Femoral Nerve Injury

Populations and Risk Factors

Post-surgical patients — hip replacement (anterior approach), pelvic surgery, abdominal surgery (retractor compression against the psoas), and inguinal hernia repair are the most common iatrogenic causes; incidence of femoral neuropathy following hip arthroplasty ranges from 0.5–3%
Individuals with pelvic or proximal femur fractures — fracture fragments or post-traumatic hematoma can compress or lacerate the nerve
Women following difficult labor and delivery — forceps-assisted delivery, prolonged lithotomy position, or fetal head compression against the pelvic sidewall can compress the femoral nerve at the inguinal ligament
Individuals with diabetes mellitus — diabetic amyotrophy (diabetic lumbosacral radiculoplexus neuropathy) produces acute, painful proximal leg weakness that preferentially affects the femoral nerve territory; this is a distinct entity from length-dependent diabetic neuropathy
Patients on anticoagulation therapy — spontaneous retroperitoneal or iliacus hematoma can compress the nerve within the psoas compartment; this is a medical emergency
Individuals with chronic psoas hypertonicity — the femoral nerve exits the psoas at its lateral border and is vulnerable to compression when the psoas is in sustained spasm (the "hugging psoas" mechanism); common in individuals with chronic hip flexor tightness, anterior pelvic tilt, or prolonged sitting
Athletes with inguinal pathology — inguinal hernia, sports hernia (athletic pubalgia), or lymphadenopathy can compress the nerve at the femoral triangle

Causes and Pathophysiology

Femoral Nerve Course and Entrapment Sites

The femoral nerve forms from the ventral rami of L2, L3, and L4 within the substance of the psoas major. It emerges from the lateral border of the psoas in the iliac fossa, crosses the iliacus muscle (which it innervates), and passes beneath the inguinal ligament into the femoral triangle. In the femoral triangle, it lies immediately lateral to the femoral artery (the mnemonic NAVeL — Nerve, Artery, Vein, empty space, Lymphatics — describes the lateral-to-medial arrangement under the inguinal ligament). The nerve then divides into anterior and posterior branches:

Anterior branch (motor and sensory): Innervates sartorius and the medial and intermediate cutaneous nerves of the thigh (sensory to the anterior and medial thigh)
Posterior branch (motor and sensory): Innervates the four heads of the quadriceps (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius) and gives off the saphenous nerve — a purely sensory nerve that descends through the adductor canal, emerges at the medial knee, and continues along the medial leg and foot

The two primary compression sites each produce different clinical presentations:

Psoas compartment (proximal site): The nerve is compressed within the psoas or at its lateral border — causes include psoas spasm, retroperitoneal hematoma, iliacus compartment hematoma (especially in anticoagulated patients), psoas abscess, or direct compression by fetal head during delivery. Because the nerve is compressed proximal to all motor branches, a proximal lesion produces complete quadriceps paralysis plus full sensory loss in the anterior thigh and medial leg (saphenous territory).
Inguinal ligament / femoral triangle (distal site): The nerve is compressed as it passes beneath the taut inguinal ligament or within the femoral triangle — causes include inguinal hernia, lymphadenopathy, femoral artery aneurysm, prolonged lithotomy position (surgical), or tight retractors during abdominal surgery. A distal lesion may spare the iliacus and some proximal quadriceps branches, producing incomplete quadriceps weakness.

Quadriceps Paralysis and Knee Buckling Mechanism

The quadriceps is the only knee extensor. When the femoral nerve is compromised, the patient cannot generate a knee extension moment during the stance phase of gait. Clinically, this manifests as:

Knee buckling: The knee collapses into flexion during weight-bearing because the quadriceps cannot stabilize the extended knee; the patient may catch themselves by slapping the hand on the thigh to manually lock the knee in extension
Stair climbing inability: Ascending stairs requires concentric quadriceps contraction; patients with complete femoral nerve palsy cannot climb stairs without handrail assistance
Compensatory gait pattern: The patient adopts a circumduction or stiff-leg gait to avoid knee flexion during swing phase; they may lean the trunk forward over the affected leg to shift the ground reaction force vector anterior to the knee axis, creating a passive extension moment that compensates for the absent quadriceps

Saphenous Nerve Significance

The saphenous nerve is clinically important because:

