Mnemonic to remember the Extraocular Muscle Involvement in Thyroid-associated Orbitopathy

Remember the order or sequence of EOM involvement in Thyroid eye disease (TED) or Thyroid associated Orbitopathy using the mnemonic IMSLOw.

  • I’M SLOw


  • I: inferior rectus
  • M: medial rectus
  • S: superior rectus
  • L: lateral rectus
  • O: obliques muscles (superior oblique and inferior oblique)

This mnemonic will help you remember that Inferior rectus is the most commonly affected EOM and first EOM to be affected in Thyroid eye disease. This is followed by Medial rectus, superior rectus and lateral rectus.

The obliques are the last to be affected and least commonly affected EOM in Thyroid eye disease.

There is some debate about this however. Some claim superior rectus is most frequent 2, but the mnemonic “SIMLOW” is not as memorable.

These are frequently asked MCQs in medical competitive exams. Also remember that the EOM enlargement in Thyroid eye disease will spare the tendons ie the tendons will not be enlarged. This is known as the Coke bottle appearance as the belly is enlarged while the tendon is spared (neck of coke bottle).

Extraocular muscle involvement in thyroid associated orbitopathy (mnemonic)

Hope this mnemonic helped. Do check out more of our medical mnemonics below.

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