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Glass horse distal limb: A comprehensive guide to the anatomy and physiology of the equine lower leg



This program was developed to help students understand the anatomy of the equine distal limb. The program combines highly interactive models with comprehensive narration and informative animations. All new interface allows manipulation of models in three dimensions. It includes QuickTime films. Some of the images are labelled.


An engaging interactive exploration of the equine distal limb that combines interactive models with narrations and highly informative animations. The interface allows manipulation of anatomical models in three dimensions. This program is recommended for veterinary students, equine practitioners and farriers.




Glass horse distal limb



An engaging interactive exploration of the equine distal limb that combines interactive models with informative narrations and highly detailed animations. The interface allows manipulation of anatomical models in three dimensions.


An engaging interactive exploration of the equine distal limb that combines interactive models with narrations and highly informative animations. The interface allows manipulation of anatomical models in three dimensions. This program is recommended for veterinary students, equine practitioners and farriers. This interactive resource is available for use on computers #1 through #4 located in the SVM Library. It is recommended that you bring headphones.


Identification and characterization of foreign bodies in the distal limb of horses poses a diagnostic challenge. The aims of this prospective experimental cadaver study were to describe the appearance of five foreign body materials within the equine hoof using CT, MRI, and digital radiography (DR) and to compare interrater agreement among three reviewers. Fifty foreign bodies consisting of five materials were implanted at a solar location or a coronary location in 25 equine cadaver feet. The images were reviewed by three equine veterinarians experienced in advanced imaging interpretation, who were blinded to the material of the foreign body. Foreign bodies were graded on visibility and appearance. Sensitivity and specificity were calculated for accurate identification of the different materials. Interrater agreement was assessed using Fleiss' kappa. Computed tomography had higher visibility score, sensitivity/specificity, and interrater agreement for detection of all materials; particularly slate, glass, and dry wood, compared to the other imaging modalities. Soaked wood and plastic had lower sensitivity (31-33%) on CT with a similar attenuation of the two materials. Foreign bodies were often visible on MRI, although with similar appearance and unclear details. On DR, only slate and glass were visible. The interrater agreement for identifying the correct material was almost perfect for slate, glass, and dry wood (κ = 0.92-1.00) and poor for plastic and soaked wood (κ


Figure 2-3 Bovine distal forelimb bones. 1, Proximal phalanx (P1); 2, middle phalanx (P2); 3, distal phalanx (P3, pedal bone); 4, fused metacarpal 3+4 (Mc 3+4 = bovine cannon bone); 5, rudimentary Mc5; 6, abaxial proximal sesamoid bone; 7, axial proximal sesamoid bone; 8, distal sesamoid (navicular) bone; 9, extensor process of pedal bone; 10, interdigital space.


DIGITS 3 AND 4 OF THE OX (there are a total of four proximal sesamoid bones, and two distal sesamoid bones (aka navicular bones) per limb in the OX).


A2.2 Identify and describe the joints, joint angles, and joint actions of the (distal) thoracic limb; describe the location of muscle groups that result in flexion/extension of these joints.


Fig 2-5: Left Forelimb. Lateral View of the Metacarpophalangeal (Fetlock, MCP) Joint (joint capsule/pouch in green). The joint has a dorsal and palmar pouch. The palmar pouch is usually injected using a lateral approach, with the limb planted on the ground (weight bearing). The injection site is between the palpable suspensory ligament, distal part of the lateral splint (button) and the lateral proximal sesamoid bone. Alternatively, injection of the fetlock joint can be performed by penetrating the lateral (or medial) collateral sesamoidean ligament, with the limb flexed. The advantage of this approach is that it causes less hemorrhage in the joint compared to the palmar approach (Equine Joint Injection and Regional Anesthesia by Moyer, Schumacher, Schumacher, 2011; image from Equine Anatomy Guide: The Forelimb; Mansour, Steiss, Wilhite)


