Biomedical subjects

M Müller-Gerbl

Publications and source records attributed to M Müller-Gerbl.

At least 19 recordsLinked to original sources

PubMed2005

A prospective morphological study of facet joint integrity following intervertebral disc replacement with the CHARITE Artificial Disc.

In degenerative disc disease (DDD), increased loading in the posterior column increases facet joint subchondral bone density and may lead to facet joint degeneration. While spinal fusion is commonly used to treat patients with symptomatic DDD, increased stress at the levels adjacent to fusion may accelerate facet joint and adjacent segment degeneration. Artificial disc replacements have been developed as an alternative to fusion. In this prospective study, the effects of disc replacement with the CHARITE Artificial Disc on facet joint loading and integrity were evaluated. Thirteen patients aged <50 years with symptomatic DDD were recruited. Computed tomography (CT) osteoabsorptiometry was performed prior to the implantation of the CHARITE Artificial Disc and six months after. With this technique, increases or decreases in facet joint loading and integrity are indicated by corresponding changes in subchondral bone density. Changes in the distribution of load alter the distribution of the areas of maximum bone density. Clinical outcome was also assessed at pre-operative and 6 and 12 month post-operative visits using the Visual Analogue Scale back and leg pain scores, the Oswestry Disability Index and the Short Form-36 (SF-36) questionnaire. The height of the intervertebral space at the operated level was monitored by lateral X-ray. Subchondral bone density was evaluated in the facet joints of all 13 patients at the operated level, 12 patients at the level above the operated segment, and five patients at the level below the operated segment. Quantitative measurements revealed no significant increases (> or =3%) in subchondral bone density of the facet joints at any level in any patient. Significant decreases (> or =3%) in subchondral bone density were measured at the operated level in 10/13 patients, at the level above the operated segment in 6/12 patients, and at the level below the operated segment in 3/5 patients. There were no changes in the distribution of the areas of maximum bone density in any of the studied facet joints at 6 months compared with pre-operative measurements. Clinical outcome scores were improved at 6 and 12 months compared with baseline. The mean intervertebral space height at the operated level was increased following implantation of the CHARITE Artificial Disc and was 1.8 times greater than the pre-operative height at both 6 and 12 months. In this study, replacement of degenerated intervertebral discs with the CHARITE Artificial Disc was not associated with increased loading of the facet joints at the operated or adjacent levels. Decreases in subchondral bone density may indicate reduced loading in the posterior column following disc replacement compared with loading in the pre-operative degenerated spine. Further study is required to establish the baseline for healthy subchondral bone density and to compare this baseline with long-term measurements in patients undergoing disc replacement.

Adult↗

PubMed2004

Quantitative assessment of periarticular osteopenia in patients with early rheumatoid arthritis: a preliminary report.

BACKGROUND: Involvement of the metacarpophalangeal (MP) joints is one of the major problems in patients with rheumatoid arthritis (RA). Although several data about the cumulative influence of steroid intake on bone are available, the course of demineralisation in RA has not been described by quantitative methods until now. PATIENTS AND METHODS: Computed tomography (CT) sections of 96 MP joints in 12 RA patients and of 32 MP joints in four age-matched healthy controls were investigated. Patients were classified according to Steinbrocker. Densitometric evaluation of subchondral bone density was performed by CT osteoabsorptiometry (CT-OAM). Quantitative CT-OAM was used to evaluate mineralisation of the articular surfaces in MP joints. RESULTS: In the distal articular surface of MP joints, the number of density maxima was reduced from 3 to 2.1+/-0.3, 1.9+/-0.5 and 1.3+/-0.3 in RA patients with early, mild to moderate, and severe disease, respectively. Means of calcium concentrations were 633.4+/-35. 3 mg Ca2+/mL, 518.9+/-56.2 mg Ca2+/mL, 497.7+/-23.8 mg Ca2+/mL and 455.1+/-28.6 mg Ca2+/mL for controls and RA patients with early, mild to moderate, and severe RA, respectively. Mineralisation of the distal articular surface was significantly reduced in all groups of RA patients [probability (p) = 0.005]. Regarding the number of density maxima, no differences were detected in the proximal articular surface of normal and RA fingers. However, mineralisation of the proximal articular surface was significantly reduced in all groups of RA patients (p = 0.004). Means of calcium concentrations of the proximal articular surface were 494.1+/-48.5 mg Ca2+/mL, 413.0+/-16.2 mg Ca2+/mL, 406.0+/-51.4 mg Ca2+/mL, 390,4+/-41.1 mg Ca2+/mL for controls and RA patients with early, mild to moderate, and severe RA, respectively. CONCLUSION: Patients with early and untreated RA show loss of mineralisation and altered morphology of the MP joints of the hand, even before corticosteroid therapy. CT-OAM provides evidence for an early alteration of functional anatomy in MP joints.

