Technic and Practice of Chiropractic

by Joy Maxwell Loban

SPECIAL NERVE CONNECTIONS

This section does not purport to state with any degree of completeness the various nerve-paths by which spinal vertebrae come into relation with all, or nearly all, the peripheral organs of the body. It merely points out some of the more interesting and important connections, some of the paths which serve to explain the common effects of vertebral adjustment. It is not expected that this resume of the subject will be more than suggestive to the student; certainly it cannot, in so brief a space, be a complete exposition.

Outline of Nerve System

Let us begin with the observation that almost every organ of the body, including the central nerve organs themselves, may be adversely affected by spinal subluxation impinging spinal nerve axons at their exit from, or entrance through, intervertebral foramina, or by spinal subluxation producing direct impingement upon some part of the sympathetic system and similarly interfering with its power to functionate.

The Nerve System may be divided into two great divisions, the central axis and the peripheral system which distributes nerve energy from, and brings stimuli to, the central axis. The central axis consists of the brain and spinal cord; the peripheral system of 12 pairs of nerves attached to the brain and having exit (except the eighth) through foramina in the base of the cranium, 31 pairs of spinal nerves emerging through intervertebral foramina whose parts are movable upon each other (except the foramina for sacral and coccygeal nerves), and an intricate system of sympathetic fibres and ganglia arranged in a double chain of ganglia in front and at the sides of the vertebral column, three great prevertebral plexuses, the cardiac, coeliac, and hypogastric, and numerous scattered ganglia and communicating cords which bind the ganglia together and connect them with spinal or cranial nerves and with the periphery.

The peripheral system is somewhat complex and numerous intercommunications are established by which nerve impulses originating in the central axis and leaving by one part of the peripheral system may exercise a controlling influence over another part. Plexuses, or intertwinings of nerve axons, are so numerous and complicated that it is difficult to follow each set of nerve stimuli from their origin to their final destination and effect without considerable study.

Direct Distribution of Spinal Axons

The spinal nerve axons, taken as a whole, establish paths between the motor gray of the ventral horn of the spinal cord and all voluntary muscles of the body below the head except the trapezius and sternomastoid, partially innervated by the eleventh cranial, and between the sensor cells of the dorsal spinal gray and gracile and cuneate nuclei of the medulla on the one hand and the sensor end organs in skin and mucuous membrane, muscles, tendons, and joints on the other. The ventral cornu receives impulses from the cortico-spinal axons of the direct pyramidal, crossed pyramidal, rubrospinal, and other smaller tracts which bring the spinal gray under the direct voluntary domination of the volitional centers in the brain or of the indirectly voluntary pathway through the cerebellum. The spinal nerves are the direct media for motion of the body or its parts in relation to its environment. The sensor gray of the cord is similarly in communication with the conscious sensation area in the cerebrum and with the cerebellum by way of the dorsal tracts of the cord, the lemnisci, and the cerebellar peduncles.

In the main these nerves of motion and sensation are arranged as follows:

The Cervical plexus is composed of the intertwining of axons from the anterior primary divisions of the four upper Cervical nerves. Its branches pass to and innervate many voluntary muscles of the neck and side and back of head, and supply sensor fibres to the adjacent cutaneous areas. Branches also communicate with the last three cranial nerves and one long branch, the Phrenic, or Internal Respiratory Nerve of Bell, passes through the neck and thorax to the diaphragm, as its motor nerve.

The Brachial plexus is made up of the anterior primary divisions of the four lower Cervical nerves and the greater part of the first Thoracic. It is distributed chiefly to the voluntary muscles and integument of the shoulder and arm, forearm, and hand, but sends branches to some muscles of the neck and upper back as well. It, like the Cervical plexus, receives branches from, but gives none to, the Cervical sympathetic.

The Thoracic nerves are not arranged in plexiform fashion like those above but pass separately, for the most part, to their destinations. They are distributed to the walls of the thorax and abdomen following the curve of the ribs in direction. The last Thoracic sends one division downward as far as the outer aspect of the ilium.

