Autonomic state in pain and correction

[Diane]

Structure of sympathetic ganglia (cont.): interneurons

P 1299 Gray's:

The existence of interneurons in sympathetic ganglia has been amply confirmed (Williams 1967; Williams & Palay 1969; Libet & Owman 1974), consisting of the SIF cells identified in sympathetic ganglia in many mammals, including man (Eranko & Harkonen 1965; Jacobowitz 1970). Small chomaffin cells also occur in sympathetic ganglia, as recognized by Kohn in 1898. Coupland (1965a) amongst other modern workers, has ascribed them to all ganglia of the sympathetic trunk and to other sites in human neonatal material. The distinction between SIF cells and chomaffin cells appears uncertain in many accounts. The supposed two types have been identified in ganglia by separate techniques (chromaffin reaction and formalin-induced flourescence) which cannot be applied together to a single cell. In the sympathetic ganglia of rats (Santer et al 1975) SIF cells were found to be more numerous than chromaffin cells and their modes of distribution showed some differences. Both contain catecholamines, some possibly only enough to be revealed by the more sensitive formaldehyde-induced flourescence technique (Falck-Hillarp), whereas others may have sufficient to produce a positive chromaffin reaction (Gabella 1976). Both types may be interneurons (Santer et al 1975; Gabella 1976) Greegard and Kebabian (1974) have suggested that the SIF cells release dopamine, which is then bound by dopamine receptors on ganglionic neurons causing hyperpolarization via a cyclic AMP-dependent 'second messenger' system. In the ganglia of some species, two types of SIF cell have been described (Williams et al 1975): a minority, with long processes, end near ganglionic neurons and hence can be regarded as interneurons (Type I), while the more numerous Type II cells have shorter processes ending near blood vessels. In bovine superior cervical sympathetic ganglia, 24% of SIF cells were described as Type I and 20% were so described in cats. Although the secretory granules in Type I cells may act directly on ganglionic neurons, some SIF cells, presumably Type II, may secrete into local blood vessels (Poloyni et al 1977), exerting more distant effects. The functions of SIF cells in neurotransmission in sympathetic ganglia have been reviewed by Eranko (1978) and Szurszewski and King (1989), and quantification of numbers, dimensions and packing density of ganglionic neurons are reported by Gabella (1976).

The axons of the principal ganglionic cells are narrow, nonmyelinated postganglionic fibres, distributed to effector organs in various ways:

1. Those from a ganglion of the sympathetic trunk may return to the spinal nerve of preganglionic origin through a grey ramus communicans, usually joining the nerve just proximal to the white ramus, to be distributed through ventral and dorsal spinal rami to blood vessels, sweat glands, hairs etc., in their zone of supply. Segmental areas vary in extent and overlap considerably. The extent of innervation of different effector systems, for example vasomotor, sudomotor etc., by a particular nerve may not be the same.

2. Postganglionic fibres may pass in a medial branch of a ganglion direct to particular viscera.

3. They may innervate adjacent blood vessels or pass along them externally to their peripheral distribution.

4. They may ascend or descend before leaving the sympathetic trunk as 1., 2., or 3. Many fibres are distributed along arteries and ducts as plexuses to distant effectors.

Fusion of grey and white rami may also occur, for example in the thoracic region; grey rami may also contain fasiculi of thick myelinated fibres which are somatic efferents using a grey ramus to reach the paravertebral muscles (see below), for example in the cervical region. For details of rami communicantes and their variations consult Winckler (1961).

Next, functional significance.

[Diane]

Structure of sympathetic ganglia: Functional significance, higher autonomic control

P. 1300 Gray's:

Functional significance
Postganglionic fibres which return to the spinal nerves supply vasoconstrictor fibres to blood vessels, are secretomotor to sweat glands and motor to the arrectores pilorum in their dermatomes. Those which accompany the motor nerves to peripheral nerves contain post-ganglionic sympathetic fibres. Those reaching the viscera are concerned with general vasoconstriction, bronchial and bronchiolar dilation, modification of glandular secretion, pupillary dilation, inhibition of alimentary muscle contraction, etc. A single preganglionic fibre probably synapses with the postganglionic neurons in only one effector system; hence effects such as sudomotor and vasomotor actions can be separate. This is not necessarily true of visceral afferent fibres.

Higher autonomic control
Peripheral autonomic activity is integrated at higher levels in the brainstem and cerebrum, including various nuclei of the brainstem reticular formation, thalamus, and hypothalamus, the limbic lobe and prefrontal cortex, together with the ascending and descending pathways which interconnect these regions (see details of these given earlier in this section). It is now recognized that central control of the cardiovascular system is exerted by a longitudinally arranged series of parallel pathways involving specific regions of the neuraxis extending from cerebral cortex to spinal cord (Loewry & Spyer 1990).

