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PubMed2001

[Surgical concepts and results in necrotizing fasciitis].

INTRODUCTION: Necrotizing fasciitis (NF) is a rapidly progressive soft tissue infection involving primarily the superficial fascia and subcutaneous tissue. The disease is caused by Streptococcus pyogenes or synergistic infection of anaerobic and facultative anaerobic bacteria. Further characteristics are severe, intolerable pain and a mortality of 30-50%. PATIENTS AND METHODS: From January 1996 to January 2000 12 patients underwent treatment for NF. The patients' charts were investigated retrospectively. RESULTS: In 7 patients the bacterial cultures showed a mixed, polymicrobial infection and in 5 cases only Streptococcus pyogenes. The NF was localized at the upper extremity (2), abdomen (3), back (1), hip (2) and lower extremity (4). The area involved was 8 (4-11)% of the total body surface. The surgical procedures in 12 patients were debridement (60x), local transposition flap (2), free muscle flaps (3), lower leg amputation (1) and split thickness skin graft (3x). Four patients developed streptococcal toxic shock syndrome and two died. In total there were four deaths with a mortality of 33%. In the "survivor group" the time to diagnosis was 2.8 (1-7) days, the time to radical surgery 3.3 (1-9) days. In the "mortality group" it was 6.8 (3-10) days or 9.3 (6-12) days. CONCLUSION: The prognosis of NF seems to be influenced by the site of the infection, because 4 out of 6 patients with NF of the abdomen, back or hip died, but all patients with NF of the extremities survived. The age of the patient is not a key parameter, because also young and previously healthy people also die from the streptococcal toxic shock syndrome. The interval between diagnosis and radical debridement appears to be the crucial factor in terms of prognosis, since early diagnosis and prompt, radical surgery improves the survival rate.

Adult↗

PubMed1996

Anatomic basis of the lower trapezius musculocutaneous flap.

Differences in the description of the blood supply of the lower trapezius m. and the fact that all former findings are based on very few cases caused us to reinvestigate the arterial supply of the lower trapezius m. Based on the anatomic investigation of 70 human cadavers, the trapezial branch of the dorsal scapular a. was found to be the constant vessel to the lower trapezius m. The origin of the dorsal scapular a., however, was found to be very variable. In 45% it was a direct branch of either the subclavian a. or the costocervical trunk. In the remaining 55% the dorsal scapular a. formed different trunks with the superficial cervical a. and/or suprascapular a. branching off either the subclavian a., the thyrocervical trunk, or the internal thoracic a. Additional segmental musculocutaneous perforators also supply the lower part of the trapezius m. and the overlying skin. Consequently, the lower or ascending part of the trapezius m. has a vascular pattern type V. Thus, the lower trapezius musculocutaneous flap merits consideration in head and neck reconstruction.

Back↗

PubMed1991

[A case of epidural lipomatosis presenting spinal ataxia].

A 41-year-old man was doing well until July 1989, when he noted numbness over soles, followed 4 months later by difficulty in walking. These symptoms were progressively getting worse, and he was admitted to our department on June 12, 1990. General physical examination was unremarkable. Neurologically cranial nerves were intact except old right, traumatic strabismus. Muscle tone and deep tendon reflexes were normal throughout, but bilateral Babinski and Chaddock reflexes were present. Mild weakness of lower extremities were found on muscle testing (4/5). In sensory system, superficial sensory disturbance below T10 was seen, and markedly diminished vibration and position senses of lower extremities were noted. Cerebellar test was intact, although unsteadiness was found on heel-shin test. Romberg sign was definitely positive. His gait was wide-based and ataxic. Laboratory data showed no abnormalities in CBC, chemistry, urinalysis, serological tests and endocrinological examinations. Spinal MRI (Siemens 1.5 Tesla) showed abnormal deposition of epidural fatty tissues compressing spinal cord with flattening of cord from T4 to T8. Spinal ataxia as compressive myelopathy due to epidural lipomatosis was considered and he underwent laminectomy from T4 to T8 with improvement in walking. Epidural lipomatosis is an unusual cause of spinal cord compression, presenting compressive myelopathy, radiculopathy, cauda equina syndrome, intermittent claudication, or back pain. Most of cases were associated with long-term administration of adrenocortical steroid hormone, or underlying diseases, except only 3 cases including ours. This is the first case of spinal epidural lipomatosis presenting progressive gait disturbance due to spinal ataxia.