It is the terminal sensory branch of the femoral nerve and has the longest course — from the femoral triangle, through the adductor canal (where it is vulnerable to entrapment by the vastoadductor membrane), to the medial knee, medial leg, and medial foot
Saphenous nerve entrapment at the adductor canal produces chronic medial knee pain that mimics knee joint pathology — patients are frequently misdiagnosed with medial meniscal or MCL pathology because the pain is localized to the medial knee without a clear neurological complaint
The saphenous nerve accompanies the saphenous vein — varicose vein surgery or saphenous vein harvesting for coronary artery bypass grafting can injure the nerve, producing chronic medial leg dysesthesia

Double Crush Phenomenon

The femoral nerve can be compressed at multiple sites: the lumbar spine (L3–L4 disc protrusion compressing the nerve root), the psoas compartment, and the inguinal ligament. Proximal compression at the spine reduces axoplasmic flow and lowers the nerve's tolerance to compression at a distal site. Clinically, a patient with L3 radiculopathy who also has psoas hypertonicity may present with disproportionately severe femoral nerve symptoms because both compression sites combine to exceed the threshold for symptomatic neuropathy.

Signs and Symptoms

Complete Femoral Nerve Lesion (Proximal — Psoas Level)

Motor: Complete quadriceps paralysis — inability to extend the knee against gravity; hip flexion markedly weak (loss of iliacus innervation); knee buckling during gait; inability to climb stairs; visible quadriceps atrophy develops within weeks
Sensory: Numbness or paresthesia over the anterior thigh (intermediate and medial cutaneous nerves) and medial leg/foot (saphenous nerve); may extend from the inguinal region to the medial malleolus
Reflex: Absent patellar reflex (the patellar reflex arc passes through L2–L4 via the femoral nerve — this is the single most important clinical finding distinguishing femoral nerve injury from musculoskeletal conditions)
Gait: Wide-based or circumduction gait; hand-to-thigh compensation; cannot ascend stairs without assistance

Partial Femoral Nerve Lesion (Distal — Inguinal Level)

Motor: Incomplete quadriceps weakness — some heads may be partially innervated; hip flexion may be preserved if the iliacus branch exits proximal to the compression site; knee extension is reduced but not absent
Sensory: Anterior thigh numbness; saphenous nerve involvement is variable depending on which branches are affected
Reflex: Diminished but not necessarily absent patellar reflex
Functional: Knee gives way during unexpected loading (stepping off a curb, stairs) but is stable during level walking

Saphenous Nerve Entrapment (Isolated)

Chronic medial knee pain — aching or burning at the medial knee that mimics meniscal or MCL pathology
Paresthesia or numbness along the medial leg and medial foot
No quadriceps weakness, no patellar reflex change — this distinguishes saphenous entrapment from femoral nerve injury
Symptoms may worsen with sustained knee extension (which tensions the nerve through the adductor canal)

Assessment Profile

Subjective Presentation

Chief complaint: "My knee gives out when I walk — it just buckles"; "I can't climb stairs anymore"; "My thigh is numb and the knee won't hold me up"; post-surgical: "Since the hip surgery, I can't straighten my knee"
Pain quality: Deep aching in the anterior thigh; burning or lancinating neuropathic pain radiating from the groin down the anterior thigh; saphenous nerve involvement adds medial knee and medial leg pain; pain may be most severe at the inguinal crease or deep in the pelvis (psoas compression)
Onset: Post-surgical — symptoms noticed immediately upon recovery from anesthesia; traumatic — following pelvic/femoral fracture or difficult delivery; insidious — progressive weakness with psoas spasm or diabetic amyotrophy; sudden severe groin/thigh pain with weakness in an anticoagulated patient suggests retroperitoneal hematoma
Aggravating factors: Weight-bearing activities (walking, stairs, rising from a chair); hip extension (stretches the femoral nerve); sustained standing on the affected leg; hip flexor stretching (tensions the nerve at the psoas)
Easing factors: Sitting (reduces knee extension demand); using a cane or walker to offload the affected leg; hip flexion (slackens the nerve at the psoas level)
Red flags: Sudden severe groin or thigh pain with rapid-onset quadriceps weakness in a patient on anticoagulants → suspect retroperitoneal or iliacus hematoma; emergency referral for imaging — this is a surgical emergency if the hematoma is expanding; progressive bilateral thigh weakness → suspect spinal cord pathology or bilateral radiculopathy; bowel/bladder changes → cauda equina syndrome; emergency referral