The sympathetic trunks are two ganglionated, irregular nerve cords extending from the cranial base to the coccyx. In the neck each lies posterior to the carotid sheath and anterior to the cervical transverse processes; in the thorax each is anterior to the heads of the ribs, in the abdomen anterolateral to the lumbar vertebral bodies and in the pelvis anterior to the sacrum and medial to the anterior sacral foramina. Anterior to the coccyx the two trunks meet in the single, median, terminal gangion impar.

Cervical sympathetic ganglia are usually reduced to three by fusion; from the cranial pole of the superior ganglion issues the internal carotid nerve, as a continuation of the sympathetic trunk, acompanying the internal carotid artery though its canal into the cranial cavity. There are from 10-12 (usually 11) thoracic ganglia, four lumbar and four or five in the sacral region.

Next: CRANIAL PART OF THE SYMPATHETIC SYSTEM

[Diane]

CRANIAL PART OF THE SYMPATHETIC SYSTEM

In the interests of keeping threads on select topics all linked together:
So what is it about the ANS we should know if we're dealing with skin? With pain?
Another link to an article on autonomics and headache.

After a bit of a break, back to Gray's, page 1300:

CRANIAL PART OF THE SYMPATHETIC SYSTEM
This begins on each side as the internal carotid nerve, a branch of the superior cervical ganglion containing the postganglionic fibres of its neurons. Ascending behind the internal carotid artery it divides in the carotid canal into branches, one medial and the others lateral to the artery. The larger, lateral branch gives filaments to the internal carotid and forms the lateral part of the internal carotid plexus; the medial branch also gives filaments to the artery and, continuing on, forms the medial part of the internal carotid plexus.

Internal carotid plexus
This surrounds its artery and occasionally contains a small medial carotid ganglion; elsewhere it has some scattered postganglionic neurons. Laterally the plexus communicates with the trigeminal and pterygopalatine ganglia, the adducent nerve and tympanic branch of the glossopharyngeal; it also distributes filaments to the wall of the internal carotid artery. One or two filaments join the adducent nerve as it lies on the lateral side of the internal carotid artery. The branch to the pterygopalatine ganglion is the deep petrosal nerve, which perforates the cartilage filling the foramen lacerum and forms with the greater petrosal nerve the nerve of the pterygoid canal, traversing the canal to the pterygopalatine ganglion. The communication with the tympanic branch of the glossopharyngeal nerve is effected by the superior and inferior caroticotympanic nerves in the posterior wall of the carotid canal.

The medial part of the internal carotid plexus is inferomedial to the part of the internal carotid artery which indents the cavernous sinus lateral to the sella turcica; it gives branches to the artery and to the oculomotor, trochlear, ophthlamic and abducent nerves and the ciliary ganglion. It also sends vasomotor rami along branches of the internal carotid to the hypohysis cerebri (p. 1887).

The branch to the oculomotor nerve joins the nerve near its point of division and the branch to the trochlear joins it in the lateral wall of the cavernous sinus; filaments also connect with the medial side of the ophthalmic nerve and with the abducent. The filament to the ciliary ganglion, from the anterior part of the plexus, enters the orbit via the superior orbital fissure; this ramus may join the ciliary ganglion directly or unite with the communicating branch from the nasociliary nerve (p. 1228); or it may travel in the ophthalmic nerve and its nasociliary branch. Its fibres traverse the ganglion without synapsing and enter the short ciliary nerves to be distributed to the blood vessels of the eyeball. Fibres supplying the dilator pupillae usually travel via the ophthalmic, nasociliary and long ciliary nerves but occasionally via the short ciliary. Some fibres may also innervate the ciliaris muscle. The preganglionic fibres concerned leave the spinal cord predominantly in T1, pass to and through the cervicothoracic ganglion and ascend in the cervical sympathetic trunk to relay in the superior cervical ganglion.

The internal carotid plexus is prolonged around the anterior and middle cerebral arteries and the ophthalmic arteries, reaching the pia mater along the cerebral vessels; along the ophthalmic artery they pass into the orbit where the plexus accompanies each branch of that vessel. Filaments on the anterior communicating artery connect the sympathetic nerves of the right and left sides and may be associated with a small ganglion. Much of this detail depends on rather old observations; continued disagreement and discrepancy have been reviewed by Mitchell (1953) and Purves (1972). Electron microscopy shows that the sympathetic innervation of the cerebral arterial tree is like that of other vascular systems and the terminals of this rich perivascular plexus have been shown histochemically and immunohistochemically to contain NA and NPY in various mammals, including man (Iwayama 1970; Matsuyama et al 1985). The sources of these sympathetic vasoconstrictor nerve fibres are the internal carotid and vertebral plexuses. It should be noted that, in cerebral vessels, some NPY-containing fibres are of parasympathetic origin, and also contain ACh- containing nerves present in some cerebral vessels after sympathectomy may be of central origin (Edvinsson 1991).

Next: Cervical part of the sympathetic system.

