Myology of the Pharyngoesophageal Segment: Gross Anatomic and Histologic Characteristics

Abstract

Although numerous studies have been performed on the function and dysfunction of the pharyngoesophageal segment, few studies have investigated features of the musculature in this area. Thus, the purpose of this study was to systematically exam. ine the structure (gross anatomy and histology) in this area and to relate these findings to the functions of the pharyngoesophageal segment. Twenty-one autopsy and surgery patients underwent careful measurement and observation of 1. the vertical (cephalad-caudad) height of the cricopharyngeus muscle (CP); 2. the presence or absence of Kilfian's dehiscence; and 3. the separation or blending of the CP with the upper esophageal circular muscles. Of the 21 subjects, muscle specimens were removed from 8 (4 autopsy, 4 surgical) to include a muscle strip from the upper esophageal circular muscles, CP, and inferior pharyngeal constrictor and submitted to a battery of histological and histochemical tests. Gross anatomic measurements of the vertical height of the CP were substantially longer than those reported elsewhere. Killian's dehiscence was shown to be present in fewer than one third of the specimens. Histology of these muscles also showed significant differences from the muscles discussed in other published reports, particularly when fresh and autopsy material were compared. These specialized muscles, therefore, require further detailed study.

Morphometric and anthropometric analysis of Killian's triangle

“…Perrott described such a weak place in the cricopharyngeal region in a part of the 40 specimens that he examined but without giving more detailed anatomical information on it 13. The only report on the accurate prevalence of Killian's triangle comes from Kelly and Kuncl, who report an existent triangle on six of the 21 (28.6%) nonfixed specimens they examined with the same percentage for males (4/14) and females (2/7) 14. However, they did not mention a precise method of definition of the Killian's triangle.…”

Swallowing Disorders in the Elderly

“…88 This region, between the pars fundiformis and the pars obliqua, is called Killian's dehiscence because it is relatively devoid of muscle fibers. 8 Understanding the physiological and anatomical relationships of the UES is critical to the diagnosis and treatment of CP dysfunction.…”

Extracellular Matrix Composition of the Cricopharyngeus Muscle

“…Versican, a large proteoglycan, regulates the water content of tissues, participates in the assembly of different ECM components, and plays an important regulatory role in cell biology [20]. Because of its location, the CPM is subject to more trauma than most limb muscles [6] and is frequently exposed to physical and chemical stressors [5]. Signs of muscle cell regeneration and degeneration in the CPM have been previously described by Cruse et al [7]; these processes are probably a consequence of the act of swallowing over a lifetime.…”

“…The endomysial composition of the CPM presumably plays an important role in the muscle's physiological properties. However, few studies have assessed the CPM's normal histological structure in humans, and there is little information about the composition of the muscle's ECM [3][4][5][6][7][8].…”