Straight leg raise testing
Screening exam for a herniated disk (Sn 68-80%)
Lifting leg causes radicular<unk>  of affected leg radiating to BELOW the knee<unk>  is worsened by ankle dorsiflexion<unk>  may be relieved by pressing across biceps femoris and pes anserinus tendons behind knee ('bowstringing')
Crossed Straight leg raise testing (high Sp, low Sn)
Lifting the asymptomatic leg causes radicular<unk>  down the affected leg
Nerve root compromise
Rectal exam, perineal sensation, palpable bladder?
To rule out cauda equina syndrome
Screening exam for a herniated disk (Sn 68-80%)
Lifting leg causes radicular<unk>  of affected leg radiating to BELOW the knee<unk>  is worsened by ankle dorsiflexion<unk>  may be relieved by pressing across biceps femoris and pes anserinus tendons behind knee ('bowstringing')
Lifting the asymptomatic leg causes radicular<unk>  down the affected leg
To rule out cauda equina syndrome
Pregnancy test
Only necessary if concerned for infection, tumor, or rheumatologic cause
CBC, UA, ESR (90-98% Sn for infectious etiology)
Consider post void residual
Can be done with non invasively with Ultrasound
CBC, UA, ESR (90-98% Sn for infectious etiology)
Can be done with non invasively with Ultrasound
Plain films
Only necessary if suspect fracture, tumor, or infection
Part of ACEP Choosing wisely 
MRI
Only necessary if suspect infection, neoplasm, epidural compression syndromes
Consider for back<unk>  >6-8wks
Ultrasound
Rule-out AAA
Only necessary if suspect fracture, tumor, or infection
Part of ACEP Choosing wisely
Only necessary if suspect infection, neoplasm, epidural compression syndromes
Consider for back<unk>  >6-8wks
Rule-out AAA
Lower back pain
Spine related
Back pain 
Acute ligamentous injury
Hip pain
Acute muscle strain
Hip pain 
Disk herniation 