Esophageal Anatomy of the Llama (Lama glama)

• Published in: International journal of morphology 2009-09, Vol.27 (3), p.811-817
• Main Authors: Sukon, Peerapol, Timm, Karen I, Valentine, Beth A
• Format: Article
• Language: English
• Subjects: ANATOMY & MORPHOLOGY
• ISSN: 0717-9502; 0717-9502
• DOI: 10.4067/S0717-95022009000300028

This study describes gross, microscopic and muscle fiber anatomy of the esophagus of the llama, Lama glama. The esophagus was studied grossly in twenty-five adult llamas and a subset of ten with normal esophageal physiology was used for the microanatomic studies. Esophageal length was 122 ± 7 cm with two-thirds of the length in the neck and the remainder in the thorax, consistent with the long neck of the llama. Esophageal diameter increased steadily from 2.5 ± 0.3 cm in the cranial cervical region to 3.9 ± 0.8 cm in the caudal thoracic region. The mucosal epithelium was keratinized stratified squamous and there were abundant submucosal glands throughout the esophagus. The entire muscularis of the esophagus was striated muscle in two general layers but also with a somewhat random orientation of fibers. The tunica muscularis steadily increased in thickness from 3.43 ± 0.30 mm in the cranial cervical region to 4.39 ± 0.39 mm in the middle thoracic region. In the llama Type 2 muscle fibers predominated in the esophageal musculature, with the percentage of Type 1 fibers increasing from 1% cranially to 33% in the caudal thoracic region of the esophagus. This study of the normal llama esophagus enhances our knowledge of this species and provides the basis for future study of pathological conditions of the esophagus.