Computed Tomography and Cross-sectional Anatomy of the Normal Dromedary Camel Tarsus (One Humped Camel)

Arthrocentesis approaches to the phalangeal joints of the one humped camel (Camelus dromedarius)

Irrespective of the exceptional adaptation of dromedaries to harsh environmental conditions, they remain highly susceptible to joint lameness resulting from a range of diverse factors and conditions. The joints most often affected by traumatic osteoarthritis in dromedaries are the metacarpophalangeal and metatarsophalangeal joints. A comprehensive understanding of joint anatomy and topography of the dromedary is required to perform arthrocentesis correctly on affected joints. Forty-two distal limbs were taken from 28 camels and studied by gross dissection, casting, ultrasonography, and computed tomography (CT). Representative three-dimensional models of the joint cavities, recesses, and pouches were obtained using different casting agents. This study provides a detailed description of dorsally, axially, and abaxially positioned joint recesses, as well as palmar/plantar positioned joint pouches. The safety and feasibility of the different arthrocentesis approaches were evaluated. The traditional dorsal arthrocentesis approach of the metacarpophalangeal, metatarsophalangeal, proximal interphalangeal, and distal interphalangeal joints, has limitations due to the risk of damaging the tendon structures and articular cartilage, which can lead to joint degeneration. A lateral arthrocentesis approach via the proximal palmar/plantar pouches of the metacarpophalangeal/metatarsophalangeal and proximal interphalangeal joints is recommended. This approach eliminates the potential needle injury to the articulating joint cartilage and other surrounding joint structures, such as tendons, blood vessels, and nerves.

Bilateral dorsal rotation of the talus with tibiotarsal, talocalcaneal, and proximal intertarsal joint subluxation in an alpaca

CASE DESCRIPTION

A 14-month-old female alpaca presented with a 3-week history of acute left hind limb lameness and swelling of the left tarsal region.

CLINICAL FINDINGS

Radiography revealed intermittent dorsal rotation of the talus with tibiotarsal, talocalcaneal, and proximal intertarsal joint subluxation.

TREATMENT AND OUTCOME

In an attempt to stabilize the talus, screws were placed in the distomedial aspect of the talus and the plantaromedial aspect of the central tarsal bone, and a stainless-steel wire was placed around the screws in a figure-eight pattern. The screw head of the proximal screw broke within 4 weeks after surgery, but subluxation did not recur, and the lameness resolved. Seven months later, the same condition was diagnosed in the opposite hind limb and was treated similarly. Implants remained intact on this side, but the animal started to show signs of pain and inability to flex the tarsal joint, prompting removal of the distal screw. Subsequently, the animal became sound and produced 2 healthy crias, but was euthanatized 4 years after the second surgery because of coccidiosis.

CLINICAL RELEVANCE

Dorsal rotation of the talus with tibiotarsal, talocalcaneal, and proximal intertarsal joint subluxation is a sporadic condition in New World camelids. This report provides the first account of successful treatment by surgical stabilization of the medial aspect of the proximal intertarsal joint.

Intra-articular injection in the hind limb joints of dromedary camels (Camelus dromedarius) using anatomical and arthrographic-guided landmarks

Background and Aim:

A healthy joint is an important structure for the proper movement of the camel limb. Intra-articular (IA) injection is frequently used in veterinary practice for diagnostic and therapeutic purposes of joint injuries. Thus, the current study aimed to describe the injection of the hindlimb joints in dromedary camels based on the anatomical and arthrographic-guided landmarks.

Materials and Methods:

Eighteen orthopedically sound adult camels (mean±standard deviation age: 78±12 months) of both sexes were included in this study. Three camels were euthanized to identify anatomical features in the hindlimb joints and related structures. IA injections were performed in the hindlimbs of 5 camel cadavers to evaluate the optimal IA injection site, which was confirmed by arthrography. The optimized IA injection technique was applied in 10 live camels and confirmed by arthrocentesis and arthrography. For each joint, injection criteria (number of attempts, difficulty of injection, and successful injection) were assessed, scored, and statistically compared to the other joints.

Results:

The summation of IA injection criteria scores was significantly higher (p<0.05) in the femorotibial, femoropatellar, tibiotarsal, fetlock, pastern, and coffin joints in comparison to the hip joint.

Conclusion:

Anatomical and arthrographic-guided techniques offer considerable advantages for the characterization of anatomical landmarks and selection of the appropriate IA injection site in the hindlimb in dromedary camels. Furthermore, a reference approach for camels was established that is different from the approach for cattle and horses.

Magnetic resonance imaging of the normal dromedary camel tarsus

Background

Magnetic resonance imaging (MRI) is the most versatile and informative imaging modality for the diagnosis of locomotor injuries in many animal species; however, veterinary literature describing the MRI of the dromedary camel tarsus is lacking. Our purpose was to describe and compare the MRI images of twelve cadaveric tarsi, examined in a 1.5 Tesla MRI scanner, with their corresponding anatomical gross sections. Turbo spin-echo (TSE) T1-weighted (T1), T2-weighted (T2), proton density-weighted (PD), and short tau inversion recovery (STIR) sequences were obtained in 3 planes. Tarsi were sectioned in sagittal, dorsal, and transverse planes. MRI images from different sequences and planes were described and compared with the anatomical sections.

