4,503
edits
Changes
Jump to navigation
Jump to search
Tendons - Horse Anatomy (view source)
Revision as of 13:10, 11 October 2012
, 13:10, 11 October 2012→Flexors
===Flexors===
===Flexors===
'''''Cunean Tendon'''''
*'''Origin''': Cranial tibial muscle in the distal tibia/proximal talus region
*'''Insertion''': Medially on the fused first and second tarsal bones
*'''Action''': Aids tarsal flexion
In the horse, the medial insertion of the cranial tibial muscle (tibialis cranialis) is known as the cunean tendon. There is an associated synovial fluid-filled space known as the cunean bursa, which is also species specific.
<br>
'''''Common Calcaneal Tendon'''''
*'''Origin: Caudal to the stifle joint
*'''Insertion: Calcanean tuberosity
*'''Action''' of components:
**''Biceps femoris'': Extends the hip, abducts the limb, extends the stifle, flexes the stifle (via caudal aspect) and extends the hock
**''Abductor cruris caudalis'': Abducts proximal limb and flexes the stifle
**''Semitendinosus'': Extends the hip, adducts and draws back the limb, extends the stifle and hock
**''Semimembranosus'': Extends the hip, adducts and draws back the limb, rotates limb inward, extends the stifle and hock
**''Gastrocnemius'': Flexes the stifle and extends the 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 synovial fluid-filled '''calcanean bursa''' lies between the SDFT and the '''calcanean tuberosity'''.
<br>
'''''Peroneus Tertius'''''
*'''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)
*'''Action''': Passively flexes the tarsal joint when the stifle joint 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.
<br>
'''''Superficial Digital Flexor Tendon'''''
*'''Origin''': Proximal/mid-tibia
*'''Insertion''': Calcanean tuberosity and middle phalanx
*'''Action''': Extends the digit, assists in extending the hock and flexing the 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 middle phalanx.
In contrast to the thoracic limb, there is no accessory ligament of the SDFT in the pelvic limb.
<br>
'''''Deep Digital Flexor Tendon (DDFT)'''''
*'''Origin''': Deep digital flexor muscle, distal to the tarsus
*'''Insertion''': Flexor cortex of distal phalanx
*'''Action''': Flexes the distal phalanx
The DDFT runs on the plantar aspect of the metatarsus distally, over the distal sesamoid bone ('''navicular bone'''). Its passage over the navicular bone is facilitated by the synovial fluid-filled '''navicular bursa''' before inserting on the flexor cortex of the distal phalanx.
The accessory ('''check''') ligament connects the DDFT to the third metatarsal. This forms part of the '''stay apparatus''' by removing tension from the main body of the DDFT.
<br>
'''''Suspensory Ligament'''''
*'''Origin''': Third metatarsal (cannon) and distal tarsal bones
*'''Insertion''': Proximal sesamoids, joins long digital extensor tendon
*'''Action''': Prevents fetlock hyperextension and limits plantar flexion
Originating from the proximal aspect of the third metatarsal (cannon) and distal tarsal bones, the SL of the pelvic limb is relatively thinner and longer than that of the forelimb. It lies within the metatarsal groove deep to the DDFT. Continuing distally it bifurcates into two '''extensor branches''', as in the thoracic limb, which insert on the '''proximal sesamoid bones'''. Identical to in the thoracic limb, medial and lateral branches then join the long digital extensor tendon.
==References==
==References==