A17 - Vaginae et bursae synoviales of the equine hindlimb

Question 1

Give the accessory structures of muscles and define them

Answer 1

• Recessus: dilation of the joint capsule (not in this topic)
• ​Retinaculum: Thickened part of the fascia, which participates in fastening of the tendons without synovial layer (not in this topic)
• Bursa: Closed cavity that contains synovia
• Vagina synovialis: tendon sheath

Question 2

Bursa

Give the structure of the bursa

Answer 2

• Closed cavity that contains synovia
• Major role: padding
• soma bursa may communicate with the cavity of a nearby joint
• Layers:
  
  • Stratum synoviale
  • Stratum fibrosum
• Types:
  
  • ​Bursa synovialis submuscularis
  • ​Bursa synovialis subfacialis
  • ​Bursa synovialis subtendinea
  • ​Bursa synovialis subcutanea

Question 3

Vagina synovialis

Answer 3

• Vagian synovialis = tendon sheath
• Some tendon sheaths may communicate with the cavity of nearby joint
• Role:
  
  • Padding
  • Providing sliding surface
  • Nutrition
• Vagina synoviales communis (contains more tendons)
• General structure (numbers on picture):
  
  1. Stratum fibrosum
  2. Stratum synoviale parietalis (lamina externa)
  3. Cavitas synovialis
  4. Stratum synoviale visceralis (lamina interna)
  5. Mesotendineum (blood and nerve supply of the tendon runs through this)

Question 4

Hindlimb (eq)

Answer 4

• Bursa subcutanea trochanterica
  
  • ​Skin → trochanter major
• ​Bursa subcutanea iliaca (coxalis)
  
  • ​Skin → tuber coxae
  • Run next to:
    
    • A. circumflexa ilium profunda
    • N. cutanea femoris lateralis
• ​Bursa subfascialis prepatellaris
  
  • ​Fascia → patella
• ​​Bursa subtendiae prepatellaris
  
  • ​M. quadriceps femoris→ patella
• ​Bursa infrapatellaris proximalis
  
  • ​Lig. patellae intermedium → patella
• ​Bursa infrapatellaris distalis
  
  • ​Lig. patellae intermedium → tibia
• ​Bursa subcutanea calcanea
  
  • Skin → tendo plantaris at tuber calcanei
• ​Bursa calcanea m. flexoris digitorum superficialis (​Bursa subtendinea calcanea)
  
  • ​​Tendo m. gastrocnemii → tendo m. flexor digitorum superficialis
  • Extends one hand’s with proximal over the tarsus
  • Extends until the middle of the tarsus distally, located between the tendo plantaris and the lig. plantare longum
  • Eq: communicate with bursa tendinis calcanei
• ​Bursa tendinis calcanei
  
  • ​Tendo accessorius → tendo m. gastrocnemii
  • Eq: communicates with bursa calcanea m. flexoris digitorum superficialis

On the flexor side of the tarsus:

• All tarsus flexors and digital extensors run in their own tendon sheath
  
  • In canine, the m. ext. digitorum lateralis and the m. fibularis brevis run in a common tendon sheath
• Bursa subtendinea m. tibialis cranialis
  
  • ​medial insertion tendo of m. tibialis cranialis → inserting part om medial collateral ligament of tarsus

On the extensor side of the tarsus:

• M. flexor diitorum superficialis
  
  • ​Galea calcaneia fastens it onto the tuber calcanei
• M. flexor digitorum profundus
  
  • ​Each part runs on the tarsus in their own tendon sheath
  • M. flexor digitorum profuncus is fastened by the retinaculum flexorium
  • M. flexor digitorum medialis and m. tibialis caudalis runs on the sulcus mallelus medialis
  • M. flexor digitorum lateralis runs on the sustentaculum tali
• Because of these, there is no need for proximal common tendon sheath
• Vagina tendineum digitorum pedis
  
  • ​Distal common tendon sheath
  • Behind the fetlock joint, on the surface of the scutum proximale
  • Fastened by the lig. anulare digiti
  • Contains:
    
    • The tendon for both digital flexors:
      
      • M. flexor digitorum superficialis
      • M. flexor digitorum profundus
    • ​​Manica flexoria
      
      • ​​T​**​he superficial digital flexor’s tendon surrounds the deep digital flexor’s tendon)
• Bursa subtendinea m. extensoris digitori longi
  
  • ​M. extensoris digitori longi → fetlock joint
• Bursae subtendineae mm. interosseum pedis
  
  • ​Under the tractus appositus (Ex. m. interosseus medius) on both sides, at the ventral lateral/medial margins of the fetlock joint before they merge with the a m. extensor dig. longus
• Bursae podotrochlearis pedis
  
  • ​M. flexor digitorum profundus → distal sesamoid bone