Adult↗

PubMed1979

Chronic pain syndromes and their treatment. III. The piriformis syndrome.

The piriformis is a deep-seated muscle, most of its muscular portion being part of the dorsal wall of the pelvis. The lateral portion and its insertion is extra-pelvic and lies deep to the glutei. Like more superficially located and therefore more easily accessible skeletal muscles, the piriformis too can be the seat of trigger points, giving rise to symptoms indistinguishable from those of other causes of low backache, unless a deliberate search is made for the signs specific to the piriformis syndrome. Having made a presumptive diagnosis, confirmation is gained by palpating the muscle itself via rectum or vagina and reproducing the pain by digital pressure. If this test also is positive, the muscle is injected, the approach being either through the sciatic notch, from the perineum, or through the vagina. Immediate relief of pain is experienced after the solution of local anaesthetic and steroid has been deposited deep within the fleshy portion of the muscle.

Adult↗

PubMed2005

The internal brachial ligament versus the arcade of Struthers: an anatomical study.

Management of the distal part of the medial intermuscular septum and the internal brachial ligament (both described by Struthers in 1854), the medial head of the triceps, and the "arcade of Struthers" (a concept created by Kane et al. in 1973) is still unclear regarding anterior transposition of the ulnar nerve because of anatomical controversies. Dissection of the medial aspect of 30 arms was performed. The internal brachial ligament was found in 22 of 30 cases (73 percent). It separated from the medial septum at an average distance of 11.5 cm above the medial epicondyle, ran medially and then anterior to the ulnar nerve, and finally joined back at the septum at an average distance of 8.2 cm. In the other 27 percent of cases, the ulnar nerve traveled down the arm, passing entirely posterior to the septum. When the internal brachial ligament was present, it always supported the origin of the most superficial layer of the medial head of the triceps, from the inferior border of the teres major to its fusion back to the septum. This layer appeared as an oblique muscular curtain covering the medial aspect of the ulnar nerve. No local thickening was found in the brachial fascia covering these muscular fibers. Muscular fibers were not observed medial to the nerve when the internal brachial ligament was absent. This anatomical study confirms the descriptions of the internal brachial ligament made by Struthers. Foranatomical reasons, the authors propose cancelling the concept of the arcade of Struthers.

Adult↗

PubMed1991

The treatment of atypical lipoma with liposuction.

Large lipomas may best be treated with liposuction. Once a lipoma enlarges to 4 cm or more, liposuction has several advantages over conventional surgery. A well-demarcated lipoma 15 cm in diameter and deep to muscle was treated by liposuction. Biopsy showed an atypical lipoma. Because the entire tumor was removed by liposuction, we feel that the prognosis is excellent. The cosmesis and morbidity results were far superior to those anticipated with conventional excisional surgery. Small superficial lipomas may be treated by suction lipectomy and the surrounding area can be contoured symmetrically at the same time, whereas large ones can be liposuctioned completely without extensive surgical extirpation and morbidity. Because such big lesions may represent atypical lipomas or liposarcomas, care must be taken to remove the entire tumor.

Adult↗

PubMed2002

Stimulation of the greater occipital nerve induces increased central excitability of dural afferent input.

Patients with primary headaches often report pain that involves not only the front of the head, innervated by the first (ophthalmic) division of the trigeminal nerve, but also the back of the head, innervated by the greater occipital nerve (GON) that is a branch of the C(2) spinal root. The aim of this work was to study the physiology of trigeminocervical input in a model of cranial nociception by describing a population of nociceptive neurones that receive convergent input from the supratentorial dura and the GON. Rats were anaesthetized with pentobarbital, paralysed and ventilated. The parietal dura above the middle meningeal artery was stimulated through a closed cranial window. The GON was exposed in the neck and stimulated. Recordings were made from 67 neurones (52 wide dynamic range neurones/15 nociceptive-specific-neurones) in the C(2) spinal dorsal horn, which responded to stimulation of the dura and the GON. Most neurones showed receptive fields corresponding to the first trigeminal division as well as input from C(2) skin and muscle. Neurones were recorded in superficial and deep layers of the dorsal horn. All neurones tested received input from the ipsilateral and contralateral GON (n = 5). The responses to dural stimulation were analysed before and after stimulation of the GON. Supramaximal electrical stimulation of the GON (20 s to 5 min) enhanced afferent dural input in 8/20 neurones. Application of the C-fibre activator mustard oil (MO) to the cutaneous receptive field or suboccipital muscles innervated by the GON induced an increased excitability of dural responses in 8/12 and 9/10 neurones, respectively. Stimulation of muscle afferents had a significant longer facilitatory effect than cutaneous stimulation (P < 0.05). These results show that a considerable population of neurones show convergent input from both dura as well as cervical cutaneous and muscle territories, which supports the view of a functional continuum between the caudal trigeminal nucleus and upper cervical segments involved in cranial nociception. The facilitatory effect of GON stimulation on dural stimulation suggests a central mechanism at the second order neurone level. This mechanism may be important in pain referral from cervical structures to the head and therefore have implications for most forms of primary headache.

