Search

Diagnostic cervical medial branch blocks and zygapophysial joint blocks were used to test the hypothesis that the cervical zygapophyseal joints can be the source of pain in patients with idiopathic neck pain. Complete temporary relief of all symptoms was obtained in 17 out of 24 consecutive patients. Two major groups of patients were those with neck pain and headache stemming from the C2-3 joints, and those with neck pain and shoulder pain stemming from the C5-6 joints. Internal-control observations in nine of the 17 patients established the diagnostic validity of the blocks used. The high yield of positive responders in this study probably reflects the propensity of patients with zygapophysial joint syndromes to gravitate to a pain clinic when this condition is not recognised in conventional clinical practice.

Rhizolysis has been regarded as a controversial, but safe, procedure for the treatment of back pain. A case of a neuralgia-like pain syndrome resulting from transection of the lateral branches of the lumbar dorsal rami during rhizolysis is reported. The anatomy of the lumbar lateral branches is described, and their vulnerability is discussed. Attention is drawn to the likelihood of this complication with the use of rhizolysis in the vicinity of cutaneous branches of the dorsal rami

Low back pain, referred pain in the lower limbs, and spasm of the back, gluteal, and hamstring muscles are clinical features which can be induced in normal volunteers by stimulating structures which are innervated by the lumbar dorsal rami. Conversely, they can be relieved in certain patients by selective interruption of conduction along dorsal rami. These facts permit the definition of a lumbar dorsal ramus syndrome, which can be distinguished from the intervertebral disc syndrome and other forms of low back pain. The distinguishing feature is that, in lumbar dorsal ramus syndrome, all the clinical features are exclusively mediated by dorsal rami and do not arise from nerve-root compression. The pathophysiology, pathology, and treatment of this syndrome are described. Recognition of this syndrome, and its treatment with relatively minor procedures, can obviate the need for major surgery which might otherwise be undertaken.

The thoracolumbar fascia was studied by dissection in ten adult human cadavers. The posterior layer of this fascia was found to consist of two laminae. The superficial lamina is formed by the aponeurosis of latissimus dorsi. The deep lamina consists of bands of fibers passing caudolaterally from the midline. Both laminae form a retinaculum over the back muscles, and the deep lamina constitutes a series of accessory posterior ligaments that anchor the L2 to L5 spinous processes to the ilium and resist flexion of the lumbar spine. The function of these ligaments is enhanced by the contraction of the back muscles and the action of certain, restricted portions of the abdominal muscles.

The anatomy of the vertebral nerve was investigated in humans and in monkeys. The effect of stimulation of the vertebral nerve and the cervical sympathetic trunk in the monkey was studied. The vertebral nerves in man and monkey represent a series of deep grey rami communicantes which form intersegmental neural arcades around the vertebral artery between C7 and C3. Above C3 the vertebral artery is accompanied by direct branches from the C1-3 ventral rami. Electrical stimulation of either the vertebral nerve or the cervical sympathetic trunk had a minimal effect on vertebral blood flow. In contrast, sympathetic stimulation had pronounced effects on carotid flow and resistance. Anatomically and physiologically there are no grounds to support the hypothesis that irritation of the "vertebral nerve" is the pathogenetic mechanism of cervical migraine.

The lumbar intervertebral discs are supplied by a variety of nerves. The posterior aspects of the discs and the posterior longitudinal ligament are innervated by the sinuvertebral nerves. The posterolateral aspects of the discs receive branches from adjacent ventral primary rami and from the grey rami communicantes near their junction with the ventral primary rami. The lateral aspects of the discs receive other branches from the rami communicantes. Some rami communicantes cross intervertebral discs and are embedded in the connective tissue of the disc deep to the origin of psoas. Such paradiscal rami are likely to be another source of innervation to the discs. The anterior longitudinal ligament is innervated by recurrent branches of rami communicantes.

Dissections of five human adult cadavers revealed that the C2 spinal ganglion bears a constant relationship to the dorsal aspect of the lateral atlanto-axial joint. Radiologically, the ganglion lies extradurally opposite the midpoint of the silhouette of the lateral atlanto-axial joint space. Needles can be introduced onto this target point using fluoroscopic control and used to perform selective local anesthetic blocks of the C2 spinal nerve. This technique is applicable in cases where it is difficult to decide on clinical grounds whether occipital headaches are due to an upper cervical abnormality or are a symptom of tension headache or common migraine. In particular the technique anesthetizes the otherwise inaccessible articular branches of the median and lateral atlanto-axial joints which may be an occult source of headache.

Microdissection and histologic studies were undertaken to determine the innervation of the cervical intervertebral discs. The cervical sinuvertebral nerves were found to have an upward course in the vertebral canal, supplying the disc at their level of entry and the disc above. Branches of the vertebral nerve supplied the lateral aspects of the cervical discs. Histologic studies of discs obtained at operation showed the presence of nerve fibers as deeply as the outer third of the anulus fibrosus. These anatomic findings provide the hitherto missing substrate for primary disc pain and the pain of provocation discography.

