Muscle
Crura of the diaphragm
Lumbar anchors of the posterior diaphragm
High-yield
The esophageal hiatus is surrounded chiefly by right crural muscle. The aorta instead passes behind the median arcuate ligament between the crura.
Overview
The crura attach the diaphragm to the upper lumbar bodies and discs. The right attachment usually extends lower than the left. Fibers ascending from this region contribute to the muscle around the esophageal opening, coupling breathing mechanics with support of the gastroesophageal junction.
Reference facts
- Origin
- Usually the bodies and discs of L1–L3 on the right and L1–L2 on the left; the attachment extent varies.
- Insertion
- Muscular fibers ascend into the diaphragm toward its central tendon, with crural fibers surrounding the esophageal hiatus.
- Innervation
- Motor supply arrives through the phrenic nerves, principally C3–C5.
- Action
- Assist inspiratory expansion and provide an external muscular contribution to closure around the distal esophagus.
- Blood supply
- Inferior phrenic branches contribute prominently to the crural region, within the diaphragm's wider arterial network.
Clinical correlation
Separation or widening of the crural margins can accompany hiatal hernia and reduce support of the antireflux barrier. Crural contraction is one component of this barrier, alongside the lower esophageal sphincter and junctional geometry.
Frequently asked questions
What does the crura of the diaphragm do?
The crura of the diaphragm assist inspiratory expansion and provide an external muscular contribution to closure around the distal esophagus.
What nerve innervates the crura of the diaphragm?
The crura of the diaphragm is innervated by the motor supply arrives through the phrenic nerves, principally C3–C5.
Where does the crura of the diaphragm attach?
Origin: Usually the bodies and discs of L1–L3 on the right and L1–L2 on the left; the attachment extent varies. Insertion: Muscular fibers ascend into the diaphragm toward its central tendon, with crural fibers surrounding the esophageal hiatus.
What is the blood supply of the crura of the diaphragm?
Inferior phrenic branches contribute prominently to the crural region, within the diaphragm's wider arterial network.