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==Introduction==
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For general skeletal anatomy, follow links in blue. The following section will concentrate on anatomy specific to the horse.
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==Thoracic Limb==
 
==Thoracic Limb==
 
===[[Forelimb - Anatomy & Physiology#Scapula|Scapula]]===
 
===[[Forelimb - Anatomy & Physiology#Scapula|Scapula]]===
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The spine of the scapular ends in a bony prominence ventrally, known as the '''acromion'''. In the horse, this structure becomes smaller distally. A second bony prominence, the '''tuberosity''', exists dorsal to the middle of the scapular spine.
 
The spine of the scapular ends in a bony prominence ventrally, known as the '''acromion'''. In the horse, this structure becomes smaller distally. A second bony prominence, the '''tuberosity''', exists dorsal to the middle of the scapular spine.
   
===[[Forelimb - Anatomy & Physiology#Humerus|Humerus]]===
 
===[[Forelimb - Anatomy & Physiology#Humerus|Humerus]]===
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The intertubercular groove has a central sagittal ridge.
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*The '''intertubercular groove''' has a central sagittal ridge.
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*The '''lesser tubercle''' is divided into two parts.
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*The '''teres major tuberosity''' is found on the medial shaft, just proximal to its middle.
 
===[[Forelimb - Anatomy & Physiology#Radius and Ulna|Radius and Ulna]]===
 
===[[Forelimb - Anatomy & Physiology#Radius and Ulna|Radius and Ulna]]===
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#Proximally (mediolaterally):radial, intermediate, ulnar and accessory bones.
 
#Proximally (mediolaterally):radial, intermediate, ulnar and accessory bones.
 
#Distally: 1st carpal bone is small or absent, II-IV are all present.
 
#Distally: 1st carpal bone is small or absent, II-IV are all present.
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===[[Forelimb - Anatomy & Physiology#Metacarpals and Metatarsals|Metacarpals and Metatarsals]]===
 
===[[Forelimb - Anatomy & Physiology#Metacarpals and Metatarsals|Metacarpals and Metatarsals]]===
 
Horses are '''perissodactyl''' '''unguligrade''' animals. Unguligrade means that horse's bear their weight on a horny covering (hoof) that surrounds their distal phalanx, perissodactyl means that they have only one weight-bearing digit. They are virtually identical in their structure in the hindlimb and forelimb. The main differences are in the forelimb we have metacarpals and the metacarpophalangeal joint, the hindlimb equivalents are the metatarsals and the metatarsophalangeal joint. Also in anatomical planes we use the term palmar for forelimb and plantar for hindlimb. These terms are all interchangable in the below article depending on whether you want to talk about the fore or hindlimb.
 
Horses are '''perissodactyl''' '''unguligrade''' animals. Unguligrade means that horse's bear their weight on a horny covering (hoof) that surrounds their distal phalanx, perissodactyl means that they have only one weight-bearing digit. They are virtually identical in their structure in the hindlimb and forelimb. The main differences are in the forelimb we have metacarpals and the metacarpophalangeal joint, the hindlimb equivalents are the metatarsals and the metatarsophalangeal joint. Also in anatomical planes we use the term palmar for forelimb and plantar for hindlimb. These terms are all interchangable in the below article depending on whether you want to talk about the fore or hindlimb.
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Only Metacarpal III ('''cannon bone''') remains complete whilst metacarpals II and IV are greatly reduced and are known as the '''splint bones'''. Metacarpal III has a distal articular surface with two condylar areas separated by a '''sagittal ridge'''. This separates the two sesamoids on the palmar aspect of the joint and ensures only sagittal movement of the fetlock. There is also a transverse ridge leading to two radii of curvature. The proximal part has articulating facets on its palmar side where the splint bones articulate. It has a '''metacarpal tuberosity''' on the dorsomedial surface of the proximal end. The splint bones are held to metacarpal III by strong ligaments which are usually ossified and can lead to lameness if there is excessive bone production. They curve away distally from the main shaft and end in palpable nodules 2/3rds to 3/4s the way down the cannon bone.
 
Only Metacarpal III ('''cannon bone''') remains complete whilst metacarpals II and IV are greatly reduced and are known as the '''splint bones'''. Metacarpal III has a distal articular surface with two condylar areas separated by a '''sagittal ridge'''. This separates the two sesamoids on the palmar aspect of the joint and ensures only sagittal movement of the fetlock. There is also a transverse ridge leading to two radii of curvature. The proximal part has articulating facets on its palmar side where the splint bones articulate. It has a '''metacarpal tuberosity''' on the dorsomedial surface of the proximal end. The splint bones are held to metacarpal III by strong ligaments which are usually ossified and can lead to lameness if there is excessive bone production. They curve away distally from the main shaft and end in palpable nodules 2/3rds to 3/4s the way down the cannon bone.
 
