Anterior Spinal Nerve Research Articles

External oblique abdominal muscle: A new look on its blood supply and innervation

Numerous reports have discussed the use of the external oblique abdominal muscle as a pedicled or a free flap for defect coverage. A detailed description of the supplying vessels and nerves is a prerequisite for successful tissue transfer but so far is not available in the literature. A study of the arteries and nerves supplying the external oblique abdominal muscle was carried out in 42 cadavers after injection of a mixture of latex and bariumsulfate. In seven fresh cadavers the motor branches were identified with the Karnovsky technique. Three different groups of arteries were identified as the nuturing vessels. The cranial part of the muscle is supplied by two branches of the intercostal arteries. While the lateral branches run on the outer surface of the muscle together with the nerves, the anterior branches enter the muscle from its inner surface. The caudal part of the muscle derives its main blood supply from one or two branches of the deep circumflex iliac artery (94.7%) or the iliolumbar artery (5.3%). The external oblique abdominal muscle is innervated by motor branches of the lateral cutaneous branches of the anterior spinal nerves in a segmental pattern. With the exception of the subcostal nerve the motor branches enter the outer surface of the muscle digitation arising from the rib above. The results show that the cranial half of the external oblique abdominal muscle has a strictly segmental blood and nerve supply while the caudal half of the muscle derives its main blood supply from one artery but still shows a segmental innervation. Anat Rec 255:388–395, 1999. © 1999 Wiley-Liss, Inc.

External oblique abdominal muscle: a new look on its blood supply and innervation.

Numerous reports have discussed the use of the external oblique abdominal muscle as a pedicled or a free flap for defect coverage. A detailed description of the supplying vessels and nerves is a prerequisite for successful tissue transfer but so far is not available in the literature. A study of the arteries and nerves supplying the external oblique abdominal muscle was carried out in 42 cadavers after injection of a mixture of latex and bariumsulfate. In seven fresh cadavers the motor branches were identified with the Karnovsky technique. Three different groups of arteries were identified as the nurturing vessels. The cranial part of the muscle is supplied by two branches of the intercostal arteries. While the lateral branches run on the outer surface of the muscle together with the nerves, the anterior branches enter the muscle from its inner surface. The caudal part of the muscle derives its main blood supply from one or two branches of the deep circumflex iliac artery (94.7%) or the iliolumbar artery (5.3%). The external oblique abdominal muscle is innervated by motor branches of the lateral cutaneous branches of the anterior spinal nerves in a segmental pattern. With the exception of the subcostal nerve the motor branches enter the outer surface of the muscle digitation arising from the rib above. The results show that the cranial half of the external oblique abdominal muscle has a strictly segmental blood and nerve supply while the caudal half of the muscle derives its main blood supply from one artery but still shows a segmental innervation.

Lumbosacral anterolateral spinal arteries and brief review of "accessory" longitudinal arteries of the spinal cord.

The lumbosacral anterolateral spinal arteries (LALSA) were studied in 14 injected lumbosacral spinal cords. Contrary to many previously published opinions, which claimed that virtually all of the formerly described "accessory" longitudinal arteries of the vasa corona, were too inconstant to be of significance, the LALSA in this series were reliably present bilaterally and averaged a length of 8.4 cm. They ran in the acute angles formed by the emergence of the fascicles of the lumbosacral anterior spinal nerve roots and in this position, served as the origin for most of the proximal radicular arteries that supply the cranial half of the motor roots of the cauda equina. A review of the literature and analysis of other accessory longitudinal spinal arteries revealed that two other pairs of accessory spinal vessels, the lateral cervical spinal arteries (LCSA) and the lateral spinal arterial axes (LSA), have a demonstrable functional role and were sufficiently constant, along with the LALSA, to warrant inclusion in detailed descriptions of human spinal cord vasculature.

Guillain-Barré syndrome: MR imaging findings of the spine in eight patients.

