Volkmann's Canals Research Articles

Healing of burns of the skull: a histological study

A histological study of burns of the calvarium is reported with reference to depth of necrosis, pyogenic infection and, especially, repair processes. It is based on 14 specimens from 9 subjects—biopsies in 6 cases and necropsy specimens in the 3 others. They ranged from 6 days to 12 months after the accident, most being between 4 and 15 weeks. Necrosis in some extended through the full thickness of the skull (full-thickness necrosis), but deep parts had remained viable in others (partial-thickness necrosis). Necrosis seems largely ischaemic in origin, through heat destruction of the epicranial blood supply. Pyogenic infection of necrotic bone was common, invading through the outer table, and was usually clinically silent. It could be restricted to the outer table or extend deep into the diploë, and certain specimens showed gross histological infection of the whole thickness of the skull. One was a sequestrum. Repair seems slow in onset and is prolonged. The earliest evidence of healing was in a specimen at 4 weeks after burning. Healing proceeded from viable soft tissue within the calvarial plate after partial-thickness necrosis and from the dural membrane after both partial-thickness and full-thickness necrosis. In the former mode, fibrovascular proliferation and invasion within diploëic spaces is associated with appositional seams of new bone on old trabeculae, but much new spongy bone had also formed in the diploë in one case. Osteoclastic resorption was common. Healing from the dura is manifest as fibrovascular invasion of the diploë via Volkmann's canals and sometimes also by new bone deposition on the surface of the inner table. Healing from the periphery into the necrotic centre was studied in one case and was very limited. The question of progressive creeping substitution of necrotic bone by new bone is discussed with reference to possible final replacement by a new calvarial plate. For this, early skin closure of the burn is likely to be required to prevent or reduce pyogenic bone infection.

Tissue fluid movement in compact bone.

AbstractThorotrast (colloidal thorium dioxide) was released into tibial marrow cavities of 12 adult cats and into the tibial nutrient arteries of ten adult cats. Following regular intervals the tibiae were removed, fixed, decalcified in formic acid, and prepared histologically.The label indicated the general tissue fluid drainage of the tibia is in the perivascular connective tissue of Volkmann's canals from the marrow cavity to the periosteal lymphatic vessels.The tissue fluid flow appears to pass from the Haversian vessel through the canalicular‐lacunar complex to the peripheral lacunae of the osteone. Its path from this point has not been observed.

The Role of the Diaphyseal Medulla in the Repair and Regeneration of the Femoral Shaft in the Adult Cat

1. A surgical procedure is described which permits selective removal of the medulla froms the diaphysis of the cat femur and the study of the role of marrow elements in bone regenerations and repair. 2. In this experimental model, endosteal-callus formation, in the presence of marrow, precedes and exceeds periosteal-callus formation in the healing of a partial osteotomy without displacement. Cartilage was formed infrequently in the reactive bone callus and only after severing of the fibrous portions of the periosteum. 3. After removal of the medulla, residual narrow elements in the distal and proximal metaphyses and in the surviving endosteum of the Haversian and Volkmann canals appeared to initiate the repair processes which led to complete reconstitution of the medulla. The sequence of events during bone repair repeated the phases of embryonic membranous-bone development. The restorations of the medulla and its contributions to bone healing emphasize the importance of its role osteogenesis. 4. The disruption of the nutrient vessels during removal of the diaphyseal medulla was followed by reorganizations of the greater portions of the cortex of the diaphysis associated with marked though transient periosteal new-bone formation. The response elicited resembled that seen in hypertrophic pulmonary osteoarthropathy. As healing progressed the periosteal new bone was partly resorbed and partly reintegrated into the remodeled cortex of the diaphysis. 5. The experimental offers opportunities for the study of bone inductions and for the testing of substances which might enhance or delay bone repair.