Afferent Pathways↗

PubMed1997

Classification and reconstructive options in foot plantar skin avulsion injuries.

Between 1989 and 1994, 28 patients who had plantar avulsion injuries were treated. Patient ages averaged 30 years (range 7 to 62 years). Length of follow-up averaged 20 months. Five patients (18 percent) were classified as having suprafascial avulsions, where the shearing plane was limited to the superficial subcutaneous layer, leaving the deeper subcutaneous fat. Twenty-three patients (82 percent) were classified as having subfascial avulsions, where the stripping force extended deep into the plantar aponeurosis. For the suprafascial avulsions, defatting these flaps and replacing them with full-thickness skin grafts was the treatment of choice. For the subfascial group, the avulsions with proximally based flaps (4 patients) that were well nourished by mediolaterally orientated neurovascular bundles could be treated by sewing the avulsed flaps tension-free back to their former positions. For the subfascial group with distally based flaps (19 patients), the avulsed flaps were supplied by anteroposteriorly orientated vascular plexuses that were compromised. Primary revascularization of the soft tissue should be considered whenever possible. Among them, 10 patients attempted microvascular salvage. Only 3 patients succeeded with revascularization. In the remaining 16 patients, the avulsed flaps went on to partial or complete necrosis, and these required secondary reconstruction with free muscle flaps for heel defects.

Adolescent↗

PubMed1995

Thymic vascular system of the European common frog, Rana temporaria: a scanning electron-microscopic study of vascular casts.

Vascular corrosion casts of the thymus of adult individuals of the European common frog, Rana temporaria, were analysed by scanning electron microscopy. The main arterial vessel, which is derived either from the temporal artery or from the auricular ramus, approaches the central territory of the gland and branches into "twigs" that, on penetrating the parenchyma, give rise to capillaries. Most of these capillaries run vertically towards the surface of the gland; they either join the superficial capillary plexus or follow this plexus for a variable distance and then run back towards the medulla, forming capillary loops. The former capillaries link with the extensive venous plexus composed of irregular meshes, whereas the latter capillaries join the venules at the cortico-medullary boundary and finally escape into collecting veins on the gland surface. The venous twigs, which join together near the gland, form the main thymic vein, which empties into the external jugular vein. The details of the thymic vasculature of the anuran amphibian, R. temporaria, are compared with those described in mammalian species, viz. the mouse, rat and guinea pig.

Animals↗

PubMed2006

Direct repair for treatment of symptomatic spondylolysis and low-grade isthmic spondylolisthesis in young patients: no benefit in comparison to segmental fusion after a mean follow-up of 14.8 years.