Adult↗

PubMed2003

[Functional CT imaging: Load-dependent visualization of the subchondral mineralization by means of CT osteoabsorptiometry (CT-OAM)].

PURPOSE: Functional computed tomography for visualization and quantification of subchondral bone mineralization using CT osteoabsorptiometry (CT-OAM). MATERIALS AND METHODS: Tarsometatarsal (TMT) and metatarsophalangeal (MTP) joints of 46 human hallux valgus (HV) specimens were examined (sagittal 1/1/1 mm) on a single slice CT scanner SCT (Somatom Plus 4, Siemens AG). Subchondral bone pixels were segmented and assigned to 10 density value groups (Delta 100 HU, range 200 - 1200 HU) the pixels using volume rendering technique (VRT). The data analysis considered the severity of HV as determined by the radiographically measured HV-angle (a. p. projection). RESULTS: CT-OAM could generate reproducible densitograms of the distribution pattern of the subchondral bone density for all four joint surfaces (TMT and MTP joints). The bone density localization enables the assignment to different groups, showing a characteristic HV-angle-dependent distribution of the maximum bone mineralization of the load-dependent densitogram (p < 0.001). CONCLUSION: CT-OAM is a functional CT technique for visualizing and quantifying the distribution of the subchondral bone density, enabling a noninvasive load-dependent assessment of the joint surfaces. Load-dependent densitograms of hallux valgus specimens show a characteristic correlation with an increase of the HV-angle.

Absorptiometry, Photon↗

PubMed2002

Subchondral mineralization patterns of the glenoid after tear of the supraspinatus.

Clinical experience has shown that in many cases of rupture of the supraspinatus tendon the head of the humerus shifts upward against the acromion. This implicates alterations in the stress acting on the joint surface. Accordingly, this should be reflected by changes in the distribution of the subchondral mineralization on the glenoid. Computed tomography osteoabsorptiometry was used to evaluate the distribution patterns on the subchondral bone plate of the glenoid in 67 human shoulders. The position of the two most frequent density maxima was determined by a standard procedure. In macroscopically normal specimens (n = 24) every case had an anterosuperior density maximum and the majority (75%) also had a posterior positioned maximum. In some instances a third maximum, placed centrally (17%) or in an anteroinferior position (4%) was seen. In shoulders with a torn supraspinatus tendon (n = 43) a third density maximum frequently appeared in the center of the glenoid (42%); however, most notable was a significant change of the posterior maximum position toward central and superior. With increasing size of the tendon defect an extension of the shift of the posterior maximum (superiorly and centrally) was observed in contrast to the constant anterior maximum. The changes in the distribution of glenoid subchondral bone mineralization in shoulders with a supraspinatus tear must be regarded as a morphologic parameter for the altered long-term stress acting on the joint surface.

Aged↗

PubMed2001

[Anatomy and biomechanics of the upper ankle joint].

The ankle joint as a component within the construction of the foot must be seen as a compromise between the static and dynamic demands made upon it. In this article the structure and function of the ankle joint are described with special reference to the formation of morphological parameters such as the distribution of subchondral mineralization, cartilage thickness, subarticular cancellous bone and mechanical properties. These parameters could be seen as a biological reflection of the individual mechanical conditions.

Ankle Joint↗

PubMed1999

Quantitative determination of joint incongruity and pressure distribution during simulated gait and cartilage thickness in the human hip joint.