To evaluate magnetic resonance (MR) imaging findings of the spine in patients with Guillain-Barré syndrome. MR imaging findings in eight patients (three male, five female; age range, 2-47 years) with Guillain-Barré syndrome were retrospectively reviewed. Guillain-Barré syndrome was diagnosed mainly on the basis of symptoms and also on the basis of supportive ancillary data, such as the results cerebrospinal fluid analysis and electrophysiologic evaluation. In addition, follow-up MR imaging was performed in three patients, who had slight clinical improvement. All patients had thickening of the intrathecal spinal nerve roots and cauda equina, with varying degrees of enhancement on gadolinium-enhanced axial T1-weighted images. Two enhancement patterns were noted. One was enhancement of both the anterior and posterior spinal nerve roots (n = 2); the other was enhancement of the anterior spinal nerve roots only (n = 6). Follow-up MR imaging in the three patients with slight improvement of symptoms revealed that the thickening and the degree of enhancement of the spinal nerve roots were diminished. Although the enhancement of the intrathecal spinal nerve roots is not specific to Guillain-Barré syndrome and can be seen in neoplasia and other inflammatory processes, the enhancement of only the anterior spinal nerve roots is strongly suggestive of Guillain-Barré syndrome.

Intraoperative Electroneurodiagnostics (Transcranial Electrical Motor Evoked Potentials) to Evaluate the Functional Status of Anterior Spinal Roots and Spinal Nerves During Brachial Plexus Surgery

Intraoperative Electroneurodiagnostics (Transcranial Electrical Motor Evoked Potentials) to Evaluate the Functional Status of Anterior Spinal Roots and Spinal Nerves During Brachial Plexus Surgery

The Pial Ligaments of the Anterior Spinal Artery and Their Stretch Receptors

The pial sheath of the anterior spinal artery displays a system of ligaments that course along the ventral surfaces of the anterior spinal artery and its medullary feeder arteries on the lower half of the spinal cord. Frequently, discrete ligamentous straps extend from these anterior spinal artery ligaments to the sheath of an anterior spinal nerve root to reinforce the general cauda equina pial connections to this system. Microscopy of ligament sections revealed that numerous Golgi-type neurofascicular receptors were oriented longitudinally among the ligament fascicles and associated with well-myelinated nerves. As this type of mechanoreceptor has been known only in association with stretch reflex mediation in the musculoskeletal system, it appeared likely that these anterior spinal artery ligaments and their homologous type of receptors may be implicated in sensing distraction of the thoracolumbar spinal cord and protectively modifying the actions of the involved spinal musculature.

The Pial Ligaments of the Anterior Spinal Artery and Their Stretch Receptors

The pial sheath of the anterior spinal artery displays a system of ligaments that course along the ventral surfaces of the anterior spinal artery and its medullary feeder arteries on the lower half of the spinal cord. Frequently, discrete ligamentous straps extend from these anterior spinal artery ligaments to the sheath of an anterior spinal nerve root to reinforce the general cauda equina pial connections to this system. Microscopy of ligament sections revealed that numerous Golgi-type neurofascicular receptors were oriented longitudinally among the ligament fascicles and associated with well-myelinated nerves. As this type of mechanoreceptor has been known only in association with stretch reflex mediation in the musculoskeletal system, it appeared likely that these anterior spinal artery ligaments and their homologous type of receptors may be implicated in sensing distraction of the thoracolumbar spinal cord and protectively modifying the actions of the involved spinal musculature.

Anterior cord decompression and spinal stabilization for patients with metastatic lesions of the spine.

Metastatic lesions involving the spine may cause vertebral body collapse, resulting in either spinal instability or neural compression, or both. Progressive destruction of the vertebral body by the tumor may cause increasing spinal instability, leading to a kyphotic deformity and further neural deficit. Anterior decompression allows direct excision of the tumor focus and direct neural decompression. Because of postoperative irradiation, conventional bone grafts are rarely incorporated. Over an 8-year period, 52 patients with spinal instability secondary to metastatic pathological fractures of one or more vertebrae underwent anterior decompression and stabilization by replacement of the affected vertebral bodies with methyl methacrylate, polymerizing in situ. No postoperative external support was required, and the acrylic fixation achieved by this method was not affected adversely by subsequent irradiation to a mean of 4020 rads. Forty patients had major neurological impairment preoperatively and required anterior spinal cord and/or nerve root decompression prior to fixation. Of these, 21 had complete neurological recovery postoperatively, 13 others were improved significantly, five remain unchanged, and one patient deteriorated neurologically. There were three cases with failure of fixation. Seven other patients did not benefit from the procedure because of specific complications or the advanced state of their disease. The remaining 42 patients had good relief of pain and restoration of spinal stability, which did not deteriorate during the follow-up period, ranging from 6 to 100 months postoperatively.

