https://upload.orthobullets.com/topic/2002/images/emg of muscles.jpg
https://upload.orthobullets.com/topic/2002/images/LE dermatomes_moved.jpg
https://upload.orthobullets.com/topic/2002/images/brachial plexus fixed._moved.jpg
  • Warning: the table below is a simplification as muscles are often innervated by multiple nerve root
    • for example, ankle dorsiflexion usually has a contribution from both L4 and L5  
Primary Motion
Primary Muscles
L1      Iliac crest and groin Cremasteric
L2,3 Hip flexion
Hip adduction
iliopsoas (lumbar plexus, femoral n.)
hip adductors (obturator n.)
 Anterior and inner thigh None
L4 Knee extension (also L3)
quadriceps (femoral n.
 Lateral thigh, anterior knee, and medial leg Patellar
L5 Ankle dorsiflexion (also L4) tibialis anterior (deep peroneal n.)  Lateral leg & dorsal foot
Foot inversion tibialis posterior (tibial n.)
Toe dorsiflexion EHL (DPN), EDL (DPN)
Hip extension hamstrings (tibial) & gluteus max (inf. gluteal n.)
Hip abduction  gluteus medius (sup. gluteal n.
S1 Foot plantar flexion
Foot eversion
gastroc-soleus (tibial n.)
peroneals (SPN)
 Posterior leg Achilles
S2 Toe plantar flexion FHL (tibial n.), FDL (tibial
 Plantar foot None
S3,4 Bowel & bladder function bladder  Perianal
History & Symptoms
Characteristic symptoms
systemic symptoms (weight loss) tumor, infection
evaluation of localized axial pain tumor, infection
mechanical pain instability, discogenic pain
radicular pain HNP
night pain tumor
referred pain peptic ulcer disease, cholecystiits, nephrolithiasis, PID, pancreatitis
concomittant pain hip & shoulder
psychogenic secondary gain
Inspection & Palpation
  •  Inspection
    • skin
      • looking for prior scars, cafe au lait spots
Motor Exam
Muscle Grading System (ASIA)
0 Total paralysis
1 Palpable or visible contraction
2 Active movement, full range of motion, gravity eliminated
3 Active movement, full range of motion, against gravity
4 Active movement, full range of motion, against gravity and provides some resistance
5 Active movement, full range of motion, against gravity and provides normal resistance
NT Patient unable to reliably exert effort or muscle unavailable for testing due to factors such as immobilization, pain on effort or contracture.
Sensory Exam
Sensory Grading System (ASIA)
0 Absent
1 Impaired
2 Normal
NT Not Testable
Specific Tests
  • Special tests
    • straight leg raise 
  • Brachial Plexus Illustration 
  • Sensory Illustration 
Clinical Findings
Neurologic etiology
Paresthesias alone medial aspect of knee Irritation of saphenous division of femoral nerve • Psoas absces 
• Saphenous n. compression (surfing)
A Trendelenburg gait Injury to L5 nerve root Paracentral L4/5 HNP
Waddel Signs
  • Waddell identified 5 exam findings that correlated with non-organic low back pain. The tests include
Finding Description
1. Tenderness a. superficial - pain with light touch to skin
b. deep - nonanatomic widespread deep pain
2. Simulation a. pain with light axial compression on skull 
b. pain with light twisting of pelvis
3. Distraction No pain with distracted SLR
4. Regional a.nonanatomic or inconsistent motor findings during entire exam 
b. nonanatomic or inconsistent sensory findings during entire exam
5. Overreaction Overreaction noted at any time during exam


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(OBQ13.22) A Trendelenburg gait would most likely be caused by which of the following lumbar conditions. Review Topic

QID: 4657

L3/4 far lateral disc herniation




L3/4 central disc herniation with impingement on the bilateral descending nerve roots




L4/5 far lateral disc herniation




L5/S1 far lateral disc herniation




L5/S1 paracentral disc herniation



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