Abdomen: Cards 4-1 to 4-31


Cards 4-1 to 4-31

Bones and Joints

4-1 Bony Framework of Abdomen


4-2 Anterior Abdominal Wall: Superficial Dissection

4-3 Anterior Abdominal Wall

4-4 Anterior Abdominal Wall

4-5 Anterior Abdominal Wall

4-6 Anterior Abdominal Wall: Deep Dissection

4-7 Posterior Abdominal Wall: Internal View

4-8 Posterior Abdominal Wall: Internal View


This dome-shaped musculofibrous septum arises from the circumference of the thoracic outlet, with fibers arising from a sternal portion (xiphoid process), a costal portion (lower 6 costal cartilages), and a lumbar portion (L1-3 vertebrae).


The muscles converge and insert into the central tendon.


Attached to the ribs and lumbar vertebrae, the muscular diaphragm draws the central tendon downward and forward during inspiration. This increases the volume of the thoracic cavity and decreases the volume of the abdominal cavity.


Phrenic nerve (C3, C4, and C5).


The diaphragm has 3 large openings: the caval hiatus for the inferior vena cava (at the level of the T8 vertebra), the esophageal hiatus (at the level of the T10 vertebra), and the aortic hiatus (in front of the T12 vertebra).

Where the diaphragm passes over the aorta, it forms an arch called the median arcuate ligament. As the diaphragm passes over the psoas major muscle, it forms the medial arcuate ligament; and where it passes over the quadratus lumborum, it forms the lateral arcuate ligament.


If an inflamed visceral structure (e.g., gallbladder) contacts the underside of the diaphragm, the parietal peritoneum may become inflamed and the pain will be passed along the sensory axons of the phrenic nerve (C3-5) on the right side to the corresponding dermatomes in the lower neck and shoulder region. This is an example of referred pain from the abdomen to a somatic region of the body.

Atlas Plate 258

See also Plate 192


4-9 Autonomic Nerves and Ganglia of Abdomen


Sympathetic and parasympathetic nerves innervate the viscera of the abdominal cavity. Sympathetic nerves coursing in the thoracic splanchnic nerves (from T5-12 spinal cord levels) and lumbar splanchnics (upper lumbar levels) synapse largely in 3 major collections of ganglia: celiac, superior mesenteric, and inferior mesenteric ganglia. A nerve plexus continuing from this most inferior ganglion gives rise to the superior hypogastric plexus, which provides sympathetic innervation to pelvic viscera.

Parasympathetic innervation to the upper two thirds of the abdominal viscera (derived from the foregut and midgut portions of the embryonic gut) comes from the vagus nerve. The remaining portions of the abdominal and pelvic viscera (embryonic hindgut) receive parasympathetics from S2, S3, and S4 via pelvic splanchnic nerves.

Most of these autonomic fibers reach the viscera by traveling on the blood vessels originating from the celiac trunk and the superior and inferior mesenteric arteries.


Autonomic fibers to the bowel synapse on ganglion cells of the enteric nervous system, an intrinsic plexus of ganglia (myenteric and submucosal) for fine control of bowel function.

Atlas Plate 297

4-10 Autonomic Reflex Pathways: Schema

Jun 16, 2016 | Posted by in ANATOMY | Comments Off on Abdomen: Cards 4-1 to 4-31

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