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===[[Forelimb - Anatomy & Physiology#Phalanges|Phalanges]]===
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===[[Equine - Anatomy & Physiology#Phalanges|Phalanges]]===
 
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'''''Proximal Phalanx'''''
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The proximal phalanx proximally has two shallow articular surfaces separated by a small sagittal groove. Distally there are two convex areas separated by a sagittal groove.
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'''''Middle Phalanx'''''
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The middle phalanx is half the length of the proximal phalanx, its proximal articular surface is ridged so it can articulate with proximal phalanx and the distal end resembles that of the proximal phalanx.
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'''''Distal Phalanx'''''
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The distal phalanx is rounded to a point distally. The proximal articular surface has two concavities separated by a ridge. The palmar border meets with the distal sesamoid bone. The dorsal aspect has a marked '''extensor process''', where the common digital extensor attaches. The solar surface has two distinct areas, the more palmar area is the roughened flexor surface and the remainder is smooth, concave and crescent-shaped. The parietal surface of the distal phalanx is that which conforms to the hoof wall. It is rough, porous and has processes on each side heading in a palmar direction. The ungual (collateral) cartilages attach to these processes, they are squarish plates which are palpable above the level of the hoof. They become more fibrous in life and may ossify.
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'''''Distal Sesamoid (Navicular) Bone'''''
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{{Learning
 
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|dragster = [[Equine Skeletal Anatomy Dragster resource|Equine Skeleton]]<br>[[:Category:Equine Thoracic Limb Dragster|Equine Forelimb Resources]]
The distal sesamoid in horses is known as the navicular bone. It is elongated transversely and articulates with both the distal and middle phalanx. The navicular is separated from the deep digital flexor tendon by a bursa; the flexor surface of the navicular is covered by cartilage. The proximal and distal ends are grooved and possess large foramina. The bone also has a sagittal ridge.
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}}
    
==Pelvic Limb==
 
==Pelvic Limb==
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Within the equine '''[[Hindlimb - Anatomy & Physiology#Ilium|ilium]]''', the '''tuber coxae''' is visible and an important palpable landmark. The '''iliac crest''' is thin and concave whilst the '''ileal wing''' is orientated in an vertical manner. The '''[[Hindlimb - Anatomy & Physiology#Pubis|pubis]]''' has a '''pubic groove''' that crosses the ventral surface of the iliopubic eminence towards the acetabulum. In the groove lies the accessory ligament of the head of the femur. Specifically in the stallion, a dorsal pubic tubercle exists. The '''[[Hindlimb - Anatomy & Physiology#Ischium|ischium]]''' has an '''ischial tuberosity''' that is linear in shape whilst the '''ischial arch''' is shallow and irregular. The '''[[Hindlimb - Anatomy & Physiology#Femur|femur]]''' has a notched femoral head that is wedge-shaped and opens towards the medial side of the head. The '''greater trochanter''' extends beyond the the dorsal limit of the femoral head. The horse has an extra process called the '''third trochanter''' that is situated on the lateral aspect of the proximal third of the shaft and allows the superficial gluteal muscle to insert here. The caudal distal aspect of the femoral shaft is hollowed out forming the '''supracondylar fossa''' providing a larger area of origin for the superficial digital flexor muscle. The medial trochlear ridge is larger than lateral trochlear ridge and has a protuberance projecting proximally.
 
Within the equine '''[[Hindlimb - Anatomy & Physiology#Ilium|ilium]]''', the '''tuber coxae''' is visible and an important palpable landmark. The '''iliac crest''' is thin and concave whilst the '''ileal wing''' is orientated in an vertical manner. The '''[[Hindlimb - Anatomy & Physiology#Pubis|pubis]]''' has a '''pubic groove''' that crosses the ventral surface of the iliopubic eminence towards the acetabulum. In the groove lies the accessory ligament of the head of the femur. Specifically in the stallion, a dorsal pubic tubercle exists. The '''[[Hindlimb - Anatomy & Physiology#Ischium|ischium]]''' has an '''ischial tuberosity''' that is linear in shape whilst the '''ischial arch''' is shallow and irregular. The '''[[Hindlimb - Anatomy & Physiology#Femur|femur]]''' has a notched femoral head that is wedge-shaped and opens towards the medial side of the head. The '''greater trochanter''' extends beyond the the dorsal limit of the femoral head. The horse has an extra process called the '''third trochanter''' that is situated on the lateral aspect of the proximal third of the shaft and allows the superficial gluteal muscle to insert here. The caudal distal aspect of the femoral shaft is hollowed out forming the '''supracondylar fossa''' providing a larger area of origin for the superficial digital flexor muscle. The medial trochlear ridge is larger than lateral trochlear ridge and has a protuberance projecting proximally.
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===[[Equine - Anatomy & Physiology#Phalanges|Phalanges]]===
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{{Learning
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|dragster = [[Equine Skeletal Anatomy Dragster resource|Equine Skeleton]]<br>[[:Category:Equine Pelvic Limb Dragster|Equine Hindlimb Resources]]
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}}
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==Webinars==
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<rss max="10" filter="equine" highlight="none">https://www.thewebinarvet.com/orthopaedics/webinars/feed</rss>
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[[Category:Horse Anatomy]]