Human Anatomy, Part 2 - K. A. Dyubenko, A. K. Kolomiytsev, Yu. B. Chaykovsky 2008

Special Part
Autonomic nervous system, systema nervosum autonomicum
Sympathetic trunk

The sympathetic trunk, truncus sympatheticus, is a paired Structure consisting of a series (22-25) of paravertebral ganglia, ganglia trunci sympathici, interconnected by interganglionic branches, rami interganglionares. Both trunks lie on either side of the spine, merging in the coccygeal region to form an unpaired ganglion, ganglion impar. According to the division of the spine, the sympathetic trunk is subdivided into cervical, thoracic, lumbar, and sacral parts.

The cervical part of the sympathetic trunk is located on the Deep Muscles of the Neck. It consists of 2-6, but most commonly three, ganglia (Fig. 205).

The superior cervical ganglion, ganglion cervicale superius, is spindle-shaped and lies at the level of the II—III CERVICAL VERTEBRAE POSTERIOR to the Internal Carotid Artery. It gives rise to the following:

1. The jugular nerve, nervus jugularis, runs along the Internal jugular vein, giving off branches in the jugular foramen region to the ganglia of the glossopharyngeal and vagus nerves, as well as to Branches of the Hypoglossal nerve.

2. The internal carotid nerve, nervus caroticus internus, accompanying the artery of the same name, forms the internal carotid plexus, plexus caroticus internus, on its surface, which extends to its branches. Through the latter, sympathetic nerve fibers reach the tympanic cavity, hypophysis, lacrimal gland, trigeminal ganglion, and the oculomotor, trochlear, and abducens nerves. The deep petrosal nerve, nervus petrosus profundus, branches off from the plexus and joins the greater petrosal nerve to form the nerve of the pterygoid canal.

3. The external carotid nerves, nervi carotici externi, pass to the artery of the same name, forming the external carotid plexus, plexus caroticus externus, around it, which extends to all its branches.

4. The laryngopharyngeal branches, rami laryngopharyngeales, participate in The formation of the laryngopharyngeal plexus, which innervates the vessels and Glands of the mucous membrane of the Pharynx and Larynx.

5. The superior cervical cardiac nerve, nervus cardiacus cervicalis superior, which runs to the cardiac plexus.

6. Gray rami communicantes, rami communicantes grisei, to the I-IV cervical Spinal Nerves. Through these branches, postganglionic fibers—processes of Neurons from the superior cervical ganglion—pass to the named nerves, entering the composition of their branches.

The middle cervical ganglion, ganglion cervicale medium, is inconstant, sometimes consisting of two small-sized ganglia. It lies at the level of the VI cervical vertebra, posterior to the inferior thyroid artery. This ganglion gives rise to:

1. The middle cervical cardiac nerve, nervus cardiacus cervicalis medius, to the cardiac plexus.

2. Gray rami communicantes to the V-VI cervical nerves.

The inferior cervical ganglion occurs independently or fuses with the first thoracic ganglion, forming the cervicothoracic (stellate) ganglion, ganglion cervicothoracicum (stellatum). It lies at the level of the VII cervical vertebra or the neck of the first rib posterior to the vertebral artery. It gives rise to:

1. The vertebral nerve, nervus vertebralis, which forms the vertebral plexus, plexus vertebralis, around the artery of the same name, extending to the Basilar artery and its branches.

2. Branches to the Subclavian Artery, which form the subclavian plexus, plexus subclavius, around it. Along the course of the arterial branches, nerve fibers extend from the plexus to the thyroid, parathyroid, Thymus, and Mammary Glands, and the upper limb.

3. The inferior cervical cardiac nerve, nervus cardiacus cervicalis inferior, which runs to the cardiac plexus.

4. Gray rami communicantes to the VII-VIII cervical nerves.

The thoracic part of the sympathetic trunk consists of 9-12 ganglia located anterior to the heads of the Ribs beneath the endothoracic fascia, fascia endothoracica (Fig. 206). These ganglia give rise to:

1. The thoracic cardiac nerves, nervi cardiaci thoracici, running from the 2nd-5th thoracic ganglia to the cardiac plexus, as well as to the thoracic aortic plexus.

2. Fine branches from the 5-6 upper ganglia to the aorta, which form the thoracic aortic plexus, plexus aorticus thoracicus, from which branches extend to the Esophagus (forming the esophageal plexus, plexus oesophagealis) and the Lungs (forming the pulmonary plexus, plexus pulmonalis).

3. The greater splanchnic nerve, nervus splanchnicus major, formed by the convergence of individual branches from the 5th-9th thoracic ganglia. The nerve penetrates between the medial and intermediate crura of the Diaphragm into the Abdominal cavity, where it enters the celiac plexus, plexus coeliacus.

4. The lesser splanchnic nerve, nervus splanchnicus minor, formed by the convergence of branches from the 10th-11th thoracic ganglia. It passes through the diaphragm alongside the preceding nerve and enters the celiac and renal plexuses.

5. The renal branch, ramus renalis, from the 12th thoracic ganglion to the renal artery and its branches. It forms the renal plexus, plexus renalis, around the artery.

6. Gray rami communicantes to the thoracic spinal nerves.

The lumbar (abdominal) part of the sympathetic trunk consists of 3-5 ganglia located along the medial margin of the psoas major Muscle. The ganglia of the left and right sides are interconnected by transverse anastomoses. The ganglia give off the following:

1. Lumbar splanchnic nerves, nervi splanchnici lumbales, formed by the branches of the two upper lumbar ganglia, pass to the celiac, abdominal aortic, renal, and suprarenal plexuses.

2. Gray rami communicantes to the lumbar spinal nerves.

The sacral part of the sympathetic trunk consists of 3-4 ganglia located on the pelvic surface of the sacrum, medial to the sacral foramina. As in the lumbar region, the ganglia of the left and right sides are connected by transverse anastomoses. The ganglia give rise to:

1. Sacral splanchnic nerves, nervi splanchnici sacrales, which, together with fibers from the inferior mesenteric plexus, provide sympathetic innervation to the pelvic Organs.

2. Gray rami communicantes that reach the sacral spinal nerves.

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Fig. 204. Diagram of the Sympathetic part of the Autonomic Nervous system

Fig. 207. Diagram of the Parasympathetic part of the autonomic nervous system