Fig 2-6: Left Forelimb. Dorsal View of the Proximal Interphalangeal (Pastern, PIP) Joint (joint capsule/pouch in green). Dorsal approach to the pastern joint: The joint has a dorsal and palmar pouch. It is usually accessed by injection of the dorsal pouch. The landmarks for the dorsal approach include the eminence on distal P1 (which serves for attachment of the lateral collateral ligament of the pastern joint) and the common digital extensor tendon. The needle is inserted deep to the tendon of the common digital extensor distal to the lateral bony eminence of P1. (Equine Joint Injection and Regional Anesthesia by Moyer, Schumacher, Schumacher, 2011; image from Equine Anatomy Guide: The Forelimb; Mansour, Steiss, Wilhite)


Bandsaw section though an equine foot near the sole (LEFT). 1, thick wall in toe region; 2, thinner wall in quarter and heel region; 3, laminar dermis; 4, distal phalanx (P3); 5, small part of navicular bone; 6, deep digital flexor tendon (DDFT); 7, digital cushion. Bandsaw section of a horse hoof (RIGHT). 1, external surface of the hoof wall; 2, pigmented hoof wall; 3, non-pigmented hoof wall white line; 4, horny and dermal laminae; 5, cut surface of distal phalanx (P3); 6, horn tubule (small white dot); 7, intertubular horn (dark area between white dots). (images from )


Figure 3. A 19 ga butterfly needle placement for RIVP in the dorsal common digital v. of the bovine distal limb. Photo courtesy Dr. John Gilliam, Oklahoma State University.


Positioning of the limb within the CT-gantry using two stands and a glass container to collect exiting perfusate. For this scan, only the left tube of the perfusion system was connected to the radial vein, allowing drainage of blood and contrast agent through the catheter of the median artery.


A native CT scan was acquired extending from just proximal to the proximal sesamoid bones to the distal-most aspect of the hoof, using parameters adapted from Van Hamel and colleagues (23): 140 kV, 200 mA, 2 mm slice thickness, 1 mm increment and a pitch of 0.688. Subsequently perfusion was performed in three phases, based on the MPMCTA-protocol (19): (1) perfusion through the median artery (100 mL/min for 110 s), (2) perfusion through the radial vein (100 mL/min for 50 s), and (3) arterial-venous combined (AVC) dynamic perfusion through both vessels simultaneously (100 mL/min for 30 s plus the duration of the scan). This protocol uses a volume of 360 mL contrast medium per limb. Images were acquired in all three phases using the same parameters as for the native scan. During the arterial and venous phase scans, the perfusion was stopped just before the scanning process, whereas the AVC dynamic phase scans were performed during simultaneous arterial and venous injection of the contrast agent.


The injury may be sustained by running into, brushing against, kicking at, or stepping on an object, or by becoming entangled in barbed or smooth wire or a rope (Figure 13.1). Horses that jump fences may sustain blunt trauma resulting in an abrasion or a penetrating wound, often on the dorsal surface of the pastern. Blunt trauma to the dorsal surface of the carpus can occasionally cause a substantial hematoma or hygroma (Figure 13.2). Penetrating wounds from jumping injuries often occur just proximal to the coronet on the hindlimb or at the distal end of the antebrachium, and, often, a splinter of wood becomes embedded in soft tissue (Figure 13.3). Horses that become entangled in barbed wire may sustain a serious wound, such as a degloving injury, which is particularly common in the metacarpal or metatarsal region (Figure 13.4), or a laceration that extends into a synovial cavity (Figure 13.5) or through a heel bulb (Figure 13.6). The extensor or flexor tendons may also be injured. For more information regarding injuries to tendons and their sheaths, see Chapter 17.


Wounds involving the distal aspect of the limb are often more problematic than wounds located elsewhere because their close proximity to the ground makes them more likely to become contaminated, and because skin in the distal portion of the limb is less vascular than skin located elsewhere. A wound to the distal aspect of the limb is much more likely to involve a vital structure because the distal aspect of the limb is populated by a high number of synovial structures, ligaments, and tendons. 2ff7e9595c


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