Lateral Femoral Cutaneous Nerve Anatomy

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Questions and Answers

The lateral femoral cutaneous nerve originates from which specific segments of the lumbar plexus?

  • S1-S2
  • L2-L3 (correct)
  • L3-L4
  • L1-L2

The lateral femoral cutaneous nerve contains both motor and sensory fibers, facilitating both cutaneous sensation and muscular control in the lateral thigh.

False (B)

Describe the anatomical relationship of the lateral femoral cutaneous nerve relative to the anterior superior iliac spine (ASIS) and the femoral nerve, detailing its positional relevance for diagnostic palpation.

The lateral femoral cutaneous nerve is lateral to the ASIS and relatively close to it, while the femoral nerve lies medial to the ASIS, closer to the midpoint between the ASIS and the pubic tubercle. This anatomical arrangement is crucial for accurately palpating the LFC nerve.

Meralgia paresthetica arises from the ______ of the lateral femoral cutaneous nerve, commonly due to entrapment at the inguinal ligament or external compression.

<p>compression</p> Signup and view all the answers

Match the grade of nerve injury in meralgia paresthetica with its typical mechanism of injury:

<p>Neuropraxia = Internal compression from soft tissue or external compression sources. Axonotmesis/Neurotmesis = Iatrogenic causes, such as post-surgical complications, injections, or the presence of systemic pathologies.</p> Signup and view all the answers

What is the most common etiological factor associated with the development of meralgia paresthetica?

<p>Entrapment of the nerve at the inguinal ligament (B)</p> Signup and view all the answers

Meralgia paresthetica typically presents with bilateral symptoms, affecting both lateral thighs equally due to its systemic etiology.

<p>False (B)</p> Signup and view all the answers

Describe the expected changes in muscle tone upon palpation of the lateral thigh in a patient experiencing meralgia paresthetica and explain the underlying rationale.

<p>Muscle tone remains generally unchanged, because meralgia paresthetica affects sensory nerves, not motor nerves, so muscle innervation and tone remain intact. Palpation primarily aims to assess sensory changes.</p> Signup and view all the answers

Symptoms of meralgia paresthetica, notably numbness, paresthesia, and burning pain, characteristically occur in the ______ lateral thigh.

<p>upper</p> Signup and view all the answers

Match the aggravating and relieving factors with their respective effects on the symptoms of meralgia paresthetica:

<p>Walking and Standing = Aggravate symptoms Sitting = Relieves symptoms</p> Signup and view all the answers

Which of the following differential diagnoses should be considered when evaluating a patient presenting with suspected meralgia paresthetica?

<p>L2 dermatome radiculopathy (D)</p> Signup and view all the answers

Lumbar cutaneous nerves will have higher pain wrapping than LFC distribution

<p>True (A)</p> Signup and view all the answers

Detail how lumbar cutaneous nerves' distribution differs from that of the lateral femoral cutaneous nerve, with precise anatomical landmarks, to guide differential diagnosis.

<p>Lumbar cutaneous nerves (iliohypogastric, subcostal) exhibit a distribution characterized by low back pain wrapping around the obliques, situated more proximally compared to the distribution of the LFC nerve, which primarily affects the lateral thigh.</p> Signup and view all the answers

When assessing a patient for meralgia paresthetica using the prone knee bending test, cervical rotation should be performed ______ to the side being tested to maximize neural tension.

<p>ipsilateral</p> Signup and view all the answers

Match the components of the prone knee bending test with their corresponding procedural steps:

<p>Cervical Rotation = Ipsilateral to the side being tested Hip Position = Extended and adducted Knee Position = Flexed as much as possible</p> Signup and view all the answers

What constitutes a positive finding during the prone knee bending test in the assessment of lateral femoral cutaneous nerve compromise?

<p>Subjective report of symptom recreation (C)</p> Signup and view all the answers

The pelvic compression test for meralgia paresthetica involves actively provoking symptoms to assess the nerve's response to compression.