The objective of this study was to provide quantitative data on hip-joint incongruity and pressure during a simulated walking cycle and on articular-cartilage thickness in the same set of specimens. Using a casting technique in eight specimens of the human hip (age: 18-75 years), we determined the width of the joint space (incongruity) required at minimal load for contact at four phases of the gait cycle. The pressure distribution, measured with pressure-sensitive film, was determined at physiologic load magnitudes on the basis of in vivo measurements of hip-joint forces. Cartilage thickness was assessed with A-mode ultrasound. At minimal loading, the average maximum width of the joint space ranged from 1.1 to 1.5 mm in the acetabular roof, with the contact areas located ventro-superiorly and dorso-inferiorly throughout the gait cycle. At physiological loading, the width decreased and the contact areas covered the complete articular surface during midstance and heel-off but not during heel-strike or toe-off. The pressure distribution was inhomogeneous during all phases, with average maximum pressures of 7.7 +/- 1.95 MPa at midstance. The cartilage thickness varied considerably throughout the joint surfaces; maxima greater than 3 mm were found ventro-superiorly. These data can be used to generate and validate computer models to determine the load-sharing between the interstitial fluid and the solid proteoglycan-collagen matrix of articular cartilage, the latter being relevant for the initiation of mechanically induced cartilage degeneration.

Adolescent↗

PubMed1999

[Quantitative determination of pressure distribution in the hip joint during the gait cycle].

The objective of this investigation was the experimental determination of the contact pressures in the hip joint for characteristic phases of the gait cycle. The joint forces determined in vivo with telemetric endoprosthesis by Bergmann et al. (1993) were converted into a pelvic reference system, based on kinematic gait analysis. In eight cadaveric hip joints (age 18-75 yrs.) the reaction forces were applied corresponding to four phases of the gait cycle (heel strike, mid-stance, heel off, toe off) and the pressure distribution determined with FUJI pressure sensitive film. We found maxima of 10 MPa during mid stance. The areas of highest pressure were located in the ventro-superior aspect of the acetabulum (anterior part of the acetabular roof) and in the dorso-inferior aspect of the lunate surface. The pressure distribution was relatively constant during the four phases and the maxima did not vary proportional to the applied load. The normal pressure distribution in the hip appears to be determined by the physiological incongruity of the articular surfaces and the inhomogeneous bony support of the acetabulum. During operative interventions this normal load transfer should be restored as accurately as possible.

Adolescent↗

PubMed1999

Patterns of subchondral bone mineralization in the wrist after midcarpal fusion.

Midcarpal fusion represents a salvage procedure in cases of advanced carpal collapse, which unloads the scaphoid compartment and redirects the load to the intact lunate compartment of the radiocarpal joint. The aim of this study was to obtain further information about the loading conditions in the living subject by evaluating the pattern of subchondral bone mineralization in patients who have undergone midcarpal fusion of the wrist. Between 4 and 42 months after the surgery, 9 male patients were examined by means of computed tomographic osteoabsorptiometry. All of them showed peak mineralization in the lunate fossa of the radius. Six patients had only one large density maximum in this fossa and no corresponding maximum in the scaphoid fossa. In accordance with our expectations, loading after midcarpal fusion was found to be transmitted mainly through the lunate compartment, a result that was observed even after as little as 4 months, and that thus confirmed subchondral bone mineralization as a valuable parameter for assessment of long-term stress distribution.

Absorptiometry, Photon↗

PubMed1999

[Morphological aspects of load bearing of the wrist joint after midcarpal partial arthrodesis].

Midcarpal fusion is a reliable treatment for advanced carpal collapse following scaphoid nonunion or scapholunate dissociation. It remains, however, unclear if the alignment of the fused carpal bones influences the redirection of load towards the lunate. The objective of this study was to assess the actual loading conditions after midcarpal fusion in patients by evaluating the patterns of subchondral bone mineralization in the distal articular surface of the radius. Nine patients, who were treated by midcarpal fusion with complete excision of the scaphoid, were examined after an average of 22 months postoperatively by means of CT osteoabsorptiometry. All patients showed peak mineralization in the lunate fossa of the distal articular surface of the radius. Six patients with correct carpal alignment had one large density maximum in the lunate fossa and none in the scaphoid fossa. Patients with incomplete correction of the radial translocation of the capitate, incomplete excision of the scaphoid, or incomplete correction of the extension position of the lunate, showed a second density maximum in the scaphoid fossa. These findings emphasize that a correct carpal alignment is necessary to achieve a complete unloading of the degeneratively altered scaphoid fossa.

Absorptiometry, Photon↗

PubMed1998

The subchondral bone plate.

