“TM” most often refers to temporomandibular problems (TMJ / TMD) or, less commonly in medical texts, “transient monocular” vision loss; the causes are completely different, so I’ll cover both briefly so you can match what you meant.

If you meant TMJ / TMD (jaw joint)

Temporomandibular disorders (TMD, often shortened in conversation to “TMJ problems” or just “TM”) are usually multifactorial , meaning several things pile up at once.

Common contributing causes include:

  • Jaw overuse and muscle strain (teeth grinding or clenching, especially at night; chewing gum a lot; nail‑biting).
  • Malocclusion or bite issues in some people (how the upper and lower teeth meet), though this alone is rarely the only cause.
  • Direct injury to the jaw, chin, or face (falls, blows, whiplash, intubation).
  • Joint changes such as disc displacement, arthritis (osteoarthritis, rheumatoid, other inflammatory joint diseases).
  • Stress, anxiety, and other psychosocial factors that increase clenching, muscle tension, and pain sensitivity.
  • General pain‑sensitivity disorders (widespread pain, fibromyalgia‑like conditions) that make jaw muscles and joints more reactive.

A typical mini‑story that fits many patients: someone under high stress starts clenching their teeth, jaw muscles become overworked, the small joint disc in front of the ear gets irritated or slips slightly, and over time they feel jaw pain, clicking, or locking when opening their mouth.

If you meant this type of “TM,” red‑flag symptoms that should be checked by a clinician or dentist include:

  • Jaw locking open or closed.
  • Sudden major change in your bite.
  • Severe, one‑sided facial pain, swelling, or fever.

If you meant transient monocular vision loss (“TMB”, “amaurosis fugax”)

In neurology and ophthalmology, “TMB” or “transient monocular blindness/vision loss” is a brief episode where vision in one eye goes dark or very dim, then returns to normal.

Key causes are usually vascular or eye‑related :

  • Emboli or clots from the carotid artery or heart that briefly block retinal blood flow (a form of transient ischemic attack).
  • Severe narrowing of the carotid artery reducing blood supply (hemodynamic hypoperfusion).
  • Inflammation of blood vessels, especially giant cell arteritis in older adults.
  • Vasospasm (temporary spasm of small arteries).
  • Eye diseases that transiently raise eye pressure or affect the optic nerve: angle‑closure glaucoma, papilledema, optic nerve ischemia.
  • Less common neurological causes such as retinal or visual migraines and seizures.

This type of “TM” is a medical urgency because it can be a warning sign of stroke or serious eye disease. Anyone who suddenly loses vision in one eye, even if it comes back, should be assessed quickly in an emergency or urgent‑care setting.

What you can do next

  • If you meant jaw TMJ/TMD : a dentist, oral and maxillofacial specialist, or orofacial pain clinic can evaluate your bite, jaw joint, and muscle function and discuss treatment options.
  • If you meant vision “TM” (one‑eye blackout episodes) : seek urgent medical evaluation (emergency room, urgent eye clinic, or stroke service), especially if you have cardiovascular risk factors such as high blood pressure, smoking, diabetes, or high cholesterol.

If you tell me which “TM” you had in mind (jaw vs. eye vs. something else), I can walk through causes, tests, and typical treatments in more detail.