[Diane]

CERVICAL PART OF THE SYMPATHETIC SYSTEM: Superior cervical ganglion

CERVICAL PART OF THE SYMPATHETIC SYSTEM
The cervical part of each sympathetic trunk contains three interconnected ganglia, the superior, middle and cervicothoracic which send grey rami communicantes to all the cervical spinal nerves but receive no white rami communicantes from them; their spinal preganglionic fibres emerge in the white rami communicantes of the upper thoracic spinal nerves which enter the corresponding thoracic sympathetic ganglia, through which they ascend into the neck. In their course, the grey rami communicantes may pierce the longus capitus or the scalenus anterior. For details of the cervical grey rami see Potts (1925), Pick and Sheehan (1946), Sunderland and Bedbrook (1949).

Superior cervical ganglion
This is the largest of the three, adjoins the second and third cervical vertebrae and is probably formed from four fused ganglia corresponding to C1-4. Anterior to it is the internal carotid artery and sheath, while posterior to it is the longus capitus. The internal carotid nerve (see above) ascends from it into the cranial cavity; the lower end of the ganglion is united by a connecting trunk to the middle cervical ganglion. Its branches consist of lateral, medial and anterior groups.

The lateral branches are the grey rami communicantes to the upper four cervical spinal nerves and to some of the cranial nerves; delicate filaments pass to the inferior vagal ganglion and to the hypoglossal nerve; a branch, the jugular nerve, ascends to the cranial base and divides into two, one part joining the inferior glossopharyngeal ganglion and the other the superior vagal ganglion; other twigs pass to the superior jugular bulb and associated jugular glomus or glomera and some to the meninges in the posterior cranial fossa.

The medial branches of the superior cervical ganglion are the laryngopharyngeal and cardiac. The laryngopharyngeal branches supply the carotid body and pass to the side of the pharynx, joining glossopharyngeal and vagal rami to form the pharyngeal plexus (p. 1252). A cardiac branch arises by two or more filaments from the lower part of the superior cervical gangion, occasionally receiving a twig from the trunk between the superior and middle cervical ganglia. It is thought to contain only efferent fibres, the preganglionic outflow being from the upper thoracic segments of the spinal cord, and to be devoid of pain (sic) fibres from the heart (p.1306). It descends behind the common carotid artery, in front of the longus colli, crossing anterior to the inferior thyroid artery and recurrent laryngeal nerve. The courses on the two sides then differ. The right cardiac branch usually passes behind or sometimes in front of the subclavian artery and posterolateral to the brachiocephalic trunk to the back of the aortic arch where it joins the deep (dorsal) part of the cardiac plexus. It has other sympathetic connections: about midneck it receives filaments from the external laryngeal nerve; inferiorly, one or two vagal cardiac branches join it; as it enters the thorax it is joined by a filament from the recurrent laryngeal nerve. Filaments from the nerve also communicate with the thyroid branches of the middle cervical ganglion. The left cardiac branch, in the thorax, is anterior to the left common carotid artery and crosses in front of the left side of the aortic arch to reach the superficial (ventral) part of the cardiac plexus. Sometimes it descends on the right of the aorta to end in the deep (dorsal) part of the cardiac plexus. It communicates with the cardiac branches of the middle cervical and cervicothoracic sympathetic ganglia and sometimes with the inferior cervical cardiac branches of the left vagus; branches from these mixed nerves form a plexus on the ascending aorta.

The anterior branches of the superior cervical ganglion ramify on the common and external carotid arteries and the branches of the latter, forming a delicate plexus around each in which small ganglia are occasionally found. The plexus around the facial artery supplies a filament to the submandibular ganglion; the plexus on the middle meningeal artery sends one ramus to the otic ganglion and another the external petrosal nerve, to the facial ganglion. Many of the fibres coursing along the external carotid and its branches ultimately leave them to travel to facial sweat glands via trigeminal nerve branches.

Next, middle cervical ganglion.

[Diane]

Middle cervical ganglion

P. 1302 Gray's:

Middle cervical ganglion
This is the smallest of the three. It is occasionally absent and may then be replaced by minute ganglia in the sympathetic trunk or may be fused with the superior ganglia. It is usually found at the sixth cervical vertebral level, anterior or just superor to the inferior thyroid artery, or it may adjoin the cervicothoracic ganglion (see below); it is probably a coalescence of the ganglia of the fifth and sixth cervical segments, judging by its postganglionic rami, which join the fifth and sixth cervical spinal nerves but sometimes also the fourth and seventh. The ganglion also has thyroid and cardiac branches. It is connected to the cervicothoracic ganglion by two or more very variable cords: the posterior usually splits to enclose the vertebral artery; the anterior loops down anterior to and then below the first part of the subclavian artery, medial to the origin of its internal thoracic branch, and supplies rami to it. This loop is the ansa subclavia; it is frequently multiple, lies closely in contact with the cervical pleura and generally connects with the phrenic nerve. Similar connections with the vagus nerve are of uncertain significance.