Pauwels (1965) and subsequent workers in the same field have shown that the distribution of the subchondral density within a joint surface can serve as a parametric measurement which reflects the main stress acting on a joint. Our own investigations on anatomical specimens have demonstrated that this subchondral mineralization does indeed show regular distribution patterns from which conclusions about the mechanical situation within an individual joint may be drawn. Since radiographical densitometry and histological methods are only available for determining the adaptive reaction of the bone to the particular mechanical situation in a joint after death, the information obtained applies only to an end situation and tells us nothing about the development of the changes with time. Furthermore, investigations carried out on human specimens by radiographical densitometry mostly apply to samples of a particular age, since such specimens can be acquired only from departments of pathology, forensic medicine or anatomy. The functional reactions of the bone tissue to repeated long-term changes in the loading--lengthy immobilization and subsequent remobilization, for instance, or heavy loading over a considerable period of time--cannot be followed by any ordinary method in experimental animals, since the death of the animal is a prerequisite for the precise quantitative examination of the bone tissue. This applies also to attempts to follow the process by means of animal experiments. CT OAM has been developed as a method which, based on CT, can provide a surface representation of the 3-D density distribution in the joints of living subjects. Comparative studies were carried out to establish and confirm the validity of the procedure. These have shown (1) that the results obtained from anatomical specimens are identical with those obtained in the living; (2) that secondary CT sections are suitable for evaluation and that the spectrum of joint surfaces examined can be extended to include the whole joint (if this were not so, effects caused by the apparatus--particularly the partial-volume effect--would render the procedure impossible); and finally (3) that the distribution of the Hounsfield density within the subchondral bone represents the distribution of the mineralization. The mineralization patterns found by us in different joints of normal subjects have shown that these patterns can be brought into line with current models of joint mechanics. The radiocarpal joint, for instance, has revealed the various types of loading occurring within physiological limits. Information has also been obtained about the age-related changes taking place in the hip, wrist and ankle joints. The increase of the total mineralization in gymnasts can be related to the qualitative and quantitative adaptation to an increased peak loading, and reduced mineralization to a lengthy reduction in use during, for instance, postoperative immobilization. In groups of patients with various diseases of mechanical origin (shoulder instability, malalignment of the main axis, defective repositioning of healed fractures, rupture of the rotator cuff, meniscectomy or rupture of the anterior cruciate ligament), a pattern of mineralization is found which is different from the normal picture. These findings reflect the abnormal mechanical situation. The mineralization pattern of the femoropatellar joint has revealed the differing etiologies of medial and lateral cartilage damage and the examination of patients with lunatomalacia has made it possible to recognize a genetic disposition. The postoperative comparison of the mineralization patterns of patients with genu varum who have undergone a correction osteotomy and the results of animal experiments on various procedures for reconstructing the anterior cruciate ligament or a primary replacement of the meniscus, have produced results which make it possible to judge the success or failure of the operation. (ABSTRACT TRUNCATED)

Calcification, Physiologic↗

PubMed1998

[Stress on the wrist joint in semilunar bone necrosis--a morphologic study in vivo].

The distribution of subchondral mineralization of the distal articular surface of the radius was examined by CT osteoabsorptiometry in both wrists of twelve patients showing different stages of Kienböck's disease. The pattern of density distribution had already been demonstrated in previous studies to be an adequate parameter for assessing axial loading across the wrist joint in the patients. Contrary to the anticipated presence of predominant stress in the lunate compartment, some patients showed identical stress in the compartment of the scaphoid, and the balanced loading of both compartments, as before. Even when in early stages of the disease the lunate type of mineralization appeared more often, it was still not possible to demonstrate general excessive stress on the lunate. We have therefore concluded that the main stress in the scaphoid compartment might be a secondary effect, which is to be regarded as the expression of the advancing destruction of the lunate and consequent loss of load transmission through this compartment. This hypothesis is also supported by the fact that, in progressive stages of Kienböck's disease, the density maximum in the fovea lunata, generally present in healthy people, is absent. Furthermore, in patients with necrosis of the lunate, the total mineralization in terms of the maximal density values in the distal joint surface of the radius is in the majority of cases less than in the normal subject. In two cases, even the density maximum was absent from the fovea lunata of the contralateral wrist joint, without there being any clinical signs suggesting a possible lunate necrosis on this side. We interpret these pathological changes in the unaffected wrist joint as a further indication that we are dealing with a congenital predisposition which affects both wrist joints.

Absorptiometry, Photon↗

PubMed1997

[Acromio-humeral distance and acromial shape in 3-dimensional computerized tomography reconstruction. Side comparison in supraspinatus outlet syndrome].