The aim of the present study was to assess the long-term clinical, functional, and radiographic outcome of direct repair of spondylolysis using cerclage wire fixation according to Scott in young patients with symptomatic spondylolysis or low-grade isthmic spondylolisthesis as compared to the outcome after uninstrumented posterolateral in situ fusion. Twenty-five out of 28 patients of the direct repair group (89%) and 23 out of 28 of the fusion group (82%) were available for follow-up examination. The assessment by independent observers included a structured interview (Oswestry questionnaire [ODI], visual analogue scale, SRS questionnaire), a clinical examination, functional testing, plain radiography, and MRI. The groups were comparable as to the mean age at operation (18.2 vs. 16.2 years.), the follow-up time (14.8 vs. 15.0 years), and the amount of preoperative slip (7.2 vs. 13.1%). The mean ODI and SRS total scores were significantly better in the fusion group (4.3 [0-16] and 96 [57-117]) as compared to the direct repair group (11.4[0-52] and 87[53-107]; P=0.02 and P=0.011, respectively). In functional testing, both groups reached normal values for abdominal and back muscle strength. The lumbar spine flexion and extension ROM was decreased in both groups showing no statistical difference between the groups. Significant progressive narrowing of the olisthetic disc was detected on the plain radiographs after direct repair. On the flexion-extension radiographs, in the direct repair group, the mobility in the lytic/olisthetic segment was decreased in comparison to normal values from the literature. The mobility at the level above the operated segment was decreased in the direct repair group as compared to the fusion group (P=0.057). On T2-weighted MR images in the direct repair group, the signal intensity of the disc below the affected vertebra was decreased in 17/23 (74%) patients. There was no difference between the groups in the nucleus signal intensity of the adjacent disc above the operated segment. No association between the disc degeneration on MRI and the outcome of the patients could be established. In the direct repair group the following complications were seen: transient nerve root irritation (2), superficial infection (1), UTI (1); in the fusion group the complications were: subcutaneous seroma (2) and UTI (1). There were six re-operations, cerclage removal(4), conversion into segmental fusion(2) in the direct repair group, and one re-operation, instrumented respondylodesis, in the fusion group. In conclusion, the results of direct repair of the spondylolysis using cerclage wire fixation according to Scott were very satisfactory in 76% of the patients after a mean follow-up of 14.8 years. After direct repair, the ODI deteriorated with time leading to a clinically moderate but statistically significant difference in favour of segmental fusion. Lumbar spine mobility was decreased after direct repair. Secondary segmental instability above the spinal fusion was not detected. The procedure does not seem to be capable of preventing the olisthetic disc from degeneration. The theoretical benefits of direct repair could not be proven.

Adolescent↗

PubMed1993

Dynamics of reflex cocontraction in hermit crab abdomen: experiments and a systems model.

1. Both stretch and release of the ventral superficial muscles (VSM) in the abdomen of the hermit crab, Pagurus pollicarus, activate the VSM motoneurons in the intact animal and in the isolated abdomen. 2. This reflex was studied by recording intracellularly from muscle fibers innervated by single motoneurons during stretch and release of the VSM. The three motoneurons of the right fourth segment respond to both stretch and release with a phasic burst lasting approximately 250 ms. The burst in the two tonic motoneurons has two components, a short burst lasting 10-20 ms, with a latency from the beginning of stretch of 60-90 ms, and a longer burst of variable length, with a latency of 120 ms. Ramp stretches of different amplitudes and velocities were used to show that the first component is proportional to the absolute value of the second derivative of force and the second component to the absolute value of the first derivative of force. 3. Stretch and release of the VSM also simultaneously evoke phasic bursts in the motoneurons of the dorsal superficial muscles and the VSM circular muscles (functional antagonists of the longitudinal VSM), as well as in contralateral homologues of the same segment and in ipsilateral homologues of the next anterior segment. The effect of this coactivation is to stiffen the abdomen in response to perturbations in any direction. 4. Stretch or release of phasic mechanoreceptors in the VSM evokes this reflex. Isometric electrical stimulation of the isolated muscle also activates them, showing that they are transducing changes in force and suggesting that they operate to increase muscle stiffness by positive feedback. 5. A mathematical systems model of this reflex, composed of two parallel pathways activating the motoneurons, was constructed. The first pathway produces a signal proportional to the absolute value of the second derivative of force, the second pathway a signal proportional to the first derivative of force. The sum of the signals from the two pathways is filtered by an adaptation process, which is followed by a low-pass filter representing muscle activation kinetics. The muscle activation signal is then fed back to multiple muscle force. 6. Simulations using this model generate the phasic bursts to stretch and release as well as reproducing the frequency dependence of this reflex. The predominant action of this reflex is to enhance muscle stiffness.

Abdomen↗

PubMed2004

Cutaneous myoepithelioma: a clinicopathologic and immunohistochemical study of 14 cases.

