LAB 5 Pelvic Limb
Pelvic Osteology and Syndesmology
Left Pelvic Limb Removal
Lab Objectives:
• To study the osteology of the pelvis.
• To identify attachments of the sacrosciatic and sacroiliac ligaments and associated foramina.
• To identify the parts of the proximal femur and associated ligaments and tendons.
• To expose and reflect the caudal thigh muscles.
• To expose and reflect the gluteal muscles.
• To expose the sciatic nerve and the ventral branches that form it. To observe bony structures adjacent to the sciatic nerve and ventral branches.
• To remove the left pelvic limb without damage to the external genitalia.
Anatomical Terms:
Osteology and Associated Structure
tuber coxae
tuber sacrale
sacrosciatic ligament
ischium
ischiatic spine
tuber ischii
ischial arch
greater sciatic foramen
lesser sciatic foramen
pelvic inlet
pelvic outlet
sacroiliac joint
wing of the sacrum
ilium
iliac body and wing
femur
greater trochanter
third trochanter
head of the femur
Proximal Pelvic Limb Muscles & Associated Structures
biceps femoris m.
semitendinosus m.
semimembranosus m.
gluteobiceps m. (bov)
superficial gluteal m.
middle gluteal m.
accessory gluteal m.
trochanteric bursa
deep gluteal m.
sciatic n.
internal obturator tendon (eq)
accessory ligament of the femoral head
ligament of the femoral head
caudal gluteal a.
Instructor Commentary:
The pelvis is formed by a strong ligamentous attachment of the pelvic bone to the sacrum. The pelvic bone is formed by fusion of three bones, ilium, ischium and pubic bone. All three bones intersect in the acetabulum. Be sure to remember that ilium is bone, ileum is gut. Ischiatic is an adjective referring to the ischium. Note that dropping the i and h of ischiatic yields the term sciatic, a synonym. The ischiatic spine is the dorsal edge of the ischium and the caudal part of the ilium. The sacrosciatic ligament is broad ligament that extends from the sacrum to the ischiatic = sciatic spine. This ligament is common in herbivores. The caudal edge of the sacrosciatic ligament is equivalent to the sacrotuberous ligament of the dog. During rectal palpation of a cow or mare the sacrosciatic ligament is easily felt as a hard flat sheet forming the lateral wall of the pelvis. The lesser sciatic foramen can be palpated per rectum in cows as a dimple like "hole" between the sacrosciatic ligament and the more ventral bone (ischium). This foramen is caudal within the pelvis so it can be palpated when the palpator's wrist is in the anus.
The wide spread of the tuber coxae is not present in foal or calf but develops as the abdomen fills with a voluminous gut that requires a wide abdomen. The main support of the gut is a wide rectus abdominis muscle together with extensive abdominal oblique muscles. The main place of origin for the internal abdominal oblique m. is the tuber coxae which are wide and strong to support heavy viscera.
Dissection Images:
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