Thyroid branches accompany the inferior thyroid artery to the thyroid gland, communicating with the superior cardiac, external laryngeal and recurrent laryngeal nerves, and send branches to the parathyroid glands. Fibres to both glands are in part vasomotor but some reach the secretory cells (Raybuck 1952).

The cardiac branch, the largest sympathetic cardiac nerve, either arises from the ganglion itself or caudal to it. On the right side it descends behind the common carotid artery, in front of or behind the subclavian, to the trachea where it receives a few filaments from the recurrent laryngeal nerve before joining the right half of the deep (dorsal) part of the cardiac plexus. In the neck, it connects with the superior cardiac and recurrent laryngeal nerves. On the left side the cardiac nerve enters the thorax between the left common carotid and subclavian arteries to join the left half of the deep (dorsal) part of the cardiac plexus. Fine branches from the middle cervical ganglion also passs to the trachea and oesophagus.

I didn't know before that the vertebral artery usually tunnels through the posterior cord connecting the MCG to the next one down, the cervicothoracic.

[Diane]

Cervicothoracic (stellate) ganglion

P 1303 Gray's:

Cervicothoracic (stellate) ganglion
This is irregular in shape and much larger that the middle cervical ganglion. It is probably formed by a fusion of the lower two cervical and first thoracic segmental ganglia, sometimes including the second and even third and fourth thoracic ganglia. The first thoracic ganglion may be separate, leaving an inferior cervical ganglion above it. The sympathetic trunk turns backwards at the junctions of the neck and thorax and so the long axis of the cervicothoracic ganglion becomes almost anteroposterior. The ganglion lies on or just lateral to the lateral border of the longus colli between the base of the seventh cervical transverse process and the neck of the first rib (which are posterior to it), the vertebral vessels being anterior. Below it is separated from the posterior aspect of the cervical pleura by the suprapleural membrane; the costocervical trunk branches near its lower pole. Lateral is the superior intercostal artery.

A small vertebral ganglion may be present on the sympathetic trunk anterior or anteromedial to the origin of the vertebral artery and directly above the subclavian. When present, it may provide the ansa subclavia and is joined to the cervicothoracic ganglion by fibres enclosing the vertebral artery. It is usually regarded as a detached part of the middle cervical or cervicothoracic ganglion. Like the middle cervical ganglion it may supply grey rami communicantes to the fourth and fifth cervical spinal nerves. The cervicothoracic ganglion sends grey rami communicantes to the seventh and eighth cervical and first thoracic spinal nerves and gives off a cardiac branch, branches to nearby vessels and sometimes a branch to the vagus nerve.

The grey rami communicantes to the seventh cervical spinal nerve vary from one to five; two, the usual number, are shown in 8.398, 399. A third often ascends medial to the vertebral artery in front of the seventh cervical transverse process, connects with the seventh cervical nerve and sends a filament upwards through the sixth cervical transverse foramen in company with the vertebral vessels to join the sixth cervical spinal nerve as it emerges from the intervertebral foramen. An inconstant ramus may traverse the seventh cervical transverse foramen. Grey rami to the the eighth cervical spinal nerve vary from three to six in number.

The cardiac branch descends behind the subclavian artery and along the front of the trachea to the deep cardiac plexus. Behind the artery it connects with the recurrent laryngeal nerve and the cardiac branch of the middle cervical ganglion, the latter often being replaced by fine branches of the cervicothoracic ganglion and ansa subclavia.

Branches to blood vessels form plexuses on the subclavian artery and its branches. The subclavian supply is derived from the cervicothoracic ganglion and ansa subclavia, extending to the first part of the axillary artery; a few fibres may extend further. According to Pearson and Sauter an extension of the subclavian plexus to the internal thoracic artery is joined by a branch of the phrenic nerve (p. 1265). The vertebral plexus is derived mainly from a large branch of the cervicothoracic ganglion which ascends behind the vertebral artery to the sixth transverse foramen, reinforced by branches of the vertebral ganglion or the cervical sympathetic trunk which pass cranially on the ventral aspect of the artery; from this plexus deep rami communicantes join the ventral rami of the upper five or six cervical spinal nerves. The plexus contains some neuronal cell bodies and continues into the skull along the vertebral and basilar arteries and their branches as far as the posterior cerebral artery, where it meets a plexus from the internal carotid. Some consider the vertebral plexus to be the main intracranial extension of the sympathetic system (Lazorthes 1949; Mitchell 1952). The plexus on the inferior thyroid artery reaches the thyroid gland, connecting with recurrent and external laryngeal nerves, the cardiac branch of the superior cervical ganglion, and the common carotid plexus.

