L01 - Defining the Pelvic Region Flashcards
What makes up the articulated pelvis
2 innominate bones: ilium, ischum and pubis
sacrum - 5 sacral vertebrae fusion
coccyx - 4 coccygeal vertebrae fusion
What make up the innominate bones? locate these on diagram
illiac fossa ischial spine ischial tuberosity inferior ramus of pubis bone superior ramus of pubis bone
What’s in the articulated pelvis?
diagram
L5 posterior sacral formamina sacrum sacrococcygeal joint coccyx pubic symphysis sacroiliac joint intervertebral disc
Pelvic liagements
diagram
- Sacroiliac : between the sacrum and the ilium, has an anterior and posterior components
- Sacrococcygeal : between the sacrum to the coccyx
- Sacrospinous : between the ischial spine and the sacrum/coccyx
• Sacrotuberous : posterior to the sacrospinous; between the lateral aspect of sacrum+coccyx onto medial margin of ischial
tuberosity
Perineum
what is it
Refers to the space located at the pelvic outlet and inferior to the pelvic diaphragm (ie muscles of the pelvic floor)
It can be said to describe the narrow region between the thighs
Diamond-shaped surface extending from the mons pubis (in females) to the medial surface of the thighs and posteriorly to
the gluteal folds
Perineum triangles
what does the midpoint of this line define
• A transverse line joining the two ischial tuberosities splits the perineum into two triangles:
Urogenital and anal triangles
• The mid point of this line defines the perineal body
• The perineal body sees the convergence of several sphincter and perineal pouch muscles
Perineum
what are the bones, ligaments, foramina and other features that are present here
pubic symphysis inferior pubic ligament ischial tuberosity perineal membrane deep perineal pouch pubic arch orbiturator foramen inf pubic ramus
Perineum
what does the deep and superficial perineal pouch each enclose
- Deep perineal pouch, encloses:
- Urethra
- Vagina, in females
- Glands, such as bulbourethral (Cowper) glands in males
- Perineal muscles that act as sphincters, such as compressor urethrae or urethrovaginal sphincter in females
’ Superficial perineal pouch, encloses:
• Urethra
• Vagina, in females; root of penis in males
• Glands, such as Bartholin in females (the equivalent to Cowper glands in males)
• Perineal muscles that provide support to the external genitalia, such as the bulbospongiosus or ischiocavernosus
muscles
Pelivic brim
what is formed by
diagram
• Formed by the: Promontory and ala (wing) of sacrum (black line)
Right + Left linea terminalis: Arcuate line (blue line) Pectineal line (green line)
Pelvic cavity (true)
what are the borders of it and what does it contain
The pelvic cavity (true) • Borders: Posterior — sacrum/coccyx Anterior — pubic symphysis Inferior — pelvic floor Superior— pelvic brim Lateral — obturator internus m
• Contents:
Reproductive organs/tracts
Bladder
Rectum
Pelvic musculature
what muscles line the wall and the floor
The pelvic musculature ' Composed of muscles that: line the wall: Piriformis Obturator internus
line the floor:
Coccygeus
Levator ani (iliococcygeus, pubococcygeus and puborectalis)
Piriformis and obturator internus
origins and insertion and where it goes through
• Piriformis :
from the anterior surface of sacrum;
through the greater sciatic foramen ie over the ischial spine;
inserts onto the greater trochanter of femur
• Obturator internus : from the internal surface of the obturator membrane;
through the lesser sciatic foramen ie below the ischial spine; also inserts onto the greater trochanter of femur
Pelvic floor muscles
on diagram
puborectalis muscle pubococcygeus muscle illiococcygeus muscle coccygeus muscle piriformis muscle
where do the
coccygeal
illiococcygeus
pubococcygeus
puborectalis
originate, go through and insert?
• Coccygeal: from the ischial spine to the inferior end of the sacrum + coccyx
• Iliococcygeus : from the tendinous arch — a line extending from the ischial spine to the posterior aspect of the pubic bone — to the
annococcygeal body
• Pubococcygeus: from the posterior aspect of the pubic bone and inserting to the coccyx (lateral fibres) or merging with the
contralateral fibres of the same named muscle (medial fibres)
• Puborectalis : a continuous muscle that originates from the posterior aspect of the pubic bone and slings behind the rectum
Pelvic floor blood supply and drainage
Arteries:
Anterior division of internal iliac, providing several branches, e.g. uterine, vesical or internal pudendal
Gonadal, from abdominal aorta, supplying the gonads
Veins:
Internal iliac, to common iliac veins
Gonadal, to IVC or L renal vein