The Lumbar, Sacral, and Pudendal plexuses are formed of the ventral divisions of the Lumbar, Sacral, and Coccygeal nerves and distribute branches to the integument and voluntary muscles of the lower abdomen, pelvis, and lower extremities. From two of the sacral nerves branches known as “Visceral” pass through the plexus to terminate in the walls of the uterus and rectum.

All of the thoracic nerves and the first and second, sometimes the third and fourth, lumbar give off branches to the sympathetic ganglia, known as white rami communicantes.

Direct Distribution of Cranial Nerves

The distribution of the 12 pairs of cranial nerves is not so definitely to voluntary muscles and to areas from which conscious sensation is to be derived as is the case with the spinal, although the cranial nerves present many analogies with the spinal and there is abundant reason for considering them as in one series of 43 pairs. There is direct distribution of some cranial nerve fibres to secreting glands, but these fibres are probably merely derived from sympathetic trunks and carried in company with the axons of cranial origin. There is also some direct distribution of cranial nerve axons to visceral walls made of non-striated muscle, as in the case of the vagus distribution to the respiratory and alimentary tracts and that of the spinal accessory to the heart. This is a resemblance to the sympathetic.

The cranial nerves carry afferent impressions from the special sense organs, except those of the sense of touch, which function is divided with the spinal nerves.

Various intercommunications exist between the cranial and sympathetic divisions of the peripheral system, by means of which axons starting with one division may be finally distributed with another, or by which an axon of the sympathetic may pass to one of the sensor ganglia of the cranial system and influence its nutrition and condition, and therefore its power to act. There is a limited intermingling of spinal fibres with the lower cranial.

Distribution of Sympathetic

The sympathetic system directly innervates most of the nutritive or vegetative system, the alimentary tract and its accessory organs, the vascular systems, the genito-urinary system, and the ductless glands. To a limited degree it shares this control with the cerebro-spinal and to a much greater degree it brings the central axis into indirect connection with these viscera.

Gray says, “The distinction of the sympathetic system from the cerebrospinal system is made merely for reasons of convenience. The two systems are intimately connected and the sympathetic is morphologically a derivative of the central axis disseminated in connection with the nutritive apparatus and establishing relationships among the vegetative organs.”

Structure of Nerve Pathways

Most pathways which carry nerve impulses from their origin or inception to the organ in which they are finally expressed as action of some sort or translated into sensation or into stimuli which pass out reflexly over a connected neuron, are composed of more than one neuron. The neurons of a nerve pathway are arranged end to end with the axons all pointing in one general direction so that the nerve energy travels always in the same direction over the entire nerve path. Impulses are transferred from the first neuron in the chain to the second, and from second to third, etc., by contact of the telodendria of the one neuron with the dendrites or receptive processes of the next. Part of the nerve pathway may be within the central axis and part within the trunk of a peripheral nerve.

Several peripheral pathways for afferent impulses may be joined to an efferent pathway so as to complete reflex arcs and the efferent cell be under the controlling influence of some upper neuron coming down from the central axis with the power either to permit or to inhibit the reflex acts which would otherwise take place as a result of peripheral stimuli. Several such lower cells may be under the domination of one upper neuron.

In some instances the nutrition of ganglia or nerve trunks, or of parts of the central axis itself, is under the control of sympathetic neurons terminating in connection therewith, so that interruption of the normal action of the sympathetic neuron may be followed by effects manifested through some distant part of the cerebrospinal system. In the following pages we shall discuss nerve pathways with reference to the explanation of diseases caused by vertebral subluxation impinging nerves either by tension or constriction, and therefore our grouping of parts will differ somewhat from any anatomical or physiological grouping with another object in view.

Important Nerve Pathways

To brain: C 2, 3, or 4 to superior cervical ganglion by direct impingement, through internal carotid nerve to sympathetic plexuses following branch arteries from Circle of Willis. The blood-supply of the brain is under control of the cervical sympathetic and most brain lesions or diseases are due to vascular changes leading to anaemia, hyperaemia, inflammation, or hemorrhage.