The preganglionic fibres for the head and neck emerge from the spinal cord in the upper five thoracic spinal nerves (mainly the upper three), ascending in the sympathetic trunk to synapse in the cervical ganglia. The preganglionic fibres supplying the upper limb stem from upper thoracic segments, probably T2-6 (or 7), ascending via the sympathetic trunk to synapse mainly in its cervicothoracic ganglion, whence postganglionic fibres pass to the brachial plexus (mainly its lower trunk). Most of the vasoconstrictor fibres for the upper limb emerge in the second and third thoracic ventral roots; the arteries can thus be denervated by cutting the sympathetic trunk below the third thoracic ganglion, severing the rami communicantes connected with the second and third thoracic ganglia or by cutting the ventral roots of the second and third thoracic spinal nerves (intradurally). The white ramus to the cervicothoracic ganglion is not cut, partly because it does not convey many vasomotor or sudomotor fibres to the upper limb but mainly because it contains most of the preganglionic fibres for the head and neck; these ascend the trunk to the superior cervical ganglion, from which postganglionic branches supply vasoconstrictor and sudomotor nerves to the face and neck, secretory fibres to the salivary glands, dilator pupillae (and probably cilaris oculi), non-striated muscle in the eyelids and the orbitalis. Destruction of this nerve would thus lead to meiosis, ptosis, enopthalmos and loss of sweating on the face and neck (Horner's syndrome) and possibly some disturbance of accomodation. For a review consult Haxton (1954) and Bannister and Mathias (1992).

Blood vessels of the upper limb beyond the first part of the axillary artery receive their sympathetic supply via branches of the brachial plexus adjacent to them, e.g. the median nerve supplies branches to the brachial artery and palmar arches, the ulnar nerve supplies the ulnar arery and palmar arches and the radial nerve supplies the radial artery.

The first and second (and occasionally the third) intercostal nerves may be interconnected anterior to the necks of the ribs by filaments containing postganglionic fibres from their grey rami; these fibres provide another path by which postganglionic nerves can pass from the upper thoracic ganglia to the brachial plexus.

Why anyone would want to manipulate all this I have no idea. Wait a minute, I do... by pretending that none of it exists in that moment in time, in the neck within one's hands? Sorry, it doesn't all go away just because you close your mind to its existence. You can't wish it away. It's going to be there whatever you do to someone's neck, so start learning less violent ways of treating it.

Next, the thoracic part of the sympathetic system.

[aléa]

P 1303 Gray's:


Why anyone would want to manipulate all this I have no idea. Wait a minute, I do... by pretending that none of it exists in that moment in time, in the neck within one's hands? Sorry, it doesn't all go away just because you close your mind to its existence. You can't wish it away. It's going to be there whatever you do to someone's neck, so start learning less violent ways of treating it.

Next, the thoracic part of the sympathetic system.

Can you imagine that therapists do know that ? Can you imagine osteopathy, or chiro, as a reflex therapy ? How do you think manipulations work ?

Saying that, I'm not a manipulation fanatic.

[Diane]

Alea, let me be clear that when I used the term "manipulation" I was referring to HVLA thrust type cracking. I'm not at all opposed to "handling" of the neck. I understand reflexive treatment fairly well, I think. Thank you for your input.

[Barrett Dorko]

Diane,

I think the work you've done here should be required reading in every PT program.

In my experience, (years of that every day) manipulation doesn't result in much of anything - no increase in range, no change in symptoms. Every once in a great while people would be briefly better, sometimes worse. There was no predicting any of this.

There's a discussion on RE about the persistance of symtomotology after "whiplash." Various studies indicate that these aren't just driven by financial considerations. It seems that the anatomical reality of the region and its connection to the possibility of physiologic irritation is something that should always be considered.

It seems to me that the neck's typical lack of response to manipulation is a testament to its adaptability.

[Diane]

THORACIC PART OF THE SYMPATHETIC TRUNK

The neck is an interesting place
1. with all this essential wiring to vital food intake structures and airways and balance/equilibrium function;
2. vital tubing (vessels) and cord (to rest of body);
3. given the fact that embryologically the diaphragm and heart start out in there and that maybe part of the brain still thinks they are in there;
4. given the fact that even if it is strained, say in a whiplash accident, it still has to support the head? i.e., no way to rest it other than lay it down, or immobilize it in a collar (shown to be couterproductive for all sorts of reasons);
5. given the above, is it any wonder the brain may feel more greatly threatened when the neck is injured in, say, whiplash, in terms of a persistent pain state in the neck representation, than if, say, in a knee representation if a knee is dinged on the dashboard in the same accident?

