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Central nervous system disorders

Spina bifida

Chiari malformation

Dandy-Walker malformation


Tethered spinal cord syndrome

Aqueductal stenosis

Septo-optic dysplasia

Cerebral palsy

Spinocerebellar ataxia (NORD)

Transient ischemic attack

Ischemic stroke

Intracerebral hemorrhage

Epidural hematoma

Subdural hematoma

Subarachnoid hemorrhage

Saccular aneurysm

Arteriovenous malformation

Broca aphasia

Wernicke aphasia

Wernicke-Korsakoff syndrome

Kluver-Bucy syndrome

Concussion and traumatic brain injury

Shaken baby syndrome


Febrile seizure

Early infantile epileptic encephalopathy (NORD)

Tension headache

Cluster headache


Idiopathic intracranial hypertension

Trigeminal neuralgia

Cavernous sinus thrombosis

Alzheimer disease

Vascular dementia

Frontotemporal dementia

Lewy body dementia

Creutzfeldt-Jakob disease

Normal pressure hydrocephalus


Essential tremor

Restless legs syndrome

Parkinson disease

Huntington disease

Opsoclonus myoclonus syndrome (NORD)

Multiple sclerosis

Central pontine myelinolysis

Acute disseminated encephalomyelitis

Transverse myelitis

JC virus (Progressive multifocal leukoencephalopathy)

Adult brain tumors

Acoustic neuroma (schwannoma)

Pituitary adenoma

Pediatric brain tumors

Brain herniation

Brown-Sequard Syndrome

Cauda equina syndrome

Treponema pallidum (Syphilis)

Vitamin B12 deficiency


Friedreich ataxia

Neurogenic bladder


Neonatal meningitis


Brain abscess

Epidural abscess

Cavernous sinus thrombosis

Creutzfeldt-Jakob disease

Central and peripheral nervous system disorders

Sturge-Weber syndrome

Tuberous sclerosis


von Hippel-Lindau disease

Amyotrophic lateral sclerosis

Peripheral nervous system disorders

Spinal muscular atrophy


Guillain-Barre syndrome

Charcot-Marie-Tooth disease

Trigeminal neuralgia

Bell palsy

Winged scapula

Thoracic outlet syndrome

Carpal tunnel syndrome

Ulnar claw

Erb-Duchenne palsy

Klumpke paralysis


Myasthenia gravis

Lambert-Eaton myasthenic syndrome

Autonomic nervous system disorders

Orthostatic hypotension

Horner syndrome

Nervous system pathology review

Congenital neurological disorders: Pathology review

Headaches: Pathology review

Seizures: Pathology review

Cerebral vascular disease: Pathology review

Traumatic brain injury: Pathology review

Spinal cord disorders: Pathology review

Dementia: Pathology review

Central nervous system infections: Pathology review

Movement disorders: Pathology review

Neuromuscular junction disorders: Pathology review

Demyelinating disorders: Pathology review

Adult brain tumors: Pathology review

Pediatric brain tumors: Pathology review

Neurocutaneous disorders: Pathology review




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USMLE® Step 1 questions

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USMLE® Step 2 questions

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High Yield Notes

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USMLE® Step 1 style questions USMLE

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USMLE® Step 2 style questions USMLE

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A 52-year-old man presents to the emergency department to evaluate low back pain. The patient was using the rowing machine at the gym when he felt a “pop” in his back followed by pain. He is otherwise healthy and does not take any medications daily. Vital signs are within normal limits. On physical examination, the patient has tenderness to palpation over the lumbar spine and diminished sensation over the anterior aspect of the left leg. The patient has 4/5 strength with hip flexion on the left compared to 5/5 strength on the right. Which of the following physical examination maneuvers is most likely to demonstrate a positive finding given this patient’s clinical presentation? 

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Samantha McBundy, MFA, CMI

Stefan Stoisavljevic, MD

Evan Debevec-McKenney

Sciatica is a condition where there’s pain that starts in the lower back which then travels down the leg. Since the pain is associated with injury or compression of the sciatic nerve and follows the path of the sciatic nerve, it makes sense to name it sciatica.

The sciatic nerve is the longest and widest nerve in the body. It’s formed by the spinal nerves L4, L5, and S1-3, which leave the spinal canal through intervertebral foramen, an opening located between the vertebrae and behind the intervertebral discs. These nerves travel to the area in front of the sacrum, and join to make the sacral plexus.

All the nerves in the plexus, except S3 are split into two divisions: anterior and posterior. Anterior divisions of the L4, L5, S1, S2 and the entire S3 nerve create the tibial nerve, while posterior divisions of the L4, L5, S1 and S2 form the common fibular nerve. These two nerves are bound together by connective tissue and make up the sciatic nerve.

The sciatic nerve then passes beneath the piriformis muscle and through the greater sciatic foramen which is an opening formed by the pelvic bone, sacrospinous, and sacrotuberous ligaments.

It then travels down the back of the thigh to the back of the knee where it splits into the tibial and common fibular nerves. The sciatic nerve innervates the muscles in the back of the thigh. The Tibial nerve innervates the muscles of the posterior compartment of the leg and intrinsic flexors of the foot.

The Common fibular nerve is in charge of the muscles in the anterior and lateral compartments of the leg and intrinsic extensors of the foot. Now, each spinal nerve is in charge of the sensation of a specific area of the skin, called a dermatome.


Sciatica is a term used to describe symptoms of lower back pain, numbness, or tingling that originate in the lower back and travel down the sciatic nerve. It is often due to a spinal disc herniation pressing on one of the lumbar or sacral nerve roots. Other common causes are spinal stenosis, degenerative disc diseases. Treatment options include physical therapy, pain medication, exercise, and in some cases, surgery.


  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
  5. "Sciatica" British Journal of Hospital Medicine (2016)
  6. "Late sciatic nerve entrapment following pelvic plate reconstruction in total hip arthroplasty" The Journal of Arthroplasty (1998)

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