To meninges: Loop between first and second cervical nerves to trunk ganglion of vagus and through meningeal branches of vagus (P), or by way of internal carotid nerve to pial sympathetic plexuses. (P) The connection of the first, second, or third cervical with cerebral meningitis is established clinically but there is still doubt as to the explanation.

Eye and Muscles, Retina, Optic Nerve: The external muscles of the eye, the four recti and two oblique with the levator palpebrae superioris, are innervated by the Oculomotor, or third cranial, and the fourth and sixth cranial, which receive branches from the cavernous plexus of the sympathetic derived from the internal carotid branch of the superior cervical ganglion. As the ganglion lies in front of the transverse processes of the second, third, and fourth cervical vertebrae, direct impingement upon it by subluxation of one of these vertebrae may cause strabismus or other affection of the external ocular muscles.

The eye-ball receives filaments from the ciliary or ophthalmic ganglion, which in turn is connected with the cervical ganglion by way of cavernous plexus and internal carotid nerve. This pathway controls the radial fibres of the iris and dilates the pupil as a part of the light accommodation reflex mechanism. Loss of pupillary reaction, especially with small pupils, suggests upper cervical subluxation.

The retina, containing the cells of origin of the optic nerve axons and being the special end-organ of the sense of sight has no direct spinal or sympathetic connections but its blood-supply, and therefore its nutrition, is influenced by branches from the sympathetic which enter with the central artery of the retina. Retinal hemorrhage has been cured by cervical adjustment, C 2, 3, or 4.

The conjunctiva is innervated by the sympathetic and by the fifth cranial, or trigeminal.

Olfactory Nerve: Nerve of smell, distributed to the Schneiderian membrane over the upper portion of the nasal septum and over the upper lateral wall. There is no known connection by which the trunk of the olfactory nerve can be reached by adjustment but the condition of the special end organs in the membrane and their ability to functionate depend not only upon the integrity of their axons but also upon the nutrition and moisture of the membrane in which they are embedded. This is under the control of the Vidian nerve and of branches from the spheno-palatine, or Meckel’s ganglion, both connected with the carotid plexus of the sympathetic and therefore responsive to adjustment of C 2, 3, or 4. This is also the route by which epistaxis is usually checked.

The external nasal muscles, like those of the rest of the face except some of the muscles of mastication, get their supply from the facial nerve, which connects with the sympathetic plexus on the middle meningeal artery. It may be said parenthetically here that peripheral facial paralysis (Bell’s palsy) yields to adjustment and proves the value of this connection. The nasal integument is under the sensor control of the trigeminal and trophic disturbances may result from its involvement.

Trigeminal Nerve: This is the great sensor nerve of the face and carries a motor division, the inferior maxillary, to some of the muscles of mastication, as the temporal, masseter, and buccinator. It has connected with it four ganglia, which also receive sympathetic roots, and the ganglion of origin of its sensor axons, the Gasserian or semilunar, also receives direct sympathetic communications. The importance of this communication is shown by the powerful effect of adjustment of third or fourth Cervical for tic dolouroux.

Ear: The external ear receives branches from the vagus and from the first and second cervical nerves. The middle ear and Eustachian tube are supplied by the tympanic plexus made up of branches from the glosso-pharyngeal, otic ganglion, facial nerve and the small deep petrosal from the sympathetic on the carotid artery. By all these routes communication from the third and fourth cervicals is possible but especially is the latter important. The fourth cervical is the especially frequent subluxation with middle ear disease. To the internal ear and auditory or acoustic nerve there appears to be no direct route from the spine. It has not yet been conclusively established within the writer’s knowledge that adjustments will affect auditory deafness but Meniere’s Disease, inflammation of the semicircular canals, has been cured repeatedly by adjustments of Atlas or Axis, by what route I am unable to state.

