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Biomedical subjects

P Posel

Publications and source records attributed to P Posel.

15 recordsLinked to original sources

Investigations on mechanism of Salter-1-fractures of the greater trochanter.

This study aims at clarifying why the apophysis of the greater trochanter very rarely separates, in contrast to other apophyses of the hip region. The inclination and area measurement of the greater trochanteric growth plate and the mode of insertion of the muscles on the apophysis were analyzed on the basis of 16 anatomic femoral specimens from newborn to children of 14 years of age. The physiological muscle cross section Q of the muscles inserting at the greater trochanter was determined on 6 specimens. In a cross-sectional radiological study, carried out on 1350 hip joints of healthy children, the inclination of the greater trochanter growth plate was measured. The anatomical and radiological findings show that the nearly plane-shaped greater trochanter growth plate remains inclined at a 50 degree angle to the horizontal body line and is loaded from a diagonally craniolateral direction throughout the total growth period. The lateral surface of the apophysis is covered by a fibrous connection which joins the insertion areas of the gluteus medius, minimus and vastus lateralis muscles. The vastus lateralis muscle is intimately bound to the vastus intermedius muscle by fibrous tissue. According to the results of the physiological muscle cross sections these four muscle groups can form a counteracting muscle sling, which transforms the traction forces at the surface of the greater trochanter into pressure forces in line with a tension band effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

The transgluteal approaches to the hip.

The transgluteal approach to the hip, first described by Bauer et al. in 1979, has since become a recognized routine method. Its longitudinal incision of the fibers of the gluteus medius and minimus and the vastus lateralis muscles takes advantage of the tendinous junction of these muscles over the greater trochanter. This paper describes the modifications of the transgluteal approach described in the literature and compares them to the original procedure. In 52 hip specimens, including attached muscles, the insertions and different variations of the junction of the gluteus medius, minimus and vastus lateralis muscles over the greater trochanter are described and statistically analysed. In 59.6% of all specimens there proved to be a united tendinous junction of all the muscles referred to above, while in 40.4% autonomous insertions of the gluteus medius and/or gluteus minimus were seen. In accordance with the anatomical results, the form of incision described by the original authors can be considered the most favourable. In roughly one-third of all hip operations, autonomous insertions of gluteus medius and minimus must be taken into account, since otherwise total or partial upward displacement of the autonomous muscle insertions could occur.

Adult↗

[Implantation technique of tumor and crutch prostheses].

Using anatomic specimens from 58 fixed femurs, we analyzed the point of insertion and junctional variations of the gluteus medius, minimus and vastus lateralis over the greater trochanter. On six specimens the physiological muscle cross-section Q was determined for the muscles inserting at the greater trochanter. The results showed that the gluteus medius and minimus, as well as the vastus lateralis generally insert at the lateral and ventral surfaces of the greater trochanter. In 59.6% of all cases these muscles form a joint tendon junction. In 21.1% the gluteus medius inserts autonomously and with 13.5% the gluteus minimus inserts independently. In 5.8% of all specimens all three muscles insert autonomously. The average physiological muscle cross-section of the gluteus medius and minimus added up to 37.83 cm2 and that of the vastus lateralis and the fibrously connected vastus intermedius came to 36.14 cm2. Accordingly the extensor muscles of the knee, together with the counteracting gluteus medius und minimus, form a muscle sling that puts a pressure load on the greater trochanter from the lateral cranial direction. An operating technique for the implantation of tumor prostheses using this muscle sling is introduced. Hereby the greater trochanter and inserted musculature remain intact and are placed hoodlike on the implanted tumor prosthesis. Postoperatively, the procedure results in good muscle function with early exercise tolerance.

Adult↗

[Anatomic markers of the thorax and mediastinum].

A basic Survey of thoracic gross anatomy is given. The particular importance of the spacial relationship of the organs (Thymus, esophagus, heart, lungs), the tubular systems (vessels, bronchi) and their variations is stressed. The lymphatic pathways of the lungs and their surroundings are analyzed. Selected axial cuts illustrate the topographic peculiarities of mediastinum and pleural spaces.

Humans↗

[Tarsal tunnel syndrome. Nerve compression syndrome in the foot].