Observation

Local inspection: Quadriceps atrophy — visible flattening of the anterior thigh compared contralaterally; the vastus medialis obliquus (VMO) is often the first head to show visible wasting; in chronic cases, the affected thigh circumference is measurably reduced; skin trophic changes (shiny, thin skin) may be present over the anterior thigh in chronic denervation
Posture: Anterior pelvic tilt may indicate psoas hypertonicity contributing to the compression; compensatory knee locking in hyperextension during standing (the patient pushes the knee into hyperextension to avoid buckling)
Gait: Knee buckling during the loading response of gait — the knee collapses into flexion as weight is accepted; hand-to-thigh support (the patient places the hand on the anterior thigh to manually stabilize the knee); circumduction of the affected leg to avoid knee flexion during swing phase; inability to ascend stairs without handrail; Trendelenburg gait is not typically present (gluteal innervation is from the superior and inferior gluteal nerves, not the femoral nerve)

Palpation

Tone: Quadriceps — hypotonic, flaccid, reduced bulk (denervated muscle); VMO is often the most noticeably atrophied head; psoas — assess carefully for hypertonicity; the psoas is palpated through the abdominal wall with the patient supine and knees flexed; a hypertonic psoas feels firm and tender and may reproduce thigh symptoms when compressed (the "hugging psoas" sign); iliacus — palpable just medial to the ASIS within the iliac fossa; may be hypertonic and contribute to inguinal compression
Tenderness: Femoral triangle — focal tenderness at the midpoint between the ASIS and the pubic tubercle (the femoral nerve lies lateral to the femoral artery); before applying pressure, palpate for the femoral arterial pulse — if pulsation is felt, reposition immediately to avoid compressing the femoral artery against the inguinal ligament; psoas — deep tenderness through the abdominal wall, which may reproduce anterior thigh symptoms; referred path tenderness: tenderness may extend along the anterior thigh following the intermediate and medial cutaneous nerve branches, and along the medial knee and leg following the saphenous nerve — this mapped distribution confirms neural involvement rather than local musculoskeletal pathology; adductor canal — tenderness at the medial mid-thigh where the saphenous nerve passes beneath the vastoadductor membrane (relevant when saphenous entrapment is suspected)
Temperature: Usually normal; the affected thigh may feel slightly cool in chronic cases due to reduced muscle metabolic activity in the atrophied quadriceps; no significant thermal asymmetry unless concurrent vascular compromise exists
Tissue quality: Quadriceps — soft, flaccid, inelastic; the muscle belly feels reduced in bulk and lacks the firm tone of innervated tissue; psoas — may feel dense and fibrotic if chronically hypertonic; the inguinal ligament may feel taut and unyielding; in chronic cases, the anterior thigh skin may show trophic changes (smooth, thin, reduced hair growth)

Motion Assessment

AROM: Knee extension — markedly weak or absent; the patient cannot extend the knee against gravity from a seated position (this is the defining functional test — gravity-eliminated testing may show trace contraction in partial lesions); hip flexion — reduced if iliacus is involved (proximal lesion); sartorius function (hip flexion with external rotation) may be preserved or reduced depending on the lesion level; hip adduction, abduction, and extension — normal (obturator and gluteal nerves intact)
PROM / end-feel: Knee and hip PROM typically full unless secondary contracture has developed; prone knee bend (hip extension with passive knee flexion) may reproduce anterior thigh pain or paresthesia — this is the femoral nerve stretch test; the end-feel during prone knee bend should be tissue stretch (quadriceps/hip flexors); if it provokes neuropathic symptoms, the neural component is confirmed
Resisted testing: Knee extension — weak or absent (L3–L4: quadriceps); hip flexion — reduced if proximal lesion (L2–L3: iliacus, psoas); knee flexion — normal (hamstrings, sciatic nerve); hip adduction — normal (obturator nerve); hip abduction — normal (superior gluteal nerve); the pattern of isolated knee extension weakness with preserved knee flexion and hip abduction/adduction is diagnostic for femoral nerve pathology