Teeth and Gums: It is probable that the only connection between the vertebrae and the teeth is an afferent one by way of the trigeminal. Toothache may be stopped by adjustment of C 3, or C 4, but no evidence is at hand to show that the condition of the teeth is improved or that more than a temporary effect can be had. Trophic changes in the gums may be due to vascular disturbances controlled by the sympathetic.

Tongue: The hypoglossal, motor nerve to both the intrinsic and extrinsic muscles of the tongue, receives direct axons from the loop between the first and second Cervical nerves. Sympathetic fibres pass to the blood-vessels and secreting glands of the tongue.

Tonsils: Receive fibres from the spheno-palatine ganglion and by this means are brought under the domination of C 2, 3, and 4. Abundant clinical evidence in tonsilitis, simple, follicular, and suppurative, proves this to be the practically, as well as anatomically, correct nerve connection.

Salivary Glands: The parotid receives branches from the great auricular nerve from the second and third cervical, and from the sympathetic on the external carotid artery, branches from the superior cervical ganglion. The submaxillary and sublingual glands are connected with the submaxillary ganglion, which receives a sympathetic root and which, with the chorda tympani also carrying fibres derived from the sympathetic, controls the secretions of these glands.

Pharynx: The pharyngeal plexus is a mixture of sensory axons from the glosso-pharyngeal, motor components from the vagus and probably sensor from the same nerve, and sympathetic branches from the superior cervical ganglion. All of these may be influenced by the upper cervical adjustment.

Larynx: According to anatomy the larynx is innervated by the superior and inferior, or recurrent, branches of the vagus and by sympathetic branches from the superior cervical ganglion. Clinically the sixth cervical adjustment cures laryngitis and aphonia. The explanation probably lies in the fact that the thyroid branches of the middle cervical ganglion, lying in front of the transverses of the sixth, communicate within the thyroid gland with the recurrent laryngeal and with the external laryngeal branch of the superior laryngeal.

Thyroid Gland: “The nerves to the thyroid are amyelinic and are derived from the middle and inferior ganglia of the sympathetic.” (Gray.) The middle cervical ganglia are situated in front of the transverse processes of the sixth cervical vertebra. Clinically, the sixth cervical reaches goitre.

Muscles of Neck: The platysma is supplied by the facial nerve; the sternomastoid by the spinal accessory and cervical plexus; the infrahyoid region by the first three cervical nerves; the suprahyoid region by the facial and the ansa cervicalis; the anterior and lateral vertebral muscles by the cervical nerves from second to seventh inclusive, but especially the second, third, and fourth. It will be seen that muscular disturbance in the neck may result from any cervical subluxation. Torticollis, which usually involves the sternomastoid, yields to the second cervical most frequently.

Lymph Nodes of Head and Face: These lymph nodes are controlled by the cervical sympathetic. Pathological changes in one or more nodes requires careful cervical palpation to determine the presence of a subluxation away from the affected side.

Muscles of Back: The trapezius is innervated by the spinal accessory and by the third and fourth cervical nerves; the latissimus dorsi by the sixth, seventh, and eighth cervical through the middle or long subscapular. Occasionally a tender nerve, traceable from the lower reaches of the latissimus to the cervical region has mislead the practitioner into imagining a cervical connection over the back with internal viscera.

The second layer of the back is supplied by the third, fourth, and fifth cervical nerves. The third layer is innervated by the middle and lower cervical and upper three thoracic nerves except the serratus posticus inferior which is supplied by the ninth, tenth, and eleventh thoracic. The fourth and fifth layer are supplied by the posterior primary divisions of the spinal nerves and any given section of these layers may be traced to a vertebra directly above, or cephalad.

Thoracic Walls: The parietal muscles of the thorax are innervated by the intercostal nerves and a very definite segmental association with the spine is traceable.

Diaphragm: Phrenic nerve, which arises from fourth cervical chiefly; lower intercostals, especially eighth and ninth; and phrenic plexus of the sympathetic which may sometimes be reached from the fourth or fifth dorsal vertebrae through the gangliated cord. For motor disturbances of the diaphragm adjust fourth cervical.

