2 DiaphragmA diaphragm is a muscular sheet with an inferior and a superior fascia:Superior fascia = parietal thoracic fascia.Inferior fascia = transversalis fascia.Separates thorax and abdomen.In moderate expiration:Reaches level of 5th rib on right side and 5th IC space on left.
4 Central Tendon “Y-shaped” Attaches to lumbar vertebrae via crura. Pierced by three openings (described later).
5 Central Tendon Three parts to central tendon: Fig. 2.71 Right: Middle: Largest part.Middle:Left:Smallest part.Fig. 2.71
6 Crura Muscular pillars Originate from lumbar vertebrae: Right from L3. Left from L2.Right swings left and forms a weak sphincter around the esophagus.
7 Arcuate Ligaments Median: Medial: Lateral: Around aortic opening. Bridges proximal ends of crura.Medial:From deep fascia of psoas major muscle.From transverse process to body of L1.Lateral:From deep fascia of quadratus lumborum muscle.From transverse process of L1 to rib 12.