Special Test Cluster

Test	Positive Finding	Purpose
Prone knee bend (Nachlas test) (CMTO)	Prone position, passive knee flexion with hip extension reproduces anterior thigh pain or paresthesia; symptoms may radiate from the groin to the anterior thigh	Stretch the femoral nerve and L2–L4 nerve roots; the primary provocative test for femoral nerve tension; analogous to the SLR for the sciatic nerve
Patellar reflex (CMTO)	Hyporeflexia or areflexia (diminished or absent knee-jerk response)	Confirm disruption of the L2–L4 femoral nerve reflex arc; absent patellar reflex is the single most important differentiating finding — no musculoskeletal condition of the knee produces this finding
Myotomal testing (L2–L4) (CMTO)	Weakness of knee extension (L3–L4) and hip flexion (L2–L3) with preserved hip abduction (L5) and ankle dorsiflexion (L4–L5)	Localizes the lesion to the femoral nerve / L2–L4 nerve roots; the myotomal pattern distinguishes femoral nerve pathology from more diffuse neuropathy
Femoral nerve stretch (ELY's test) (supplementary)	Side-lying or prone; passive hip extension with knee flexion reproduces anterior thigh symptoms	Supplementary nerve tension test; similar to prone knee bend but performed in different positions for patient comfort
Thomas test (CMTO — rule out)	Positive Thomas test (hip cannot fully extend) indicates hip flexor contracture but does not reproduce neurological symptoms	Rule out hip flexor contracture as the sole cause of anterior thigh symptoms; a positive Thomas test without neuropathic symptoms suggests muscular, not neural, pathology
SLR (straight leg raise) (CMTO — rule out)	Reproduction of posterior leg symptoms (sciatic distribution) rather than anterior thigh symptoms	Rule out sciatic nerve or L4–L5/L5–S1 radiculopathy; SLR stresses the sciatic nerve, not the femoral nerve

Vascular safety note: When palpating the femoral triangle during assessment, always palpate for the femoral arterial pulse first. If pulsation is felt directly beneath the palpating finger, reposition laterally — the femoral nerve lies lateral to the artery. Direct sustained pressure on the femoral artery risks vascular compromise and is a critical safety concern. If a pulsatile mass is felt, suspect femoral artery aneurysm — do not compress; refer for vascular evaluation.

Differential Diagnoses

Condition	Key Distinguishing Feature
L3–L4 lumbar radiculopathy	Low back pain as a primary complaint; positive SLR or prone knee bend; Spurling's-equivalent (lumbar extension with lateral flexion) may reproduce symptoms; MRI shows foraminal or central stenosis; may coexist with peripheral femoral nerve compression (double crush)
Trochanteric bursitis (GTPS)	Lateral hip pain, not anterior thigh; tenderness over the greater trochanter; no quadriceps weakness; patellar reflex normal; no sensory loss; pain with resisted hip abduction and side-lying
Rectus femoris strain	Acute onset during explosive hip flexion or kicking activity; focal tenderness at the rectus femoris origin (AIIS) or musculotendinous junction; no sensory loss; patellar reflex normal; resisted hip flexion with knee extension reproduces pain
Meralgia paresthetica (lateral femoral cutaneous nerve)	Lateral thigh numbness and burning — not anterior or medial; no motor weakness; patellar reflex normal; compression is at the inguinal ligament but involves a different nerve (purely sensory); common in obesity and tight clothing
Diabetic amyotrophy	Acute painful proximal leg weakness; often bilateral (though asymmetric); weight loss and systemic features; may mimic femoral nerve injury but affects multiple nerve territories; diabetic history; refer for electrophysiological studies and endocrine management

CMTO Exam Relevance

Classified as A4 neurological condition — lumbar plexus / peripheral nerve injury
The prone knee bend (Nachlas test) is the primary provocative test for femoral nerve tension — equivalent in concept to the SLR for the sciatic nerve; expect exam questions pairing the prone knee bend with anterior thigh symptoms
Absent patellar reflex is the classic differentiating finding — no musculoskeletal condition of the knee (bursitis, strain, meniscal injury) produces an absent patellar reflex; its presence clinches the neurological diagnosis
The "hugging psoas" concept is testable — a hypertonic psoas can physically compress the femoral nerve at its lateral border, creating functional entrapment without structural pathology
Double crush: L3 disc protrusion compromising the L3 root + psoas compression of the femoral nerve = disproportionate symptoms from two subclinical sites
Saphenous nerve as a source of medial knee pain is a common exam scenario — the stem describes chronic medial knee pain with normal knee assessment findings; the answer is saphenous nerve entrapment at the adductor canal
Safety question: When palpating the femoral triangle, always identify the femoral pulse first — the nerve is lateral to the artery; direct pressure on the artery is a contraindication

