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===Metacarpophalangeal (Fetlock) Joint===
 
===Metacarpophalangeal (Fetlock) Joint===
The fetlock joint allows flexion and extension movements. This joint is associated with a pair of sesamoid bones on the palmar surface. Between the sesamoids in a groove lies articular cartilage which articulates with the sagittal ridge of [[Bones and Cartilages - Horse Anatomy|metacarpal III]]. The joint capsule runs between all bones in the joint and  attaches to the articular cartilage of the sesamoids. It has an extensive pouch under the extensor tendon continuing a quarter the length up [[Bones and Cartilages - Horse Anatomy|metacarpal III]]. The '''collateral ligaments''' bind the [[Bones and Cartilages - Horse Anatomy|metacarpal bone]] to the proximal phalanx, with a deep branch attaching to the sesamoid bone. The '''palmar/intersesamoidean ligament''' is a mass of fibrocartilage that embed the sesamoid bones. The palmar aspect of it forms a groove for the deep flexor tendon to run in. The '''collateral sesamoid ligaments''' connect the outer aspect of the sesamoids to the proximal phalanx and there is a distinct branch that attaches to [[Bones and Cartilages - Horse Anatomy|metacarpal III]]. The '''distal sesamoid ligaments''' are a collection of ligaments that are very marked in the horse and connect the distal surface of the sesamoids to the palmar aspect of the phalanx. These ligaments include the '''short ligaments''', '''cruciate ligaments''', '''oblique ligament''', '''straight ligament''' and the '''palmer annular ligament'''. The '''short ligaments''' connect the axial base of the sesamoids to the lateral/medial aspect on the palmar margin of the proximal phalanx. These are the deepest of the ligaments. The '''cruciate ligaments''' are paired ligaments from the base of the sesamoids that diagonally cross to attach to the proximal phalanx. It lies superficial to the short ligaments. The '''oblique ligament''' is a triangular shaped ligament, the base of which attaches to the sesamoids and their interconnecting ligament and the point attaches to the rough palmar aspect of the proximal phalanx. It is superficial to the cruciates. The '''straight ligament'''  proximally attaches like the oblique but attaches as a flat band to the edge of the complementary fibrocartilage of the proximal end of the middle phalanx. Finally, the '''palmar annular ligament''' wraps around the sesamoids, flexor tendons and their associated sheaths.
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The fetlock joint is the articulation between the trochlea of metacarpal III (carpal bone), the proximal phalanx and the proximal sesamoid bones; it allows flexion and extension movements. The joint capsule is divided into a dorsal and palmar pouch.  The dorsal pouch extends between metacarpal III (cannon bone) and the common digital extensor tendon.  The palmar pouch lies between metacarpal III (cannon bone) and the suspensory ligament.  It has an extensive bursa under the common digital extensor tendon, continuing a quarter of the length up [[Bones and Cartilages - Horse Anatomy|metacarpal III]].  This joint is associated with a pair of proximal sesamoid bones on the palmar surface. Between the sesamoids, in a groove, lies articular cartilage which articulates with the sagittal ridge of [[Bones and Cartilages - Horse Anatomy|metacarpal III]]. The joint capsule runs between all bones in the joint and  attaches to the articular cartilage of the sesamoids.
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Ligamentous support:
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*'''Collateral ligaments''' bind the [[Bones and Cartilages - Horse Anatomy|metacarpal bone]] to the proximal phalanx, with a deep branch attaching to the sesamoid bone.  
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*'''Palmar/intersesamoidean ligament''' is a mass of fibrocartilage that embeds the sesamoid bones. The palmar aspect of it forms a groove for the deep flexor tendon to run in, allowing frictionless movement.
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*'''Collateral sesamoid ligaments''' connect the outer aspect of the sesamoids to the proximal phalanx and there is a distinct branch that attaches to [[Bones and Cartilages - Horse Anatomy|metacarpal III]].  
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*'''Distal sesamoid ligaments''' are a collection of ligaments that are very marked in the horse and connect the distal surface of the sesamoids to the palmar aspect of the phalanx. These ligaments include the '''short ligaments''', '''cruciate ligaments''', '''oblique ligament''', '''straight ligament''' and the '''palmar annular ligament'''.  
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** The '''short ligaments''' connect the axial base of the sesamoids to the lateral/medial aspect on the palmar margin of the proximal phalanx. These are the deepest of the ligaments.  
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** The '''cruciate ligaments''' are paired ligaments from the base of the sesamoids that diagonally cross to attach to the proximal phalanx. They lie superficial to the short ligaments.  
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** The '''oblique ligament''' is a triangular shaped ligament, the base of which attaches to the sesamoids and their interconnecting ligament and the point attaches to the rough palmar aspect of the proximal phalanx. It is superficial to the cruciates.  
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** The '''straight ligament'''  proximally attaches like the oblique, but attaches as a flat band to the edge of the complementary fibrocartilage of the proximal end of the middle phalanx.
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** The '''palmar annular ligament''' wraps around the sesamoids, flexor tendons and their associated sheaths.
 
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