Abdominal Muscles: These are supplied by the lower intercostals and the transversalis and internal oblique make connection with L 1 by the iliohypogastric. Cremaster is supplied by L 1 and 2 by way of the genital branch of the genitofemoral.

Perineal Muscles: The anterior perineal group are supplied by the perineal branch of the internal pudic which traces to the second, third, and fourth sacral nerves. The posterior perineal and ischiorectal region is also supplied by the sacral and coccygeal nerves.

Trachea and Bronchi: Vagus and sympathetic filaments from first and second thoracic ganglia. The latter receive preganglionic fibres from first dorsal nerve in all probability, as this adjustment reaches the bronchi.

Lungs: The third thoracic ganglia connect with the pulmonary plexus and establish a connection from third dorsal vertebra direct to the lung parenchyma. The Pleurae have a similar connection or may sometimes be reached by the first dorsal.

Heart and Pericardium: In 55% of all heart disease or improper action the second dorsal is responsible; in 40% the first dorsal, and perhaps in the remaining 5% the atlas or axis. The former nerves (T 1 and 2) furnish pre-ganglionic fibres which stream upward through the gangliated cord to terminate in the three cervical ganglia in relation with the dendrites of new neurons (amyelinic) which form the superior, middle, and inferior cardiac nerves and pass into the thorax to mingle with vagal fibres to form the superficial and deep cardiac plexuses, controlling the heart. Probably the upper cervicals occasionally affect the vagus through the loop between the first and second cervical nerves.

Thoracic Aorta: Controlled by sympathetic from first thoracic ganglion or last cervical ganglion, and thus by seventh cervical or first dorsal vertebra.

Abdominal aorta—Coeliac Axis: The upper portion of the abdominal aorta is innervated by the coeliac or solar plexus of the sympathetic. Sub-plexuses from the coeliac accompany the various branches of the aorta and are widely distributed to the blood-vessels and to the glands and non-striated muscle of the abdominal organs. The coeliac plexus receives fibres from the right vagus and from the greater, lesser, and least splanchnic nerves, by the latter route making connection with the thoracic ganglia of the sympathetic from fifth to last. These ganglia receive pre-ganglionic fibres from the thoracic spinal nerves in the form of white rami communicantes, so that it is not incorrect to say that the coeliac plexus and its branches are largely controlled by the condition of the last eight thoracic nerves.

Through this intricate plexus it is difficult to trace the relations of each abdominal organ with the particular vertebrae of which subluxation would produce disease in said organ. By the aid of clinical experimentation covering a period of years and by diligent search among anatomies and physiologies, we have arrived at the conclusions indicated in succeeding statements.

The most important spinal connection with the abdominal blood-vessels is that of the fifth dorsal vertebra, for the fifth dorsal nerve, by its rami, seems greatly to influence the caliber of the aorta and coeliac axis.

A. Cortico Spinal nerve. B. Spino Ganglionic nerve.
C. Ganglio Ganglionic nerve. D. Ganglio Peripheric nerve.
E. Blood Vessel Wall.

Parker

Fig. 32. Schematic representation of nerve pathway from brain to periphery by way of sympathetic.

Liver: Fourth thoracic nerves (especially the right) to gangliated cord, via great splanchnic nerve to coeliac plexus, by hepatic plexus to interior of liver. The hepatic plexus gives off the cystic plexus which controls the gall-bladder.

Stomach: Sixth and seventh dorsal nerves by white rami to and through the ganglia of the gangliated cord to coeliac plexus. The gastric plexus is an offshoot of the coeliac and gives off Auerbach’s plexus to the muscular coat, and Meissner’s plexus to the submucous and mucous coats of the stomach. The nutrition of the stomach walls, their peristaltic action, and the secretory action of the stomach glands are thus brought under the direct influence of the sixth or the seventh dorsal subluxation.

Pancreas: Eighth dorsal nerve by great splanchnic to coeliac plexus, to hepatic and superior mesenteric plexuses, and by the pancreatico-duodenal branches of the former and pancreatic branches of the latter to the pancreas.