Congenital hypomyelination neuropathy: Glial bundles in cranial and spinal nerve roots

Autopsy examination of a 3 1/4-year-old child with a severe congenital hypomyelination neuropathy showed the anterior spinal nerve roots and motor cranial nerves to be almost devoid of myelin in their subarachnoid course. The posterior spinal nerve roots and peripheral nerves were less severely affected. Onion bulb formation was minimal and was present only in the sural nerve. There was extensive glial overgrowth in cranial nerves and spinal nerve roots adjacent to the brainstem and spinal cord. The extent and severity of glial overgrowth were similar to that described in Werdnig-Hoffmann disease and morphologically appeared as glial bundles. These glial bundles are most likely secondary to chronic myelin and axonal damage.

Gross demonstration of atrophic cauda equina roots in motor neuron disease: an improved method.

In patients who have died of advanced motor neuron disease, one of the most impressive gross anatomical findings is the disparity in size and texture of the anterior and posterior spinal nerve roots, brought about by progressive atrophy of the former and generally good preservation of the latter. When it comes to demonstrating this difference in photographs for medical students, resident teaching, or for neuropathology conferences, it is rather difficult to arrange the respective nerve root pairs in a fashion that would make them easy to compare, 1 because whether the spinal cord is photographed from the front or the back, the dorsal and ventral nerve roots tend to overlap. 2,3 Moreover, in the cauda equina, photographed in the usual way, the motor and sensory Fig 1.—Side view of spinal cord and cauda equina from 54-year-old woman with advanced motor neuron disease. Atrophic anterior roots (right) combed apart from posterior

Werdnig-Hoffmann disease: proposal of a pathogenetic mechanism.

Light and electron microscopic study and morphometric analysis were performed on the spinal cords and roots from six cases of acute Werdnig-Hoffmann disease and four control cases, in search of the pathogenesis of the selective motor neuron changes considered primarily responsible for Werdnig-Hoffman disease. This investigation posits a centrifugal traction mechanism based upon the discovery of cylindrical outgrowths of glial bundles, selective loss of large myelinated fibers, and axonal degeneration in the proximal portion of anterior spinal roots (and to a lesser extent in posterior spinal roots) in all six disease cases. This traction mechanism exerts principally upon anterior spinal nerve roots and can account for morphologic and morphometric data characteristically ascribed to Werdnig-Hoffmann disease.

Study of the sympathetic vasoconstrictor nerves to the vessels of the dog hind limb.

In anesthetized dogs, the vasoconstrictor nerves to the vessels of the hind limb left the spinal cord in the anterior spinal nerve roots from T-10 through L-4 levels. Maximal vasoconstrictor responses occurred on stimulation of the T-12, T-13, and L-l roots; none occurred on stimulation of roots caudal to L-4. The nerves first entered the lumbar paravertebral chain at or above L-1; the last point of entry was at the L-4, L-5 level. No fibers left the lumbar chain at L-1, L-2, and L-3 levels. The first point of exit was at L-4, and nerves continued to leave as far distal as S-1, The most caudal point examined. The maximal response to stimulation of the lumbar chain was at the L-4, L-5 level. With a single exception, the responses to electric stimulation of the anterior spinal nerve roots, lumbar chain, or sympathetic ganglia were confined to the vessels of the ipsilateral limb. In 22 dogs with unilateral sympathectomy (L-2 through L-7), changes in hind-limb vascular resistance were induced reflexly or by electric stimulation of the anterior spinal roots. The results indicated that sympathetic control of the resistance vessels of the hind limb was still absent 77 days after sympathectomy.

