Sacral Plexus - Part 1 Flashcards
The sacral plexus if formed by what?
Anterior primary ram of L4, L5, S1-S3, and part of S4
The contributions of L4 and L5 to the sacral plexus are by way of what?
The lumbosacral trunk
The sacral plexus forms on the ______ surface of what muscle?
Anterior
piriformis
Shortly after exiting the IVF/sacral foremen the nerve roots contributing to the sacral plexus divide into what?
Anterior and posterior divisions
The nerve to the quadratus femoris and gemellus inferior contain fibers from what nerves?
L4, L5, and S1
Quadratus femoris and gemellus inferior do what action?
Lateral rotation and adduction of thigh
The nerve to the quadratus femoris and gemellus inferior leave the pelvis through what?
Greater sciatic foramen
Is the obturator internus inside or outside the pelvis?
inside
Is the gemellus superior inside or outside the pelvis?
outside
The nerve to the obturator internus and gemellus superior carries fibers from which nerves?
L5, S1 and S2
The nerve to the obturator internus and gemellus superior exits the pelvis via what?
Greater sciatic foramen
The nerve to the obturator internus and gemellus superior gives off what branches after exiting the pelvis through the greater sciatic foremen?
Branches to gemellus superior
After giving off branches to the gemellus superior, the nerve to the obturator internus and gemellus superior does what?
Re- enters the pelvis through the lesser sciatic foramen
After re-entering the pelvis via the lesser sciatic foremen, the nerve to the obturator internus and gemellus superior supplies what?
Obturator internus
The obturator internus and gemellus superior contribute to what actions?
Lateral rotation and abduction of the thigh
The pudendal nerve contains fibers from what?
S2, S3, S4
The pudendal nerve leaves the pelvic cavity through what?
Greater sciatic foramen
After leaving the greater sciatic foremen, the pudendal nerve arches around what?
Ischial spine
After leaving the greater sciatic foremen and arching around the ischial spine, the pudendal nerve enters the perineum via what?
Lesser sciatic foramen
Once the pudendal nerve exits the lesser sciatic foremen if enters what?
The pudendal canal
The pudendal canal is inferior to what?
Pubic symphysis
The pudendal nerve travels through the pudendal canal in order to reach what in males and females?
Penis - males
Clitoris - females
What is the terminal branch of the pudendal nerve?
Dorsal nerve of the pens/clitoris
What branches come off the pudendal nerve within the pudendal canal?
Inferior rectal nerve
perineal nerve
Dorsal nerve of the penis/clitoris (terminal)
The inferior rectal nerve carries what type of information?
Sensory and motor
The inferior rectal nerve carries sensory information from where?
Skin around angus
Inferior 2/3 of anal canal
The inferior rectal nerve carries motor supply to what muscle?
External anal sphincter
The perineal nerve (off the pudendal nerve) divides into what?
Deep and superficial branches
The deep branches of the perineal nerve supply what muscles? (4)
External anal sphincter
bulbospongiosis
ischiocavernosus
Superficial transverse perineum
The superficial branches of the perineal nerve carries sensory fibers from what area in males?
Posterior scrotum,
Urethral mucosa
Bulb of penis
The superficial branches of the perineal nerve carries sensory fibers from what are in females?
Labium majorum
External urethral orifice
vestibule
The terminal branch of the pudendal nerve, the dorsal nerve of the clitoris/penis, supplies what muscles?
Deep transverse perineum
Urethral sphincter muscles
The dorsal nerve of the penis carries sensory information from where?
Corpus cavernosum
glans penis
Skin covering the penis
The dorsal nerve of the clitoris carries sensory information from where?
Corpus cavernosum
clitoris
Individual muscular fibers off of the sacral plexus contain fibers from S4 supply what muscles?
levator and
coccygeus muscles
The pelvic splanchnic nerves contain fibers from what?
S2, S3, and S4
Which nerves are off of the anterior division of the sacral plexus?
Pelvic splanchnic nerves
Muscular fibers of S4
Pudendal nerve
Nerve to the obturator internus and gemellus superior
Nerve to the obturator externus and gemellus inferior
What nerves come off of the posterior division of the sacral plexus?
Nerve to piriformis
Superior gluteal nerve
Inferior gluteal nerve
Perforating cutaneous nerve
What two nerves are formed by branches of BOTH the anterior and posterior divisions?
Posterior cutaneous nerve of the thigh
Sciatic nerve
Common fibular nerve
The nerve to the piriformis carries fibers from what?
S1 and S2
The nerve to the piriformis supplies what?
Piriformis muscle
The superior gluteal nerve is made up of fibers from what?
L4, L5, S1
The superior gluteal nerve leaves pelvis through what and superior to what?
Greater sciatic foremen
piriformis
The superior gluteal nerve splits into what?
Superior and inferior branches
The superior branch of the superior gluteal nerve supplies what muscles?
gluteus medius and minimus
The inferior branch of the superior gluteal nerve supplies what muscles?
Gluteus medius, minimus, and tensor fascia lata
The inferior gluteal nerve carries fibers from what?
L5, S1, and S2
The inferior gluteal nerve leaves the pelvis via the _____ inferior to what?
Greater sciatic foremen
piriformis
The inferior gluteal nerve innervates what muscle?
Gluteus maximus
