Download Location of Retropharyngeal Lymph Nodes in Sheep

Location of Retropharyngeal Lymph Nodes in Sheep
The medial retropharyngeal lymph nodes are located just above the pharynx and larynx,
and medial to the hyoid bones. The nodes are not immediately apparent when the head
is removed through the atlanto-occipital joint as they are covered by the hypaxial muscles
attaching to the base of the brain, as well as by fat and salivary tissue (Figure 1), but they
can be easily palpated by running a finger along the inside of each hyoid bone. The nodes
are discrete, oval and not lobulated like the adjacent salivary glands. Their location in relation to other landmarks, after removal of fat and overlying muscle, is illustrated in Figure 2.
Figure 1: Head removed through the
atlanto-occipital joint. The hyoid bones
and medial retropharyngeal nodes are
concealed by hypaxial muscles (M), fat
and salivary tissue. Note the carotid
arteries (C), parotid lymph node (PLN)
and parotid salivary glands (PSG).
PSG
PSG
M
PLN
C
HB
RLN
Figure 2: After removal of the overlying muscular
tissue and fat, the medial retropharyngeal lymph
nodes (RLN) are clearly visible, dorsal to the
pharynx and medial to the hyoid bones (HB).