyroidism. Square wrists, that is, those whose dorsal-volar distance is close to the medial-lateral distance with a ratio greater than 0.7

Answer 27

Entrapment can occur either at the ulnar groove or at the cubital tunnel.

Answer 28

crosses the elbow and passes through the cubital tunnel.

Answer 29

formed by the medial epicondyle and the olecranon process. The ulnar nerve runs through this groove as it crosses the elbow. The groove is easily palpable when the arm is extended at the elbow. As the elbow is bent, the groove disappears and the ulnar nerve is relatively superficial.

Answer 30

Patients with a remote history of supracondylar fracture can develop such a bony deformity and nerve impringement

Answer 31

under a ligamentous band that stretches from the medial epicondyle to the olecranon of the ulna and then blends into the aponeurosis of the two heads of flexor carpi ulnaris muscle. This humeroulnar aponeurotic arcade or cubital tunnel can be from 0.5 cm to 2 cm distal to the medial epicondyle, or end of the ulnar groove. Pressure in the cubital tunnel can increase as the elbow is flexed.

Answer 32

Intermittent numbness and tingling in the distribution of the ulnar nerve is usually the first symptom of ulnar palsy. Patients can wake up with elbow pain radiating into the fifth digit. There can be cramping and aching in the hypothenar eminence. Symptoms can be exacerbated by flexion of the elbow. Patients may complain about a generalized loss of strength in the hand or loss of dexterity.

Answer 33

fifth finger, both palmar and dorsal surfaces, and usually half of the ring finger. Sensory deficits that split the ring finger are classic for an ulnar nerve injury.

Answer 34

Light touch and two-point discrimination

Answer 35

proximally at about the wrist crease.

Answer 36

the medial antebrachial cutaneous nerve, a branch of the brachial plexus. This area should not be involved in ulnar lesions at the elbow.

Answer 37

grasp and pinch strength.

Answer 38

the first dorsal interosseous and the abductor digiti minimi. The hands are placed on a flat surface and the patient is asked to spread the fingers apart and resist the examiner’s attempt to bring the fingers closer together. Atrophy of the hypothenar eminence and the first dorsal interosseous can often be seen. Clawing of the ring and little finger is common in chronic cases.

Answer 39

Palpation of the ulnar groove and over the cubital tunnel. Flexion of the elbow beyond 90 degrees can often provoke sensory complaints or pain

Answer 40

Electrodiagnostic testing. Nerve conduction studies will usually show slowing across the elbow and sometimes a drop in response amplitude across the elbow. Inching techniques can sometimes localize the site of compression to the ulnar groove or the cubital tunnel.

Answer 41

an elbow pad to reduce trauma to the nerve or by avoiding prolonged flexion at the elbow. More severe cases may require surgery. The precise site of entrapment will determine the surgical procedure, which can include transposition of the nerve, decompression at the aponeurosis, or even medial epicondylectomy.

Answer 42

Resting a bent elbow on a hard surface is a behavior that can provoke ulnar palsy.

Answer 43

A cervical rib is the most discussed source of compromise in thoracic outlet syndrome. An anomalous fibrous band from the transverse process of the last cervical vertebra to the first rib is a common cause of impingement. Entrapments by the scalenes, subclavius, and pectoralis minor muscles have all been reported. Hyperextension injuries of the neck can lead to intrascalene muscle hemorrhage and swelling with resultant scar formation in the muscle or around the brachial plexus.

Answer 44

the lower trunk of the brachial plexus is most involved

Answer 45

compromise of the axillary and subclavian vessels.

Answer 46

whether they are primarily arterial, venous, or neurologic and can vary with shoulder position

Answer 47

ischemic in nature and include pain, paresthesias, coldness, and color change. Some patients complain of fatigue and soreness in the arm

Answer 48

swelling, and cyanosis, as well as pain and paresthesias.

