High-yield overview
The Neural Grid of the Lower Limb
L1-S4Roots
PsoasLumbar Bed
PiriformisSacral Bed
SciaticMajor Output
KEY DIVISIONS
Lumbar
PatternL1-L4
TreatmentFemoral, Obturator, LFCN
Sacral
PatternL4-S4
TreatmentSciatic, Gluteal, Pudendal
Lumbosacral
PatternL4-L5
TreatmentConnecting Trunk
Critical Must-Knows
- Lumbar Plexus forms WITHIN the substance of Psoas Major.
- Sacral Plexus forms on the ANTERIOR surface of Piriformis.
- Femoral and Obturator nerves arise from same roots (L2,3,4) but diverge (Femoral = Posterior division, Obturator = Anterior).
- Genitofemoral nerve runs ON the surface of Psoas (L1,2).
- Lateral Cutaneous Nerve of Thigh (L2,3) passes under Inguinal Ligament (ASIS compression).
Clinical Pearls
- "Obturator nerve is the only branch of the Lumbar plexus to enter the thigh via the obturator foramen.
- "Furcal Nerve: The specific root (usually L4) that contributes to BOTH plexuses via the Lumbosacral Trunk.
- "Femoral Nerve is formed by POSTERIOR divisions (supplies extensors/anterior skin).
- "Obturator Nerve is formed by ANTERIOR divisions (supplies adductors/medial skin).
Clinical Imaging
Imaging Gallery
Surgical Corridors
Lateral Spine Surgery (XLIF)
Trans-Psoas Approach.
- The lumbar plexus lies in the posterior third of the psoas muscle.
- As you go from L1 to L5, the plexus migrates anteriorly.
- Risk: At L4/5, the nerve roots are very frequent and anterior. Neural monitoring is mandatory.
Pelvic Trauma
Retroperitoneal Hematoma.
- Fractures of the pelvis/sacrum can cause massive bleeding.
- Compression of the lumbosacral plexus manifests as diffuse weakness (Femoral + Sciatic).
| Nerve | Roots | Motor | Sensory |
|---|---|---|---|
| Iliohypogastric | T12, L1 | Transversus/Oblique | Suprapubic/Gluteal |
| Ilioinguinal | L1 | Transversus/Oblique | Groin/Scrotum |
| Genitofemoral | L1, L2 | Cremaster | Ant Thigh/Scrotum |
| Lat Cutaneous | L2, L3 | None | Lateral Thigh |
| Femoral | L2, L3, L4 | Quads/Iliacus/Sart | Ant Thigh/Med Leg |
| Obturator | L2, L3, L4 | Adductors | Medial Thigh |
Mnemonic
I Get Leftovers On FridaysLumbar Plexus Branches
| I | Iliohypogastric (L1) |
| I | Ilioinguinal (L1) |
| G | Genitofemoral (L1, L2) |
| L | Lateral Cutaneous (L2, L3) |
| O | Obturator (L2, L3, L4) |
| F | Femoral (L2, L3, L4) |
| I | Iliohypogastric (L1) | G | Genitofemoral (L1, L2) | O | Obturator (L2, L3, L4) |
| I | Ilioinguinal (L1) | L | Lateral Cutaneous (L2, L3) | F | Femoral (L2, L3, L4) |
Hook:The order they emerge (superior to inferior).
Mnemonic
2 from 1, 2 from 2, 2 from 3Root Values - Rule of 2s
| Ilio | Hypogastric/Inguinal L1 (1 root) |
| Genito | Femoral L1, L2 (2 roots) |
| Lat | Cutaneous L2, L3 (2 roots) |
| Fem/Obt | Femoral/Obturator L2, L3, L4 (3 roots) |
| Ilio | Hypogastric/Inguinal L1 (1 root) | Lat | Cutaneous L2, L3 (2 roots) |
| Genito | Femoral L1, L2 (2 roots) | Fem/Obt | Femoral/Obturator L2, L3, L4 (3 roots) |
Hook:Nerves get bigger as you go down.
Mnemonic
S-I-P-P-SSacral Plexus Branches
| S | Superior Gluteal (L4-S1) |
| I | Inferior Gluteal (L5-S2) |
| P | Posterior Cutaneous of Thigh (S1-S3) |
| P | Pudendal (S2-S4) |
| S | Sciatic (L4-S3) |
| S | Superior Gluteal (L4-S1) | P | Pudendal (S2-S4) |
| I | Inferior Gluteal (L5-S2) | S | Sciatic (L4-S3) |
| P | Posterior Cutaneous of Thigh (S1-S3) |
Hook:Major branches leaving the pelvis.
