Survey of Topographical Anatomy (Ukázka, strana 99)

1 2 Fig. 69 The crossing of the uterine arteries and the ureters. Scheme 1 – uterine artery, 2 – ureter

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Fig. 70 The arteries and veins of the rectum. Scheme 1 – inferior mesenteric artery, 2 – superior rectal artery, 3 – common iliac artery, 4 – internal iliac artery, 5 – middle rectal artery, 6 – internal pudendal artery, 7 – inferior rectal artery, 8 – inferior rectal vein, 9 – internal pudendal vein, 10 – middle rectal vein, 11 – internal iliac vein, 12 – inferior vena cava, 13 – superior rectal vein (via the inferior mesenteric vein into the portal vein)

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arteries. The veins, originating from the plexuses, are relatively short. In the rectal wall there is an important area of portocaval anastomoses (the superior rectal vein opens into the inferior mesenteric vein and further into the portal vein, while the middle and inferior rectal veins open into the internal iliac vein and further into the system of the inferior vena cava).

The lymphatics are mostly drained into the internal iliac nodes (but also into the external and common ones), from the uterus also into the lumbar and superficial inguinal nodes. Therefore uterine tumors can metastase in different directions. Also, the ovarian lymphatics are drained into the lumbar nodes.

The autonomic nervous plexus, the inferior hypogastric plexus (or pelvic plexus) is the continuation of the sympathetic superior hypogastric plexus. It also contains numerous parasympathetic fibers originating in spinal cord segments S2–S4 and continuing to the organs via the sacral splanchnic nerves.

Its extensions continue to the particular organs from the inferior hypogastric plexus: middle rectal, vesical, prostatic, deferential and uterovaginal plexuses.

The sympathetic fibers of this plexus cause vasoconstriction, constriction of the smooth muscle cells of the urethral sphincter, prostate and seminal glands, and of the internal anal sphincter.

The parasympathetic fibers of the pelvic plexus cause vasodilatation, above all in the cavernous bodies; they further innervate the detrusor of the urinary bladder and depress the tone of the internal anal sphincter.

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Topographical anatomy of the back The back (dorsum) is designed as the dorsal part of the trunk from the superior nuchal line to the apex of the coccyx. The lateral border on the neck goes from the mastoid process of the temporal bone to the acromion, then to the inferior scapular angle and along the scapular line to the iliac crest and along the margins of the sacrum to the coccyx.

The base of the back represents the vertebral column in whole extent, in the thoracic part also the dorsal parts of the ribs. The whole longitudinal area above the vertebral column is the vertebral region, above the sacrum the sacral region. The dorsal side of the neck (see above) is the posterior cervical region. In the thoracic part of the back, the scapular region is defined as the extent of the scapula; this region will be described as a part of the topography of the upper extremity. The area bordered from the 12th rib caudally to the iliac crest is defined as the lumbar region.

The division of the back into particular region has only informative importance, because the structure of all of them differs only very little. Therefore, the layers of the back will be described in general and later on a few important differences will be mentioned.

On the back, the spinous processes of the vertebrae are visible and palpable in its whole length, in the sacral region, also the dorsal surface of the sacrum. In individuals with well developed musculature, a groove above the spinous processes is visible. In the lumbar and sacral region a typical flattening called the rhomboid of Michaelis is visible. Its lateral points are the lateral lumbar fossae (of Venus) above the posterior superior iliac spines, the cranial one is above the spinous process of L5, and the caudal one at the level of S3 where both gluteal regions join and the intergluteal cleft (crena analis) begins. This structure is better visible in females. The shape of the back depends on the configuration of the vertebral column, and in the thoracic segment on the position of the scapulae.

The skin of the back is rather thick, tough, and in the cervical region covered by hairs. The layer of the subcutaneous connective tissue is variably high, in obese individuals substantially thick. The next layer is the dorsal fascia, called the posterior lamina of the thoracolumbar fascia in the lower part of the back, and in the cervical region, the nuchal fascia, which completely covers the superficial muscles.

The back muscles are described in detail in systemic anatomy, therefore here they will only be mentioned as they follow in layers from the surface to the depth.

1. The superficial layer represents a group of spinohumeral muscles: the trapezius and latissimus dorsi.

2. The second layer represent the spinoscapular muscles: the rhomboidei and levator scapulae.

3. The spinocostal muscles are in the third layer: the serratus posterior superior and inferior.

4. The deep dorsal muscles follow in deeper layers (epaxial, autochtonous), innervated by the posterior rami of spinal nerves. Their most superficial layer are represented by the cervical spinotransversal muscles: the splenius capitis and the splenius cervicis.

5. The erectores spinae consist of the long spinotransversal muscles running along the whole vertebral column: the iliocostalis (lumborum, thoracis, cervicis), longissimus (thoracis, cervicis, capitis) and spinalis (thoracis, cervicis, capitis).

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