_1_, Inferior common ligament; _2_, _2′_, tendons of crura; _3_,
lumbar sympathetic trunks; _4_, external spermatic nerve; _5_, _5′_,
great splanchnic nerves; _6_, cisterna chyli (opened); _7_, _7′_,
œsophageal continuations of vagus nerves; _8_, lymph gland; _9_,
coronary ligament of liver (cut); _10_, right lateral ligament of
liver (cut); _11_, left lateral ligament of liver (cut); _12_,
falciform ligament of liver (cut); _A.l._, lumbo-costal arch;
_N.i._, intercostal nerve; _C.d._, right crus; _C.s._, left crus;
_A_, aorta; _Ca_, cœliac artery; _Oe._, œsophagus; _V.c._, posterior
vena cava; _V.p._, phrenic veins. (After Schmaltz, Atlas d. Anat. d.
Pferdes.)
]
The diaphragm is pierced by three foramina. (1) The =hiatus aorticus= is
an interval between the two crura and below the last thoracic vertebra.
It contains the posterior aorta, vena azygos, and cisterna chyli. (2)
The =hiatus œsophageus= (or foramen sinistrum) perforates the right crus
near its junction with the tendinous center. It is situated a little to
the left of the median plane and two or three inches below the
thirteenth thoracic vertebra (in expiration). It transmits the
œsophagus, the vagus nerves, and the œsophageal branch of the gastric
artery. (3) The =foramen venæ cavæ= (s. dextrum) pierces the tendinous
center about an inch to the right of the median plane, and about six
inches below the twelfth thoracic vertebra (in expiration). The vena
cava is firmly attached to the margin of the opening.[49]
_Relations._—The thoracic surface is related to the endothoracic fascia,
pleuræ, pericardium, the bases of the lungs, and the ribs in part. The
abdominal surface is in great part covered by the peritoneum, and is
related chiefly to the liver, stomach, spleen, pancreas, kidneys and
adrenals, and the anterior flexures of the colon. The sympathetic and
splanchnic nerves pass between the crus and the psoas muscles on each
side. The asternal vessels perforate the edge of the muscle at the ninth
costo-chondral joint.
_Blood-supply._—Phrenic and asternal arteries.
_Nerve-supply._—Phrenic nerves (from the fifth, sixth, and seventh
cervical nerves).