Answer 49

numbness of the medial forearm and ulnar side of the hand. This can be followed by an aching pain, poorly localized in the arm and anterior chest. Later patients may complain of clumsiness or weakness in the hand and fingers. Atrophy of both the thenar and hypothenar eminences can be seen

Answer 50

Anterior flexion of the shoulders. Abduction and supination of the arm can also elicit symptoms. Certain activities that affect shoulder position can exacerbate the symptoms, such as carrying a heavy briefcase, combing one’s hair, or using a mouse.

Answer 51

usually affects the lower trunk of the brachial plexus first, which results in sensory deficits on the ulnar side of the hand with weakness and atrophy of the thenar eminence. As the syndrome progresses, sensory loss can involve all five fingers. True neurogenic thoracic outlet syndrome initially causes weakness of median innervated hand muscles and later ulnar innervated muscles. Atrophy of both thenar and hypothenar eminences can occur.

Answer 52

usually does not cause loss of strength, but arm and hand muscles may fatigue with use. Vascular compression can cause diffuse but usually only subjective sensory deficits. Swelling, color changes, and temperature differences can all be seen

Answer 53

involves extending the arm at shoulder height to the side and supinating the hand. The manuever can elicit both signs, that is, loss of radial pulse, and an increase in sensory symptoms.

Answer 54

stresses the brachial plexus by again extending the arm to the side and then tilting the head to the opposite side. This maneuver stretches the plexus on the side of the extended arm and in neurogenic thoracic outlet syndrome will provoke symptoms on that same side.

Answer 55

Early neurogenic thoracic outlet syndrome often presents with a normal electrodiagnostic study. One of the first electrodiagnostic abnormalities seen is a reduction in the amplitude of the medial antebrachial cutaneous sensory response. Later ulnar sensory responses in the hand will be diminished. Late responses such as F-waves will become prolonged and conductions across the plexus will be slowed as plexopathy progresses. Needle examination may elicit denervation changes in both median and ulnar innervated hand muscles in advanced cases.

Answer 56

Correction of shoulder posture can improve if not completely eliminate the symptoms of thoracic outlet syndrome in many cases. Exercises that strengthen the rhomboid and trapezius muscles can improve shoulder posture. Clavicle straps can help maintain correct shoulder posture. The most common surgical procedures are resection of cervical rib and fibrous band, and scalenectomies. Both procedures carry significant morbidity.

Answer 57

The injection of botulinum toxin into the scalene muscles has been shown to be effective in some cases of thoracic outlet syndrome. Other muscles, including subclavius, pectoralis minor, trapezius, and levator scapula also have been injected with good results

Answer 58

dysphagia, dysphonia, and muscle weakness.

Answer 59

seen in professional musicians who play string instruments, nursing mothers, and computer users, especially on the side that operates the mouse. Bony deformities from clavicular fracture, cervical ribs, and sloped shoulders all predispose one to thoracic outlet syndrome. Recent trauma to the shoulder or neck, even without fracture, can predispose a patient to thoracic outlet syndrome.

Answer 60

Entrapment of the lateral femoral cutaneous nerve of the thigh.

Answer 61

The lateral femoral cutaneous nerve of the thigh arises from upper lumbar roots, travels through the pelvis, and exits into the leg at the upper lateral end of the inguinal ligament. The nerve is usually trapped as it passes under or through the inguinal ligament. Blunt trauma to this area can cause damage to the nerve.

Answer 62

More chronic episodic external compression from tight-fitting clothes, a holster, or tool belt can provoke meralgia. However, entrapment most often is related to increased intra-abdominal pressure from weight gain or pregnancy. Mass lesions, including lipomas and fibroids

Answer 63

Patients complain of unpleasant sensations and numbness in the lateral thigh. Light touch in the area can be unpleasant. Even clothing or touching the area can be unpleasant. Walking, standing, or lying flat can sometimes exacerbate symptoms.

Answer 64

The lateral femoral cutaneous nerve is a purely sensory nerve that supplies just the lateral thigh. Therefore, findings are completely sensory. Sensory loss can be identified in a portion of the distribution of the nerve, usually the area that the hand touches when it’s in the pants pocket.