Acetylcholinesterase activity of motor and sensory nerve fibers in the spinal nerve roots of the rat.

The histochemical and cytochemical distribution of acetylcholinesterase activity in the anterior and posterior spinal nerve roots and ganglia of the rat was demonstrated by the Karnovsky method using acetyl and butyrylthiocholine as substrates and eserine and DFP as inhibitors. Light and electron microscopic examination of transverse frozen sections enabled the simultaneous visualization of end product in relationship to the various fiber components of each nerve root. While the enzymatic activity of the anterior roots was consistantly observed in the large extrafusal and small intrafusal motor fibers a relatively greater amount of precipitate occurred in aggregates of myelinated and unmyelinated fibers believed to represent preganglionic sympathetic nerves. In contrast, no significant enzymatic activity could be demonstrated in the myelinated nerve fibers of the posterior root. In the sensory sytem, the limited enzymatic precipitate was largely restricted to the unmyelinated afferent fibers and to their small cell bodies in the dorsal root ganglia. The ultrastructural distribution of enzymatic activity was located in the granular endoplasmic reticulum and perinuclear spaces of the ganglion cells. Within peripheral nerves this end product occurred between the apposing axonal and Schwann cell membranes and along the membranous aspect of occasional axoplasmic vesicles of both myelinated and unmyelinated nerve fibers.

Pathological findings following the intrathecal injection of ethyl alcohol in man

The pathological findings at necropsy in six cases of paraplegia treated with subarachnoid ethyl alcohol injection are described. The most important sequel to the alcohol injections was a toxic radiculitis involving the cauda equina and resulting in more severe degeneration of the posterior than the anterior spinal nerve roots. A toxic myelitis involving a small peripheral rim of the caudal part of the spinal cord and leptomeningeal fibrosis causing partial obliteration of the subarachnoid space were also found. The presence of regenerating myelinated nerve fibres of peripheral nerve type in the subarachnoid space is described. The time sequence of the histological changes of central chromatolysis is discussed.

Early development of the head and pharynx of Neoceratodus with a consideration of its phylogeny

The development of the head and pharynx of larvae of Neoceratodus (ranging in length from 11.5 to 34. 5 mm) was investigated form microscopic transverse serial sections. The structures studied included the chondrocranium and visceral arches, ossifications, cranial and anterior spinal nerves, musculature and vascular system. These components of Neoceratodus are compared with similar ones, likewise investigated, in Rana temporaria and Rana esculenta (33 and 26 mm long, respectively), and in various genera of Urodela, either previously investigated by the author or by reference to the earlier literature.Some new homologues of the various morphological components of the head and pharynx of these groups are suggested.On the basis of the larval structure an assessment is made of the classical view of a close phylogenetic relationship between Neoceratodus and the two amphibian groups. it is concluded that they share a common derivation from pro‐dipnoan‐amphibian stock—of crossopterygian ancestry—in the early Devonian: a conclusion which supports an earlier somewhat similar view of Goodrich.It is further considered that there is evidence of a quasi parallel evolution between Neoceratodus and Urodela, though some assumed similarities in larval structure are spurious; nevertheless, in some ways, they are more similar than are Neoceratodus and members of the Anura.A common origin of Neoceratodus (Dipnoi) and the amphibian groups supports the vie of a monophyletic derivation of the Tetrapoda.

HUMORAL FACTOR FROM THE BRAIN WHICH ACTIVATES GASTRIC MOTILITY.

When the vagus nerves in the neck of the dog are cut and the ends toward the brain are stimulated, gastric contractions follow. These contractions are not abolished by section of the cervical spinal cord, section of anterior and posterior thoracic and lumbar spinal nerves, section of the splanchnic nerves, or paralysis or excision of the celiac plexus. Evidence for the existence of a humoral blood-borne substance originating in the brain was obtained by experiments with an isolated perfused head, by perfusion of isolated stomachs by donor dogs, by cross-perfusion between two dogs, and by plasmapheresis. stimulates the stomach.

