Veterinary Gross Anatomy

Sacro-iliac joint

SACRO - ILIAC ARTICULATIONS
(Ox, Horse, Dog)

Ox

 It is diarthrosis between the articular surfaces of the ilium and sacrum.

• Ligaments
  • Capsular ligaments
  • Dorsal sacro-iliac ligaments –connects the dorsum of the sacral spines to the tuber sacrale. In t he spinal attachment it blends with supraspinous ligament.
  • Lateral sacro-iliac ligament is a thick, irregularly quadrilateral sheet, placed above the sacro-sciatic ligament and below the dorsal sacro-iliac ligament. It is attached anteriorly to the tuber sacrale and the medial border of the ilium above the greater sciatic foramen and ventrally to the lateral border of the sacrum. Its lateral surface is in contact with the middle gluteus and biceps femoris and superficial gluteus muscle. Its deep face is related to dorsal and lateral coccygeal muscles.
  • Ilio -lumbar ligament attaches the ilium to the transverse process of the lumbar vertebrae.
  • Sacro-sciatic ligament is a vast membranous expansion situated in the pelvis between the sacrum and the os coxae.
    • It is irregularly quadrilateral in shape and forms the lateral wall of the pelvis.
    • Its dorsal border is attached to the lateral surface of the sacrum and the first two or three coccygeal bones attaches it.
    • Its inferior is attached to ischiatic spine and tuber ischii.
    • It forms between these two attachments and the bones two foramina the greater and lesser sacro-sciatic foramina for the passage of structures out of the pelvic cavity.
    • Its posterior border forms the lateral boundary of the pelvic outlet.
    • The lateral face of this ligament is covered by the gluteus medius and biceps femoris, which derive part of their origin from it.
    • The posterior part of the medial face gives origin to the retractor ani.
• Motion
  • Is appreciable in this joint.

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Horse

• The sacro-sciatic ligament is broader.
• The greater sciatic foramen transmits the posterior gluteal vessels and nerves and the lesser sciatic foramen transmits the tendon of the obturator internus and is pyriform.

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Dog

• The sacro-sciatic ligament is a narrow thin band, which extends from the part of the lateral margin of the sacrum to the tuber ischii.

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