Topic:Navicular Bone
The navicular bone is a small, boat-shaped bone located in the hoof of a horse, specifically situated behind the coffin bone and beneath the deep digital flexor tendon. It plays a role in the biomechanics of the equine foot by acting as a fulcrum for the deep digital flexor tendon, aiding in the horse's movement and weight distribution. The navicular bone is part of the navicular apparatus, which includes surrounding ligaments and the bursa, a fluid-filled sac that reduces friction. Issues with the navicular bone and associated structures can lead to a condition known as navicular syndrome, which is characterized by lameness and pain in the front feet. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, function, and pathophysiology of the navicular bone, as well as diagnostic and treatment options for navicular-related conditions in horses.
[Scanning electron microscopy of the synovial membrane of the distal phalangeal joint and the navicular bursa in horses]. 20 extremities of horses were used to investigate the synovial membrane of the distal interphalangeal joint and the navicular bursa. From each extremity five specimens were taken from the distal interphalangeal joint capsule, two further from the navicular bursa. Synovial villi were found near the articular cartilage as well as everywhere where the joint capsule did not form a tight periostal cover or was not connected with ligaments or tendons. Some lay between the articular surfaces of the phalanx media and phalanx distalis. Besides synovial villi and synovial folds "trabecular-like" cords o...
Use of autogenous cancellous bone grafting in the treatment of septic navicular bursitis and distal sesamoid osteomyelitis in horses. Six horses with septic navicular bursitis or distal sesamoid osteomyelitis were treated by means of surgical debridement and lavage, followed by packing of the wound created in the bottom of the foot with an autogenous cancellous bone graft. Two horses were euthanatized, one 18 months after surgery because of complications in the contralateral support limb, and one 68 days after surgery because of continuing severe lameness. Four horses were alive 9, 16, 21, and 42 months after surgery. One horse was used as a broodmare and did not have observable lameness. Two horses were being ridden. The re...
[Radiologic follow-up examination of podotrochlosis]. X-rays of 205 horses having navicular disease and having been reexamined up to six times are evaluated. For this, the x-rays of each foreleg are evaluated in the dorsopalmar (Oxspring) and lateromedial view. Additionally to changes of the navicular bone, changes of the distal part of the toe are also assessed. Differences can be found in the radiographic process in view of the limitation of vascular foramina and cyst-like lesions. Vascular foramina with sclerotic rim grow less frequent than poorly defined ones and therefore allow for easier prognostication. Cyst-like lesions with sclerotic rim...
Sensory innervation of the navicular bone and bursa in the foal. The sensory innervation of the navicular bone (os sesamoideum distale) and its suspensory ligaments [ligamenta sesamoidea collateralia (CSL) and ligamentum sesamoideum distale impar or distal sesamoidean impar (DS-impar) ligament] and the navicular bursa (podotrochlearis) was examined in the neonatal foal using immunocytochemistry. With antisera raised to substance P (SP) and human calcitonin gene-related peptide (CGRP), immunoreactive nerves were demonstrated to innervate the CSL and navicular bursa. Within CSL, and SP- and CGRP-like nerves were present in the synovial lining of the navicular...
Bilateral hind limb hypoplasia in a foal. Hypoplasia affecting both hind limbs was observed in a neonatal foal. Scintigraphy aided in establishing diagnosis and prognosis. Radiography revealed an abnormally shaped middle phalanx and lack of the distal phalanx and navicular bone in the right hind limb, with an abnormally shaped distal phalanx and navicular bone in the left hind limb. Scintigraphic findings were closely correlated with the radiographic findings. Radiographic and scintigraphic findings were confirmed at postmortem examination.
A silver-impregnation and immunocytochemical study of innervation of the distal sesamoid bone and its suspensory ligaments in the horse. The innervation of the navicular bone (os sesamoideum distale) and its suspensory ligaments (ligamenta sesamoidea collateralia) (CSL) or proximal suspensory ligament and the ligamentum sesamoideum distale impar or the distal sesamoidean impar ligament (DS-impar ligament) was examined using combined anatomical techniques of silver impregnation and immunocytochemistry. Silver impregnation studies revealed an abundance of nerve fibres present in both the CSL and DS-impar ligament with the latter having relatively more nerve fibres. These silver-impregnated nerves coursed parallel to and were asso...
Immunocytochemical and dye distribution studies of nerves potentially desensitized by injections into the distal interphalangeal joint or the navicular bursa of horses. To determine whether the distal interphalangeal (DIP) joint directly or indirectly communicates with the navicular bursa (bursa podotrochlearis) and to identify sensory nerves in these synovial structures that might be desensitized by intra-articular injections of anesthetics, Evans blue dye in physiologic saline solution, Luxol fast blue dye with mepivicaine, or commercial latex was injected into the DIP joint (5 ml) or the navicular bursa (3 ml) of 152 digits obtained from horses or ponies at necropsy. The digits were frozen, cut with a band saw, and examined for distribution of dye or latex...