Overview
The Lumbosacral Plexus is the neural network supplying the lower limb, pelvis, and perineum. It is functionally two plexuses (Lumbar and Sacral) connected by the Lumbosacral Trunk. The lumbar plexus forms within the Psoas major muscle, while the sacral plexus lies on the surface of the Piriformis muscle.
Neurovascular
Lumbar Plexus (T12-L4)
Formed by the ventral rami of L1-L4 (with contribution from T12).
Location:
- Embedded within the posterior third of the Psoas Major muscle, anterior to the transverse processes of lumbar vertebrae.
Emergence:
- Lateral Border: Iliohypogastric, Ilioinguinal, Lateral Cutaneous, Femoral.
- Anterior Surface: Genitofemoral.
- Medial Border: Obturator, Lumbosacral Trunk.
Anatomical Imaging
Lumbar Plexus Terminal Branches
Classification Systems
Anatomical Variants (Zones of Emergence)
While not a formal classification, the relationship of the Lumbar Plexus to the Psoas is categorized for lateral spine surgery:
- Zone 1 (Posterior): Safe zone.
- Zone 2 (Middle): Danger zone (Femoral Nerve).
- Zone 3 (Anterior): Vascular zone.
The plexus migrates from Zone 1 to Zone 2/3 as you descend from L1 to L4.
Clinical Implication:
- At L1/2, the plexus is dorsal (Zone 1), making lateral access safe.
- At L4/5, the plexus is ventral (Zone 2/3), making lateral access high risk.
Pre-operative MRI is essential to map this migration in each patient.
Surface Anatomy
Key Surface Landmarks
- ASIS: Anterior Superior Iliac Spine. Origin of Inguinal Ligament.
- Pubic Tubercle: Insertion of Inguinal Ligament.
- Psoas Major: Palpable in thin patients in the iliac fossa (flex hip against resistance).
Nerve Projections
- Femoral Nerve: Mid-inguinal point (midway between ASIS and Pubic Symphysis). Lateral to the pulse.
- LFCN: 2cm medial and inferior to the ASIS (variable).
- Sciatic: Midpoint between Ischial Tuberosity and Greater Trochanter.
- Pudendal: Medial to Ischial Spine (trans-vaginal or trans-gluteal palpation).
Knowledge of these landmarks facilitates targeted nerve blocks in the emergency department (e.g., Fascia Iliaca Block).
Clinical Assessment
Lumbosacral Plexopathy
- Distribution: Weakness spanning both Femoral (Quads) and Sciatic (Hamstrings/Ankle) territories.
- Reflexes: Loss of both Knee (L3/4) and Ankle (S1) jerks.
- Sensation: Widespread loss.
Specific Signs
- Cremasteric Reflex (L1/2): Stroke inner thigh → Testicle elevation (Genitofemoral).
- Meralgia Paresthetica: Burning pain lateral thigh. Tapping ASIS (Tinel's).
Root vs Plexus
| Feature | Root (Radiculopathy) | Plexus |
|---|---|---|
| Distribution | Dermatomal (Single strip) | Multi-dermatomal / Regional |
| Weakness | Myotomal (Specific muscles) | Multiple muscles + compartments |
| Pain | Radiating (Electric shock) | Deep, aching, poorly localized |
| Paraspinals | Denervated (EMG positive) | Normal (Sparing) |
Differential Diagnosis
A regional lower-limb deficit can arise at the root, plexus or peripheral nerve. The table below separates the common mimics of a lumbosacral plexopathy.