Answer 65

It can be technically difficult to elicit sensory responses from the lateral femoral cutaneous nerve in normal individuals. This makes interpretation of a lost or diminished response suspect

Answer 66

Obesity, pregnancy, diabetes, and tight-fitting clothes, Pelvic osteotomy and use of stabilization devices during spine surgery

Answer 67

Pain control with medication is the standard treatment. Symptoms resolve within 6 months for the vast majority of patients using only these conservative measures. Nerve blocks have been successful in some cases. There are also some reports of successful treatment with pulsed radiofrequency. The utility of surgical intervention remains limited.

Answer 68

used to describe entrapment of the posterior tibial nerve at the medial ankle

Answer 69

The tarsal tunnel is formed by the ankle bones and the flexor retinaculum. Through the tunnel passes the posterior tibial nerve, tendons of the foot and toe flexors, and the posterior tibial artery. Increased pressure in the tunnel brings on the syndrome.

Answer 70

an ankle fracture or sprain, arthritic changes, tenosynovitis, or fluid collection. Mass lesions in the tarsal tunnel like ganglion cysts or convoluted blood vessels, can also lead to compression of the posterior tibial nerve.

Answer 71

The primary complaint is foot pain, often described as burning. Many patients will isolate the burning to the sole of the foot. Painful numbness will often disturb sleep. Walking and standing can exacerbate symptoms.

Answer 72

calcaneal, medial plantar, and lateral plantar

Answer 73

Intrinsic foot muscles primarily toe flexors and abductors, can be affected but clinical testing of these muscles can be difficult. Motor findings, including weakness and atrophy, are therefore usually evident only late in tarsal tunnel syndrome. Pressure over the affected tarsal tunnel is usually painful. Eversion and dorsiflexion can also provoke symptoms.

Answer 74

Nerve conduction studies can reveal both motor and sensory slowing through the tarsal tunnel. The syndrome is usually unilateral so comparisons with the unaffected side make electrodiagnosis easier. Needle examination of intrinsic foot muscles can be misleading. Some 10% to 20% of normal intrinsic foot muscles may demonstrate denervation changes, that is, fibrillations and positive waves, as a result of direct muscle trauma from walking.

Answer 75

Anti-inflammatory medication can be useful in certain cases in which tenosynovitis or arthritis is suspected. Surgical decompression is highly effective

Answer 76

Ankle trauma even if remote is common in tarsal tunnel syndrome. Rheumatoid arthritis and diabetes mellitus both increase the risk for tarsal tunnel syndrome.

Answer 77

Pressure on an interdigital nerve in one of the intermetatarsal spaces can cause pain and numbness in the distal foot and toes.

Answer 78

distal branches of the lateral and medial plantars.

Answer 79

chronic pressure and trauma between the metatarsal heads, against the transverse metacarpal ligament. At times, an actual scar, or neuroma, will form. This most commonly occurs between the third and fourth metatarsal heads but can involve other interdigital nerves

Answer 80

The primary complaint is burning pain in the ball of the foot that radiates to one or two toes. The corresponding toes may feel numb. Pain will be worse with weight bearing.

Answer 81

Pain can be elicited by pushing on the ball of the foot over the affected interdigital nerve. At times altered sensation can be demonstrated on the adjoining sides of the affected toes, though this can often be difficult or nonreproducible.

Answer 82

difficult and often unreliable. Both orthodromic and antidromic sensory or mixed nerve studies using both surface electrodes and near-needle electrodes have been described, but none are routinely performed

Answer 83

Conservative measures including physical therapy, orthotics, and avoiding offending footwear are often successful. Interdigital anesthetic nerve blocks, often with corticosteroids, have been effective in some patients.

Answer 84

Now neurolysis of the interdigital nerve or removal of the neuroma (neurectomy) are the most common surgical options. The larger the neuroma, especially if it is greater than 5 mm across, the more likely neurectomy is to be successful. Surgical risks include permanent loss of sensation and recurrent neuroma.

Answer 85

Activities that increase trauma to the foot can all increase one’s risk for interdigital neuropathy. Ill-fitting shoes, especially high heels, also predispose one to develop Morton’s neuroma.