Mechanical irritations of the supraspinatus tendon due to a reduction of the subacromial space are considered to be a potential cause of supraspinatus outlet syndrome. The aim of the current study was, therefore, to provide a method of improved measurement of the acromiohumeral distance and the evaluation of the acromial shape. In seven patients aged 50-60 years with unilateral supraspinatus outlet syndrome, imaging with standardized, high-resolution computed tomography (CT) was performed in order to demonstrate the acromion and the subacromial space three-dimensionally. The acromiohumeral distance was measured in three reconstructed frontal sections, and the two sides of each patient were directly compared. The acromial shape was compared with the classification of Bigliani as derived from conventional radiography. Whereas the Constant Score was found to be significantly reduced in the diseased shoulders (p < 0.01), the acromiohumeral distance was not significantly lower in three standardized frontal sections. In five cases the classification of the acromial form from the conventional radiograph was confirmed by 3D CT, whereas in two cases it was shown to be different. Our results suggest that primary or secondary changes of the acromial form can be more accurately evaluated with 3D CT than with conventional radiography. A direct comparison of the two sides in patients with supraspinatus syndrome does not suggest a reduction of acromiohumeral distance in the diseased shoulder.

Female↗

PubMed1997

Determination of subacromial space width and inferior acromial mineralization by 3D CT. Preliminary data from patients with unilateral supraspinatus outlet syndrome.

A reduction of the subacromial space and an increased subacromial pressure have been considered to play an important role in the pathogenesis of rotator cuff lesions. The objective of the current study was to develop a CT based method for measuring the acromiohumeral distance and inferior acromial mineralization. In seven patients with unilateral rupture of the rotator cuff and two with impingement syndrome, transverse CT images were obtained at a section thickness of 1 mm with muscular relaxation in a standardized position. The bones were then reconstructed three-dimensionally, and the minimal vertical distance between the acromion and the humerus was determined in three secondary frontal images on both sides. The distribution of mineralization within the inferior surface of the acromion was assessed using CT osteoabsorptiometry. Although the Constant score was significantly reduced in the diseased shoulders, the width of the subacromial space was not routinely lower than on the contralateral side. In seven cases the maximal inferior acromial mineralization was identical in both shoulders, and in two cases it was lower on the affected side. These preliminary data suggest that with muscular relaxation no narrowing of the subacromial space can be detected in secondary frontal CT images, and that a potential increase of subacromial pressure is not high enough to cause a measurable increase in inferior acromial bone density. The method presented makes it possible to investigate the pathogenesis of the supraspinatus outlet syndrome in vivo with greater precision than has so far been possible with conventional radiography.

Acromion↗

PubMed1997

Direct comparison of contact areas, contact stress and subchondral mineralization in human hip joint specimens.

X-ray densitometric and CT osteoabsorptiometric findings suggest that in the human hip subchondral mineralization patterns change from bicentric to monocentric as a function of age. It has been hypothesized that these changes indicate an alteration in the geometric configuration of the joint from incongruous to congruous, possibly associated with the onset of osteoarthrosis. The purpose of this study was therefore to directly compare contact rates, contact stress and subchondral mineralization in the hip joint. Twelve specimens without cartilage lesions (ages 34-86 years) were investigated. Simulating the mid-stance phase, the contact areas were determined by polyether casting and the contact stress with Fuji film. The distribution of subchondral mineralization was assessed non-invasively with CT osteoabsorptiometry. At small loads the load-bearing areas were located at the periphery of the lunate surface. In some joints they were found in the acetabular roof and expanded, with higher loads, to the center of the lunate surface and the anterior and posterior horns. In other joints, the contact areas were recorded at lower loads in the anterior and posterior horns, and only at higher forces they merged in the acetabular roof. The maximal contact stress ranged from 8 t 9 MPa at 300% body weight. Maxima of subchondral mineralization were recorded in the acetabular roof, in the anterior and posterior horns, or in all three locations. There was no clear correlation between the distribution of contact and pressure, and the pattern of subchondral bone density. Incongruity is shown to strongly affect the distribution of contact and pressure in the human hip joint. However, the pattern of subchondral mineralization cannot be readily explained in terms of the contact areas and contact stress during mid-stance. Incongruity may give rise to tensile stresses in the subchondral bone, and the construction of the pelvis as a whole may play an important role in subchondral bone loss loads and adaptation.

Adult↗

PubMed1997

Altered patterns of subchondral bone mineralization in Kienböck's disease.