| Diagnosis | Distribution | Discriminator | Key Test |
|---|---|---|---|
| Lumbosacral plexopathy | Multi-myotomal, often femoral + sciatic | Paraspinals spared; reduced SNAPs | MR neurogram + EMG/NCS |
| Polyradiculopathy / cauda equina | Multi-dermatomal, may be bilateral | Saddle anaesthesia, bladder/bowel signs; SNAPs preserved | Urgent MRI lumbosacral spine |
| Single radiculopathy (e.g. L5) | Single dermatome/myotome | Denervated paraspinals; preserved SNAPs | MRI + EMG paraspinal sampling |
| Femoral mononeuropathy | Quads weak, knee jerk lost | Adductors (obturator) spared | Saphenous SNAP, femoral imaging |
| Diabetic amyotrophy | Asymmetric proximal, painful, weight loss | Subacute onset in diabetic; monophasic | Clinical + EMG, glucose |
| Meralgia paresthetica | Lateral thigh sensory only | No motor loss; Tinel at ASIS | LFCN block / nerve conduction |
| Peripheral vascular / claudication | Activity-related, relieved by rest | Pulses, ankle-brachial index abnormal | ABI, duplex / angiography |
Controversies & Areas of Uncertainty
- Neuromonitoring efficacy in trans-psoas surgery: Triggered EMG is standard, but it monitors motor roots poorly and does not reliably detect femoral nerve stretch. Saphenous SSEP and quadriceps MEP improve sensitivity, yet no randomised trial proves a reduction in permanent deficit, and limiting retraction time alone is insufficient.
- Prepsoas (ATP/OLIF) vs trans-psoas access: Lower neural morbidity favours prepsoas corridors, but they carry sympathetic chain and vascular risks and cannot reach every level. The optimal corridor at L4-5 remains debated.
- Immunotherapy for diabetic / non-diabetic radiculoplexus neuropathy: Microvasculitis suggests an immune mechanism, but controlled evidence for corticosteroids or IVIg is weak; most clinicians treat supportively given the monophasic natural history.
- Timing of decompression for compressive lesions: For retroperitoneal/iliopsoas haematoma, the threshold between reversal-and-observe versus surgical evacuation is not standardised; decisions rest on progression of deficit and haemodynamics rather than haematoma size alone.
- Surgical repair of traumatic plexus injury: Direct repair of the lumbosacral plexus is technically demanding with guarded results, and the role and timing of nerve grafting versus tendon transfers and orthotics is unresolved.
Investigations
MRI
- MRI Lumbar Spine: Rule out disc pathology.
- MRI Pelvis (Neurogram): The gold standard for plexus visualization. Can identify:
- Tumors (Neurofibroma, Schwannoma).
- Psoas Hematoma (Hypointense/Heterogeneous).
- Piriformis pathology.
CT
- CT Abdomen/Pelvis: Essential in trauma to identify retroperitoneal bleed or fractures compressing the plexus (LI/SI joint).
Contrast is required to differentiate hematoma from muscle for accurate sizing.
Management Strategy
Management Principles
| Etiology | Management | Surgical Indication |
|---|---|---|
| Hematoma (Anticoag) | Reverse agents, Observe | Progressive deficit / Compartment Syn |
| Trauma (Fracture) | Reduce fracture, Stabilize | Bone fragment on nerve |
| Tumor | Biopsy, Resect | Mass effect / Malignancy |
| Diabetic Amyotrophy | Glycemic control, Pain mgmt | None |
- Observation: Most stretch injuries or hematomas recover with time.
- Surgery: Direct repair of plexus injuries is technically difficult and outcomes are guarded. Decompression (e.g., removing bone fragment or hematoma) is more common.
Timing of surgery depends on the progression of neurological deficit and the stability of the patient.
Surgical Technique
Protecting the Plexus
- Acetabular Surgery: In anterior approach (Ilioinguinal), isolate Femoral Nerve and protect with vessel loop.
- Spine Surgery (XLIF): Use EMG monitoring. Place dilators in the anterior third of the disc space at L4/5 to avoid the forward-migrating plexus.
Strict hemostasis is vital to prevent post-op retroperitoneal hematoma.
Complications
- Chronic Pain: Complex Regional Pain Syndrome (CRPS) is a risk.
- Motor Deficit: Quadriceps weakness (Femoral) leads to knee instability (Buckling). Adductor weakness leads to gait disturbance.
- Sensory Loss: Ulceration in anesthetic areas (Foot/Heel).
- Sexual Dysfunction: Pudendal nerve involvement can cause erectile dysfunction or loss of sensation.
- Lumbosacral Trunk Injury: Often missed in pelvic fractures. Presents with non-specific foot drop and weak glutes. Requires screw removal if caused by excessive length during fixation.
- Abdominal Wall Weakness: Iliohypogastric nerve injury (via lateral ports) causes a bulge (pseudo-hernia) due to paralysis of the conjoint tendon.
