Plastic deformation of the ulna in association with anterior radial head dislocation represents up to 31% of anterior Monteggia lesions. Complete transverse or short oblique fracture.Incomplete (greenstick or buckle) fracture.Monteggia fractures in children may be categorized according to the type of ulnar injury, as follows: When the various fracture types occur in the immature bone of children, distinct patterns result and influence treatment considerations. Monteggia fractures in the pediatric population typically manifest with unique features that have led to a decreased emphasis on the direction of the radial head dislocation and an increased focus on the character of the fracture of the ulna. Of the Monteggia fractures, Bado type 1 is the most common (59%), followed by type 3 (26%), type 2 (5%), and type 4 (1%). The Bado classification of Monteggia fracture types is based on the recognition that the direction in which the apex of the ulnar fracture points is the same direction as the radial head dislocation 4. Type 4 – Fracture of the proximal or middle third of the ulna and radius with anterior dislocation of the radial head.Type 3 – Fracture of the ulnar metaphysis with lateral dislocation of the radial head.Type 2 – Fracture of the proximal or middle third of the ulna with posterior dislocation of the radial head.this type was originally described by Monteggia in 1814.classic Monteggia fracture-dislocations.Type 1 – Fracture of the proximal or middle third of the ulna with anterior dislocation of the radial head.In 1967, Bado coined the term Monteggia lesion and classified the injury into the following four types 3: Neural injuries are generally traction injuries and result from stretching around the displaced bone or from energy dispersed during the initial injury. The close proximity of these nerves may lead to injuries when a Monteggia fracture occurs. The median and ulnar nerves enter the antecubital fossa just distal to the elbow. The posterior interosseous nerve travels around the neck of the radius and dives under the supinator as it courses into the forearm. The ulna and interosseous membrane also may provide stable platforms for dislocation of the proximal radius, leading to the Monteggia fracture. The ulna provides a stable platform for rotation of the radius and forearm. The distal ulna and radius also articulate at the distal radioulnar joint 2. The radius and ulna are closely invested by the interosseous membrane, which accounts for the increased risk of displacement or injury to the radius when the ulna fractures. The radial head articulates with the humeral capitellum and the radial notch of the proximal ulna. These ligaments stretch or rupture during radial head dislocation 1. The annular and radial collateral ligaments stabilize the radial head. The elbow joint is crossed by three major nerves. Ligaments on the inner and outer sides of the elbow hold the joint together and muscles surround the joint on the front and back sides. The ulna is on the “pinky finger side” of the forearm. The ulna is the other forearm bone between the elbow and wrist, running next to the radius.The radius is on the “thumb side” of the forearm. The radius is one of the forearm bones between the elbow and wrist.The humerus is the upper arm bone between the shoulder and the elbow.To the authors’ knowledge this is the rst description of a Monteggia fracture in a lemur species.The elbow is a joint made up of three bones-the humerus, radius, and ulna. e surgical technique described in this case enabled good stabilisation and healing of the fracture, without compromising pronation and supination, which is valuable for primate species. Surgical treatment in domestic carnivore species usually includes ulnar fracture repair and radio- ulnar xation that impairs or limits pronation and supination. Although many reports of such fractures exist in the veterinary literature, their true prevalence is currently undocumented in all animal species. Monteggia fractures are rare, representing 1 to 2% of human forearm fractures. Surgical treatment included repair of the fracture using an intramedullary pin inserted in retrograde fashion associated with a capsular prosthesis made of suture attached to two periarticular screws, and second intention healing of the wound. A 12 year old female Ring-Tailed Lemur (Lemur catta) was diagnosed with a type III Monteggia fracture associated with a wound on the mediodorsal side of the forearm.
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