A19 - Sacrum, art. sacroiliaca

Question 1

Sacrum

General information

Answer 1

• The sacral vertebrae and their ossified intervertebral discs are fused to form a single bone, the sacrum
• The fusion is usually completed by 1.5 years in carnivores
• Fusion leads to loss of flexibility of the sacral vertebral colum
  
  • This increases the effectiveness of the transmission of the forward impetus in locomotion from the hindlimbs of the vertebral column
• The dorsal surface gives attachment of hip, rump and hamstring musculature
• Provides passage of the dorsal spinal nerve plexus lumbosacralis
• The second sacral vertebrae gives rise to ala sacralis

Question 2

Sacrum

Structures

Answer 2

• Basis ossis sacri
  
  • Processus articularis cranialis (on 1^st sacral vertebrae)
  • Promontorium
• Pars lateralis
  
  • Ala sacralis
  • Facies auricularis
  • Tuberositas sacralis
• Facies dorsalis
  
  • Crista sacralis mediana (bo, old eq)
  • Crista sacralis intermedia (bo)
  • Foramina sacralia dorsalia
  • Crista sacralis lateralis
• Facies pelvina
  
  • Foramina sacralia ventralia
  • Lineae transversae
• Apex ossis sacri
  
  • Processus articularis caudalis (on last sacral vertebrae)
• Canalis sacralis
• Foramina intervertebralia

Se definisjon i egne notater

Question 3

Sacrum

Give the interspecies differences

Answer 3

• Crista sacralis mediana (bo, old eq)
• Crista sacralis intermedia (bo)
• Car: rectangular shape
• Other species: triangular shape

Question 4

Sacroiliac joint

1. Type of joint
2. Ligaments
3. Draw

Answer 4

• Amphiarthrosis
• Plane joint (monoaxial)
  
  • ​Movement: slightly movable joint
• They form the pelvic ring
• Between facies auricularis of sacrum → facies auricularis of ilium (on facies sacropelvina)

Ligaments of art. membri pelvini

• Membrana obturatoria (eq)
  
  • Close to for. obturatorium
• Lig. sacrotuberale (ca)
  
  • Os sacrum and 1^st caudal vertebrae → tuber ischiadicum
• Lig. sacrotuberale latum (un)
  
  • Os sacrum and 1^st caudal vertebrae → spina ischiadica and tuber ischiadicum
• For. ischiadicum majus (un)
  
  • Between i**nc. ischiadica major, os scarum and lig. sacrotuberale latum
• For. ischiadicum minus (eq)
  
  • Incisura ischiadica minor → lig. sacrotuberale (un: lig. sacrotuberale latum)

Ligaments of art. sacroiliaca:

• Ligg. sacroiliaca v​entralia
  
  • ​Surrounding joint capsule
  • Ala sacralis → ilium
• Ligg. sacroiliaca interossea
  
  • ​Surrounding joint capsule
  • Tuberositas sacralis → tuberositas iliaca
• ​Ligg. sacroiliaca dorsalia
  
  • Sacrum → ilium
• Lig. sacrotuberale (ø fe)

Symphysis pelvina:

• Symphysis pubica
• Symphysis ischiadica