Internal Tendon Research Articles

Cell populations of tendon: A simplified method for isolation of synovial cells and internal fibroblasts: Confirmation of origin and biologic properties

Tendons transmit the force of muscle contraction to bone to effect limb movement. Special structural and biological properties of tendon have developed to facilitate force transmission. The tendon has a complex organization of cells surrounding the collagen bundles inside tendon as well as at the tendon surface. Internal cells may act to maintain the bulk of the collagen in tendon. External cells in the epitenon may provide lubrication for tendon gliding. To develop better understanding of these processes and the roles the cell populations play, we isolated cells from the surface and interior of tendon and studied them in vitro. Flexor tendons from 8-week-old white Leghorn chickens were separated into two distinct cell populations: the outer synovial cells and the fibroblasts more internal in tendon. These cell populations were discernible by their locations in the intact tendon, determined by sequential enzymatic and physical release from their substrata. Initially, some cells eluted in Hanks' salt solution (HSS) (population 1); then synovial cells were released after a 2-min treatment with 0.5% collagenase (population 2). Next, a population of synovial cells was released in high yield by treatment with 0.25% trypsin (step III, population 3). Step III, population 3 cells were used as synovial cells (SCs). Next, a population of SCs and fibroblasts were released by scraping with a rubber policeman (population 4). Subsequently, fibroblasts were released after incubation with 0.5% collagenase (population 5). A more direct procedure (procedure 2) to isolate the synovial and internal tendon cells involved treatment in 0.5% collagenase followed by sedimentation at 900 g. Cells that sedimented were largely fibroblasts, whereas the cells that remained at the top of the tube were largely SCs. Cells designated as SCs, isolated by procedure 2, most likely contained surface cells from epitenon and internal interfascicular cells from endotenon and paratenon. Surface tendon cells separated by sequential enzymatic and physical release from their substrata (by procedure 1) had all the following characteristics: distinct subpopulations of cells based on morphology; presence of cytoplasmic, lipid-containing vesicles; decreased sensitivity to trypsin; and reduced generation time as compared with that of internal fibroblasts. Conversely, the internal fibroblasts (IFs) appeared to represent a more uniform population based on morphological characteristics.

Anatomical and electromyographic studies of the lateral pterygoid muscle.

The relationships of the lateral pterygoid muscle within the infratemporal fossa were observed by conventional dissections and by examination of specimens sectioned in the horizontal and frontal planes. The following less well-known features were noted. At the origins of the superior and inferior heads there are regions in which the fibres are interlaced or closely overlapped by fibres of either the temporalis muscle or the medial pterygoid muscle. Fibres of the superior head insert not only into the meniscus of the temporomandibular joint, but also into the pterygoid fovea at the neck of the mandibular condyle. Specimens sectioned through the origin of the inferior head of the muscle show internal tendon lamellae consistent with a pennate structure. Electromyographic (EMG) activity was recorded in five healthy subjects using concentric needle and fine-wire electrodes. Strong to very strong activity was consistently observed in the superior head during clenching and tooth gnashing. The inferior heads were silent or had negligible to slight activity most of the time during ipsilateral movements or clenching, but were co-activated bilaterally, with strong to very strong activity during jaw opening, protrusion, swallowing, tooth gnashing and during passive retrusion. They showed marked activity unilaterally during contralateral movements.

前腕重度損傷の骨折治療経験

Ten cases of severely injured open fractures of the forearm were treated in our clinic. In six of them, internal fixation using intramedullary nail was undertaken. In two, plate, and in further two, a combination of plate and intramedulary nail was used. Internal fixation and tendon and nerve repair was performed primarily. Skin coverage was delayed. After removal of fixators, refractures occured in the group using a combination of plate and intramedullary nail. One nonunion was observed in the plate fixation group. In all but one case, solid union was obtained. We had no experience of deep infection in this series.

Morphological basis of the feeding mechanics in the shingle-back lizard Trachydosaurus rugosus (Scincidae, Reptilia).

This report details certain morphological aspects of the feeding system of the lizard Trachydosaurus rugosus, an opportunistic omnivore, as a first step toward a functional characterization of its masticatory system. The skull is relatively solid and internally well braced; its anterodorsal elements are tightly tied to the integument and covering osteoderms. There is potential for intracranial kinesis and streptostyly. At small gapes, mandibular movements seem to be restricted to relatively simple, hingelike actions by a series of mechanical stops. The dentition features a progression of smaller to larger teeth posteriorly along the tooth row. The jaw adductor musculature is massive; other jaw muscles are relatively simple. The external adductor mass is particularly noteworthy in that it is subdivided into four mechanical units by a complex internal tendon tract (the coronoid aponeurosis). The internal adductor is composed of two separate gross muscles, pseudotemporalis (PST) and pterygoideus (PT). Each of these is subdivided into two main units by aponeurotic sheets, the PST by parts of the coronoid aponeurosis and the PT by a separate series. The form of the aponeurotic system in Trachydosaurus confounds the separation and identification of the adductor muscles and their component parts along the lines of traditional nomenclature, and underscores the need for separating criteria based on homology from those reflecting morphological and possibly functional divisions.

II. On the epipubis in the dog and fox

In 1871 I gave a brief description of a structure which I had observed in the dog, in the following terms:— “In the myology of the dog, the insertion of the tendon of the external oblique muscle of the abdomen presents some interesting peculiarities. The outer and posterior fibres of this muscle end in a fascia, which is partly continued over the thigh as fascia lata , and partly forms an arch (Poupart’s ligament) over the femoral vessels; by its inner end it is inserted into the outer side of a triangular fibro-cartilage, the broad base of which is attached to the anterior margin of the pubis, between its spine and the symphysis, while its apex lies in the abdominal parietes. The internal tendon of the external oblique unites with the tendon of the internal oblique to form the inner pillar of the abdominal ring, and is inserted into the inner side of the triangular fibro-cartilage. The pectineus is attached to the ventral face of the cartilage; the outer part of the tendon of the rectus into its dorsal face; but the chief part of that tendon is inserted into the pubis behind it. This fibro-cartilage appears to represent the marsupial bone, or cartilage, of the Monotremes and Marsupials.” The only reference to this statement which I have met with is by Professor Macalister, in his “Introduction to the Systematic Zoology and the Morphology of Vertebrate Animals” (1878), p. 265:— “Professor Huxley describes a fibro-cartilaginous 'marsupial’ above the pubis, from whose anterior surface the pectineus arises. I have failed to satisfy myself of its existence as a constant structure in many dogs, in the common and Bengal foxes, in the dingo, jackal, Canis pallipes , and wolf.”