Rehabilitation Protocol
- Gait Training: Knee bracing for femoral neuropathy (locking knee during stance).
- Strengthening: Core and unharmed limb compensation.
- Desensitization: For neuropathic pain.
- Orthotics: AFO for foot drop (Sciatic component).
Prognosis
- Stretch/Compression: Good prognosis if cause removed early.
- Diabetic Amyotrophy: Self-limiting but takes 12-18 months.
- Trauma (Avulsion): Poor prognosis. Root avulsions do not recover.
- Hematoma: Variable. Early decompression improves outcome.
Evidence Base
Anatomical Safe Working Zones for the Transpsoas Approach
Uribe JS, Arredondo N, Dakwar E, Vale FL • J Neurosurg Spine (2010)
Key Findings:
- Cadaveric study (20 lumbar segments): all of the lumbar plexus, including roots, lay within psoas dorsal to the posterior quarter of the vertebral body (Zone IV)
- Safe disc-space target was the mid-posterior quarter (Zone III) from L1-2 to L3-4, but moved anteriorly to the Zone II/III junction (mid-vertebral body) at L4-5
- Genitofemoral nerve emerges from the medial psoas border at L3-4 and is at risk in Zone I anteriorly at lower levels
Clinical Implication: Stay in the mid-to-posterior disc at upper levels but move toward the mid-body at L4-5, and use neuromonitoring during transpsoas access.
Transpsoas vs Prepsoas Lateral Interbody Fusion: Neural Complications
Spiessberger A, Arvind V, Dietz N, et al. • Clin Spine Surg (2020)
Key Findings:
- Meta-analysis of 115 studies and 13,260 patients (2,450 prepsoas, 10,810 transpsoas)
- Transient psoas weakness or thigh/groin numbness was far higher with the transpsoas approach (26% vs 4%)
- Motor neural injury was also higher transpsoas (1.3% vs 0.4%); vascular and visceral injury rates were similar between approaches
Clinical Implication: The trans-psoas corridor traverses the lumbar plexus, so thigh symptoms are common and a prepsoas (ATP/OLIF) corridor reduces neural morbidity.
Femoral Nerve Monitoring During Lateral Lumbar Interbody Fusion
Silverstein JW, Block J, Smith ML, et al. • Spine J (2021)
Key Findings:
- Multicentre series of 172 transpsoas LLIF procedures using femoral nerve evoked potentials (saphenous SSEP plus quadriceps MEP)
- In 11% the surgeon was alerted to femoral nerve deterioration during retraction; prompt countermeasures (loosen/remove retractor, raise blood pressure) restored signals with no postoperative deficit
- The two cases that ignored alerts both developed anterior thigh numbness and quadriceps weakness; limiting retraction time alone did not prevent injury
Clinical Implication: Continuous femoral nerve neuromonitoring detects hyperacute conduction failure and lets the surgeon reverse retractor-related injury in real time.
Diabetic and Nondiabetic Lumbosacral Radiculoplexus Neuropathy
Dyck PJB, Windebank AJ • Muscle Nerve (2002)
Key Findings:
- Diabetic amyotrophy is a subacute, painful, asymmetric lower-limb neuropathy with weight loss that becomes bilateral and motor-predominant
- Nerve biopsy shows ischaemic injury and microvasculitis, supporting an immune-mediated rather than purely metabolic mechanism
- It is a monophasic illness with prolonged morbidity but gradual recovery; immunomodulatory therapy remained under trial
Clinical Implication: Recognise diabetic amyotrophy clinically to avoid unnecessary spinal surgery and to focus on pain control and rehabilitation.
Nerve Palsy and Leg Lengthening in THA for Hip Dysplasia
Eggli S, Hankemayer S, Muller ME • J Bone Joint Surg Br (1999)
Key Findings:
- Review of 508 THAs for developmental dysplasia: eight nerve palsies (six sciatic, two femoral)
- No statistical correlation between the amount of lengthening and palsy (p=0.47)
- Palsy correlated instead with operative difficulty - prior surgery, severe deformity, acetabular defect or flexion contracture (p=0.041)
Clinical Implication: Nerve injury in dysplastic THA is driven by mechanical trauma and case complexity, not lengthening alone - protect the femoral and sciatic nerves in difficult exposures.
