Cervical Region 
visible without magnification, contrasting with the 
surrounding tissue by their red color and discrete 
boundaries. Additional nodes lie between the two 
sahvary glands and the laryngeal surface of the 
parotid gland {Inn. mandibu lares caudales). They 
are medial to the facial vein. 
The retropharyngeal lymph complex {lympho- 
centrum retropharyngeum) consists of two lymph 
nodes {Inn. retropharyngei). They lie deep to the 
sternocephalic and cleidocephalic muscles, dorso- 
lateral to the carotid artery and extend from the 
pharynx to the thyroid gland. Usually the parotid 
node {In. parotideus) can be found under the paro- 
tid gland caudal to the ear. 
Superficial cervical lymph nodes are not found in 
this species. The deep cranial cervical node {In. 
cervicalis profundus cranialis) is located between 
the trachea and the lateral margin of the omohyoid 
muscle. Via the rostral mandibular nodes, it drains 
the tongue, floor of the mouth, face, and cheek 
pouches, and itself drains the neck musculature and 
pharynx and empties into the jugular system. The 
deep caudal cervical lymph node {In. cervicalis pro- 
fundus caudalis) is located between the trachea and 
the insertion of the sternocephalic muscle. It drains 
the neck musculature and the pharynx and empties 
into the jugular system. 
The axillary lymph node {In. axillaris) (usually 
one large node, occasionally two small nodes) is 
situated between lateral thoracic wall and teres 
major muscle, near the insertion of the latissimus 
dorsi muscle (Fig. 3-12). It drains the pectoral 
limb, thoracic and dorsal skin, lateral abdominal 
wall, the accessory axillary lymph node and over- 
flows to the subclavian vein. 
The accessory axillary lymph node {In. axillaris 
accessorius) is situated between the long head of the 
triceps brachii and the latissimus dorsi muscles. It 
drains the pectoral limb and skin of the thorax, and 
flows to the axillary lymph node. 
3.5 LARYNX 
The larynx is situated behind the root of the 
tongue and ventral to the pharynx. It is a sphincter 
valve at the entrance to the windpipe, preventing 
food from entering the trachea, and controlling the 
air flow. The larynx may be up to 9 mm long and 
has an outer diameter of about 6 mm (Figs. 3-13, 
3-14, 3-15, 3-16). In one year old males, it weighs 
222±36 mg and in females, 185±36 mg (Table 5), 
when freed of all superficial muscles. The larynx is 
positioned between the caudal ends of the mandibles 
and is adjoined to the proximal part of the overly- 
ing esophagus (Fig. 2-3). Laterally, the larynx is 
flanked by the thyroid and parathyroid glands 
{glandula thyreoidea et glandula parathyreoidea) 
which extends to the level of the cricoid cartilage 
(Figs. 3-13, 3-14). Cranially, the interior of the 
larynx empties through the laryngeal opening 
{aditus laryngis) into the dorsal part of the pharynx, 
while caudally the larynx merges into the trachea. 
The larynx of the European hamster contains 
three single median cartilages: thyroid {cartilago 
thyreoidea), cricoid {cartilage cricoidea) and epi- 
glottis {cartilago epiglottic a); and three paired 
cartilages: arytenoid {cartilago arytenoidea), corni- 
culate {cartilago corniculata) and cuneiform {carti- 
lago cuneiformis), the latter two of which are 
identifiable only under magnification (Figs. 3-17, 
3-18). 
The thyroid cartilage (Fig. 3-18), which defines 
the body of the larynx, has a concave shape, open 
dorsally. It is formed by two sagittal cartilaginous 
plates {laminae thyreoideae) that bend ventrally 
towards the median plane where they fuse to form 
a ventral median crest. The dorsal edge of each 
lamina extends cranially as a short horn {cornu 
rostrale) and caudally as a longer horn {cornu 
caudale) with another short horn {cornu dorsale) 
projecting from the dorsal edge of the lamina. The 
lamina has an oblique ridge, running caudally on 
the dorsolateral surface, which serves as the inser- 
tion of m. cricothyreoideus. 
The smaller cricoid cartilage, which is overlapped 
craniolaterally by the caudal thyroid horns, is 
shaped like a signet ring. It is composed of elastic 
cartilage and consists of the arch {arcus cricoideus) 
and lamina {lamina cricoidea) (Fig. 3-18). A con- 
nective tissue membrane, the crico-thyroid ligament, 
{lig. cricothyreoideum) is stretched over a cartila- 
ginous free space between the thyroid cartilage and 
the cricoid arch. A dorsal median ridge {crista 
mediana) projects caudally over the first one to 
two tracheal rings. 
The arytenoid cartilages are paired sagittal 
67 
