Changes

===Extensors===

===Extensors===

'''''Long Digital Extensor Tendon'''''  

'''''Long Digital Extensor Tendon'''''  

*'''Origin''': Long digital extensor muscle proximal and dorsolateral to the tarsus (hock)

*'''Origin''': Long digital extensor muscle proximal and dorsolateral to the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|tarsus]] (hock)

*'''Insertion''': Extensor process of [[Phalanges - Horse Anatomy#Distal Phalanx|distal phalanx]]

*'''Insertion''': Extensor process of [[Phalanges - Horse Anatomy#Distal Phalanx|distal phalanx]]

*'''Action''': Extends the digit, flexes the tarsus

*'''Action''': Extends the digit, flexes the tarsus

The long digital extensor tendon extends distally on the dorsolateral aspect of the tarsus and metatarsus, surrounded by a synovial sheath from mid-tarsus to 3-4cm distal to the tarsus. The branches of the interosseous muscle (suspensory ligament) join this tendon before its insertion on the '''extensor process''' of the [[Phalanges - Horse Anatomy#Distal Phalanx|distal phalanx]].  The long digital extensor tendon is joined by the lateral digital extensor tendon in the proximal metatarsal region.  

The long digital extensor tendon extends distally on the dorsolateral aspect of the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|tarsus]]  and [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|metatarsus]] , surrounded by a synovial sheath from mid-tarsus to 3-4cm distal to the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|tarsus]] . The branches of the interosseous muscle (suspensory ligament) join this tendon before its insertion on the '''extensor process''' of the [[Phalanges - Horse Anatomy#Distal Phalanx|distal phalanx]].  The long digital extensor tendon is joined by the lateral digital extensor tendon in the proximal metatarsal region.  

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'''''Lateral Digital Extensor Tendon'''''  

'''''Lateral Digital Extensor Tendon'''''  

*'''Origin''': Lateral digital extensor muscle proximal  and lateral to the tarsus (hock)

*'''Origin''': Lateral digital extensor muscle proximal  and lateral to the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|tarsus]]  (hock)

*'''Insertion''': Dorsal [[Phalanges - Horse Anatomy#Proximal Phalanx|proximal phalanx]]

*'''Insertion''': Dorsal [[Phalanges - Horse Anatomy#Proximal Phalanx|proximal phalanx]]

*'''Action''': Aids long digital extensor in digit extension and tarsal flexion

*'''Action''': Aids long digital extensor in digit extension and tarsal flexion

   

   

The lateral digital extensor tendon passes over the lateral aspect of the hock, held in place by the '''extensor retinaculum''' and surrounded by a protective synovial sheath. It joins the '''long digital extensor tendon''' in the proximal metatarsal region.

The lateral digital extensor tendon passes over the lateral aspect of the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|hock]] , held in place by the '''extensor retinaculum''' and surrounded by a protective synovial sheath. It joins the '''long digital extensor tendon''' in the proximal metatarsal region.

===Flexors===

===Flexors===

*'''Insertion: Calcanean tuberosity

*'''Insertion: Calcanean tuberosity

*'''Action''' of components:  

*'''Action''' of components:  

**''Biceps femoris'': Extends the hip, abducts the limb, extends the stifle, flexes the stifle (via caudal aspect) and extends the hock

**''Biceps femoris'': Extends the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|hip]] , abducts the limb, extends the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|stifle]] , flexes the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|stifle]]  (via caudal aspect) and extends the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|hock]]

**''Abductor cruris caudalis'': Abducts proximal limb and flexes the stifle

**''Abductor cruris caudalis'': Abducts proximal limb and flexes the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|stifle]]

**''Semitendinosus'': Extends the hip, adducts and draws back the limb, extends the stifle and hock

**''Semitendinosus'': Extends the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|hip]] , adducts and draws back the limb, extends the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|stifle]]  and [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|hock]]

**''Semimembranosus'': Extends the hip, adducts and draws back the limb, rotates limb inward, extends the stifle and hock

**''Semimembranosus'': Extends the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|hip]] , adducts and draws back the limb, rotates limb inward, extends the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|stifle]]  and [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|hock]]

**''Gastrocnemius'': Flexes the stifle and extends the hock

**''Gastrocnemius'': Flexes the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|stifle]]  and extends the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|hock]]

The common calcaneal tendon is the continuation of the ‘hamstring’ group of muscles (''biceps femoris'', ''abductor cruris caudalis'', ''semitendinosus'', ''semimembranosus'', ''gastrocnemius'' and ''SDFT'') on the caudal aspect of the proximal limb.  

The common calcaneal tendon is the continuation of the ‘hamstring’ group of muscles (''biceps femoris'', ''abductor cruris caudalis'', ''semitendinosus'', ''semimembranosus'', ''gastrocnemius'' and ''SDFT'') on the caudal aspect of the proximal limb.  