Anyway, moving on to another interesting bit:
P. 1303, Gray's:

THORACIC PART OF THE SYMPATHETIC TRUNK
The thoracic sympathetic trunk contains ganglia almost equal in number to those of the thoracic spinal nerves (11 in more than 70%, occasionally 12, rarely 10 or 13). The first thoracic ganglion is usually fused with the inferior cervical, forming the cervicothoracic ganglion; Jit and Mukerjee (1960) found a fused ganglion in 80 out of 100 dissections. Rarely the middle cervical or second thoracic ganglion may be included. The succeeding ganglion is counted as the second in order to make the other ganglia correspond numerically with other segmental structures. Except for the lowest two or three the thoracic ganglia lie against the costal heads, posterior to the costal pleura; the lowest two or three are lateral to the bodies of the corresponding vertebrae. Caudally, the thoracic sympathetic trunk passes dorsal to the medial arcuate ligament (or through the crus of the diaphragm) to become the lumbar sympathetic trunk. The ganglia are small and interconnected by intervening segments of the trunk. Two or more rami communicantes, white and grey, connect each ganglion with its corresponding spinal nerve, white rami joining the nerve distal to the grey. Sometimes a grey and white ramus fuse to form a 'mixed' ramus (p. 1298).

The medial branches from the upper five ganglia are very small, supplying filaments to the thoracic aorta and its branches. On the aorta they form a fine thoracic aortic plexus with filaments from the greater splanchnic nerve. Rami of the second to fifth or sixth ganglia enter the posterior pulmonary plexus; others, from the second to fifth ganglia, pass to the deep (dorsal) part of the cardiac plexus. Small branches of these plumonary and cardiac nerves pass to the oesophagus and trachea. The medial branches from the lower seven ganglia are large, supplying the aorta and uniting to form the greater, lesser and lowest splanchnic nerves, the last not always being identifiable.

The greater splanchnic nerve consisting mainly of myelinated preganglionic efferent and visceral afferent fibres, is formed by branches from the fifth to ninth or tenth thoracic ganglia; but fibres in the upper branches may be traced to the first or second thoracic ganglion. Its roots vary from one to eight, four being the most usual number. It descends obliquely on the vertebral bodies, supplies branches to the descending thoracic aorta and perforates the ipsilateral crus of the diaphragm to end mainly in the coeliac ganglion but partly in the aortorenal ganglion and suprarenal gland. A splanchnic ganglion exists on the nerve opposite the eleventh or twelfth thoracic vertebra in 17-68% of dissections (Jit & Mukerjee 1960); but Mitchell (1953) reported microscopic evidence that it is always present.

The lesser splanchnic nerve formed by rami of the ninth and tenth (sometimes tenth and eleventh) thoracic ganglia and the trunk between them, pierces the diaphragm with the greater splanchnic to join the aorticorenal ganglion.

The lowest (least) splanchnic nerve (or renal nerve) from the lowest thoracic ganglion enters the abdomen with the sympathetic trunk to end in the renal plexus.

Jit and Mukerjee (1960) described in great detail dissections of the thoracic sympathetic nerves in 50 cadavers and surveyed the previous findings. The incidence of the splanchnic nerves, according to seven observers, is as follows: greater - always present, lesser - 94% (86-100%), least - 56% (16-98%). A fourth (accessory) splanchnic nerve has been described by deSousa (1955) but has not been confirmed.

With all this vital wiring piercing the diaphgram I would be inclined to predict that the "green light" types delineated on Nick's mechanical peripheral NS deformation thread lately, who can't abdominally breath and whose spines seem so rigid would maybe be nonconsciously guarding/defending their sympathetic chains. I wonder if the postural restoration people have looked into sympathetic nervous system anatomy, reflected on it, allowed it to inform their thinking to any extent?

:note2: "(Ooh! Uh! ooh! uh!)
Hey don't you know..
That's the sound of the men..
Working on the chain...
Ganglia.."

[Diane]

LUMBAR PART OF THE SYMPATHETIC SYSTEM

P 1304 Gray's:

LUMBAR PART OF THE SYMPATHETIC SYSTEM
The lumbar part of each sympathetic trunk usually containing four interconnected ganglia, runs in the extra-peritoneal connective tissue anterior to the verterbral column and along the medial trunk of the psoas major. Superiorly it is continuous with the thoracic trunk posterior to the medial arcuate ligament; inferiorly, passing posterior to the common iliac artery, it becomes the pelvic trunk. On the right side it is overlapped by the inferior vena cava and on the left by the lateral aortic lymph nodes. It is anterior to most of the lumbar vessels but may pass behind some lumbar veins.

The first, second and sometimes third lumbar ventral spinal rami send white rami communicantes to the corresponding ganglia. Grey rami communicantes passing from all ganglia to the lumbar spinal nerves, are long and accompany the lumbar arteries round the sides of the vertebral bodies, medial to the fibrous arches to which the psoas major is attached.

Usually four lumbar splanchnic nerves pass from the ganglia to join the coeliac, intermestenteric (abdominal aorta) and superior hypogastric plexuses. The first lumbar splanchnic nerve, from the first ganglion joins the coeliac, renal and intermestenteric plexuses. The second nerve, from the second and sometimes the third ganglion, joins the inferior part of the intermesenteric plexus; the third nerve issues from the third or fourth ganglion, passsing anterior to the common iliac vessels to join the superior hypogastric plexus. The fourth lumbar splanchnic, from the lowest ganglion, passes dorsal to the common iliac vessels to join the lower part of the superior hypogastric plexus or the hypogastric 'nerve'.

