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## Musculature* - Can be divided into an outer longitudinal and an inner circular layer - The esophagus *does not* have the serosa layer | | Outer Longitudinal Layer | Inner circular layer | |-----|--------------------------|-----------------------| | Upper 2 to 6cm | Longitudinal muscle fiber...

## Musculature* - Can be divided into an outer longitudinal and an inner circular layer - The esophagus *does not* have the serosa layer | | Outer Longitudinal Layer | Inner circular layer | |-----|--------------------------|-----------------------| | Upper 2 to 6cm | Longitudinal muscle fiber layer | Thicker than the outer layer: geometry is helical* | | Striated muscle fibers *only* | Contraction shortens the esophagus* | | | Smooth muscle fibers gradually become more abundant | Originate from a cricoesophageal tendon arising from the dorsal upper edge of the anteriorly located cartilage | Geometry makes the peristalsis of the esophagus assume worm-like drive as opposed to segmental and sequential squeezing* Abn: *Cork-screw like pattern* on Barium swallow |