Results

The soft and osseous tissues of the dromedary camel tarsus could be clearly defined on MRI images and corresponded extensively with the gross anatomic sections. The obtained MRI images enabled comprehensive assessment of the anatomic relationships among the osseous and soft tissues of the camel tarsus. Several structure were evaluated that cannot be imaged using radiography or ultrasonography, including the transverse inter-tarsal ligaments, the talocalcaneal ligament, the short dorsal ligament, branches of the short medial and lateral collateral ligaments and the tarsometatarsal ligaments. Specific anatomical features regarding the dromedary camel tarsus were identified, including the fused second and third tarsal bone, an additional bundle of the short medial collateral ligament connecting the talus and metatarsus and the medial and lateral limbs of the long plantar ligament.

Conclusions

MRI images provided a thorough evaluation of the normal dromedary camel tarsus. Information provided in the current study is expected to serve as a basis for interpretation in clinical situations.

Computed tomography and magnetic resonance imaging study of a normal tarsal joint in a Bengal tiger (Panthera tigris)

Background

In this research, using computed tomography (CT) and magnetic resonance imaging (MRI), we provide a thorough description of the standard appearance of a right tarsal joint in a Bengal tiger (Panthera tigris). CT scans were performed using a bone and soft tissue window setting, and three-dimensional surface reconstructed CT images were obtained. The MRI protocol was based on the use of Spin-echo (SE) T1-weighted and Gradient-echo (GE) STIR T2-weighted pulse sequences. Magnetic resonance (MR) images were taken in the transverse, sagittal and dorsal planes. We also performed anatomical dissections to facilitate the interpretation of the different structures of the tarsus joint and allow comparisons with CT and MRI images.

Results

The CT images allowed us to observe differences between the bones and soft tissues of the tarsal joint. When applying the bone window setting, the obtained footage showed the anatomy between the medulla and cortex. Additionally, the trabecular bone was delineated. By contrast, the soft tissue window allowed the main soft tissue structures of the tarsal joint, including ligaments, muscles and tendons, to be differentiated. Footage of the main anatomical structures of the standard tiger tarsus was obtained through MRI. The SE T1-weighted images showed the best evaluation of the cortical, subchondral and trabecular bone of the tibia, fibula, tarsus and metatarsus bones. Nonetheless, the GE STIR T2-weighted images allowed us to better visualize the articular cartilage and synovial fluid. In both MRI pulse sequences, the ligaments and tendons appeared with low signal intensity compared with muscles that were visible with intermediate signal intensity.

Conclusions

The results of this CT and MRI study of the Bengal tiger tarsal joint provide some valuable anatomical information and may be useful for diagnosing disorders in this large non-domestic cat.

Metrical analysis of dromedary digital bones

Dromedary camels are large even-toed ungulates which are well adapted to life in large deserts. Examinations of their feet have revealed many structural peculiarities. We have measured the digital bones of the dromedary in order to determine whether there are morphometric variations in the digital bones between the lateral and medial sides in individual limbs and/or in the right and left thoracic and pelvic limbs, with the aim to clarify whether there are anatomical differences in the digital bones of dromedary as a suborder of the order Artiodactyla. Measurements were made of 240 lateral and medial proximal, middle, and distal phalanges in the left and right thoracic and pelvic limbs of ten healthy adult male dromedaries, ranging in age from 6 to 10 years. A total of 17 linear dimensions were measured using a caliper. The results indicate that there are no significant differences between corresponding measurements of digital bones of the lateral and medial in the same limb, nor between measurements of the right and left sides. The lengths and widths of the proximal and middle, and distal phalanges in the thoracic limb were found to be greater than those of the pelvic limb. The sum of the total lengths of the three phalanges of the thoracic limbs was 15 mm greater than that of the phalanges of the pelvic limbs due to a longer proximal phalanx (76 %) and middle phalanx of the former (24 %). The perspectives obtained by our morphometric study of dromedary digital bones not only provide a tool to distinguish the osteological remains of the dromedary from those of the Bactrian camel or other artiodactyls in archaeological sites, but they also suggest a possible influence of digital structure on digit functions and digital disorders.

Sectional anatomic and computed tomography features of the nasal and oral cavities of the one-humped camel (Camelus dromedarius)

The purpose of the study was to provide a description of normal cross-sectional anatomy of the camel nasal and oral cavities using computed tomography (CT) and macroscopic cross-sections. Transverse images of two isolated camel cadaver heads were obtained by an axial CT equipment. Computed tomography scans were processed with a detailed algorithm using nasal and soft tissue windows settings and compared with the corresponding frozen cross-sections of the heads, to assist in the accurate identification of nasal and oral structures. In our study, nasal window provided excellent anatomic details of nasal conchae, bones and teeth; however, other soft tissue components of the nasal and oral cavities are better differentiated using a soft tissue window. These CT images are intended to be a useful anatomic reference in the interpretation for clinical CT imaging studies of the nasal and oral cavities in dromedary camels.

Normal radiographic and ultrasonographic appearance of the adult dromedary camel tarsus (one humped camel)

Six cadaver pelvic limbs were obtained from clinically sound dromedary camels and examined radiographically and ultrasonographically using a 7.5 MHz convex transducer. Radiographic examination was performed in dorsoplantar, lateromedial, dorsolateral-plantaromedial oblique and plantarolateral-dorsomedial oblique projections, and the bony structures and articulations of the tarsal joint were outlined. The tarsus was ultrasonographically investigated in four planes (dorsal, medial, lateral and plantar), and each plane was scrutinized in four levels (calcaneal tuber, tibial malleoli, base of calcaneus and proximal end of metatarsus) in both transverse and longitudinal views. Limbs were examined grossly, frozen at -20°C and sectioned. Radiographic and ultrasonographic findings correlated well with the gross anatomy and frozen sections. The normal appearance of bony and soft structures of the tarsus described in this study provided basic reference data for ultrasonographic and radiographic investigations of tarsal disorders in the dromedary camel.