Observations on the innervation of human long bones

AbstractThe innervation of some of the long bones of the extremities of the human was studied by methylene blue immersion. Small myelinated and amyelinated nerve fibers enter the numerous foramina of the epiphyseal and metaphyseal regions of long bones, traverse the thin cortex, and supply the interior of the bone. Small myelinated fibers wind about the trabeculae of the spongiosa or spread out on the undersurface of the articular cartilage. Small knob‐like terminations end in close relationship to the endosteum.Other myelinated nerve fibers have branched free fiber endings associated with the walls of intertrabecular marrow arterioles. Amyelinated nerve fibers are usually associated with vascular walls but may also be associated with the connective tissue of the intertrabecular fat or marrow.Numerous myelinated and amyelinated nerve fibers traverse the nutrient foramen and supply the bone marrow and endosteum of the shaft of the bone.While the Volkmann's canals of the shaft receive nerve fibers from the overlying periosteum, the disposition of these fibers in the shaft of the bone has not been determined.No nerve fibers or endings were ever seen between the lamellae in any location.No function can yet be attributed to any particular type of nerve fiber or nerve ending.

The effect of ionizing irradiation on the developing maxilla and mandible

The mechanism of the medium-voltage x-ray effect on bone is apparently as follows: On contacting bone, much of the primary beam is converted to photoelectrons which are especially concentrated in the first 5 mm. of bone. The range of these electrons is short, about 50 to 100 microns. This does not permit extensive travel in calcified bone. However, the lacunae containing osteocytes are about 25 to 50 microns long, 6 to 14 microns wide, and 4 to 9 microns thick. Consequently, the photoelectrons easily traverse this distance, rebounding off the walls of the lacuna and ionizing the cellular elements within. Likewise, irradiation developing on the inner wall of a Haversian canal may readily cross its 22 to 110 microns, affecting the vessels and tissue within. Larger areas, such as the marrow cavity, are not greatly affected by short-range “scatter” from the wall. Since the osteocyte does not undergo mitosis, death of the cell with evacuation of the lacuna is the usual effect of its ionization. Devitalized bone must be resorbed and replaced by living tissue. These processes are ordinarily accomplished by (1) the cellular elements from the periosteum, either on the external surface of the bone or within the Haversian canals, or (2) by the endosteum. It was previously believed that irradiation had its initial effect on the blood vessels within the Haversian canal and that damage to the vessel wall was accompanied by thrombosis. The bone died as a result of this altered blood supply. According to recent observations, 11 the primary damage is to the osteocyte. The blood vessels respond more slowly, with a thickening of the walls of arteries and arterioles. The decreased nutritional supply is a factor during long survival periods when the osteocytes which have been injured but not destroyed are attempting to recover. However, the damage to the osteocyte is often so severe that its death is rapid and nutritional factors are a secondary concern. The periosteum within the Haversian and Volkmann canals is also readily affected by rebound across these structures. Severe injury or death of these cellular elements of the periosteum will seriously delay healing of the irradiated area. Apparently this was the situation which developed in the case reported here. There was an appreciable layering effect on the surface of the cortex, so that the back scatter contributed to the skin damage. The deeper-penetrating x-rays of the low-voltage therapy produced enough internal rebound to cause cessation of root growth in the irradiated area as well as alteration of the growth potential of the developing maxilla and mandible. Unquestionably, in the case reported here the patient received an excessive x-ray dosage (3,500 r) as far as growth was concerned but only moderate dosage from the aspect of skin irradiation. In the jaws, where bone is interposed between the soft tissues of the cheek and the pharynx, the maximum medium-voltage x-ray radiation of bone should not exceed 35 per cent of the skin dosage that is tolerated elsewhere. The precise quantity of irradiation which stops tooth development or alters growth of the maxilla or mandible is still unknown. However, it appears to lie somewhere between 800 r and 1,500 r, depending upon the age and physical characteristics of the individual patient.

An infiltration and clearing technic to reveal the vascular pattern of ethylenediamine-treated cortical bone.