Pathological changes in sensation over the sole of the foot do not always correspond to the full area of distribution of the posterior tibial nerve. Some neurologists advise separate examination of the tibial nerve, the medial and lateral plantar nerves, in order to ascertain whether either or both might be affected. 60 preparations of cadaveric feet in the Department of Anatomy were examined. Using a measuring grid, the position and size of the nerves in the tarsal tunnel were assessed and the facial band which define and divide the osteofibrous canal delineated. The corners of the measuring grid were the tip of the medial malleolus (A), the tip of the calcaneal tubercle at its greatest distance from the medial malleolus (B) and the tuberosity of the navicular bone (C). These points can also be clearly identified clinically. They define a triangle whose sides A-B and B-C are of constant equal length and whose base A-C varies little. The operative approach includes a T-shaped incision of the retinaculum. The vertical line of the T lies underneath the skin incision. The horizontal line corresponds with the upper border of the abductor hallucis muscle. The upper border of the abductor hallucis is defined and the muscle retracted medially to expose the deep fascia. This layer is removed together with the connective tissue bridge which stretches between the fascia and the calcaneus. The plantar nerves are discovered and run to the sole of the foot without further obstruction.

Diagnosis, Differential↗

Histochemistry of mucosubstances in Brunner's-gland cells and duodenal goblet cells of two New World monkey species (Saimiri sciureus and Saguinus fuscicollis).

Duodenal goblet cells and Brunner's-gland cells obtained from two species of New World monkeys (Saimiri sciureus and Saguinus fuscicollis) were studied using conventional histochemical methods and by applying a panel of 17 labelled lectins. The secretions of both goblet and Brunner's-gland cells were found to contain neutral mucosubstances, while those of goblet cells also exhibit acid and sulphated carbohydrate components. Lectin binding studies allowed a more detailed analysis of the mucus glycoproteins. Marked differences between the two examined species were not detected. N-Acetyl-galactosamine, galactose, fucose and N-Acetyl-glucosamine were found to be the predominant sugar residues in Brunner's-glands glycoproteins, with mannose and glucose being only minor components.

Animals↗

[Sutureless anastomoses in the rat, rabbit and pig].

Healing of intestinal anastomoses was found to be effective in rat, rabbit and pig even after temporary approximation by sutures for one hour. Approximation of bowel segments was achieved by interrupted inverting sutures. After one hour a fibrinous connection of inverted serosa segments was to be observed. Bursting pressure was determined on the 1st, 3rd and 7th postoperative day. There was no significant difference between sutureless and regular anastomoses. Determination of breaking strength of approximated anastomoses one hour and twenty-four hours after removal of sutures was found to be 0.19 N and 0.8 N, respectively. Extent of adhesions was similar in conventional and sutureless anastomoses. Histologic analyses revealed areas of necrosis in sutured anastomoses, whereas in sutureless anastomoses no necrosis could be detected.

Anastomosis, Surgical↗

The proximal and distal tarsal tunnel syndromes. An anatomical study.

Clinical and electromyographic studies in the tarsal tunnel syndrome may suggest compression of only one of the two terminal branches of the posterior tibial nerve. This anatomical study demonstrates the structures which may cause isolated damage to either the medial plantar or the lateral plantar nerves. A surgical approach to the tarsal tunnel is described.

Ankle Joint↗

Distal femoral fixation of the iliotibial tract.

The anatomy of the distal femoral fixation of the iliotibial tract was studied in 100 knee joints. A fiber bundle system with three main parts was isolated: (a) the supracondylar bundle oriented from proximal-lateral to distal-medial and fixed to the supracondylar area of the femur; (b) the fibers near to the septum with transverse course between superficial tract and dorsolateral femur; (c) the retrograde tracts which connect Gerdy's tubercle with the dorsolateral femur and form an arc bridging the knee joint. Distance measurements over the range of motion of the knee joint revealed isometric conditions only for the insertion point on the dorsolateral femur. The retrograde fibers are believed to be static stabilizers of the lateral side of the knee, and their insertion point on the dorsolateral femur is the correct site for refixation or reefing of the distal iliotibial tract.

Femur↗

[Tarsal tunnel syndrome].