<p>False (B)</p> Signup and view all the answers

Explain the procedure for performing the pelvic compression test, emphasizing the required patient position and the specific instructions given during the assessment to evaluate symptom alleviation.

<p>The patient lies sidelying with the affected side up. The clinician applies downward pressure to the pelvis, maintaining it for 45 seconds. After 30 seconds, inquire if the symptoms have dissipated, marking a positive test if alleviation is reported.</p> Signup and view all the answers

A positive pelvic compression test is indicated by ______ of the patient's symptoms after approximately 30 seconds of sustained downward pressure on the pelvis.

<p>dissipation</p> Signup and view all the answers

Match the findings from the pelvic compression test with their clinical implications:

<p>Symptom Dissipation = Positive test, indicating potential relief with pelvic stabilization No Symptom Change = Negative test, suggesting symptoms are not influenced by pelvic compression</p> Signup and view all the answers

Which diagnostic sign involves tapping over the lateral femoral cutaneous nerve below the inguinal ligament to potentially replicate the patient's symptoms?

<p>Tinel's Sign (A)</p> Signup and view all the answers

ADLs around external compression sources can be an advice for the Home Care for a patient.

<p>True (A)</p> Signup and view all the answers

Describe how altering ADLs, specifically those involving external compression sources, can mitigate symptoms of meralgia paresthetica as part of a home care plan.

<p>Modifying ADLs that involve external compression sources, like adjusting clothing, belts, or equipment, reduces direct pressure on the lateral femoral cutaneous nerve, alleviating compression and subsequently diminishing symptoms of meralgia paresthetica.</p> Signup and view all the answers

Posterior tilting of the pelvis is encouraged as part of home care to ______ the inguinal ligament and reduce nerve compression in meralgia paresthetica.

<p>slacken</p> Signup and view all the answers

Match the exercises recommended for home care with their intended physiological effect on managing meralgia paresthetica:

<p>Lifting Skin = Mobilizing the nerve and improving local circulation Flexing Hip Standing = Releasing tension around the inguinal ligament and enhancing nerve mobility</p> Signup and view all the answers

In cases of meralgia paresthetica, which conservative treatment option aims to release tension and improve nerve mobility by addressing trigger points that refer pain into the affected area?

<p>Trigger point therapy (D)</p> Signup and view all the answers

According to the document, 'skin rolling the entire lateral thigh' is a skin care approach that can hurt the area by irritating it even further

<p>False (B)</p> Signup and view all the answers

Explain the biomechanical rationale behind performing "cross-hands around ilium / inguinal ligament and abdomen" as a treatment for meralgia paresthetica.

<p>This cross-hand technique aims to release fascial restrictions, reduce muscle guarding, and improve tissue mobility around the ilium, inguinal ligament, and abdomen. This can decrease compression on the lateral femoral cutaneous nerve, enhancing its function.</p> Signup and view all the answers

Performing a ’Thigh 3D wringing either supine or supine with hip flexion’ helps free up tension and potentially improve blood flow around the ______ area

<p>affected</p> Signup and view all the answers

Match the different steps one should take when determining treatment:

<p>Skin Rolling the entire later thigh = For cases that haven't devolved into chronic irritation yet Side-lying lift skin and mobilise nerve (hip flex-ext) = More irritating than skin rolling but can potentially deal with adhesion</p> Signup and view all the answers

In which specific scenario should one avoid attempting to directly decompress the lateral femoral cutaneous nerve, especially if symptoms persist after pressure removal?

<p>When decompression provokes or recreates persistent symptoms. (D)</p> Signup and view all the answers

Recall that Meralgia paresthetica can be any grade of nerve injury and that Neuropraxia typically results from physical cutting of the nerve and other serious issues.

<p>False (B)</p> Signup and view all the answers

The lateral femoral cutaneous nerve emerges from underneath the [blank] to run superficially between the muscle and skin.

<p>inguinal ligament</p> Signup and view all the answers

The lateral femoral cutaneous nerve typically becomes palpable just medial to the ______ tendon due to its superficial course.

