Lec1 - Defining the Pelvic Region Flashcards
How many bones (including ligaments) make up the pelvis?
Four: Ilium Ischium and pubis Sacrum Coccyx
What is the latin for pelvis?
Os coxa
Name the four ligaments of the pelvis
Sacroiliac - between the sacrum and ilium (with anterior and posterior component)
Sacrococcygeal - sacrum to coccyx
Sacrospinous - sacrum/coccyx to ischial spine
Sacrotuberous - posterior to the sacrospinous, between the lateral aspect of the sacrum margin of the ischial tuberosity
What is the perineum?
Refers to the space located at the pelvic outlet and inferior to the pelvic diaphragm - i.e. muscle of the pelvic floor
Describe the borders/limits of the perineum
Diamond shaped surface extending from the mons pubis (in females) to the medial surface of the thighs (laterally) and posteriorly to the gluteal folds
What are the names of the two triangles that the perineum can be divided into and what is the line of division?
A transverse line from the two ischial tuberosities splits the perineum into 2 triangles:
Urogenital triangle
Anal triangle
What does the midpoint of the transverse line joining the two ischial tuberosities define?
The perineal body
What is the significance of the perineal body?
The perineal body sees the convergence of several sphincter and perineal pouch muscles
This area can also get damaged during childbirth
What does the deep perineal pouch enclose?
Urethra
Vagina in females
Glands e.g. bulbourethral (Cowper glands in males)
Perineal muscles that act as sphincters - Compressor urethrae or urethrovaginal sphincter in females
What does the superficial perineal pouch enclose?
Urethra Vagina in females Root of penis in males Glands e.g. bartholin in females Perineal muscles that provide support to the external genitalia e.g. bulbospongiosus or ischiocavernous muscles
What are the bones of the articulated pelvis?
Sacrum
Ileum, pubis, ischium
Ischial tuberosity
Ischial spine
What are the joints of the articulated pelvis?
Sacroiliac
Sacrococcygeal
Pubic symphysis
What are the ligaments of the articulated pelvis?
Sacrospinous
Sacrococcygeal
Sacrotuberous
Sacroiliac
The pelvic brim/pelvic inlet is formed by the:
Premontory and ala of the sacrum
Arcuate line
Pectineal line
What is the function of the pelvic brim/inlet?
Separates the true pelvis from the greater pelvis
What are the borders of the true pelvic cavity?
Sacrum/coccyx - posterior Pubic symphysis - anterior Pelvic diaphragm - inferior Pelvic brim - superior Obturator internus muscle - lateral
What are the contents of the true pelvic cavity?
Reproductive organs and tracts
Bladder
Rectum
Name the pelvic musculature that line the wall of the pelvis:
Piriformis
Obturator internus
Name the pelvic musculature that line the pelvic floor
Coccygeus
Levator ani
Which muscles make up the Levator ani?
Iliococcygeus
Pubococcygeus
Puborectalis
Origin and insertion of the piriformis?
Origin: Anterior surface of the sacrum
goes through the greater sciatic foramen i.e. over the ischial spine
Inserts onto the greater trochanter of the femur
Origin & insertion of the Obturator internus
Origin: internal surface of the obturator membrane
Through the lesser sciatic foramen (below ischial spine)
Inserts on to the greater trochanter of the femur
Origin and insertion of the coccygeal
Origin: ischial spine
Insertion: inferior end of the sacrum and coccyx
Iliococcygeus
Origin: tendinous arch
Insertion Anococcygeal body
What is the tendinous arch?
A line extending from the ischial spine to the posterior aspect of the pubic bone
Pubococcygeus
Origin: posterior aspect of the pubic bone
Insertion: Lateral fibres insert to the coccyx
Medial fibres insert onto the contralateral fibres of the pubococcygeus itself
Puborectalis:
Continuous muscle that
Origin: Posterior aspect of the pubic bone
Slings behind the rectum
What is the blood supply to the pelvis?
Anterior division of the iliac (uterine, vesicular and internal pudenal arteries)
Gonadal arteries supply the gonads
Where do the gonadal arteries come off the abdominal aorta and why?
Just below the level of the renal arteries
because during development the gonads develop very close to the kidneys
Veins draining the pelvis?
Internal iliac vein - to the common iliac veins
Gonadal veins - draining to the IVC or L renal vein
What are the somatic plexuses of nervous control of the pelvis?
Lumbosacral (L4-S4 joined by lumbar L4/L5)
Coccygeal (S4 -Co)
What are the nerves supplying the pelvic region?
Sciatic nerve
Superior gluteal
Inferior gluteal
Pudendal nerve
What are the visceral plexuses in this region?
Paravertebral/prevertebral
Sympathetic/parasympathetic/visceral fibres
e.g. for erection/ejaculation
e.g. inferior hypogastric plexus
Which foramen does the obturator nerve go through?
Obturator foramen
What are the nerve roots of the superior gluteal nerve?
L4, L5, S1
What are the nerve roots of the inferior gluteal nerve?
L5, S1, S2
What are the nerve roots of the sciatic nerve?
L4, L5, S1, S2
What are the nerve roots of the pudendal nerve?
S2, S3, S4
What type of innervation are the pelvic splanchnic nerves?
Parasympathetic
What time of innervation are the sacral sympathetic trunk, superior and inferior hypogastric plexuses?
Sympathetic
What nerve goes out through the greater sciatic foramen and inferior to the piriformis, around the ischial spine and back in through the inferior sciatic foramen
Pudendeal nerve
What area does the pudendal block numb?
The areas supplied by the pudendal nerve
How do you find the pudendal nerve and administer the pudendal block
Because the pudendal nerve wraps around the ischial spine, you palpate for ischial spine and administers the anaesthetic to this area to block the whole pudendal region