Massage Therapy Considerations

Primary therapeutic target: The psoas major and iliacus — these muscles form the compression chamber around the proximal femoral nerve. Releasing psoas hypertonicity decompresses the nerve at its most common entrapment site. Where the inguinal ligament is the compression site, releasing the surrounding soft tissue (inguinal ligament, iliacus, sartorius fascia) reduces the compressive force. The quadriceps itself is a secondary target — maintaining tissue elasticity in the denervated muscle to support potential reinnervation.
Sequencing logic: Release the psoas and iliacus first (proximal decompression) → release the inguinal region and femoral triangle soft tissue (distal decompression) → address compensatory patterns (hip flexor contracture, contralateral overload) → gentle quadriceps tissue maintenance → femoral nerve neural mobilization as the final step. Proximal decompression before distal work follows the same principle as ulnar or median nerve protocols.
Safety / contraindications: When palpating the femoral triangle or performing psoas release, always check for femoral arterial pulsation — if a pulse is felt directly beneath the fingers, reposition laterally (the nerve is lateral to the artery); if a pulsatile mass is felt, suspect femoral artery aneurysm and do not compress — refer for vascular evaluation; do not perform deep psoas work if retroperitoneal hematoma is suspected (anticoagulated patient with acute groin/thigh pain and weakness — this is a surgical emergency); areas of anterior thigh numbness require reduced pressure and visual monitoring; avoid aggressive quadriceps stretching (the denervated muscle cannot protect itself from overstretching)
Heat/cold guidance: Moist heat to the psoas and iliacus region (lower abdominal/inguinal area) before treatment to improve tissue pliability for deep work; moist heat to the anterior thigh before quadriceps maintenance work; avoid heat directly over areas of significant sensory loss (thermoregulation may be impaired); contrast hydrotherapy to the anterior thigh post-treatment to promote circulation in the atrophied quadriceps

Treatment Plan Foundation

Clinical Goals

Reduce psoas and iliacus hypertonicity to decompress the femoral nerve at the proximal entrapment site
Reduce soft tissue restriction at the inguinal ligament and femoral triangle
Maintain quadriceps tissue elasticity and circulation to support potential reinnervation
Address compensatory gait patterns and contralateral overloading

Position

Supine with knees flexed over a bolster (reduces psoas tension and provides comfortable access to the anterior thigh and inguinal region); the hip and knee flexion slackens the femoral nerve, reducing neural irritability during treatment
For prone knee bend assessment and posterior thigh work, reposition to prone with a bolster under the ankles
Side-lying on the unaffected side for lateral hip and iliacus work if supine is uncomfortable

Session Sequence

General effleurage to the anterior and medial thigh — assess tissue state, identify areas of muscle wasting (compare quadriceps bulk bilaterally), note temperature and skin quality changes
Psoas release — with the patient supine, knees flexed, gently palpate through the abdominal wall lateral to the rectus abdominis at the level of the umbilicus; apply sustained gentle pressure posteriorly and laterally to contact the psoas belly; check for aortic pulsation (midline) before proceeding — the aorta is medial to the psoas; if pulsation is felt, reposition laterally; sustained inhibitory pressure to the hypertonic psoas; this is the primary nerve decompression technique
Iliacus release — palpate just medial to the ASIS within the iliac fossa; the iliacus lies on the inner surface of the ilium; sustained pressure and myofascial release to reduce compression of the femoral nerve as it crosses the muscle
Inguinal region soft tissue release — gentle myofascial release along the inguinal ligament and femoral triangle; palpate for the femoral pulse first — work lateral to the pulse only; reduce fascial tension at the ligament to create more space for the nerve
Quadriceps tissue maintenance — gentle effleurage and myofascial release to all four quadriceps heads; focus on maintaining tissue elasticity rather than addressing hypertonicity (the muscle is denervated, not hypertonic); VMO receives particular attention as the first head to atrophy and the last to recover
Sartorius and adductor canal release — myofascial release along the sartorius muscle and the medial mid-thigh where the saphenous nerve passes through the adductor canal [include if medial knee pain / saphenous nerve involvement is present]
Femoral nerve neural mobilization — prone knee bend position (hip neutral or slightly extended, knee passively flexed) taken to first onset of anterior thigh symptoms, then oscillated gently within a pain-free range; performed last after all soft tissue decompression; defer if neuropathic pain is severe [subacute/chronic cases only]