Topographic Anatomy of the LFCN in Meralgia Paresthetica
Lee SH, Shin KJ, Gil YC, et al. • Muscle Nerve (2017)
Key Findings:
- Cadaveric study of 33 specimens mapping the lateral femoral cutaneous nerve at the inguinal ligament
- Mean ASIS-to-LFCN distance was 8.8 mm; in around 90% the nerve lay within 2 cm of the medial ASIS and in 76% within 1 cm
- The nerve crossed the inguinal ligament at a mean angle of 83 degrees, defining a consistent but variable entrapment point
Clinical Implication: The LFCN is reliably just medial and inferior to the ASIS - the target for Tinel testing, diagnostic block and decompression in meralgia paresthetica.
Lumbosacral Plexus Injury in Pelvic Fractures (Classic Series)
Huittinen VM, Slatis P • Acta Chir Scand (textbook-level historical reference) (1972)
Key Findings:
- Landmark cadaveric and clinical series describing lumbosacral plexus and trunk injury in displaced pelvic and sacral fractures
- The L4-L5 lumbosacral trunk crosses the sacral ala and is vulnerable in vertical-shear and posterior ring disruptions
- Prognosis depends on mechanism, with traction/stretch lesions recovering better than laceration
Clinical Implication: Document L5 and sciatic function in every displaced pelvic ring or sacral fracture; the lumbosacral trunk at the ala is the classic site of injury.
Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
CLINICAL SCENARIOStandard
Scenario 1: Post-Op Weakness
CLINICAL PROMPT
"A patient has severe groin pain and quadriceps weakness after an angiogram (femoral puncture). What is happening?"
PRACTICAL APPROACH
This suggests a retroperitoneal hematoma compressing the lumbar plexus (specifically femoral nerve). I would assess hemodynamics (blood loss) and check coagulation status. I would stop any anticoagulation. Urgent CT Abdomen/Pelvis is required. If the hematoma is large and there is progressive deficit, surgical decompression is indicated. Otherwise, reverse anticoagulation and observe. I would rule out a pseudoaneurysm.
KEY CLINICAL POINTS
Retroperitoneal Hematoma
CT Scan
Reverse Anticoagulation
COMMON PITFALLS
Assuming it's just local trauma
Missing hemodynamic instability
FURTHER QUESTIONS
"What is the prognosis?"
"Generally good if decompressed or resorbed, but recovery takes months."
CLINICAL SCENARIOStandard
Scenario 2: Lateral Thigh Pain
CLINICAL PROMPT
"A slightly obese patient complains of burning pain in the lateral thigh, worse with standing or tight belts. Examination shows sensory loss in the lateral thigh but no motor deficit. Diagnosis?"
PRACTICAL APPROACH
This is Meralgia Paresthetica, entrapment of the Lateral Cutaneous Nerve of the Thigh (LFCN) under the inguinal ligament. It is purely sensory. I would confirm with a Tinel's sign over the ASIS. Management is conservative: weight loss, loose clothing, NSAIDs. If refractory, a steroid injection around the ASIS is diagnostic and therapeutic. Surgery (neurolysis) is a last resort.
KEY CLINICAL POINTS
Meralgia Paresthetica
Purely Sensory
Conservative First
COMMON PITFALLS
Looking for weakness (there is none)
Ordering MRI Spine immediately (rule out radiculopathy first)
FURTHER QUESTIONS
"What roots are involved?"
"L2 and L3."
CLINICAL SCENARIOStandard
Scenario 3: Pelvic Fracture
CLINICAL PROMPT
"High energy pelvic fracture. Vertical shear injury. Patient has a foot drop and weak glutes. Where is the lesion?"
PRACTICAL APPROACH
This injury pattern (Combined Foot Drop + Weak Glutes) suggests a lesion at the Lumbosacral Plexus or Trunk, rather than an isolated Sciatic Nerve injury (which usually spares glutes) or Common Peroneal (spares glutes and hamstrings). The Lumbosacral Trunk (L4/5) crosses the sacral ala and is vulnerable in vertical shear fractures. I would assess with MRI Pelvis/Neurogram once stabilized.
KEY CLINICAL POINTS
Lumbosacral Trunk
Vertical Shear
Gluteal Involvement = High Lesion
COMMON PITFALLS
Calling it a Sciatic Nerve injury
Missing the gluteal weakness
FURTHER QUESTIONS
"What is the 'Far Out' Syndrome?"
