Where is a rat’s belly button? - briefly
A rat’s umbilicus is situated on the underside of its abdomen, a short distance behind the front paws. It appears as a tiny scar marking the former attachment point of the umbilical cord.
Where is a rat’s belly button? - in detail
Rats, like all placental mammals, possess an umbilical scar that marks the former attachment of the placenta. The scar is situated on the ventral midline, just posterior to the sternum and anterior to the pelvis. In a typical laboratory rat, the navel appears as a small, shallow depression or faint line roughly one to two centimeters behind the forelimbs and a few millimeters forward of the hindlimb roots.
The scar’s exact position can be identified by the following characteristics:
- Mid‑ventral alignment with the body’s longitudinal axis.
- Proximity to the xiphoid process of the sternum, but not directly under the rib cage.
- Located between the pectoral and inguinal regions, often concealed by a thin layer of fur.
- In adult rats, the scar may be partially obscured by skin folds or scar tissue, making it less conspicuous than in neonates.
Embryologically, the umbilicus forms when the umbilical cord detaches after birth, leaving a fibrous remnant that heals into a scar. Histologically, the tissue consists of dense connective tissue and a small amount of epithelial covering. The area does not contain any functional opening; it is a vestigial mark.
When dissecting or performing a necropsy, the belly button can be used as a reference point for locating abdominal organs. It lies anterior to the bladder and dorsal to the small intestine, providing a reliable landmark for surgeons and researchers.
In summary, the rat’s umbilical scar lies on the underside of the animal, centered on the ventral midline, just behind the chest and ahead of the pelvic girdle, typically appearing as a subtle indentation under the fur.