A STUDY OF THE EVOLUTION OF THE AMPHIBIAN AND DIPNOAN PRONEPHROS BY AN ANALYSIS OF ITS RELATIONSHIP WITH THE ANTERIOR SPINAL NERVES

The fact that an anterior spinal nerve and nephrostomial tubule and nephrostome are constantly associated with each other in individual specimens of urodeles, Anura and dipnoan larvae waa exploited to analyse the phylogeny of their pronephroi. Spinal nerves of numerically identical body segments but in different genera are homologous quantitatively i.e. develop from the same numbered segment as well as qualitatively; therefore it is assumed that individual but segmental pronephric units in different genera, when related to numerically identical spinal nerves, are homologous quantitatively and qualitatively also.A large number of nephrostomial units, e.g. present in the apodan Hypogeophis (Brauer, 1902) represents a primitive condition and commonly five functional units, though the fifth is reduced, are included in the pronephros of Cryptobranchus japonicus related to spinal nerves I to V (metotic segments 4 to 8; total body segments 7 to 11 inclusive). The phylogenetic development is expressed in the loss of front and rear tubules and can be traced through Hynobius retardatus, H. (Salamandrella) keyaerlingii, H. nebulosus, Necturus maculatus. Plethodon cinerevs and Ambystoma mexicanum to Triturus cristatus and Pleurodeles waltlii, which pronephroi each possess two functional nephrostomial units related to spinal nerves II and III (metotic segments 6 and 6; total body segments 8 and 9) or Salamandra maculosa and Desmognathus quadrimaculatus, where there are two units related to spinal nerves III and IV (metotic segments 6 and 7; total body segments 9 and 10).All the anuran pronephroi (except for a few which possess four units) originally are composed of three functional nephrostomid units related to spinal nerves I, II and III. If the anuran skull includes five segments (not counting the condyles) then the pronephric tubules belong to metotic segments 3, 4 and 6 or total body segments 6, 7 and 8; if the skull includes six segments the pronephric tubules would belong to metotic segments 4, 5 and 6 or total body segments 7, 8 and 9.Pronephroi of Neoceratodus and Protopterus—derived from a more numerous series of tubules (Kerr, 1919)—are each composed of two remaining funationel nephrostomial units, related to the nerves directly in front of the occipital and occipito‐spinal II arches (or their equivalent nerves in Protopterus). This arrangement probably refers the tubules to total body segments 8 and 10 and thus functional tubules of body segments 7, 9 and 11 (present in Cryptobranchus japonicus) are abaent.It is thought possible that the phylogenetic pattern described in the various specimens may provide a framework into which the pronephroi of all extant larvae of Urodela, Anura and Dipnoi can be arranged.

A study of the development of the head and pharynx of the larval urodeleHynobiusand its bearing on the evolution of the vertebrate head