*'''Origin''': Extensor fossa of femur  

*'''Origin''': Extensor fossa of femur  

*'''Insertion''':  Dorsal insertion on the proximal region of the third metatarsal (cannon) and third tarsal bones. Lateral insertion on the calcaneus and fourth tarsal bone (lateral splint)  

*'''Insertion''':  Dorsal insertion on the proximal region of the third metatarsal (cannon) and third tarsal bones. Lateral insertion on the calcaneus and fourth tarsal bone (lateral splint)  

*'''Action''': Passively flexes the tarsal joint when the stifle joint is flexed

*'''Action''': Passively flexes the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|tarsus]]  when the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|stifle]]  is flexed

The peroneus tertius is an entirely tendinous structure in the horse, forming an important component of the '''reciprocal apparatus'''. It acts to passively flex the tarsal joint when the stifle joint is flexed. The tendon forms a loop, through which the tendon of the tibialis cranialis passes. It then bifurcates at the level of the talus into dorsal and lateral branches. The dorsal branch passes deep to the cunean tendon to insert on the third metatarsal (cannon) and third tarsal bones.  The lateral branch extends distally, deep to the long digital extensor tendon and runs laterally distal to the lateral ridge of the trochlea of the talus. This lateral branch then bifurcates to insert on the calcaneus and fourth tarsal (splint) bone.  

The peroneus tertius is an entirely tendinous structure in the horse, forming an important component of the '''reciprocal apparatus'''. It acts to passively flex the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|tarsus]]  when the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|stifle]]  is flexed. The tendon forms a loop, through which the tendon of the tibialis cranialis passes. It then bifurcates at the level of the talus into dorsal and lateral branches. The dorsal branch passes deep to the cunean tendon to insert on the third metatarsal (cannon) and third tarsal bones.  The lateral branch extends distally, deep to the long digital extensor tendon and runs laterally distal to the lateral ridge of the trochlea of the talus. This lateral branch then bifurcates to insert on the calcaneus and fourth tarsal (splint) bone.  

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*'''Origin''': Proximal/mid-tibia

*'''Origin''': Proximal/mid-tibia

*'''Insertion''': Calcanean tuberosity and [[Phalanges - Horse Anatomy#Middle Phalanx|middle phalanx]]

*'''Insertion''': Calcanean tuberosity and [[Phalanges - Horse Anatomy#Middle Phalanx|middle phalanx]]

*'''Action''': Extends the digit, assists in extending the hock and flexing the stifle as part of the reciprocal apparatus

*'''Action''': Extends the digit, assists in extending the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|hock]]  and flexing the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|stifle]]  as part of the reciprocal apparatus

The superficial digital flexor tendon is a major component of the common calcaneal tendon, which forms part of the reciprocal apparatus. The SDFT arises from the superficial digital flexor muscle in the proximal/mid-tibial region and passes around the gastrocnemius tendon caudally. At the point of the hock, the SDFT widens to form a cap over the calcanean tuberosity. The '''calcanean bursa''' is a synovial fluid-filled space formed between the calcanean tuberosity and the SDFT. Distal to the calcaneus, the SDFT continues as arranged in the thoracic limb to its point of insertion on the [[Phalanges - Horse Anatomy#Middle Phalanx|middle phalanx]].  

The superficial digital flexor tendon is a major component of the common calcaneal tendon, which forms part of the reciprocal apparatus. The SDFT arises from the superficial digital flexor muscle in the proximal/mid-tibial region and passes around the gastrocnemius tendon caudally. At the point of the hock, the SDFT widens to form a cap over the calcanean tuberosity. The '''calcanean bursa''' is a synovial fluid-filled space formed between the calcanean tuberosity and the SDFT. Distal to the calcaneus, the SDFT continues as arranged in the thoracic limb to its point of insertion on the [[Phalanges - Horse Anatomy#Middle Phalanx|middle phalanx]].  

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'''''Deep Digital Flexor Tendon (DDFT)'''''

'''''Deep Digital Flexor Tendon (DDFT)'''''

*'''Origin''': Deep digital flexor muscle, distal to the tarsus

*'''Origin''': Deep digital flexor muscle, distal to the [[Joints and Ligaments - Horse Anatomy#Pelvic Limb|tarsus]]

*'''Insertion''': Flexor cortex of [[Phalanges - Horse Anatomy#Distal Phalanx|distal phalanx]]  

*'''Insertion''': Flexor cortex of [[Phalanges - Horse Anatomy#Distal Phalanx|distal phalanx]]  

*'''Action''': Flexes the [[Phalanges - Horse Anatomy#Distal Phalanx|distal phalanx]]   

*'''Action''': Flexes the [[Phalanges - Horse Anatomy#Distal Phalanx|distal phalanx]]