Adjunct Modalities

Hydrotherapy: Moist heat to the psoas region (lower abdomen) and anterior thigh before treatment to improve tissue pliability; contrast hydrotherapy to the anterior thigh post-treatment (warm 3 minutes / cool 1 minute, 3 cycles) to promote circulation in the atrophied quadriceps; test temperature tolerance on the anterior thigh if sensory loss is present
Joint mobilization: Patellofemoral mobilization — if quadriceps atrophy has led to altered patellar tracking, gentle medial/lateral and superior/inferior patellar glides maintain patellofemoral joint mobility and prevent adhesion; hip joint mobilization is typically not indicated unless concurrent hip pathology exists
Remedial exercise (on-table): Passive knee extension from a flexed position — the therapist extends the patient's knee through available range to maintain quadriceps tendon excursion and prevent knee flexion contracture; isometric quadriceps sets — if any voluntary contraction is possible, gentle isometric quad setting (pushing the knee into the table) activates whatever motor units remain and stimulates reinnervating fibers; straight leg raise with the therapist's assistance to maintain hip flexor function

Exam Station Notes

Demonstrate checking for the femoral pulse before palpating the femoral triangle — this is a critical safety step and examiners expect to see it
Perform patellar reflex testing bilaterally before treatment — absent reflex on the affected side with normal contralateral reflex is a key diagnostic finding to document
Show bilateral quadriceps circumference comparison (or visual comparison) as part of the assessment — quadriceps atrophy documentation
Verbalize the connection between psoas hypertonicity and femoral nerve compression — demonstrate understanding that releasing the psoas is decompressing the nerve, not just relaxing a tight muscle

Verbal Notes

Psoas work: explain that the treatment involves gentle pressure through the abdomen to access a deep hip flexor muscle that may be compressing the nerve; this can feel unusual or mildly uncomfortable — the patient should communicate if it becomes painful or if they feel pulsation (which would indicate the therapist is on the aorta or femoral artery)
Inguinal region: explain that work near the groin crease is necessary to address the nerve compression site; ensure verbal consent; draping maintained throughout; the patient should report any thigh tingling or numbness during the technique
Anterior thigh numbness: if the patient has reduced sensation over the anterior thigh, explain that lighter pressure will be used in this area and the therapist will monitor visually for tissue response

Self-Care

Psoas stretch — half-kneeling hip flexor stretch with the affected leg back; hold 30 seconds, 3 repetitions, twice daily; reduces chronic psoas tension that may be compressing the nerve; avoid aggressive end-range stretching that could tension the femoral nerve
Isometric quadriceps sets — seated or supine, actively contract the quadriceps (push the knee down into the surface); hold 5 seconds, 10 repetitions, 3 times daily; activates any remaining or recovering motor units; this is the earliest strengthening exercise
Knee range of motion maintenance — seated on a table edge, gently swing the lower leg through flexion and extension; prevents knee stiffness and maintains patellar tendon excursion; gravity-assisted, minimal resistance
Gait safety — use a cane on the contralateral side during walking to prevent knee buckling; consider a knee brace that prevents flexion collapse (a hinged knee brace with extension assist) during walking until quadriceps strength recovers

Key Takeaways

Femoral nerve injury (L2–L4) produces quadriceps paralysis and absent patellar reflex — these two findings together distinguish it from all musculoskeletal conditions of the anterior thigh and knee
The two primary entrapment sites are the lateral border of the psoas (proximal) and the inguinal ligament/femoral triangle (distal) — a proximal lesion produces complete quadriceps loss plus full anterior thigh and medial leg numbness; a distal lesion may be incomplete
The "hugging psoas" is the most treatable mechanism for massage therapists — psoas hypertonicity physically compresses the femoral nerve, and releasing the psoas directly decompresses it
When palpating the femoral triangle, always check for the femoral pulse first — the nerve is lateral to the artery, and direct arterial compression is a critical safety concern
Saphenous nerve entrapment at the adductor canal produces chronic medial knee pain that mimics meniscal or MCL pathology — the absence of quadriceps weakness and normal patellar reflex distinguish it from main trunk femoral nerve injury
Sudden onset of severe groin pain with quadriceps weakness in an anticoagulated patient is an emergency — retroperitoneal hematoma compressing the nerve requires immediate medical referral
The prone knee bend (Nachlas test) is the primary provocative test — it tensions the femoral nerve and L2–L4 roots, analogous to the SLR for the sciatic nerve