1. Passive Straight Leg Raise (SLR or Lasegue's sign)
-The normal leg can be raised 80 degrees; <80 degrees= tight hamstrings or a sciatic nerve problem. To differentiate, raise the leg to the point of pain, lower slightly, then dorsiflex the foot. Pain = sciatica, no pain= tight hamstrings.
-The test is positive if pain radiates down the posterior/lateral thigh past the knee. This radiation indicates stretching of the nerve roots (specifically S1 or L5) over a herniated disc.
-Pain will most likely occur between 40 and 70 degrees. Pain earlier than 30 degrees is suggestive of malingering.
-Pain in the opposite leg during a straight leg raise is suggestive of root compression due to central disc herniation.
-When compared to MRI, the straight leg raise test has a sensitivity of 0.36 and specificity of 0.74
The ipsilateral straight leg raise test has a sensitivity of 0.80 and a specificity of about 0.40.
2. Crossed Leg Raise: asymptomatic leg is raised
-Test is positive if pain is increased in the contralateral leg; this correlates with the degree of disc herniation. Such results imply a large central herniation.
-Cross SLR test is much less sensitive (0.25) but is highly specific (about 0.90). Thus, a negative test is nonspecific, but a positive test is virtually diagnostic of disc herniation.
3. Claims of weakness > a few weeks without signs of atrophy is suggestive of malingering. 
4. Symptoms of Disc Herniation
-Classically, disc herniation is associated with exacerbation when sitting or bending; and relief while lying or standing.
-Icreased pain with coughing and sneezing
-Pain radiating down the leg and sometimes the foot
-Paresthesias
-Muscle weakness, such as foot drop
-Most disk herniation cases resolve spontaneously in 4-6 weeks.
5. Red flags for more serious etiology of low back pain: Cancer 
-B symptoms: unexplained weight loss > 10 kg in 6 mos, night sweats
-Personal history of malignancy
-Age > 50 or <17
-Failure to improve with treatment
-Pain at night, at rest.
-Pain lasts > 4-6 weeks
6. Red flags for more serious etiology of low back pain: Infection
-Persistent fever
-Obvious source - endocarditis, septic joint, abscess, cellulitis, etc.
-Recent history of infection, esp bacteremia
-Immunocompromised (including diabetes, chronic steroid use)
-History of IV drug use.
7. Red flags for more serious etiology of low back pain: Cauda Equina syndrome
-Saddle anesthesia
-Urinary retention or incontinence
-Fecal retention or incontinence
-Bilateral lower extremity weakness/numbness
-Progressive neurological defecits
8. Red flags for more serious etiology of low back pain: Vascular 
-Claudication
-Known PAD, or significant risk factors.
9. Red flags for more serious etiology of low back pain: Significant nucleus propulsus herniation 
-Foot drop (L4, 5)
-Acute onset severe weakness (strength <3/5)
10. Red flags for more serious etiology of low back pain: Fracture
-History of trauma
-Osteoporosis/prolonged steroid use
-HIstory of mild trauma > 50 y/o
-Age > 70