Shape is spherical
Size varies from 1 – 5 cm in diameter
Color is pale blue with characteristics semi transparent appearance. Surface is smooth and mucous membrane is mobile over the swelling. Tenderness is absent
Fluctuation test is positive
Transillumination test is positive
Cervical lymph nodes are not enlarged. May or may not have prolongation in the neck. Classification
A ranula is a type of mucocele, and therefore could be classified as a disorder of the salivary glands. Usually a ranula is confined to the floor of the mouth (termed a "simple ranula"). An unusual variant is the cervical ranula (also called a plunging or diving ranula), where the swelling is in the neck rather than the floor of the mouth. The term ranula is also sometimes used to refer to other similar swellings of the floor of mouth such as true salivary duct cysts, dermoid cysts and cystic hygromas. The Latin word rana means "frog" (ranula = "little frog"). Treatment
Treatment of ranulae usually involves removal of the sublingual gland. Surgery may not be required if the ranula is small and asymptomatic. Marsupialization may sometimes be used, where the intra-oral lesion is opened to the oral cavity with the aim of allowing the sublingual gland to re-establish connection with the oral cavity. Epidemiology
The lesion is usually present in children. Ranulae are the most common pathologic lesion associated with the sublingual glands. Other animals
References
Kahn, Michael A. Basic Oral and Maxillofacial Pathology. Volume 1. 2001. External links

DermAtlas 259163774
This can happen at any age, whether she has bred or not, and whether it is her 1st or 10th heat, although it becomes more common as the dog gets older. The main risk period for a female is for eight weeks after her peak standing heat has ended. Normally during this period, the cervix, which was open during her heat, begins to close, and the inner lining begins to adapt back to normal. However, cystic hyperplasia of the endometrium (inner lining of the uterus) –  known as cystic endometrial hyperplasia (CEH) – may occur at this time for some animals, as an inappropriate response to progesterone. Under these circumstances, bacteria (especially E. coli) that have migrated from the vagina into the uterus find the environment favorable to growth, especially since progesterone also causes mucus secretion, closes the cervix (preventing uterine drainage), and decreases uterine contractility. The condition of the cervix is a major factor in the severity of the condition. If the cervix is open, the infected material can leave the body, and this is far easier and safer to treat. This is known as open pyometra. If the cervix is fully closed, there is no discharge from the vulva, and like in appendicitis, the uterus may rupture and pus escapes into the abdomen, causing peritonitis and possible rapid death. This is known as closed pyometra.