Spleen: The coeliac plexus, the left semilunar ganglion, and the left vagus and right phrenic nerves give off branches which form the splenic plexus. Spinal connection by way of ninth dorsal nerve, by rami communicantes to gangliated cord to great splanchnic nerve to coeliac plexus to splenic plexus. Many nerve pathways like this one are less indirect than they sound; various names have been given to different parts of the same pathway through which, often, the axons pass without interruption. On the way from the cerebral cortex to one of the abdominal viscera there may be only three, sometimes four or five, neurons connected end to end.

Duodenum: Coeliac plexus by way of duodenal branches of hepatic plexus and branches from the superior mesenteric plexus. Spinal connection from eighth dorsal nerve and possibly branches from the upper lumbar ganglia of the sympathetic may join the superior mesenteric plexus, as results in duodenal disease are occasionally reported following specific adjustment of L 1 or 2.

Jejunum and Ileum: Connection same as for duodenum, by superior mesenteric plexus. Adjustment of L 2 in typhoid fever is undoubtedly correct so that it is probable that the lumbar ganglia send branches to this vicinity.

Peritoneum: Nerve supply to the peritoneum is rather general owing to its great extent. It is supplied by the sympathetic from both the lower thoracic and lumbar portions of the gangliated cord through the various abdominal plexuses and in general it may be said that any localized peritoneal disease will yield to the same adjustment as would be made for disease in the immediately subjacent organ.

Suprarenal Capsules: These important glands are supplied by amyelinic fibres derived from the gangliated cord by the lesser splanchnic nerve and connecting with pre-ganglionic fibres from the tenth dorsal nerve. The suprarenal plexus is an offshoot of the coeliac.

Kidneys: Tenth, eleventh, and twelfth dorsal nerves by way of lesser and least splanchnic nerves to renal plexus, an offshoot of the coeliac. McConnell’s experiments and the frequently duplicated clinical feats of Chiropractors prove this to be a vital and dominant nerve pathway in kidney disease.

Ureters: Nerves derived from inferior mesenteric, pelvic, and spermatic plexuses. Most important connection seems to be from first lumbar nerve by lumbar ganglia to inferior mesenteric plexus.

Caecum and Vermiform Appendix: The inferior mesenteric plexus, which supplies these organs probably carries to them chiefly fibres derived from the lumber ganglia which complete a connection with the second lumbar vertebra, especially on the right side.

Colon: Third and fourth lumbar vertebrae, influencing lumbar ganglia and thus inferior mesenteric plexus.

Rectum: Lower lumbar ganglia by inferior mesenteric and plevic plexuses, through superior and inferior hemorrhoidal plexus to rectum. Adjustment L 4 or 5. Visceral branches from the third and fourth sacral nerves also pass directly to the rectal wall and sacral adjustment may affect rectum or anus.

Bladder: The urinary bladder is innervated by the vesical plexus from the pelvic, and by sacral nerve fibres direct. It is said that the vesical plexus contains many spinal nerve fibres which are derived from the second and fourth lumbar nerves especially. Clinically the second or the fourth lumbar will control the bladder much oftener than the sacrum.

Prostate Gland, Seminal Vesicles, Penis, and Urethra: By the vesical and prostatic plexuses derived from the pelvic plexuses, divisions of the hypogastric plexus, which is formed of the abdominal aortic plexus and filaments from the lumbar ganglia. The latter receive filaments from the second and third lumbar nerves. There is a connection with the sacral nerves also by the pelvic plexus, though the lumbar adjustment appears the more potent.

Testes and Scrotum: Ilioinguinal from second lumbar, genital branch of genito-femoral from second and third lumbar nerves, internal pudic nerve from the pudendal plexus, and spermatic and pelvic plexuses. The most effective adjustment for scrotal or testicular diseases is L 3.

Uterus and Vagina: Uterovaginal plexus from the pelvic and containing spinal nerve fibres from L 4, L 5, and sacrum.