The early development of the head and pharynx ofHynobius nebulosus(11.5 to 32 mm long) andretardatus(27 and 37 mm specimens) was investigated in some detail from transverse serial microtome sections. Analysis included the chondrocranium, jaws and hyobranchial skeleton, ossifications, cranial and anterior spinal nerves, musculature, blood system and other associated anatomical features. The structure of the skeletogenous elements in general agreed with earlier descriptions. However, a rudimentary fenestra lateralis nasi is found in the nasal capsule ofH. nebulosus, hitherto not reported, and a complete cartilaginous processus pterygoideus, confluent with the trabecula and inner margin of the lamina orbito-nasalis described by Edgeworth (1923a), was not extant in anyHynobiusspecimen.H. retardatushas a hypoglossal foramen (and nerve) and joins H. nebulosus (Fox 1957),Cryptobranchus japonicusandalleghaniensisas the only living Amphibia to possess this structure. The neural arch homology of the occipital crest is reaffirmed. The columella stilus of the 32 mmH. nebulosusis confluent with the pterygo-quadrate cartilage and because the hyoid and columella have a common blastematous origin inHypogeophis(Marcus 1910), it is suggested that there was an ancestral cartilaginous continuity between the hyoid and pterygo-quadrate cartilage, similar to the commissura terminales of the branchiale. This feature would further emphasize the branchial segmental homologies of the mandibular cartilage, hyoid and branchiale. The pattern of the cranial nerves is similar to that of other urodele larvae and the arrangement of the profundus and maxillaris nerves supports the view of the descent of urodeles from porolepiforme crossopterygians (Jarvik 1942). There is a segmental series of eleven head-pharynx segments, a complete branchial segment including a levator muscle, nerve, cartilage bar and gill cleft. Each post-hyoid segment is complete except for the absence of branchiale V and VI, and behind the fourth functional gill cleft there are three vestigial blind ones and then the larynx and trachea leading to the lungs. The masseter (2nd segment), digastricus (3rd segment), dilator laryngeus (10th segment) and trapezius (11th segment) are considered to be the homologues of the other six intervening levator gill arch muscles. The arytenoid and tracheal cartilages are considered to be branchial bars of the 10th and 11th segments respectively, and the lungs to have developed from gill pouches of the 11th segment which failed to reach the exterior early in vertebrate evolution. The classical view of the homology of the laryngo-tracheal skeleton with a branchial bar enunciated by Gegenbaur and Wilder independently in 1892 is therefore upheld; disagreement is merely a numerical one. The basic segmental components of the amphibian head and pharynx are modified in ontogeny by omission, distortion or addition, in order to fit the animal for a terrestrial existence.

Subarachnoid Alcohol Block in Paraplegia

I NVOLUNTARY reflex spasm of the paralyzed muscles is present to some degree with most patients following permanent injury to the spinal cord. The etiology of these powerful muscular contractures remains a mystery. Likewise, the absence of this mass reflex in some patients is equally difficult to explain. Immediately after injury a period of so-called spinal shock exists, during which the paralysis is of a flaccid character. Some weeks later reflex activity reappears and may progress to marked hyperactivity and involuntary muscttlar spasms. At times the reflex spasm, evoked by simply touching the skin over the paralyzed area, may be so powerful that it is physically impossible for the examiner to overcome the strength of the muscular contractions. Why are these mass reflexes so important in the management of the paraplegic patient as to justify the injection of absolute alcohol in large amounts into the subarachnoid space? Every paraplegic patient's greatest desire is to walk, even though it may be only with the aid of braces and crutches. The mass reflexes serve as a formidable obstacle to this achievement. The patient cannot maintain an erect position even if he is physically able to handle crutches with his arms and shoulders. Flexion deformities are frequent, often with secondary structural contractures. These add to the patient's discomfort and increase the danger of trophic ulcers. Control of ulcerated areas, much less repair, is impossible if the deformities persist. Reflex spasm frequently involves the pelvis and abdomen. The urinary problem is increased because of reflex bladder spasm. If a urinal is used, violent spasms may result in more frequent wetting of the bed, thus adding to the patient's discomforts and the nursing problems. Abdominal spasms are a source of great annoyance to the patient, at times painful, and greatly interfering with his rest and sleep. Anterior rhizotomy has been used to relieve mass flexion reflexes with excellent results in selected cases. 11 The procedure consists in section of the anterior spinal nerve roots from the 10th thoracic through and including the 1st sacral nerve root bilaterally. Thus, the spastic paralysis of a spinal cord lesion is converted into the flaccid paralysis of a lower motor neuron lesion. Technically, this procedure is successful in overcoming the disabling

MEDICAL ASPECTS OF SURGICAL TREATMENT OF HYPERTENSION

The effort to treat hypertension by surgical as well as medical means is a development of recent years. While the theoretical basis of certain operations used is insecure, some of the results obtained are worthy of serious study. Two operations among the many proposed appear most likely to be of some value. These are resection of the. anterior spinal nerve roots 1 and resection of the splanchnic nerves. 2 Three and one-half years ago Dr. George Heuer of the New York Hospital and I decided to study intensively the effects of these two operations on patients with hypertension. A plan was put into effect whereby the patients were studied for a long period in the Rockefeller Hospital and transferred to the New York Hospital for operation by Dr. Heuer. They were then returned for further study. In this manner we believed that the study would be as objective as possible.