The pattern of subchondral bone density, which is supposed to reflect the long-term distribution of stress, was investigated in both wrist joints of nine healthy young subjects and seven patients suffering from Kienböck's disease by means of CT osteoabsorptiometry. Two density maxima were found on the distal articular surface of the radius in the healthy subjects, corresponding to the position of the scaphoid and the lunate. Our relative quantitative results showed three different physiological types of stress indicated by the predominantly monocentric density maxima either on the scaphoid or the lunate surface of the radius and the symmetrical distribution of the mineralization. In Kienböck's disease no type of mineralization predominated. In the progressive stages the lunate density maximum was absent. The overall mineralization was generally less than in controls. Changes in the pattern of mineralization were also found on the contralateral side.

Adult↗

PubMed1997

Quantitative analysis of incongruity, contact areas and cartilage thickness in the human hip joint.

Joint incongruity and cartilage thickness have been shown to determine the contact stresses and the load partitioning between the solid and fluid phases of articular cartilage. Matrix stresses, which are relevant in the development of osteoarthrosis, can, however, not be determined experimentally but must be calculated using numerical methods. The aim of the present study was to quantify the incongruity and cartilage thickness of the human hip, in order to allow for the construction of morphologically accurate finite element models. Twelve cadaveric specimens (34-86 years), two fresh and ten fixed, were investigated. The loading configuration was based on in vivo measurements of hip joint forces during midstance. The incongruity and contact areas were determined using a polyether casting technique, in the minimally and the fully loaded state. The cartilage thickness was measured at identical coordinate points with an A-mode ultrasonic system. Generally, the contact started at lower loads at the edge of the lunate surface, and the joint space increased towards its central aspects. In some specimens the contact started in the acetabular roof, leaving a joint space of up to 2 mm in the horns of the lunate surface. In others, the initial contact was observed in the anterior and posterior horns of the lunate surface with a joint space width of up to 0.75 mm in the acetabular roof. The size of the contact areas increased from about 20% of the lunate surface to 98% at higher loads. The articular cartilage thickness ranged from 0.7 to 3.6 mm, the maxima being located in the ventral aspects of the femoral head and acetabulum. These quantitative data on joint space width, contact, and cartilage thickness in the human hip joint may be used to construct and validate finite element models which are required to elucidate the mechanical factors involved in osteoarthrosis.

Adult↗

PubMed1997

[Stress on the radiocarpal joint. CT studies of subchondral bone density in vivo].

Most concepts about the mechanism of load transmission through the radiocarpal joint have been mostly acquired from the study of cadaveric specimens. Apart from this, however, it is possible to derive direct knowledge about the actual mechanical conditions of a joint from certain morphological parameters, particularly by analysis of the subchondral mineralization. CT-osteoabsorptiometry (CT-OAM) has provided a non-invasive investigative tool by which the distribution of subchondral mineralization within the radiocarpal joint can be determined. Seventeen wrist-joints in healthy young subjects were investigated by means of CT-OAM, and the results evaluated both topographically and quantitatively. In most cases, two density maxima were found on the articular radial surface, one corresponding to the scaphoid and one to the lunate. These matched the positions of pressure peaks described in reports of research on mechanical models. The density maximum on the articular surface of the radius opposing the scaphoid is, however, rather more dorsally placed, whereas that opposing the lunate lies palmar to the radioulnar midline. This explains the transmission of force to the forearm and the geometrical configuration of the joint components. On the other hand, our quantitative results do not confirm the existence of a generally greater degree of mineralization of either one of the joint compartments. We cannot confirm theories attributing transmission of the main force through either the scaphoid or the lunate. We assume rather that the type of stress indicated by the predominantly monocentric density maxima either on the scaphoid or the lunate surface of the radius, together with the equally balanced bicentric degree of mineralization, are to be regarded as physiological.

Absorptiometry, Photon↗

PubMed1996

The vertebral column--a phylogenetic failure? A theory explaining the function and vulnerability of the human spine.

The increase in degenerative diseases of the vertebral column is often attributed to an inadequate adaptation to the upright posture in the human. On the basis of a precise analysis of the motion segments, an attempt has here been made to demonstrate that the design of the vertebrae in both the larger mammals and in humans has resulted in no qualitative differences between the stresses to which either is subjected. In the course of evolution there has certainly been an obvious conflict in aims between the need for essential stability and the desired or necessary mobility. These mutually self-limiting mechanisms are reflected in the highly specialized architecture of the ligamentous apparatus and vertebral joints. We conclude that the human vertebral column seems to be an optimized compromise of evolution.

Animals↗