James M. Morris

Role of the Trunk in Stability of the Spine

There is a great discrepancy between the force that can theoretically be applied to the spine if the role of intracavitary pressures is ignored and the force that can be tolerated experimentally by the isolated ligamentous human spine.In estimating that a force of approximately 2,071 pounds is impos

Biomechanics of the foot and ankle.

The human foot evolved to provide: (1) mechanisms to limit the excursion of the center of mass during ambulation and thereby minimize the expenditure of energy; (2) a base of support of sufficien dimensions for the stability necessary to maintain the upright position without excessive muscular activity; (3) mechanisms for flexibility to absorb the shock of the body weight and for accommodation to uneven terrain; (4) rigidity of the foot when it acts as a lever in the push-off period of stance.

Fatigue Fracture of the Femoral Neck

Forty-one fatigue fractures of the femoral neck in thirty-six patients are presented and analyzed. All occurred in men undergoing the first eight weeks of basic infantry training (with an average age of twenty-two and one-half years). The right hip was involved in eighteen patients and the left in thirteen; five had bilateral fractures. No definite relationship could be established between occurrence of fractures and length of training. Pain and stiffness in the hip region were almost always present and had lasted from one day to four weeks (generally five to ten days) prior to entry into the hospital. In those cases in which displacement occurred, there was sudden, severe pain with collapse and, generally, inability to bear weight. Most patients were found to have a limp or antalgic gait, limitation of hip motion (especially internal rotation and flexion) due to pain, and tenderness over the hip joint. Roentgenograms of sixteen femoral necks, obtained on admission of the patients to the hospital, were normal. In this group, selerosis was demonstrated one to four weeks after onset of symptoms in fourteen cases, and in three Patients fractures developed across the neck; two of these three fractures later became displaced. Sclerosis was present on admission in eleven femoral necks; in one of these a fracture line developed in three weeks. In six, there was a small calcar crack or fracture line across the neck, without displacement, and there were seven cases of displaced fracture demonstrated roentgenographically on admission. Treatment for Type I (twenty-four fractures) was conservative, consisting in bed rest followed by progressive weight-hearing. For Type II (eight fractures), treatment was also generally conservative but did include plaster immobilization and, in one case, internal fixation. In Type III (nine fractures), internal fixation was employed. In this group complications were frequent and consisted of malunion, nonunion, and avascular necrosis; in fact, in only two of these fractures did union occur initially. This course of events is attributed to poor reduction and to the nature of the fracture, which occurs in markedly osteoporotic bone. Average hospitalization of patients with Type I fractures was nine and one-half weeks; of those with Type II fractures, twelve weeks; and of those with Type III fractures, fifty-nine weeks. The term fatigue fracture may be misleading in that frequently no overt fracture line is seen. Fatigue (or stress) fracture is actually a process, an alteration of hone resulting from stress. A fracture may or may not develop, and if it does it can be considered as a complication of the stress reaction. (For simplicity, the term fatigue fracture is used throughout this paper, with the above reservation.) It seems reasonable to assume that the occurrence of fatigue fractures is not confined to military life. The overweight white-collar worker who goes on a strenuous fishing or hunting trip or starts on a program of vigorous exercise may well incur a fatigue fracture. The teenage athlete who pushes himself to the maximum at the start of the season and the less athletically inclined student who strives to do well in a physical fitness program are both prime candidates for these fractures. Unless the physician is sufficiently aware of the possibility that a fatigue fracture may have occurred, serial roentgenograms are not made and such a fracture remains undiagnosed. Generally, this is not a serious consequence with fatigue fractures of the foot or leg unless they are mistakenly treated as neoplasms. However, if those in the femoral neck are overlooked or misdiagnosed, serious sequelae, as previously illustrated, may result.

MELORHEOSTOSIS. REVIEW OF THE LITERATURE AND REPORT OF AN INTERESTING CASE WITH A NINETEEN-YEAR FOLLOW-UP.

1. A case of melorheostosis with a nineteen-year follow-up, showing marked progression of the disease process, is reported. 2. Review of the literature reveals 131 cases of melorheostosis, the characteristics of which are defined. 3. Pathological specimens from two biopsies, eighteen years apart, suggested a progression from vasculitis to vascular obliteration with fatty and mucoid degeneration and muscle atrophy. Also seen was metaplastic cartilage formation within the mesenchymal tissue with cartilage degeneration and calcification which progressed to ossification. In the later specimens intramembranous-bone formation was noted. The etiology of this vascular damage remains unknown.

