How to treat a rat's skull?

How to treat a rat's skull? - briefly

Clean the cranium with a mild detergent, rinse thoroughly, then fix in 10 % formalin for 24‑48 hours before transferring to ethanol for long‑term storage. Handle with gloves, keep the specimen dry, and label with date and source.

How to treat a rat's skull? - in detail

Treating a laboratory rat cranium requires a systematic approach to preserve bone integrity and prevent contamination. Begin with humane euthanasia following approved protocols, then position the animal supine on a dissecting tray. Use sharp scissors to make a midline incision through the skin and fascia from the occipital region to the nasal bridge, exposing the underlying musculature.

1. Muscle removal

   • Cut the temporalis and masseter muscles at their attachments to the skull.
   • Retract remaining tissues with fine forceps, discarding them in a biohazard container.

2. Skull exposure

   • Apply a scalpel to separate the periosteum from the bone surface, working in small sections to avoid fracturing delicate sutures.
   • Gently lift the periosteum with a periosteal elevator, keeping the bone clean.

3. Fixation

   • Submerge the isolated cranium in a 10 % neutral buffered formalin solution for 24–48 hours at room temperature.
   • Ensure complete coverage; stir the solution periodically to maintain uniform penetration.

4. Cleaning

   • Rinse the fixed skull in running tap water for 10 minutes to remove excess fixative.
   • Transfer to a 70 % ethanol bath for 30 minutes to dehydrate and disinfect.

5. Drying

   • Place the specimen on a wire rack in a ventilated area; allow air drying for 24 hours.
   • For rapid drying, use a low‑temperature oven (≤ 40 °C) for 2–3 hours, monitoring for cracks.

6. Storage

   • Store the dried skull in a sealed container with silica gel packets to control humidity.
   • Label with species, date of preparation, and fixation details for future reference.

Throughout the procedure, handle the bone with soft-tipped tweezers to minimize mechanical stress. Regularly inspect for cracks or mineral loss; if damage occurs, re‑immerse the specimen in a mild calcium chloride solution (0.1 % w/v) for 15 minutes to reinforce mineral content before final drying. This protocol yields a clean, stable rat cranium suitable for morphological study, imaging, or educational display.