Analogous to mixed tumors of salivary glands (" pleomorphic adenomas" ), cutaneous mixed tumors (" chondroid syringomas" ) contain a ductal (epithelial) component and a variably prominent myoepithelial component. Tumors showing purely myoepithelial differentiation (myoepitheliomas) have only recently been recognized to arise in the dermis, and to date very few cases have been described. To characterize these tumors further, 14 cutaneous myoepithelial tumors were retrieved from the authors' consult files. Eleven patients were male and 3 were female; their median age was 22.5 years (range, 10 to 63 years), and 7 patients were between 10 and 20 years old. Tumor size ranged from 0.5 to 2.5 cm (mean, 1.1 cm). Most tumors arose on the extremities: 6 on the upper limbs, 6 on the lower limbs, and 1 each on the back and nose. Ten tumors were limited to the dermis, and 5 also extended into superficial subcutis. Thirteen tumors were myoepitheliomas (lacking ductal differentiation), and 1 tumor was a myoepithelial carcinoma (exhibiting severe cytological atypia and a high mitotic rate). Histologically, 7 tumors were solid, composed of ovoid to spindled, histiocytoid, or epithelioid cells with no significant stroma, and 7 were predominantly lobulated, with cords or nests of epithelioid, plasmacytoid, or spindled cells with a variably reticular architecture and a chondromyxoid or collagenous/hyalinized stroma. One tumor was composed solely of plasmacytoid (hyaline) cells, and 1 exhibited extensive adipocytic differentiation. Among the 13 myoepitheliomas, mitoses ranged from 0 to 6 per 10 high-power fields (HPFs) (mean, 1.5); 8 tumors contained no mitoses. The myoepithelial carcinoma had 39 mitoses per 10 HPFs. By immunohistochemistry, all cases were reactive for epithelial markers (keratins and/or epithelial membrane antigen [EMA]); 13 of 14 (93%) expressed S-100 protein, 10 of 11 expressed (91%) calponin, 11 of 14 (79%) expressed EMA, 9 of 14 (64%) expressed keratins, 8 of 14 (57%) expressed smooth muscle actin, 7 of 14 (50%) expressed glial fibrillary acidic protein, 3 of 11 (27%) expressed p63, and 1 of 6 (17%) expressed desmin. All 5 cases without keratin staining were diffusely positive for EMA, and all of these cases showed a solid growth pattern. Follow-up was available for 8 patients (median follow-up, 40 months; range, 6 months to 9 years); 3 tumors (38%) recurred locally, and 1 tumor (13%) also metastasized to the lymph nodes. The case that resulted in recurrence and metastasis had the highest mitotic rate (6 per 10 HPFs) of the cytologically benign tumors. Follow-up information was not available for the myoepithelial carcinoma. This study suggests that approximately 50% of cutaneous myoepitheliomas are distinctive lesions composed of a solid proliferation of cells with abundant eosinophilic syncytial cytoplasm, which often lack immunostaining for keratin, whereas the remainder demonstrate focally reticular architecture and myxoid stroma or plasmacytoid cells, similar to their counterparts in salivary gland and soft tissue. Whereas most cutaneous myoepitheliomas behave in a benign fashion, there is apparently a significant risk for local recurrence but a low metastatic potential.

Adolescent↗

PubMedDate not supplied

Face lift, Part 4: Use of superficial musculoaponeurotic system suspending sutures.

We describe nonabsorbable sutures running from one or more sites in the superficial musculoaponeurotic system (SMAS), to other sites at a distance, or to fixed sites beyond or deep to SMAS for the purpose of pulling on or suspending the distal selected SMAS sites or changing contours between the suture ends. Our reasons for abandoning some sutures and continuing with others are stated. In face lifting, we still often employ sutures running from the anterior part of the platysma and SMAS back to the sternocleidomastoid fascia. These sutures help prevent platysma "cording" and are useful in the restoration and preservation of a more youthful profile in the neck. Examples and controls are demonstrated. These sutures and the long-term results of their use have never been shown before. Problems encountered in using suspending sutures are described.

Face↗

PubMed1995

The posterior layer of the thoracolumbar fascia. Its function in load transfer from spine to legs.