<p>sartorius</p> Signup and view all the answers

What steps should be prioritized when applying pressure in the area of the nerve

<p>Make sure symptoms do not increase = This ensures the tissue is not being harmed</p> Signup and view all the answers

After the lateral femoral cutaneous nerve crosses the thin band of sartorius, what subsequent anatomical course does it follow?

<p>It remains superficial and sends small branches over the TFL and vastus lateralis. (A)</p> Signup and view all the answers

It is always reasonable to pressure for someone who is very badly irritated, working in the area may exacerbate symptoms.

<p>False (B)</p> Signup and view all the answers

Describe the distal extent of the area of innervation of the lateral femoral cutaneous nerve on the lateral thigh.

<p>The area of innervation extends down the lateral thigh all the way to the lateral aspect of the distal thigh, and sometimes includes the lateral patellar retinaculum.</p> Signup and view all the answers

According to the given information, increased incidence of meralgia paresthetica has been noted in people with ______ compared to people without it.

<p>diabetes</p> Signup and view all the answers

Match the different potential treatments with their respective issues:

<p>Weight loss, physio, massage therapy = Helps reduce the compression and impact the root of the injury surgical decompression, injections (steroid, or nerve block) = Acts as a more invasive method of treatment</p> Signup and view all the answers

Conservative treatment options for meralgia paresthetica often focus on which primary goal?

<p>Reducing inflammation and compression (B)</p> Signup and view all the answers

As long as there is no pain, it is alright to continue irritating the nerve.

<p>False (B)</p> Signup and view all the answers

What specific aspect of sensation is primarily assessed during palpation of affected tissue in meralgia paresthetica, and why?

<p>Palpation primarily focuses on assessing changes in sensation, such as areas of numbness, paresthesia, or heightened sensitivity, because meralgia paresthetica predominantly affects sensory rather than motor nerve fibers.</p> Signup and view all the answers

We can recall that Meralgia paresthetica can be any grade of ______ injury.

<p>nerve</p> Signup and view all the answers

Match each statement in the 'Precautions' section with its implication:

<p>Working in the area that is very badly irritated, may exacerbate symptoms, but may be tolerable to the person. = Assess the benefits against the costs, this may be a risk-benefit ratio. Therefore, you must always ask how quickly symptoms dissipate after you remove your pressure. = Symptoms that stay around for a prolonged period need to be noted and taken into consideration.</p> Signup and view all the answers

Flashcards

Lateral Femoral Cutaneous Nerve (LFC)

The lateral femoral cutaneous nerve originates from the lumbar plexus, specifically from nerve roots L2-L3. It is a sensory nerve.

LFC Nerve Location

The lateral femoral cutaneous nerve is located laterally and close to the ASIS (anterior superior iliac spine).

LFC Nerve Sensory Function

The lateral femoral cutaneous nerve provides sensory function to the skin over the lateral thigh.

LFC Nerve Palpation

The lateral femoral cutaneous nerve first emerges from underneath the inguinal ligament close to the ASIS.

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Meralgia Paresthetica

Meralgia Paresthetica is the compression of the lateral femoral cutaneous nerve, resulting in pain.

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Meralgia Paresthetica Symptoms

Meralgia paresthetica often presents as burning pain in the anterolateral thigh.

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Common Cause of Meralgia Paresthetica

Meralgia paresthetica can be caused by entrapment at the inguinal ligament.

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Meralgia Paresthetica - External compression

Meralgia paresthetica can be caused by entrapment by tight clothing, belts, or equipment.

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Meralgia Paresthetica - Aggravating Factors

Walking and standing typically aggravate meralgia paresthetica symptoms, while sitting may relieve them.

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Lumbar cutaneous nerves

Lumbar cutaneous nerves radiate to the obliques and are more proximal than the LFC distribution.

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Meralgia Paresthetica - Precautions

Symptoms may be exacerbated if the area is very badly irritated. Make sure the symptoms do not increase when applying pressure.

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Meralgia Paresthetica - Treatment

Skin rolling the entire lateral thigh is a treatment.