The vascular canals of cortical bone are revealed by: (1) removing all organic tissue with ethylenediamine (ed), (2) infiltrating the Haversian and Volkmann canals with a pigment and (3) finally clearing the specimens in styrene. Buccal and lingual cortical plates of mandibles were freed of spongy bone and placed in a Soxhlet extractor. Extraction was carried out with a solution consisting of 4 volumes of ed and 1 volume of distilled water which was maintained at a temperature of 118°C for 24 hr. After extraction, the organic-free specimens were washed in water for 1 hr and dried. The dried bone was immersed in a 25% India ink suspension and placed in a vacuum chamber until bubbling ceased. The bones were then dried and the surface carbon was removed with a CO2-driven stream of dolomite powder from an Airdent unit. Compressed air was used to remove the residual dolomite powder from the specimens. They were then immersed in styrene until clear. The specimens could be studied directly from the styrene, since the inorganic portion of the bone became transparent and carbon retained on the walls of the vascular channels within the calcified tissue was clearly visible. Plastic can be substituted for styrene for infiltrating the spaces within the specimen which were previously occupied by organic material. After infiltration and curing of the plastic, the embedded specimens can be decalcified with concentrated HCl. After decalcification, the voids created by the removal of the inorganic matrix can then be filled with plastic. Substituting plastic for areas previously occupied by both the organic and inorganic elements results in an easily visualized, carbon-black three-dimensional preparation of the vascular pattern of bone.

Radiation effects on bone.

Several recent articles (3–7) have again called attention to the importance of radiation effects upon growing and adult bone. Whereas it was formerly thought that adult bone is one of the most radioresistant of normal tissues, it is now recognized that it is the soft-tissue components of the bone, such as the terminal blood vessels of the haversian and Volkmann's canals, which may be particularly affected by hyperemia and later by obliterative endarteritis. Another reason for the interest in this subject is the present tendency toward the use of higher and higher voltages for therapy, with delivery of increasing amounts of radiation to the deeper tissues. In spite of the fact that there is less differential absorption by bone from these higher voltages, nevertheless fractures have occurred following such irradiation just as with conventional cross-fire therapy, regardless of whether or not lateral pelvic portals were used. It should be remembered that the blood supply to the femoral head and neck comes fr...

Detailed roentgenologic examination of the blood supply in the jaws and teeth by applying radiopaque solutions

The following can be stated as a short summary of my observations. Around the crowns of developing teeth there is a vessel ring which, in the course of development, is transformed into an interdental meshwork. Obviously, the branch entering through the apex into the pulp is derived from this meshwork. The extraosseous blood supply of the mandible is provided by a branch of the masseteric artery, which is given off at the base of the coronoid process. This branch is almost invariably present. The coronoid process of the collum is provided by small branches of the internal maxillary artery. The anastomoses between these osseous branches and the mental artery are visible on the films also. Besides the extraosseous vessels, also branches of the external maxillary artery pass to the inner aspect of the angle of the mandible. The outer surface of the angle is supplied by the transverse facial artery or, occasionally, by direct branches of the external carotid. The part of the mandible corresponding to the trigonum retromandibulare is likely to receive blood from the mylohyoid branch. These accessory vessels cannot be demonstrated in all cases or all ages. It is their very presence and their developmental degree by which the ultimate construction of the jaws is determined. From a clinical point of view, the varieties derived from these types of blood supply are of importance. These factors may account for the fact that in a case of osteomyelitis of the mandible the lesion undoubtedly is associated with the main intraosseous artery. The mandibular branch medial to the sequestrum does not undergo necrosis, and trophic disorders do not invariably ensue in the teeth medial to the site of osteomyelitis. A decisive role in such cases is also played by the mental artery which, through its anastomoses with the arteries enumerated, is capable of securing the blood supply of the affected section of the mandible. Circulation is different in the cortex and the spongiosa. In the spongiosa the vessels pass between the trabeculae at about equal distances. In the cortex the vessels follow the Haversian bone meshwork and Volkmann's canal system. They are connected with the periosteum and the bone marrow alike. The arteries are everywhere accompanied by veins. Essentially, the blood supply of the jaws has two sources. Large or small vessels perforate the cortex and divide in the bone marrow. These vessels provide the spongiosa and the marrow. The other group furnishes blood chiefly to the cortex. They are derived from periosteal arteries and enter the bone substance as arterioles or prearterioles through the opening of Volkmann's canals facing the periosteum. This double blood supply is not separated, as the collaterals form anastomoses between them. The distribution of the two arterial systems within the bone depends on the bone structure. Particular importance is to be attributed to the ratio of the cortex to the spongiosa, the size of the marrow spaces, and the increased blood supply of the articular processes (Weinmann and Sicher 5).