5- Lower Extremities Mononeuropathies Flashcards
Draw Lumbarosacral Plexus
Lumbar Plexus ( Root - 5 Sensory Branches - 3 Muscle Groups - 1 Reflex) ππ
Root
- L2-L4 (Following dermatomes)
Sensory
- Femoral branch of genito-femoral nerve
- Obturator nerve
- Lateral femoral cutaneous nerve of thigh
- Medial & Intermediate and medial cutaneous nerves of thigh (from femoral nerve)
- Saphenous nerve (from femoral nerve)
Motor
- Iliopsoas: Lumbar spinal nerves L1-3 (psoas) and parts of the femoral nerve (iliacus).
- Quadriceps (Femoral n.)
- Adductors (Obturator n.)
Reflexes
- Knee jerk
List 6 Etiologies of Lumbosacral Plexopathy
Structural
- Retroperitoneal hemorrhage
- Abdominal Tumor
- Aneurysm
- Endometriosis
- Trauma
- Hip dislocation
Non-Structural
- Diabetic amyotrophy
- Obstetric injuries (Post-partum foot drop)
- Radiation
- Inflammation
- Infarction
Ref: Shapiro
Adductor magnus innervation ππ
Posterior branch of obturator nerve (adductor) and sciatic nerve (hamstring)
Innervation for: Foot 1st & 5th DI, Gmax & Gmed
Gmax: Inferior glute n.
Gmed, Gmini & TFL: Superior glute n.
Tibial n. branch into
Foot 1st DI: Medial planter n.
Foot 5th DI: Lateral planter n.
Anteriolateral thigh pain and paresthesia. Spot diagnosis. ππ
Meralgia paresthetica β Lateral femoral cutaneous nerve
Anteromedial leg numbness after bypass. Dx? ππ
Saphenous neuropathy β blood supply to the nerve is interrupted during surgery and ischemic neuropathy
Draw femoral triangle
Root and Branches of femoral nerve. (7 muscles and 3 sensory) ππ
Root
- L2-L4
- Posterior division of lumbar plexus
- Obturator n. β anterior division of lumbar plexus
Motor (kick)
- Iliacus & Psoas (before inguinal ligament)
- Pectineus (1/2)
- Rectus femoris
- Vastus lateralis, intermedius, medius.
Sensory
- Medial and intermediate cutaneous branch (L2-3)
- Saphenous n. β medial leg (L4)
Femoral Neuropathy Etiology, PEx, EDX, Managment
Etiology
- Iatrogenic from abdominal or pelvic surgery (most common)
- Trauma (e.g., fracture, abdominal/pelvic surgery, anterior total hip arthroplasty, direct trauma from cardiac catherization)
- Retroperitoneal hematoma
- Aortic aneurysm
- Tumor
- Lymphadenoma
- Pelvis mass
- Vaginal delivery
- Inguinal ligament entrapment
- Dancing (Hyperextension)
- Radiation
- Ischemia
Clinical presentation
- Hip flexion weakness (only in injuries above the inguinal ligament)
- Weakness of knee extension (quadriceps)
- Knee instability (collapse) during gait, lose of extension moment arm.
- Decreased sensation over the anterio-medial thigh and medial lower leg.
- Patellar reflex can be depressed or absent
NCS
- Abnormal saphenous nerve SNAP
- Abnormal CMAP to the rectus femoris
EMG
- Femoral nerve innervated muscles
Managment
- Early physical therapy for strengthening and range of motion
- Ground Reaction AFO or KAFO
Findings suggest lumbar plexopathy or L2-L4 radiculoapthy rather than femoral neuropathy ππ
Femoral Neuropathy
- Weak knee extension
- Weak hip flexion (above inguinal ligament)
- Reduced knee reflex
- Sensory loss of anteriomedial thigh
- Sensory loss of medial calf
Lumbar Plexus injury
Just taking step back in the lumbar plexus.
- Sensory loss in proximal medial thigh (Obturator n.)
- Sensory loss in lateral thigh (Lateral femoral cutaneus n.)
- Weakness in hip adductions (Obturator n.)
