William Corn, MD
William Corn, MD is a Neurological Surgery Physician in San Francisco, CA, registered under NPI 1962457903. This provider registers 2 separate taxonomy codes, which usually means they practise across more than one recognised specialty. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
The practice address on file is 1001 POTRERO AVE RM 4M62, San Francisco, CA 94110. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| G68193 | CA | Neurological Surgery Physician primary |
| G68193 | CA | Neurology Physician |
This provider holds licence G68193 issued in CA. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
- Status
- Approved
- Provider type
- Practitioner - Neurology
- PAC ID
- 4183798382
- Enrollment ID
- I20080806000539
Medicare enrolment is recorded as approved under the provider type Practitioner - Neurology. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
What Neurological Surgery covers
A neurological surgeon provides the operative and non-operative management (i.e., prevention, diagnosis, evaluation, treatment, critical care, and rehabilitation) of disorders of the central, peripheral, and autonomic nervous systems, including their supporting structures and vascular supply; the evaluation and treatment of pathological processes which modify function or activity of the nervous system; and the operative and non-operative management of pain. A neurological surgeon treats patients with disorders of the nervous system; disorders of the brain, meninges, skull, and their blood supply, including the extracranial carotid and vertebral arteries; disorders of the pituitary gland; disorders of the spinal cord, meninges, and vertebral column, including those which may require treatment by spinal fusion or instrumentation; and disorders of the cranial and spinal nerves throughout their distribution. NUCC Health Care Provider Taxonomy, code 207T00000X
All registered taxonomy codes
This provider registers 2 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207T00000X | Neurological Surgery Physician | G68193 | CA | primary |
| 2084N0400X | Neurology Physician Neurology | G68193 | CA |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1962457903 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | May 24, 2006 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | MD |
| Practice address |
1001 POTRERO AVE RM 4M62 San Francisco, CA 94110 (415) 206-4353 Fax (415) 476-5582 |
| Mailing address |
PO BOX 7464 San Francisco, CA 94120 |
| Other identifiers |
00G681930
· Medicaid (CA) |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 9 | 6 | 2 | 4 | 5 | 7 | 9 | 0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 9 | 3 | 2 | 8 | 5 | 5 | 9 | 0 |
Sum = 67 · next multiple of 10 = 70 · check digit = 3 · actual last digit = 3
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.