STUDY DESIGN: The superficial and deep lamina of the posterior layer of the thoracolumbar fascia have been studied anatomically and biomechanically. In embalmed human specimens, the posterior layer has been loaded by simulating the action of various muscles. The effect has been studied using raster photography. OBJECTIVES: To study the role of the posterior layer of the thoracolumbar fascia in load transfer between spine, pelvis, legs, and arms. SUMMARY OF BACKGROUND DATA: It has been determined whether muscles such as the gluteus maximus, latissimus dorsi, erector muscle, and biceps femoris are functionally coupled via the thoracolumbar fascia. The caudal relations of the posterior layer of the thoracolumbar fascia have not been previously studied. METHODS: Dissection was directed to the bilaminar posterior layer of the thoracolumbar fascia of 10 human specimens. The superficial and deep lamina were studied using visual inspection and raster photography. Tension to the posterior layer of the fascia was simulated by traction to various muscles and measured by studying the displacement in the posterior layer. RESULTS: Traction to a variety of muscles caused displacement of the posterior layer. This implies that in vivo, the superficial lamina will be tensed by contraction of various muscles, such as the latissimus dorsi, gluteus maximus and erector muscle, and the deep lamina by contraction of the biceps femoris. Caudal to the level of L4 (in some specimens, L2-L3), tension in the posterior layer was transmitted to the contralateral side. CONCLUSIONS: Anatomic structures normally described as hip, pelvic, and leg muscles interact with so-called arm and spinal muscles via the thoracolumbar fascia. This allows for effective load transfer between spine, pelvis, legs, and arms--an integrated system. Specific electromyographic studies should reveal whether the gluteus maximus muscle and contralateral latissimus dorsi muscle are functionally coupled, especially during rotation of the trunk. In that case, the combined action of these muscles assists in rotating the trunk, while simultaneously stabilizing the lower lumbar spine and sacroiliac joints.

Aged↗

PubMed2000

Benign lymphangioendothelioma (acquired progressive lymphangioma): a lesion not to be confused with well-differentiated angiosarcoma and patch stage Kaposi's sarcoma: clinicopathologic analysis of a series.

The clinicopathologic features of 12 cases of benign lymphangioendothelioma (acquired progressive lymphangioma) are reported. There were five male and seven female patients. Age at diagnosis ranged from 17 to 90 years (median age, 54 yrs). Development of a single macular/papular hemangiomatous or pigmented lesion was the main presenting symptom. Symptom duration before diagnosis ranged from 2 months to 20 years (median, 5.5 yrs). Tumor size ranged from 0.3 cm to 10 cm (median. 1.5 cm). Location included skin of the head and neck (n = 5), back (n = 1), breast (n = 1), shoulder (n = 1), forearm (n = 1), plantar aspect of the foot (n = 2), and oral mucosa (n = 1). No patient had any other concomitant vascular anomaly (for example, lymphangiomatosis) or was suspected to have acquired immunodeficiency syndrome. Treatment consisted of excisional biopsy in nine patients, incisional biopsy in two, and wide excision in one. Follow-up information on nine patients (range, 4-40 mos; median, 12 mos) showed two local recurrences in one patient. Microscopically, the lesions consisted of anastomosing, often widely dilated vascular structures developing in the superficial dermis. As the lesion grew within deeper dermis, the vascular spaces collapsed and dissected the dermal collagen in an angiosarcoma-like pattern. The lining endothelium was flat and monolayered, with little or no cytologic atypia and no evident mitoses. Some vascular structures contained stromal papillary projections resembling papillary endothelial hyperplasia, and intravascular red blood cells were present occasionally. Immunohistochemistry performed in eight specimens showed variable endothelial cell reactivity for CD31 (7 of 8), CD34 (7 of 7), and factor VIII-related antigen (4 of 6). A smooth muscle cell layer was observed focally around the vascular spaces in six lesions. Benign lymphangioendothelioma (acquired progressive lymphangioma) is an uncommon benign lesion that, in view of major differences in treatment and prognosis, should be distinguished from well-differentiated angiosarcoma and Kaposi's sarcoma, especially the patch stage and lymphangioma-like variants of the latter.

Adolescent↗

PubMed1973

Input from muscle and cutaneous nerves of the hand and forearm to neurones of the precentral gyrus of baboons and monkeys.