"Compression of the L5 root by an osteophyte or fracture fragment in the extraforaminal zone (between sacral ala and L5 transverse process)."
MCQ Practice Points
Obturator vs Femoral
Q: How do you differentiate L3 radiculopathy from Femoral Neuropathy clinically? A: Adductor strength. Both supply hip flexors/knee extensors (L2/3/4), but the Adductors are supplied by the Obturator Nerve (also L2/3/4).
- If Adductors clearly spared: Femoral Neuropathy.
- If Adductors weak: Plexus or Root lesion.
Genitofemoral
Q: What is the course of the Genitofemoral Nerve? A: It pierces the Psoas Major muscle anteriorly. This makes it distinct from others that emerge from the borders.
Furcal Nerve
Q: What is the 'Furcal Nerve'? A: The L4 root. It is 'forked' because it contributes to both the Lumbar Plexus (via Femoral/Obturator) and the Sacral Plexus (via Lumbosacral Trunk).
LFCN Roots
Q: What are the root values of the Lateral Cutaneous Nerve of the Thigh? A: L2, L3. Posterior divisions.
Pudendal Nerve
Q: Which roots form the Pudendal Nerve? A: S2, S3, S4. 'S2, 3, 4 keeps the poo off the floor'.
Guidelines, Registries & Global Practice
Global Epidemiology
- Iatrogenic plexus risk in lateral spine surgery: Transient thigh/groin sensory symptoms or psoas weakness occur in roughly a quarter of trans-psoas lateral interbody fusions, with persistent motor deficit in around 1 percent (Spiessberger et al., meta-analysis of more than 13,000 patients). Risk concentrates at L4-5.
- Traumatic lumbosacral plexus injury: Reported in approximately 10 to 25 percent of displaced pelvic ring and sacral fractures, especially vertical-shear and Denis zone III sacral patterns; the L5 root / lumbosacral trunk at the sacral ala is the classic site.
- Meralgia paresthetica: A common entrapment neuropathy, associated with obesity, pregnancy, diabetes, tight belts and prone positioning; the lateral femoral cutaneous nerve lies within 2 cm of the medial ASIS in around 90 percent of people.
Side-by-Side Guidance
| Body | Domain | Key Position |
|---|---|---|
| AO Spine / Lateral access consensus | Lateral interbody fusion | Stay in posterior-mid disc at upper levels, move anterior at L4-5; intraoperative neuromonitoring recommended |
| NASS / Spine societies | Neuromonitoring | Triggered and free-run EMG plus saphenous SSEP / quadriceps MEP to protect the femoral nerve in trans-psoas corridors |
| BOA / BOAST (pelvic & spinal trauma) | Pelvic ring injury | Early neurological documentation, transfer of complex ring injuries to a major trauma centre with pelvic and spinal expertise |
| AAOS / EFORT | Peripheral nerve injury | Serial examination; baseline and follow-up electrodiagnostics at 3-6 weeks; refer non-recovering lesions for nerve specialist assessment |
Registry & High- vs Limited-Resource Practice
- Registry signal: Arthroplasty registries (NJR, AOANJRR, AJRR, Swedish/Norwegian) capture nerve palsy as a revision-associated complication of complex/dysplastic hip reconstruction; case complexity rather than lengthening per se drives risk (Eggli et al.).
- High-resource settings: Intraoperative neuromonitoring, MR neurography and dedicated peripheral nerve / pelvic trauma services are routinely available, enabling early targeted decompression.
- Limited-resource settings: Where neuromonitoring or neurography is unavailable, surface anatomy and the documented "safe zones" become the primary safeguard, and serial clinical examination replaces electrodiagnostics for triage. Chronic neuropathic pain and CRPS remain major causes of long-term disability worldwide and benefit from early multidisciplinary pain management.
Clinical summary
Anatomy
- •Lumbar: L1-L4 (in Psoas)
- •Sacral: L4-S4 (on Piriformis)
- •Trunk: L4/5 (Connects them)
- •Femoral/Obt: L2/3/4
Clinical
- •Femoral: Quads (Ext)
- •Obturator: Adductors
- •LFCN: Lat Thigh Sensory
- •Sciatic: Hamstrings/Leg
Pathology
- •Meralgia: Compressive (ASIS)
- •Hematoma: Warfarin/Bleed
- •XLIF: Iatrogenic L4/5
- •Diabetes: Amyotrophy