Praise be to Allah.
The fast is not broken by the insertion of an instrument into the brain, vertebra or spinal column for the purpose of examination or taking a sample from it.
The Islamic Fiqh Council has issued a statement on things that break the fast, as follows:
The following things do not have any effect on the fast:
- Eye drops, ear drops, ear syringing, nose drops and nasal sprays – so long as one avoids swallowing any material that may reach the throat.
- Tablets or lozenges that are placed beneath the tongue for the treatment of angina pectoris etc., so long as one avoids swallowing any material that reaches the throat.
- Vaginal pessaries, douching, use of a speculum, or internal digital examination.
- Introduction of a scope or coil (IUD), etc., into the uterus.
- Introduction of a scope or catheter into the urethra (male of female), or injection of dyes for diagnostic imaging, or of medication, or cleaning of the bladder.
- Drilling of teeth (prior to filling), extraction or polishing of teeth, using a miswaak or toothbrush, so long as one avoids swallowing any material that reaches the throat.
- Rinsing, gargling or applying topical treatment in the mouth, so long as one avoids swallowing any material that reaches the throat.
- Injections, whether subcutaneous, intra-muscular or intra-venous – with the exception of those used for purposes of nutrition.
- Anaesthetics, so long as they do not supply nutrition to the patient.
- Medicines absorbed through the skin, such as creams, lotions and patches used to administer medication through the skin.
- Introduction of a catheter into the veins in order to examine or treat the vessels of the heart or other organs.
- Laparoscopy for the purpose of diagnosis or surgical treatment of the abdominal organs.
- Biopsies of the liver and other organs, so long as this is not accompanied by the administration of nutrients.
- Gastroscopy, so long as this is not accompanied by the administration of nutrients.
- Introduction of medicine or instruments into the brain or spinal cord.
- Involuntary vomiting (as opposed to self-induced vomiting).
And Allah knows best.