The natural history, diagnosis, and therapy of tarsal tunnel syndrome are given. Anatomical studies corresponding to the clinical picture and electrodiagnostic findings show two different narrow points in tarsal tunnel. Operative treatment should take into account the compression of the posterior tibial nerve by the flexor retinaculum and also of the plantar nerves under the abductor hallucis.

Ankle↗

[Magnetic resonance tomography of the kidneys: comparison with anatomic correlates].

Specimens of human kidneys (n = 24) were investigated using magnetic resonance imaging (MRI), and compared with the corresponding cross-sections that had been prepared later from the same kidneys. The tomographs reveal detailed informations of renal fine structure. In particular, parenchyma and sinus can be easily differentiated from vasculature. It is possible to visualize vessel arborization, including the arcuate vessels of the renal cortex. The clinical significance of renal MR tomographs is discussed.

Aged↗

[Age-related force distribution at the proximal end of the femur in normally growing children].

In a group of normally developed children and adolescents the age dependent distribution of forces at the proximal end of the femur was to be described. The results should explain why the shape of the proximal end of the femur changes significantly during the time of growth and why the neck shaft angle decreases. The method applied was the biomechanical computation analyzing in the coronal plane according to Pauwels' biomechanical hip model. The necessary age relevant data was derived from 675 anteroposterior pelvis radiographs of healthy children of both sexes and of varying age. The following can be put down as a result: 1. The proximal end of the femur is stressed by two resultant forces: the hip resultant force R controls the growth of the capital growth plate, the trochanteric resultant force RT regulates the growth of the greater trochanter growth plate. 2. During the growing period the hip resultant force R adjusts itself less vertically: during the second year of life it inclines at an average of 11,6 degrees towards the vertical, towards the end of the growing period it is incident with an inclination angle of 20 degrees. With the older child the magnitude of the hip resultant force R decreases in relation to the exerting body weight. 3. During the time of growth the trochanteric resultant force RT maintains its direction stability with inclination angles of 50-52 degrees towards the vertical. Its magnitude increases significantly (in relation to the exerting body weight). 4. From age 2 to 10 the projected neck shaft angle decreases from an average of 148.2 degrees to 133.7 degrees and usually remains stable. It can be concluded that the shape of the proximal end of the femur is determined by the muscle forces stimulating the greater trochanter apophysis and by gravity. With increasing age the growth of the greater trochanter apophysis shifts the insertions of abductor muscles laterally. As a result the directions of the hip abductors and the hip resultant force R incline. The neck shaft angle decreases consecutively.

Adolescent↗

[Biomechanics of the hip joint in children].

Based on the data derived from the examination of 16 infantile and juvenile anatomical hip specimens as well as the radiological examination of 1350 hip joints of healthy children, a biomechanical model of the developing hip was computed. This two-dimensional vector model describes the forces acting on the growth plates of the head and the greater trochanter during the one-legged stance. It could be proven that the apophysis of the greater trochanter is subject to compressive stress by lateral-cranial traction bands and therefore corresponds with a "pressure apophysis". The muscle forces acting on the trochanter apophysis can be combined as a trochanteric resultant RT. This stimulates a lateral-cranial growth of the trochanter apophysis. The direction of the hip abductors and, as a result, also the direction and the length of Pauwels' hip resultant R are influenced by this mechanism.

Adolescent↗

Forces acting on the juvenile hip joint in the one-legged stance.

A two-dimensional biomechanical model of the juvenile hip joint was developed to describe the forces acting on the capital epiphysis and the greater trochanter apophysis in the one-legged stance. Based on anatomic femur specimens of 16 children, ranging from toddlers to teenagers, and radiographic studies of 1,350 hip joints of healthy children, we showed that the apophysis of the greater trochanter is a pressure apophysis. If the muscular forces acting on the apophysis of the greater trochanter are added, the unit sum may be considered a resultant force acting from a craniolateral direction. The trochanteric resultant force near the end of the growth period is equivalent to approximately 1.7 times body weight. The trochanteric resultant force stimulates craniolateral growth of the greater trochanteric apophysis. This mechanism is responsible for the direction of the forces exerted by the hip abductors and thus the direction and magnitude of Pauwels' hip-joint resultant, and finally influences the neck-shaft angle.

Adolescent↗