Ovaries and Fallopian Tubes: The ovarian plexus receives fibres from the abdominal aortic and through it from the lumbar ganglia, influenced by second lumbar adjustment.

Brachial Plexus: The brachial plexus of spinal nerves arises from the nerves from the fifth cervical to the first thoracic inclusive and controls the voluntary muscles of the upper extremity, with its integument. Muscle groups, rather than single muscles, are represented for the most part in the spinal segments giving off these nerves, and the ramification of the nerves within the plexus is such that almost any given muscle might be affected by more than one spinal subluxation. Below are given the principal connections:

Pectoralis Major and Minor Muscles: Sixth or seventh cervical through internal anterior thoracic nerve and first dorsal through external anterior thoracic.

Shoulder Joint: The joint, muscles covering the joint, and integument of this region are innervated by the circumflex nerve which traces through the plexus to fifth and sixth cervical nerves. Sixth cervical adjustment usually affects this joint.

Serratus Magnus Muscle: Sixth cervical by long thoracic, or External Respiratory Nerve of Bell.

Elbow Joint: Sixth cervical vertebra by musculocutaneous nerve.

Anterior Arm Muscles: Sixth cervical.

Posterior Arm Muscles: Seventh cervical and first dorsal.

Lumbosacral Plexus: This plexus, derived from the anterior primary divisions of the lumbar, sacral, and coccygeal nerves, supplies the muscles and integument of the lower extremity, taking with it axons derived from the sympathetic by the lumbar ganglia to supply the blood-vessels, perspiratory glands and sebaceous glands of this region. The latter are responsive to adjustments of the first or second lumbar vertebrae.

Hip-Joint: Third and fourth lumbar nerves by femoral and obturator or accessory obturator nerves and fifth lumbar or first sacral by the nerve to the quadratus femoris or the great sciatic. Fourth lumbar seems the most potent connection and is usually adjusted for hip-joint disease.

Psoas Magnus Muscles: Anterior branches of the second and third lumbar nerves.

Anterior Thigh Muscles: Supplied mostly through the femoral nerve from the second and third lumbar nerves.

Internal Thigh Muscles: Second and third lumbar nerves (chiefly but not wholly) through the obturator, accessory obturator and femoral nerves.

Gluteus Maximus: From the fifth lumbar and first and second sacral nerves through the inferior gluteal branch of the sacral plexus.

Obturator Externus: Second, third, and fourth lumbar nerves through the obturator nerve.

Posterior Thigh Muscles: Fourth and fifth lumbar and sacral nerves through the great sciatic.

Great Sciatic Nerve: This great nerve, direct continuation of the sacral plexus, arises from the fourth and fifth lumbar and first three or four sacral nerves and is widely distributed to muscles and integument of the lower extremity. Sciatica, or sciatic rheumatism, is most commonly relieved by adjustment of fourth or fifth lumbar vertebra; but there is a condition commonly diagnosed as sciatica which is really a sciatic neuritis and due to vasomotor disturbance affecting the blood-supply to the nerve trunk. This responds to adjustment of first or second lumbar because the amyelinic fibres which control these blood-vessels are derived from lumbar ganglia of the sympathetic.

Anterior Leg Muscles: Fourth and fifth lumbar and first sacral nerves through the anterior tibial.

Posterior Leg Region: Fourth and fifth lumbar and first and second sacral through the internal popliteal and posterior tibial.

Knee-Joint: This joint receives branches from the great sciatic through both internal and external popliteal, and from the femoral and obturator. It is therefore connected with the lower lumbar and sacrum and with the second lumbar. The latter connection seems oftenest involved in knee joint inflammations.

Foot: Fourth and fifth lumbar and sacral nerves through the great sciatic and its branches.

Sensor Areas of Lower Extremity: In general, any given cutaneous area receives sensor branches from the nerve which supplies the subjacent muscle area. For accurate diagnostic purposes a good chart of sensor distribution may be consulted.