Treatment and pathogenesis of navicular disease (‘syndrome’) in horses. The future directions of navicular disease research are unclear. Often researchers investigate only one of the multitude of factors likely to be important in understanding the disease. Two exceptions to this is work done by Wright in this issue of EVJ and by MacGregor (1988) who compared a number of the treatment regimens (e.g. rest, warfarin, isoxsuprine, shoeing with egg bars) and found that approximately 75% of the horses improved in their performance. Perhaps this percentage of 'recovered' horses from this disease is what can be realistically expected, as often horses with navicular diseas...
A study of 118 cases of navicular disease: clinical features. The clinical features are reported from 118 horses (mean age 9.2 years) which were diagnosed as suffering from navicular disease using predetermined criteria. The animals were used for a variety of purposes and had been lame for periods between 1 and 72 months. The majority of cases (84.7%) had been treated using various techniques before evaluation. The severity of lameness was related to the duration of clinical signs: 78% of horses were bilaterally affected but there was no left:right limb predominance. Broken foot/pastern axes were recorded in 75% of horses while 45% also exhibited mediola...
A study of 118 cases of navicular disease: treatment by navicular suspensory desmotomy. The 118 horses diagnosed as suffering from navicular disease by prospective criteria were treated by desmotomy of the ligamenta sesamoidea collateralia (navicular suspensory desmotomy). Three techniques were used and a standard post-operative programme was followed with clinical and radiological evaluations at 6-monthly intervals for periods of 6-36 months after surgery. At 6 and 36 months after treatment, 76% and 42.9% of horses were sound respectively. The clinical features of age, period of lameness, severity of lameness and angular limb deformities adversely affected response to surgery. T...
A study of 118 cases of navicular disease: radiological features. Dorsoproximal-palmarodistal oblique, lateromedial and palmaroproximal-palmarodistal oblique radiographic projections were used with standard techniques to examine 118 horses with clinical signs of navicular disease. All radiological features which have previously been reported as significant changes in the navicular bones of horses with navicular disease were recorded. Comparisons were made between these features in lame limbs and sound limbs in unilaterally lame horses and most lame limbs and least lame limbs in bilateral but asymmetrically lame animals. Their relationship to the degree of la...
Biomechanical considerations in the treatment of navicular disease. In recent years much attention has been paid to vascular studies of the navicular bone in health and disease; however, the relative importance of these studies has overshadowed biomechanical factors which may yet prove to be of importance. This paper outlines the pertinent anatomy, and discusses current concepts in the aetiology and pathogenesis of the disease. It describes the treatment regimens which are based on biomechanical considerations and compares the results of some currently employed techniques. All aspects of navicular disease remain controversial. This paper is not intended to rev...
Intermittent antimicrobial infusion for management of a septic distal interphalangeal joint in a horse. A 13-month-old Quarter Horse colt sustained a puncture wound to the frog region of the foot, which penetrated the navicular bursa and distal interphalangeal joint, 7 days prior to examination. A street-nail procedure was performed to debride the tract and provide drainage of the navicular bursa and distal interphalangeal joint. An indwelling lavage system was placed through the dorsal aspect of the joint and antimicrobials were infused intermittently to supply a high local concentration of drug and to frequently lavage the distal interphalangeal joint and navicular bursa.
A comparison of responses to analgesia of the navicular bursa and intra-articular analgesia of the distal interphalangeal joint in 59 horses. Analgesia of the distal interphalangeal (DIP) joint and of the navicular bursa was performed independently in the lame or lamer forelimb of 59 horses, in which lameness was significantly improved by perineural analgesia of either the palmar digital or palmar (abaxial sesamoid) nerves. In 3 horses no improvement was detected. Lameness was improved by analgesia of the DIP joint but there was no response to analgesia of the navicular bursa in 3 horses. In 12 horses, lameness was improved by analgesia of the navicular bursa but intra-articular analgesia resulted in no change. Forty-one horses resp...
Intraosseous pressure and pathologic changes in horses with navicular disease. Navicular bone intraosseous pressure, gross pathologic, histologic, and histochemical data were collected from 8 horses with navicular disease and 4 control horses. Simultaneous navicular bone intraosseous, medial palmar arterial, and saphenous venous pressures were measured for the left and right forelimbs of each horse under general anesthesia. Gross pathologic evaluation included grading of changes on the flexor surface of the navicular bone. Safranin-O-fast green-stained sections were used for histologic-histochemical grading of the hyaline articular and fibrocartilage surfaces of the navi...
The effect of CO2 laser neurectomy on neuroma formation and axonal regeneration. In an attempt to prevent neuroma formation and digital reinnervation after sharp palmar digital neurectomy in 10 adult horses with navicular disease, 18,426 W/cm2 of CO2 laser energy was applied to the proximal nerve stump. Clinical follow-up was 4 to 23 months. In two horses, palmar digital nerve biopsies were taken at month 4 (four nerves) and month 7 (two nerves). Nine horses were sound immediately and at all follow-up examinations. None had clinical evidence of painful neuroma or digital reinnervation. Histologically, there was minimal scar tissue at the surgical site; axonal sprouts were ...
