» The Lymphatic Structures of the Head and Neck
The parotid, mandibular, and deep cervical lymph nodes have been encountered (p. 520). The superficial cervical nodes are described on page 607.
The retropharyngeal nodes are arranged in clumps on the pharyngeal wall (Fig.
18.26/19). The lateral group is also related to the guttural pouch, lying caudal to it within the atlantal fossa. Infection of these nodes, frequently leading to abscess formation (strangles), may be followed by contamination of the guttural pouch with the potential sequelae already mentioned (p. 512). The pattern of drainage is such that the medial retropharyngeal nodes serve as the collecting center for all lymph emanating from the upper part of the head (Fig. 18.41/3).Comprehension Check
Describe the anatomic basis of "roaring," a condition seen in the horse.
Use the equine skull to understand the arrangement of paranasal sinuses and describe the methods to access their interior.
Describe the anatomic relationships of the guttural pouch.
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* The barbaric custom of splitting the lateral wall of this diverticulum is known from pharaonic times and may still be encountered in the Middle East. It is of course completely without the intended effect on the efficiency of respiration. However, vigorous inspiration may induce some inward movement of the wall of the nasal passage where it is unsupported by bone, with an adverse effect on respiratory efficiency and therefore performance. To counteract this, an adhesive strip designed to be fixed across the nose a few centimeters above the nostrils is now marketed. It is claimed that when fitted to horses required to race or undergo other especially strenuous tasks, it significantly improves performance and reduces the severity of exercise-induced pulmonary hemorrhage. Corresponding benefits were previously reported of the use of a similar device by human athletes.
* It is also found in a small, strangely eclectic band of other species, including hyraxes, certain bats, and a South American mouse.