- Weak ankle dorsiflexion
L2-L4 Radiculoapthy
- Same as lumbar plexopathy
- Paraspinal muscles (low back pain as in any radiculopathy)
Shapiro Table 26.1
Lateral Femoral Cutaneous Nerve
Origin, 6 Etiologies, PEx, EDx, 4 Treatment
Origin
- L2-L3
Etiology
- Compression by low grade trauma
- Iatrogenic incisions for lower abdominal/pelvic surgeries and laparoscopic hernia repairs
- Protuberant abdomen
- Pregnancy
- Tight clothing
- Diabetes
- Tumor
- Rapid gain or weight loss can also affect the nerve
Clinical presentation & EDX
- Pure sensory syndrome with no muscle involvement
- Exacerbated with hip extension or hyperflexion (driving).
EDX (NCS)
- Abnormal lateral femoral cutaneous nerve SNAP
Treatment
- Symptoms may be self-limited, weight reduction.
- Removal of compressive clothing should occur (e.g., wide belt, compressive athletic clothing).
- Physiotherapy (Heat or TENS)
- NSAIDs
- Cortisone injections
- Capsaicin cream
- Lidoderm patches can be helpful.
- Tricyclic antidepressants: Amitriptyline
- Anti-seizure medications: Gabapentin (Neurontin), pregabalin (Lyrica), or carbamazepine (Tegretol)
- Surgical release.
Mention 5 Anatomic variations in the course of the lateral cutaneous nerve of the thigh
- Posterior to the anterior superior iliac spine (ASIS), across the iliac crest
- Anterior to the ASIS and within inguinal ligament
- Medial to the ASIS and within sartorius tendon
- Between the tendon of the sartorius muscle and the fascia of the iliopsoas
- Overlying the fascia of the iliopsoas muscle
How does a femoral nerve lesion differ from an L3 radiculopathy?
Abnormalities in the hip adductors in addition to the quadriceps muscles are present in L3 radiculopathies
Neurology Secrets 6th Edition Chapter 32 pg472
How does a femoral nerve lesion in the pelvis differ from a lesion at the inguinal level?
Weakness and denervation in the iliopsoas in addition to the quadriceps muscle indicate a femoral nerve lesion in the pelvis
Neurology Secrets 6th Edition Chapter 32 pg472
Root and Branches of Obturator nerve
Root
- L2-L4
- Anterior division of lumbar plexus
- Femoral n. β Posterior division of lumbar plexus
Branches:
- Adductor brevis
- Adductor longus
- Adductor magnus (1/2)
- Pectineus (1/2)
- Obturator externus
- Gracilis
- Cutaneous branch
Cuccurollo 4th Edition Chapter 5 EDX pg410-411
Sacral Plexopathy (Root - 5 Sensory Branches - 5 Muscle Groups - Reflex) ππ
Root
- L4-S3
Sensory
- Lateral cutaneous nerve of calf (common peroneal nerve)
- Superficial peroneal nerve (common peroneal nerve)
- Sural nerve (tibial nerve)
- Calcanean branches of sural and tibial nerves
- Posterior cutaneous nerve of thigh
Motor
- Dorsiflexion & eversion (Common peroneal n. β anterior tibial muscles)
- Planterflexion & inversion (Tibial n. β posterior tibial muscles)
- Knee flexion (Sciatic n. β Hamsting)
- Hip extensors (Inferior glute n. β Gmax)
- Abductors, internal rotators (Superior glute n. β Gmed, mini, TFL)
Reflexes
- Hamsting L5
- Ankle jerk S1
Superior Gluteal Nerve Palsy vs Inferior Gluteal Nerve Palsy (Root, Sensory, Motor)
π‘ No SNAP or CMAP studies exist
Superior Gluteal Nerve
- Root L4-S1
- Trendelenburg gait +ve (weak glut medius)
- Hip abduction and external rotation (glute medius & TFL)
Inferior Gluteal Nerve
- Root L5βS2 (one root below)
- Weakness of hip extension (glute max)
Cuccurollo 4th Edition Chapter 5 EDX pg418