One of the putative causes of headache is osteoarthritis of the C2-3 zygapophysial joint. A technique for blocking the third occipital nerve which innervates this joint was devised and used as a screening procedure for headache mediated by this nerve. Seven out of ten consecutive patients presenting with suspected cervical headache were found to suffer pain mediated by the third occipital nerve and stemming from a C2-3 zygapophysial joint. Because third occipital headache may be indistinguishable clinically from tension or other forms of headache, third occipital nerve blocks are advocated as means of establishing this largely unrecognised diagnosis.

Any structure innervated by the cervical spinal nerves can be a primary source of neck pain and referred pain to the head, upper limb or chest wall. The most likely sources of chronic pain are the cervical intervertebral discs and the cervical zygapophyseal joints. Disc pain can be diagnosed by provocative disc stimulation; zygapophyseal joint pain can be diagnosed by local anaesthetic blocks of the cervical dorsal rami. Disc pain can be treated by anterior cervical fusion and zygapophyseal pain by percutaneous radiofrequency neurotomy.

The back muscles alone are unable to provide the extensor moment required to lift large weights, and must be aided by another source of anti-flexion moments. It has been postulated that contraction of the abdominal muscles can provide an extension moment by developing tension in the thoracolumbar fascia (TLF). Anatomical studies and a biomechanical analysis, however, reveal that the anti-flexion moment generated in this way is only very small. Too little of the abdominal musculature attaches to the TLF to generate a significant tension in it. Previous calculations of the forces in the TLF have overestimated the tension developed in it because of erroneous assumptions and interpretations of the relevant anatomy. Whatever the role played by the TLF in lifting it must be essentially independent of abdominal mechanisms., (Copyright © 1987. Published by Elsevier Ltd.)

In the lumbar region the longissimus thoracis and iliocostalis lumborum are separated by the erector spinae aponeurosis and its ventral reflection--the lumbar intermuscular aponeurosis. Lumbar fibres of the longissimus arise from the ilium and the lumbar intermuscular aponeurosis and insert into the accessory processes and proximal ends of the transverse processes of the lumbar vertebrae. Lumbar fibres of iliocostalis insert into the costal elements of the first four lumbar vertebrae. The lumbar insertions of these muscles are homologous to their thoracic insertions. The lumbar intermuscular aponeurosis is homologous to the lumbar intermuscular septum in the dog, cat and monkey. The details of attachment of the lumbar fibres of the erector spinae and of the lumbar intermuscular aponeurosis should be taken into account in biomechanical analyses of the lumbar vertebral column.

Observations made in the present study of the dorsal lumbar muscles of the cat are at variance with descriptions in the available literature. The morphology of these muscles is described in detail, and a revised interpretation of this morphology is made. There are 5 muscles -- multifidus, intertransversarii mediales, lumbococcygeus, iliocostalis lumborum and longissimus lumborum. They are arranged in 5 parallel polysegmental columns and are covered by the dorsal layer of thoracolumbar fascia and the erector spinae aponeurosis. The multifidus consists of fibres connecting mamillary and spinous processes. From each mamillary process 4 sets of fasciculi arise. Each set has constant specific attachments. The intertransversarii mediales are fibres connecting accessory and mamillary process. 3 principal fasciculi arise from each accessory process and insert into particular mamillary processes at more caudal levels. The iliocostalis and longissimus arise from the ilium and from opposite surfaces of an intermuscular septum. The lumbococcygeus arises in the lumbar region from the accessory processes but inserts in the tail. Reasons for the revised nomenclature and interpretation are discussed. A specific definition of the longissimus lumborum and iliocostalis lumborum is made on the basis of their observed morphology and nerve supply. It is argued that the lumbococcygeus should be considered as the lumbar portion of sacrocaudalis dorsalis lateralis rather than part of a common muscle mass.

The L 1-4 dorsal rami tend to form three branches, medial, lateral, and intermediate, which are distributed, respectively, to multifidus, iliocostalis, and longissimus. The intertransversarii mediales are innervated by a branch of the dorsal ramus near the origin of the medial branch. The L 4 dorsal ramus regularly forms three branches while the L 1-3 levels the lateral and intermediate branches may, alternatively, arise from a short common stem. The L 5 dorsal ramus is much longer than the others and forms only a medial and an intermediate branch. Each lumbar medial branch innervates two adjacent zygapophysial joints and ramifies in multifidus, supplying only those fascicles which arise from the spinous process with the same segmental number as the nerve. The comparative anatomy of the lumbar dorsal rami is discussed and the applied anatomy with respect to 'rhizolysis', 'facet denervation' and diagnostic paraspinal electromyography is described.

The lumbosacral dorsal rami of the cat were studied by gross dissection. The L1-6 dorsal rami form three discrete branches - lateral, intermediate and medial. The lateral branches supply the iliocostalis lumborum and become cutaneous over the back. The intermediate branches ramify in the longissimus lumborum, and are separated from the lateral branches by the lumbar intermuscular septum. The medial branches supply the multifidus and have a constant branch - the nerve to intertransversarii mediales. The L7 dorsal ramus forms only medial and intermediate branches. The S1 and S2 dorsal rami form three branches, the middle of which form the ascending sacral trunk and accessory ascending sacral trunk. The ascending sacral trunk is derived from S1 and S2, the accessory ascending sacral trunk from S2. Both nerves are the exclusive nerve supply of lumbococcygeus.