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Tinel's Sign for LFC Nerve

Tapping over the LFC nerve below the inguinal ligament may recreate symptoms.

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Study Notes

Anatomy of the Lateral Femoral Cutaneous Nerve

  • Originates from the lumbar plexus, specifically nerve roots L2-L3.
  • It is a sensory nerve and lacks motor fibers.
  • Situated between the ASIS (anterior superior iliac spine) and the femoral nerve.
  • Located more laterally, in proximity to the ASIS, while the femoral nerve is positioned medially between the ASIS and the pubis, adjacent to the femoral artery.

Function

  • There is absence of motor function.
  • Provides sensory innervation to the skin over the lateral thigh.

Palpation

  • Initially emerges from underneath the inguinal ligament, very close to the ASIS.
  • Runs superficially between muscle and skin, and can initially be palpated just medial to the sartorius tendon.
  • Crosses the sartorius, remains superficial, and sends branches across the TFL and vastus lateralis.
  • Innervation area extends down the lateral thigh.
  • Muscle tone remains unchanged if there is an injury to the LFC nerve.
  • Palpation assesses sensation over the lateral thigh.

Meralgia Paresthetica

  • Name of the condition caused by compression of the lateral femoral cutaneous nerve.
  • Compressive mononeuropathy which often presents as burning pain in the anterolateral thigh.
  • Compression often occurs below the inguinal ligament as the nerve passes through a fibrous tunnel, or from external pressure from tight clothing or equipment.
  • Treatment includes surgical decompression, injections, or conservative management.
  • Can be any grade of nerve injury.
    • Neuropraxia: Results from internal compression from soft tissue or external compression from clothes/belts/equipment.
    • Axonotmesis or Neurotmesis: Results if the MOI was iatrogenic, such as post-surgery, post-injections, or due to presence of pathology such as diabetes or other metabolic pathologies.

Etiology

  • Most common cause is entrapment at the inguinal ligament.
  • Other causes include trauma, pregnancy, tight clothing, and surgery.
  • Incidence is higher in people with diabetes.

Signs and Symptoms

  • Symptoms occur in the upper lateral thigh, including numbness, paresthesia, and burning pain.
  • Walking and standing exacerbate symptoms, while sitting provides relief.
  • Often unilateral.

Differential Diagnosis

  • Includes trigger points in the vastus lateralis, vastus intermedius, gluteus minimus, and TFL.
  • Radiculopathy - L2 dermatome.
  • Lumbar cutaneous nerves will have associated low back pain wrapping around obliques and be more proximal than the LFC distribution.

Precautions

  • Working in the area may exacerbate symptoms if it is very badly irritated.
  • Ensure symptoms do not increase when applying pressure in the area of the nerve.
  • Discontinue direct decompression if symptoms persist, and do not attempt to mobilize the nerve.
  • It is important to ask how quickly symptoms dissipate after pressure is removed.

Treatment

  • Consists of skin rolling the entire lateral thigh, cross-hands around the ilium/inguinal ligament and abdomen.
  • Can address active trigger points that refer into the area, bow inguinal ligament.
  • Thigh 3D wringing either supine or supine with hip flexion.
  • Perform side-lying lift skin and mobilize nerve (hip flex-ext) and supine lift skin and mobilize nerve (knee flex-ext).
  • Techniques should be modified to suit the stage of healing and severity of condition.

Home Care

  • Modify ADLs around external compression sources.
  • Encourage posterior pelvic tilt to slacken the inguinal ligament.
  • Lift skin and flex hip standing.

Assessment

  • Prone Knee Bending Test: Involves cervical rotation to the same side (ipsilateral), hip extension and adduction, and knee flexion, recreation of symptoms indicates a positive test.
  • Pelvic Compression Test: Patient is sidelying with the affected side up, downward pressure is applied to the pelvis and maintained for 45 seconds. Asking the patient if symptoms have dissipated after 30 seconds, which would indicate a positive test.
  • Tinel's Sign: Tapping over the LFC nerve below the inguinal ligament may recreate symptoms.

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