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==Common Structures of the Distal Hindlimb==

==Common Structures of the Distal Hindlimb==

===Tibia===

===Tibia===

The tibia is one of the major weight bearing bones of the hind limb and is involved in both the stifle and hock. The tibia can be divided into three distinct sections:

The tibia is one of the major weight bearing bones of the hind limb and is involved in both the stifle and hock. The tibia can be divided into three distinct sections:

'''''Proximal Extremity'''''

1. '''''Proximal Extremity'''''

* It is three sided and has two condyles which are seperated by the '''popliteal notch''' on its caudal aspect.

 

* The condyles have an articular surface which articulates with its corresponding femoral condyle or the distal surface of the meniscus.

It is three sided and has two condyles which are seperated by the '''popliteal notch''' on its caudal aspect. The condyles have an articular surface which articulates with its corresponding femoral condyle or the distal surface of the meniscus. In between these articular surfaces lies the '''intercondylar eminence'''. The '''central intercondylar area''' divides this into a '''higher medial part''' and a '''lower lateral part'''. Cranial and caudal to the eminence are depressions where ligaments attach. The lateral side of the condyle has an articular facet for the articulation with the fibula. The '''extensor groove''' is a large notch on the craniolateral aspect which allows passage of the long digital extensor muscle.

* In between these articular surfaces lies the '''intercondylar eminence'''. The '''central intercondylar area''' divides this into a '''higher medial part''' and a '''lower lateral part'''.  

 

* Cranial and caudal to the eminence are depressions where ligaments attach.

2.'''''Tibial Shaft'''''

* The lateral side of the condyle has an articular facet for the articulation with the fibula.  

 

* The '''extensor groove''' is a large notch on the craniolateral aspect which allows passage of the long digital extensor muscle.

It is craniocaudally compressed. The '''tibial tuberosity/tibial crest''' projects cranially from the proximal part of the shaft and is an important palpable landmark. The '''cranial border of the tibia''' is an extension of the crest distally. It divides the cranial aspect of the shaft in two. The medial aspect is subcutaneous and the lateral aspect is covered in muscles.

'''''Tibial Shaft'''''

 

* It is craniocaudally compressed.

3. '''''Distal Extremity'''''

* The '''tibial tuberosity/tibial crest''' projects cranially from the proximal part of the shaft and is an important palpable landmark.

 

* The '''cranial border of the tibia''' is an extension of the crest distally. It divides the cranial aspect of the shaft in two. The medial aspect is subcutaneous and the lateral aspect is covered in muscles.

This carries the '''cochlea''' which has two grooves divided by a ridge. This central ridge is directed sagittally in most species. The cochlea articulates with the trochlear ridges of the talus. The '''medial malleolus''' lies on the medial side of the cochlea and is a bony protuberence. The lateral aspect of the cochlea is highly variable in domestic species.

'''''Distal Extremity'''''

* This carries the '''cochlea''' which has two grooves divided by a ridge.

* This central ridge is directed sagittally in most species.

* The cochlea articulates with the trochlear ridges of the talus.  

* The '''medial malleolus''' lies on the medial side of the cochlea and is a bony protuberence.  

* The lateral aspect of the cochlea is highly variable in domestic species.

'''''[[Ossification Hindlimb - Anatomy & Physiology#Tibia|Ossification Centers of the Tibia]]'''''

Click here for [[Ossification Hindlimb - Anatomy & Physiology#Tibia|ossification centers of the tibia]].

===Fibula===

===Fibula===

The fibula lies laterally to the tibia and proximally doesn't interact with the stifle joint. The fibula consists of a '''proximal head''', a '''neck''', a '''shaft''' and a distal extremity/'''lateral malleoulus'''.

 

During evolution the fibula has been reduced in size and so also in relative strength and function. The amount of reduction is highly variable in domestic species.

The fibula lies laterally to the tibia and proximally doesn't interact with the stifle joint. The fibula consists of a '''proximal head''', a '''neck''', a '''shaft''' and a distal extremity/'''lateral malleoulus'''. During evolution, the fibula has been reduced in size and so also in relative strength and function. The amount of reduction is highly variable in domestic species.

===Tarsal bones===

===Tarsal bones===

The '''tarsus/hock''' is made up of two bones that lie between the crus and metatarsals.

 

The proximal row is made of the '''talus''' and '''calcaneous''' and articulate with the tibia forming the '''tarsocrural joint'''.

The '''tarsus/hock''' is made up of two bones that lie between the crus and metatarsals. The proximal row is made of the '''talus''' and '''calcaneous''' and articulate with the tibia forming the '''tarsocrural joint'''. The distal row is made up of the central, 1st, 2nd, 3rd and 4th tarsal bones. The pattern of these bones is highly variable amongst domestic species, but in general they articulate with proximal row forming the '''tarsocrural joint''' and with the metatarsal bones forming the '''tarsometatarsal joint'''.  

The distal row is made up of the central, 1st, 2nd, 3rd and 4th tarsal bones. The pattern of these bones is highly variable amongst domestic species. But in general they articulate with proximal row forming the '''tarsocrural joint''' and with the metatarsal bones forming the '''tarsometatarsal joint'''.  

'''''Talus'''''

'''''Talus'''''

* The largest bone of the tarsus and is the medial bone of the proximal row.  

 

* It can be divided into three distinct areas; the compact '''body''', the '''trochlea''' and the '''head'''.

The largest bone of the tarsus. It is the medial bone of the proximal row. It can be divided into three distinct areas; the compact '''body''', the '''trochlea''' and the '''head'''. The '''trochlea''' has prominent sagittal ridges dorsoproximally that articulate with the sagittal grooves and intermediate ridge of the distal end of the '''tibia'''. The cylindrical '''head''' is a smaller distal trochlea that articulates with the '''central tarsal bone'''. The plantar and lateral sides articulate with the '''calcaneous'''.

* The '''trochlea''' has prominent sagittal ridges dorsoproximally that articulate with the sagittal grooves and intermediate ridge of the distal end of the '''tibia'''.

 

* The cylindrical '''head''' is a smaller distal trochlea that articulates with the '''central tarsal bone'''. The plantar and lateral sides articulate with the '''calcaneous'''.

'''''Calcaneus'''''

'''''Calcaneus'''''

* It lies laterally and plantar to the '''talus'''.

 

* It articulates medially and dorsally to the talus and distally towards the 4th tarsal bone.  

It lies laterally and plantar to the '''talus'''. It articulates medially and dorsally to the talus and distally towards the 4th tarsal bone. It has a proximal plantar projection called the '''calcaneal tuberosity''', it is this that forms the palpable '''point of the hock'''. It acts as a lever for muscles involved in hock extension. The '''susentaculum tali''' lies on the medial aspect of the distal portion of the calcaneus. It supports the deep digital flexor tendon and overlaps the talus on its plantar side.

* It has a proximal plantar projection called the '''calcaneal tuberosity''', it is this that forms the palpable '''point of the hock'''. It acts as a lever for muscles involved in hock extension.

 

* The '''susentaculum tali''' lies on the medial aspect of the distal portion of the calcaneus. It supports the deep digital flexor tendon and overlaps the talus on its plantar side.

'''''Distal Row of Tarsal Bones'''''

'''''Distal Row of Tarsal Bones'''''

==Joints of the Distal Hindlimb==

==Joints of the Distal Hindlimb==