1. The precentral bank of the Rolandic fissure of the cortical arm area has been explored with extracellular micro-electrodes in primates (baboons and monkeys) under nitrous oxide and oxygen anaesthesia, supplemented by small doses of Parkesernyl(R) and chloralose. The results in baboons and monkeys were the same.2. Single units were classified as pyramidal tract neurones or non-pyramidal tract neurones according to their antidromic responsiveness to stimuli applied in the dorsolateral funiculus at C1-2.3. Responses to electrical stimulation of the deep (motor) radial nerve, the deep palmar (motor) branch of the ulnar nerve, and the superficial (cutaneous) radial nerve could be recorded in the majority of neurones of the motor cortex provided that short trains of strong stimuli were used. Minimal responses to muscle nerve stimulation were observed in a few neurones at 1.4 x group I threshold, but most units reacted only with higher stimulus intensities (2-3 x group I threshold).4. The latencies to peripheral nerve stimulation were measured from the first peak of the incoming volley recorded at the root entry zone. The mean response latencies of pyramidal tract cells were between 20 and 25 msec; non-pyramidal tract cells were activated at slightly shorter mean latencies, the difference being significant for superficial radial nerve stimulation only (4 msec). These latencies are more than twice as long as those recorded in the postcentral gyrus, and the probability of discharge is lower than for postcentral neurones.5. A further difference between neurones of the postcentral and precentral gyrus is the pronounced convergence from different nerves and also from different modalities (cutaneous and muscle afferents) in units of the precentral cortex in contrast to units of the postcentral cortex.6. The high thresholds, necessary to activate precentral neurones by muscle nerve stimulation, make it unlikely that group I muscle afferents are involved. This is, furthermore, indicated by the lack of responsiveness to intravenous injection of succinylcholine which was, however, effective for driving neurones of the specific projection area for group I afferents, area 3a. The present experiments are consistent with the view that sensitivity of precentral neurones to muscle stretch (described in previous studies) is due to activation of secondary muscle spindle endings and their ascending pathways.7. The original hypothesis of a load compensating ;pyramidal reflex' with an oligosynaptic afferent contribution from the spindle primaries can be discarded. The present findings indicate that there is a feed-back from secondary muscle spindle afferents which, by way of a more complex pathway, can modulate the firing frequency of neurones in the motor cortex.

Animals↗

PubMed1991

[Use of deep planes in surgery of rejuvenation of the face].

Since 1976, anatomical studies intensively performed in France have demonstrated the surgical interest in using the superficial musculo-aponevrotic system in the face, and also a subperiosteal malar approach. The SMAS is mostly a surgical structure. It could be considered as a remnant of a primitive subcutaneous muscle which would have been located in the superficialis fascia; its stays outward the parotid gland. Muscular fibers have been found inside, uniting from-down the patysma muscle toward the periphery of the frontalis muscle at the top. Risorius muscle is included in this structure. Its surgical interest is that it allows to relieve skin tension during a face lift by a fibromuscular associated stretch. The modern way in face lifting should prevent the fixed appearance of a too tight skin-pull, when skin is redraped alone. Risks of facial nerve injury are minimal when the proper technique is used. It is possible, in the same way, during a blepharoplasty to stretch the orbicularis oculi muscle, like the muscular resuturing of an inguinal hernia repair. Each of this technique has its own different indications now well defined. The authors shows this experience after 150 cases of face lift operations and makes an analysis of the advantages and draw backs of using the SMAS in cases of rejuvenating face operations.

Aged↗

PubMed2006

The lumbar multifidus: does the evidence support clinical beliefs?

The contribution of the trunk muscles to spinal stability is well established. There is convincing evidence for the role of multifidus in spinal stability. Recently, emphasis has shifted to the deep fibres of this muscle (DM) and five key clinical beliefs have arisen: (i) that DM stabilizes the lumbar spine whereas the superficial fibres of lumbar multifidus (SM) and the erector spinae (ES) extend and/or rotate the lumbar spine, (ii) that DM has a greater percentage of type I (slow twitch) muscle fibres than SM and ES, (iii) that DM is tonically active during movements of the trunk and gait, whereas SM and ES are phasically active, (iv) that DM and the transversus abdominis (TrA) co-contract during function, and (v) that changes in the lumbar paraspinal muscles associated with LBP affect DM more than SM or ES. This paper reviews the biomechanical, electromyographic, histochemical and morphological data that underpin these beliefs. Although there is support for the importance of the lumbar multifidus and the specific contribution of this muscle to intervertebral control, several of the clinical beliefs have little or no support and require further evaluation. These findings have implications for clinical practice.

Adolescent↗