Lecture 8: Pelvic contents Flashcards
Describe pelvic tilt:
60 degree tilt anteriorly
- ASIS in line with pubic tubercle
Describe the pelvic boundaries:
Ant, Post and Lat walls = bone
Floor = Pelvic diaphragm
What two ligaments for the greater and lesser sciatic foramen?
Sacrotuberous and sacrospinous ligaments
Whats of note when it comes to the branches of the internal iliac:
Large branching vessels have a consistent pattern
Small branching vessels have a huge variation
What are the venous drainage of the pelvis?
Rich venous plexuses surrounding
- Bladder
- Prostate
- Rectum
- Uterus
- Vagina
All draining to internal iliac veins
What are the exceptions for venous drainage?
Deep dorsal vein of the penis / clitoris
Rest of perineum drains back with internal pudendal vein
DDVoP/C passes through anterior deficiency in Perineal membrane and then into Vesical/Prostatic plexuses
What nerves contribute to the sacral plexus? and where do the nerves it generates go?
L4,5 S1-4
Mostly going to innervate structures external to plevis BUT some important nerves to pelvis and perineum
What are the roots of the superior and inferior gluteal, what is there name based off and what do they innervate?
Superior gluteal (L4,L5,S1) - To gluteus medius and minimus
Inferior gluteal (L5,S1,S2) - To gluteal maximus
Pass superior and inferior to piriformis muscle respectively.
What contributes to the sciatic nerve? what can it be divided into and what do they pass respectively to?
Sciatic nerve L4-S3
Tibial part, usually leaves below piriformis
Common fibular part, may leave above, below or through piriformis (ANOTHER ANATOMICAL VARIATION)
What nerves contribute to the levator ani and coccygeus?
S3-S4
Damage/Compression here can result in relaxation of the external anal sphincter
What forms the pudendal nerve and whats are its functions?
S2-4
Perineum function and sensation (Motor and Sensory)
What nerves come off the pudendal n.?
- Inf. rectal
- Perineal
- Dorsal nerve to clitoris / penis
- Scrotal / labial
What is the root and action of the sciatic nerve:
L4-S3
Motor/sensory of the hamstrings / legs
What is the nerve, root, action of the post. femoral cutaneous?
S1-S3
Sensory: Post thigh, post leg and perineum
What is the nerve, root, action of the pudendal nerve?
S2-S4
Motor/sensory: Levator ani, ext. anal sphincter, ext. urethral sphincter, bulbospongiosus, ischiocavernosus, sensory to perineum and associated structures.
What is the nerve, root, action of the n. to lev ani/coccygeus:
S3-4
Motor: Lev ani. and coccygeus
What are the 2 ANS plexuses of the pelvic viscera?
- Superior hypogastric (Ant. body of L5 and sacral promontory)
- Inferior hypogastric (Right and Left) - Pelvic floor
NB both ascend to supply the terminal hindgut
What is the role of the sympathetic fibres in the ANS plexuses of the pelvis?
- L1/2 fibres
- Contract internal urethral and anal sphincters (continence)
- Ejaculation
- Moving secretions along epididymis
What is the role of the parasympathetic fibres in the ANS plexuses of the pelvis?
- S2-4 fibres
- Vasodilation i.e for erections in males and females
- Stimulate contraction of bladder
Describe the anatomy of the sympathetic innervation of the pelvis:
- L1/2 fibres mostly
- DESCEND into plevis via superior hypogastric plexus AND directly form SACRAL SPLACHNIC NERVES
- Plexus splits to form two big HYPOGASTRIC NERVES
Describe the anatomy of the parasympathetic innervation of the pelvis:
S2-4
- Ascend via hypogastric nerves to sup. hyposgastric plexus and into abdomen
- Direct into inf. hypogastric plexus.
Whats this?
Saddle fracture
