Clinical Anatomy of the European Hamster 
oral cavity, approaching to within a millimeter of 
the midline from each side. The buccal pads line 
the hard palate, and the corresponding surface of 
the lower jaw, between the molars and the incisors. 
2.9 CHEEKS 
The cheeks (buccae) of the European hamster 
are occupied by remarkable structures, the cheek 
pouches (bursae buccales), which are situated be- 
tween the skin and masticatory muscles (Fig. 2-48). 
The pouches begin at the labial commissure and 
run caudodorsally along the base of the ear muscu- 
lature, covering the ventral part of the parotid 
gland, and are applied to the dorsolateral surface 
of the neck, extending to the scapulae (Fig. 2-49). 
Their length varies with the size of the animal, the 
adult pouches ranging between 60 and 70 mm. The 
empty pouches, the mucosa of which is relaxed and 
marked by deep folds, are 12 to 15 mm wide. When 
filled, the cheek pouches become thin-walled and 
evaginate the buccal mucosa which lies immediately 
under the external skin. The diameter of the fully 
filled cheek pouches expands up to 30 mm. The 
cheek pouches are longest when empty because the 
carrying capacity, between 20 and 30 g, is not de- 
pendent upon elongation of the pouches but rather 
upon their widening. 
The pale pink, simple squamous epithelium, marked with delicate 
longitudinal folds, is covered with multiple, small papillary elevations 
visible only with the aid of magnification. 
Hamsters empty their cheek pouches by pushing 
the food mass with their forepaws out of the cheek 
pouch and into the oral cavity for mastication, 
thereby employing the underlying and supporting 
musculature (retractor bursae buccalis et retractor 
buccinator), which originates in the lumbodorsal 
fascia {fascia lumbodorsalis) at the level of the first 
two lumbar vertebrae (slightly caudal to the origin 
of these muscles in the Chinese hamster (Geyer, 
1973) and inserts on the cheek pouch in the vicinity 
of the scapula (Fig. 2-50). 
2.10 PALATE 
The palate is approximately 20 mm long and is 
divided into the rostral hard palate {palatum 
durum), which extends 20 to 25 mm from the in- 
cisors to a line posterior to the third molar, and the 
caudal soft palate {palatum molle) 7 to 9 mm long, 
which is attached to the caudal margin of the hard 
palate (Fig. 2-3). The mucous membrane of the 
hard palate lines the ventral surface of the bony 
palate and forms eight symmetrical pairs of palatine 
rugae {rugae palatinae) (Fig. 2-46); they are com- 
pact, smooth and pinkish-red in color. These rugae 
are divided into four large rostral pairs and four 
smaller caudal pairs located between the molars. 
The smaller rugae adjacent to the molars decrease 
rostrally, while the four large rostral pairs decrease 
caudally. With the exception of the fourth and also 
usually the third, or widest (9 mm), the rugae de- 
cline obliquely toward the median plane. The 
first four pairs unite in the median plane but the 
last three pairs do not completely join. In contrast 
to the Syrian golden hamster (Schwarze and 
Michel, 1959-60), the European hamster has an 
additional eighth rugal pair which completely 
coalesces in the adult and is positioned at a right 
angle to the median plane. The first rugal pair 
forms a V-shape in the median plane with its apex 
directed rostrally. At the rostral surface of the first 
pair, 0.5 to 1 mm from the lateral margin of the 
apex, lie the oral orifices {papillae inciswae) of the 
two incisive ducts. By applying pressure to the first 
rugal pair, the orifices can be made to appear. The 
rugae between the molars are flatter laterally than 
medially. At the termination of the hard palate, 
7-9 mm of caudally oriented soft palate is attached. 
The mucosa of the soft and hard palates is pinkish-red in color, com- 
pletely smooth and lined with keratinized stratified squamous epithe- 
lium (Fig. 2-51). Beneath the epithelium of the hard palate, mucous 
glands are located on either side of the median plane. These glands are 
especially prominent at the level of the orbit. 
The tonsils, which lie between the caudal ends 
of the palatine rugae in other rodents, are neither 
histologically nor grossly demonstrable in the 
hamster (Roscher, 1909; Kittel, 1953, 1955). 
2.11 GUMS AND TONGUE 
The smooth mucosal surface of the fioor of the 
mouth meets the molars laterally as the gums {gin- 
givae) and is continuous with the mucosal surface 
of the tongue {lingua). 
At the median plane from the fioor of the mouth extending to the tip 
of the tongue, the keratinized stratified squamous cell mucosa forms a 
rather indistinct lingual frenulum {frenulum linguae). 
At the base of the frenulum are located small, 
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