Radiographic/morphologic investigation of a radiolucent crescent within the flexor central eminence of the navicular bone in thoroughbreds. The source of a previously described radiolucent crescent in the flexor cortex of the distal sesamoid (navicular) bone on the palmaro45 degrees proximal-palmarodistal oblique (Pa45 degrees Pr-PaDio) clinical radiographic projection was investigated in 48 forelimb navicular bones from 24 Thoroughbreds by use of high-detail radiography and x-ray computed tomography (CT). Twenty-five of these bones also were evaluated, using microradiography and histologic examinations. Of these 25 bones, 5 had been labeled in vivo with fluorochrome markers. Tetrachrome-stained 100-microns-thick nondecalcified se...
Arthroscopic approach and intra-articular anatomy of the palmaroproximal or plantaroproximal aspect of distal interphalangeal joints. An arthroscopic approach to the palmaroproximal or plantaroproximal pouch of the distal interphalangeal joint was developed in six cadaver limbs and seven limbs of three clinically normal horses. The dorsal aspect of the proximal border and the proximal articular margin of the distal sesamoid (navicular) bone, the palmar aspect of the distal articular margin of the middle phalanx, the collateral sesamoidean ligaments of the distal sesamoid bone, and the joint capsule attachments were readily accessible. Distending the joints with fluid gave access to portions of the articular surface between t...
[Scanning electron microscopic findings of the navicular bone and deep flexor tendon in podotrochlosis of horses]. In 25 adult horses the podotrochlea of 49 forelimbs was examined by means of light and electron microscopy in order to correlate clinical and morphological findings. According to the clinical diagnosis the animals were divided into three groups: lameness due to syndrome of podotrochlosis (group 1) or due to tendopathy (group 2) and horses without lameness (group 3). The most striking pathological findings of the navicular bone and the opposite surface of the deep flexor tendon were found in horses with podotrochlosis, consisting of loss of cartilage and tendon matrix with denudation of collage...
Ankylosis of the distal interphalangeal joint in a horse after septic arthritis and septic navicular bursitis. A 6-month-old 300-kg Quarter Horse filly was treated for septic arthritis of the distal interphalangeal joint and septic navicular bursitis that developed as a result of a deep puncture to the foot. Initial treatment consisted of establishing ventral drainage for the navicular bursa, lavage of the distal interphalangeal joint, and administration of broad-spectrum antimicrobial drugs and non-steroidal anti-inflammatory drugs. Because of continuing sepsis in the distal interphalangeal joint, subsequent treatment included packing the defect in the bottom of the foot with cancellous bone in an att...
Lameness due to pain associated with the distal interphalangeal joint: 45 cases. This paper describes the clinical and radiographic features, and response to treatment, of 45 horses which showed lameness that was improved by intra-articular anaesthesia of the distal interphalangeal (DIP) joint. Although many horses had poor conformation of the foot of the lame limb, the majority showed no localising clinical signs suggestive of involvement of the DIP joint. Lameness was usually unilateral. No horse with bilateral lameness responded to treatment. Palmar digital nerve blocks frequently improved or alleviated lameness, although in some horses palmar (abaxial sesamoid) nerve b...
Soft tissue- and bone-phase scintigraphy for diagnosis of navicular disease in horses. Radiography and soft tissue- and bone-phase scintigraphy were performed on 14 clinically normal horses and 35 horses in which definite, probable, or possible navicular disease had been diagnosed. The specificity of radiography and scintigraphy in revealing signs of navicular disease were nearly equal; however, the sensitivity of scintigraphy appeared to be greater than that of radiography. The greatest sensitivity and specificity were achieved when the results of radiography and scintigraphy were evaluated together. Differences in sensitivity were greatest when scintigraphy revealed lesions no...
[Chronic disease of the two sesamoid bones of the lower foot of the horse]. The aetiology and pathogenesis of navicular bone disease and sesamoidosis are discussed on the basis of findings reported in the literature and research. A marked similarity is found to be present between the clinical presentation, aetiology and pathogenesis of these two diseases. In addition, the intra and juxta-articular signs of degeneration as seen in these diseases are similar to those seen in various forms of arthrosis. Circulatory disturbances resulting from partial or complete arterial occlusion, caused by arteriosclerosis, are likely to play an important role in the cause of degenerat...
Navicular bone disease: a comparative histomorphometric study. Twelve horses suffering from navicular bone disease were examined in a prospective, controlled histomorphometric study for six months. The objective was to compare the histology of navicular bones from untreated animals to those treated with the egg-bar shoeing technique. These data were compared to similar sections from three normal animals. The current investigation provided quantitative support to previous findings concerning clinical improvement. Detailed histology, changes in bone morphometry and pathophysiological reactions are discussed.
Development of the navicular bone in foetal and young horses, including the arterial supply. A macroscopic, arteriographic and histological study of the development and the arterial anatomy of the navicular bone of 33 foetuses and 55 young horses is described. After 125 days of gestation the blood supply consists of two routes: one situated in the superficial layer of the fibrocartilage and the other similar to the blood supply of the navicular bone of the normal mature horse. After 270 days gestation, the blood vessels in the fibrocartilage gradually regressed and retracted until they have disappeared at six months after birth. At two months after birth the first macroscopic thinning...