An In Vivo Study of Axial Rotation and Immobilization at the Lumbosacral Joint

The amount of rotation at the lumbosacral joint was studied in nine healthy young men by placement of pins into the spinous process of the fifth lumbar vertebra and into the posterior superior iliac spines of the pelvis. In this sample, approximately 6.0 degrees of rotation were found to occur at th

Lumbar spinal fusion. Assessment of functional stability with magnetic resonance imaging.

Segmental spinal instability was evaluated with magnetic resonance (MR) imaging, computed tomography (CT), and conventional radiography in 33 patients who had undergone surgical spinal fusion. In 16 of the 19 patients who had a diagnosis of solid fusion, the immobilized vertebral bodies demonstrated areas of high signal intensity on images with short repetition time (TR) and echo time (TE). The signal intensity of these areas was either less intense or normal on images with long TR and TE. In 10 of the 14 patients with segmental instability at the fusion site, subchondral vertebral bands of low signal intensity were shown on short TR/TE images, which demonstrated high signal intensity on long TR/TE images. All but two of the patients showed vertebral signal changes 12 or more months past fusion or onset of clinical symptoms. The vertebral MR signal intensity in solid lumbar fusions might be related to marrow composition changes resulting from decreased biomechanical stress, while the vertebral signal intensities in patients with unstable fusions might be related to reparative granulation tissue, inflammation, edema, and hyperemic changes. Magnetic resonance imaging appears to be unique in its assessment of functional fusion stability. Magnetic resonance may be most useful in patients symptomatic of fusion pseudarthrosis in whom conventional radiography and CT fail to demonstrate anatomic disruption.

Translational motion of the head and trunk during normal walking

Abstract Translational motion at different levels of the head and trunk in normal human subjects was measured in three dimensions at different walking speeds. Both acceleration and displacement were directly recorded in two separate experiments. Characteristic patterns of motion were observed and are related to the basic mechanics of human locomotion.

Fatigue fracture of the femoral shaft.

Thirty-eight fatigue fractures of the femoral shaft in thirty-five patients are reported on and analyzed. All but one occurred in young men undergoing the first eight weeks of basic military training. The other case was that of a seventeen-year-old youth, who was training for track. The right femoral shaft was involved in thirty fractures and the left in eight; three patients had bilateral fractures. Sixteen fractures were displaced and twenty-two were undisplaced. The most frequently encountered symptom was pain in the knee or thigh with activity. Even when the fatigue reaction or fracture was located in the upper part of the femur, symptoms were often referred to the knee. The most important aspect of treatment is early recognition in order to prevent displacement. For accurate diagnosis, an awareness of the possibility of such a fracture and complete roentgenograms of the femur are essential in patients in whom such a fracture is suspected and who complain of knee pain. Results of treatment have been satisfactory in both the displaced and undisplaced fractures. In undisplaced fractures, curtailment of physical activity by means of bed rest or use of crutches is necessary, depending on the severity of symptoms and roentgenographic appearance. Skeletal traction generally is adequate for treatment of displaced fractures, but, on occasion, open reduction and internal fixation may be employed, depending on the amount of comminution and degree of displacement.

Three-dimensional computed tomography and multiplanar reformations in the assessment of pseudarthrosis in posterior lumbar fusion patients

Three-dimensional (3-D) surface reconstructions and multiplanar computed tomography (CT) reformations were obtained in 30 patients with clinically suspected spinal fusion pseudarthrosis. The imaging studies were blind-reviewed and the results were compared with the clinical and surgical findings. Sagittal, planar, and curved coronal two-dimensional (2-D) reformations were more useful in the detection of bony nonunion than were axial CT scans, as the latter required more extensive analysis. Three-dimensional surface “cuts” adequately demonstrated pseudarthrosis in most cases. In some instances, however, segmentation artifacts created artifactual clefts or implied solidity, which contrasted with the interpretation of the 2-D Images. Sagittal 3-D cuts were helpful in demonstrating bony central and lateral stenosis. Three-dimensional surface reconstructions demonstrated superficial clefts and outlined the complex anatomy of the spinal fusions, thus facilitating pre- and intraoperative planning. The amount of bone stock available for pseudarthrosis repair at the fusion site and the need for additional harvesting of bone from the iliac crest also could be assessed easily. 3-D CT proved to be useful as an adjunctive imaging method in the evaluation of posterior lumbar fusion patients suspected of pseudarthrosis.

Surgical Improvement of the Cerebral-palsied Upper Limb: Electromyographic Studies And Results Of 128 Operations

Experience with 128 operations on the upper limbs of forty patients with cerebral palsy at Sonoma State Hospital is discussed in terms of preoperative evaluation and prerequisites for operations, electromyographic findings and their clinical applications, specific surgical measures employed and their indications, and preliminary assessment of results, which will require re-evaluation in ten years or more to determine the true results.