Pelvic nerves Flashcards
what is the lumbosacral trunk
L4 and L5 nerve roots form a lumbosacral trunk which carry nerve fibres to join S1 nerve root at the start of the sacral plexus
what is the sacral component of the sacral plexus
S1-S4
what is the largest nerve from the sacral plexus
sciatic nerve
what are the roots of the sciatic nerve
L4,L5,S1-3 (L4-S3)
the sciatic nerve forms on the anterior surface of what muscle
piriformis
where does the sciatic nerve form
anterior surface of piriformis muscle on the lateral internal wall of the pelvis
the sciatic nerve passes out of the pelvis via what to reach the gluteal region
greater sciatic notch
how is the sciatic nerve identified in the gluteal region
very large nerve passing from beneath piriformis to then pass down the posterior surface of the thigh
what does the sciatic nerve supply
posterior compartment of the thigh (hamstring muscles) and then divides into branches that supply all of the muscles of the leg and foot
it also carries sensory fibres
what are the roots of the superior gluteal nerve
L4, L5, S1
what are the roots of the inferior gluteal nerve
L5, S1, S2
what does the superior gluteal nerve supply
gluteus medius and minimus
what does the inferior gluteal nerve supply
gluteus maximus
how are the superior and inferior gluteal nerves identified in the gluteal region
pass through the greater sciatic foramen immediately above and below piriformis
what are the roots of the nerve to the obturator internus
direct L5 - S1
what does the nerve to obturator internus supply
obturator internus
may also supply superior gemellus muscle
what are the roots of the nerve to piriformis
direct from S1 - S2
what does nerve to piriformis supply
piriformis
levator ani and coccygeus both receive fibres from what nerve root
S4
levator ani receives direct fibres from S4 nerve root and also
pudendal nerve
what are the roots of the pudendal nerve
S2-4
why is the pudendal nerve important in maintaining continence
supplies both the external (voluntary) sphincters of the urethra and anal canal
the pudendal nerve forms from nerve roots ____ in the pelvis close to the ____ ____
S2-4, close to the pelvic floor
pudendal nerve passes through the ____, goes around the ____ and then through the ____ to reach the _____ and then the ____
pudendal nerve passes through the greater sciatic foramen, goes around the ischial spine and then through the lesser sciatic foramen to reach the anal triangle and then the perineum
what is used as a landmark in pudendal nerve block
ischial spine
what muscles does the pudendal nerve suppply
levator ani
external anal and external urethral sphincters
bulbospongiosus
ischiocavernosus
the pudendal nerve provides what kind of innervation
motor and sensory
the internal organs of the pelvis and the erectile tissues of the perineum are supplied by
ANS
where is the superior hypogastric plexus found
sits at the bifurcation of the aorta into the common iliac arteries
the superior hypogastric plexus carries what
sympathetic nerve fibres
where is the inferior hypogastric plexus found
internal lateral wall of the pelvis (one on each side)
the inferior hypogastric plexus carries what
mix of sympathetic and parasympathetic fibres
the vagus nerve supplies the abdominal viscera with parasympathetic innervation up until
2/3 transverse colon