Vascular branches from all lumbar ganglia join the intermesenteric (aortic) plexus. Fibres of the lower lumbar splanchnic nerves pass to the common iliac arteries, forming a plexus continued along the internal and external iliac arteries as far as the proximal part of the femoral artery. Many postganglionic fibres in the grey rami, connecting the lumbar ganglia to the spinal nerves, travel in the femoral nerve to its muscular, cutaneous and saphenous branches, supplying vasoconstrictor nerves to the femoral artery and its branches in the thigh. Other postganglionic fibres travel via the obturator nerve to the obturator artery. Considerable uncertainties persist regarding sympathetic supplies to the lower limb (Wilde 1951; Wyburn 1956; Pick 1970).

Some of this bears repeating: Many postganglionic fibres in the grey rami, connecting the lumbar ganglia to the spinal nerves, travel in the femoral nerve to its muscular, cutaneous and saphenous branches, supplying vasoconstrictor nerves to the femoral artery and its branches in the thigh. Other postganglionic fibres travel via the obturator nerve to the obturator artery. Does anyone else see the possibilities here for eliciting positive reflex autonomic activity by handling skin on the front of the thigh? Up into the hip perhaps?

Next, pelvic part of the sympathetics.

[nari]

Yep, it certainly sounds likely that skin contact--> autonomic activity is logical. Could be hard to disprove...

Nari

[Diane]

PELVIC PART OF THE SYMPATHETIC SYSTEM

P. 1305 Gray's:

PELVIC PART OF THE SYMPATHETIC SYSTEM
The pelvis sympathetic trunk lies in the extraperitoneal tissue anterior to the sacrum, medial or anterior to the anterior sacral foramina, and has four or five interconnected ganglia. Above, it continues into the lumbar trunk; below, the two trunks converge to unite in the small ganglion impar anterior to the coccyx. Grey rami communicantes pass from the ganglia to sacral and coccygeal spinal nerves but white rami communicantes are absent. Medial branches of distribution connect across the midline; twigs from the first two ganglia join the inferior hypogastric plexus (pelvic plexus) or the hypogastric 'nerve'; others form a plexus on the median sacral artery. The glomus coccygeum is supplied from the loop between the two trunks. The hypogastric 'nerve', which is usually plexiform, is a redundant term for the right and left connections, between the superior and inferior hypogastric plexuses (p. 1308).

Vascular branches
Through the grey rami many postganglionic fibres pass to the roots of the sacral plexus, especially those forming the tibial nerve, to be conveyed to the popliteal artery and its branches in the leg and foot. Others are carried in the poudendal and superior and inferior gluteal nerves to the accompanying arteries. Branches to the lymph nodes are also described (Wozniak 1966).

Preganglionic fibres for the lower limb are derived from the lower three thoracic and upper two or three lumbar spinal segments. They reach the lower thoracic and upper lumbar ganglia through white rami; some descend through the sympathetic trunk to synapse in the lumbar ganglia, whence postganglionic fibres join the femoral nerve to supply the femoral artery and its branches; other fibres descend to synapse in the upper two or three sacral ganglia, from which postganglionic axons join the tibial nerve to supply the popliteal artery and its branches in the leg and foot. Sympathetic denervation of vessels in the lower limb can thus be effected by removing the upper three lumbar ganglia and the intervening parts of the sympathtic trunk, all the preganglionic fibres to the lower limb thus being divided.

SEGMENTAL SYMPATHETIC SUPPLIES
Segmental sympathetic supplies are as follows:

(Note: I reorganized the list to have it make sense embryologically. Nothing has been excluded or added.)

Head, neck, heart: T1-5
Bronchi and lung T2-4
Upper limb: T2-5
Oesophagus (caudal part) T5-6
Stomach, spleen, pancreas T6-10
Liver and gallbladder T7-9
Suprarenal T8-L1
Small intestine T9-10
Kidney T10-L1
Tests and ovary T10-11
Large intestine to splenic flexure, prostate, prostatic urethra T11-L1
Ureter, epididymis, ductus deferens, seminal vesicles, bladder T11-L2
Uterus T12-L1
Large intestine splenic flexure to rectum L1-2
Uterine tube T10-L1
Lower limb T10-L2

There. I'm sure the nervous system would rather have the list in the order I have put it in. The previous order was according to tissue systems; musculoskeletal, thoracic organs, GI tract etc..

Yeah, Gray's really did use the word "whence." Even in 1995. That is not a typo.

The big takeaway point for me is all the sympathetic fibres in the regular nerves. It has got to feel good (everywhere) to get them liberated from the surrounding mesoderm within the leg..

Next, plexuses in the thoracic, abdominal and pelvic cavities.

