Introduction to the Pelvis and Perineum; Anal Triangle | B2 WK4 Flashcards
What are the 3 bones of the os coxae?
- Ilium
- Ischium
- Pubis
What separates the true pelvis from the false pelvis?
Pelvic inlet
What is inferior to the pelvic inlet and contains pelvic viscera?
True (lesser) pelvis
What is superior to the pelvic inlet and contains inferior abdominal viscera?
False (grater) pelvis
The linea terminalis, or pelvic brim, consists of what?
- Pubic crest
- Pectineal line (pecten pubis)
- Arcuate line
Describe the subpubic angle for a testosterone drive and estrogen-driven pelvis
Testosterone: Smaller angle
Estrogen: wider angle
Which pelvis is heart-shaped and has a small pelvic outlet
Testosterone driven
Which pelvis is oval-shaped and has a large pelvic outlet
Estrogen Driven
The presences of sacrospinous ligament and sacro-tuberous ligament convert the greater & lesser sciatic notch into…
Greater & lesser sciatic foramen
What travels through the obturator canal
Obturator Aa + N
What ligament helps to prevent sacral flexion?
Sacrotuberous ligament
What ligament helps to prevent sacral extension?
Posterior sacroiliac ligament
Lumbar plexus
T12, L1-L4
Lumbosacral trunk
L4-L5
Sacral plexus
S1-S4
Coccygeal plexus
S4-Co1
The lumbar plexus originates posterior to?
Psoas major m.
What are the main nerves of the lumbar plexus?
-Subcostal nerve (T12)
-Iliohypogastric nerve (L1)
-Ilioinguinal nerve (L1)
-Lateral femoral cutaneous nerve (L2-L3)
-Femoral nerve (L2-L4)
-Genitofemoral nerve (L1-L2)
-Obturator nerve (L2-L4)
What are the spinal nerves of the sacral plexus?
“SIPP”
1. Superior gluteal N
2. Inferior gluteal N
3. Posterior cutaneous N of thigh (post. cutaneous N)
4. Pudendal N.
Voluntary sphincters of pelvis and perineum are controlled by what nerve?
Pudendal N
Pelvic splanchnic nerves are…
Parasymphatetic
Sacral splanchnic nerves are…
Symphatetic
Describe innervation of the urinary bladder
-Autonomic nerves innervate detrusor muscle and internal urethral sphincter
-Somatic nerves innervate the external urethral sphincter (UG diaphragm)
Pelvic diaphragm = ________________ + ________________
Levator Ani Muscles + Coccygeus muscles
Levator Ani Muscle = ________________ + ________________ + ________________
Puborectalis m
Pubococcygeus m
Iliococcygeus m
What muscle relaxes during defication?
Puborectalis
What is the perineum?
The area where everything “empties out”
What two triangles make the perineum?
- Urogenital (UG) triangle
- Anal triangle
What are the boundaries of the UG triangle?
-Pubic symphsis
-Ischiopubic rami
-Line connecting ischial tuberosities
What are the boundaries of the anal triangle?
-Coccyx
-Sarcotuberous ligament
-Line connecting ischial tuberosities
What is the central tendon of the perineum derived from?
Embryological urorectal septum
What are the boundaries of the ischioanal fossa?
Lateral: Obturator internus
Medial: External anal sphincter and levator ani
Anterior: line connecting ischial tuberosities
Posterior: Gluteus Maximus
Contects of ischioanal fossa
Fat & Inf. rectal vessels and nerves
What is the function of the ischioanal fossa?
Permits distension of anal canal dring defecation
What is found within the pudendal canal?
-Pudenal Nerve
-Internal pudendal vessels
-N. to obturator internus