[Diane]

PLEXUSES IN THE THORACIC, ABDOMINAL, AND PELVIC CAVITIES

P 1306, Gray's

PLEXUSES IN THE THORACIC, ABDOMINAL, AND PELVIC CAVITIES
The larger autonomic plexuses are aggregations of nerves and ganglia situated in the thoracic, abdominal and pelvic cavities. They are the cardiac, plumonary, coeliac and hypogastric plexuses, supplying the thoracic, abdominal, and pelvic viscera, respectively. Extensions of these major plexuses pass along most branches of the large vessels which they surround and are usually named after the artery along which they are distributed. This leads to a plethora of named plexuses, often separately described in detail which may overshadow their essential unity.

CARDIAC PLEXUSES
The cardiac plexus at the base of the heart is divided into superficial (ventral) and deep (dorsal) parts which are closely connected. Several small ganglia lie within it, the most constant being the cardiac ganglion described below. Mizeres (1963) has emphasized the unity of the cardiac plexus, considering its division into two parts as an artefact of dissection; he was, however, prepared to allow regional names for its coronary, pulmonary, atrial and aortic extensions. Since major concentrations of the plexus are situated as described here, the terms superficial and deep have been retained.

More on the cardiac plexus next time.

[Diane]

CARDIAC PLEXUSES

P 1306 Gray's

Superficial (ventral) part of the cardiac plexus
This lies below the aortic arch and anterior to theright pulmonary artery. It is formed by the cardiac branch of the left superior cervical sympahetic ganglion and the lower of the two cervical cardiac branches of the left vagus. A small cardiac ganglion is usually present in this plexus immediately below the aortic arch, to the right of the ligamentum arteriosum. This part of the cardiac plexus connects with (1) the deep part, (2) the right coronary plexus, (3) the left anterior pulmonary plexus.

Deep (dorsal) part of the cardiac plexus
This is anterior to the tracheal bifurcation, above the point of division of the pulmonary trunk and posterior to the aortic arch. It is formed by the cardiac branches of the cervical and upper thoracic sympathetic ganglia and of the vagus and recurrent laryngeal nerves. The only cardiac nerves which do not join it are those joining the superficial part of the plexus.

Branches from the right half of the deep part of the cardiac plexus pass in front of and behind the right pulmonary artery; those anterior to it, the more numerous, supply a few filaments to the right anterior pulmonary plexus and continue on to form part of the right coronary plexus; those behind the pulmonary artery supply a few filaments to the right atrium and then continue into the left coronary plexus. Ther left half of the deep part of the cardiac plexus is connected with the superficial, supplying filaments to the left atrium and left anterior pulmonary plexus and then continuing to form much of the left coronary plexus.

Left coronary plexus
This is larger than the right, and is formed chiefly by the prolongation of the left half of the deep part of the cardiac plexus and a few fibres from the right; it accompanies the left coronary artery to supply the left atrium and ventricle.

Right coronary plexus
This is formed from both superficial and deep parts of the cardiac plexus, and accompanies the right coronary artery to supply the right atrium and ventricle.

Atrial plexuses
Described by Mizeres (1963), these are derivatives of the right and left continuations of the cardiac plexus along the coronary arteries. Their fibres are distributed to the corresponding atria, overlapping those from the coronary plexuses.

All the cardiac branches of the vagus and sympathetic contain both afferent and efferent fibres, except the cardiac branch of the superior cervical sympathetic ganglion, which is purely efferent. The efferent preganglionic cardiac sympathetic fibres arise in the upper four or five thoracic spinal segments; they pass by white rami communicantes to synapse in trhe upper thoracic sympathetic ganglia, though many ascend to synapse in the cervical ganglia. Post-ganglionic fibres from the thoracic and cervical ganglia form the sympathetic cardiac nerves, which accelerate the heart and dilate the coronary arteries. Of the sympathetic fibres from the first four or five thoracic spinal segments, the upper pass to the ascending aorta, pulmonary trunk and ventricles, the lower to the atria.

The efferent cardiac parasympathetic fibres from the dorsal vagal nucleus and neurons near the nucleus ambiguus run in vagal cardiac branches to synapse in the cardiac plexuses and atrial walls. These vagal fibres slow the heart and cause constriction of the coronary arteries (p. 1500). In man (like most mammals) intrinsic cardiac neurons are limited to the atria and interatrial septum (Davies et al 1952; King & Coakley 1958); they are most numerous in the subepicardial connective tissue near the SA and AV nodes. There is now evidence that these intrinsic ganglia are not simple nicotinic relays but may also act as sites for integration of extrinsic nervous inputs and form complex circuits for the local neuronal control of the heart and perhaps even local reflexes (consult Saffrey et al 1992).

Thus does the CNS remain aware of its own heart beating. The segmental sympathetic supplies to head neck AND heart, are T1-5. The heart started out in the neck and then the head and neck grew away from it.

Something I'd like to accomplish one fine day is to learn to (confidently) visualize the difference between white and grey rami communicantes without all that complex wiring and function blurring together in my mind.