Exam 3- Sacral Plexus Flashcards
What branch of the sacral plexus travels through the sacral hiatus
Posterior ramus of S5
Which way does the posterior sacral rami decrease in size?
Superior to Inferior
The posterior rami of S1-S3 divide into what two branches
Medial and lateral branches
What branch of the posterior rami of S1-S3 is motor?
The medial branch is motor, supplies the adjacent Multifidus
The lateral posterior branches of S1-S3 supply the
Skin over the buttocks and combine with L5 and S4
What branches of the sacral plexus combine with the coccygeal posterior rami to supply the skin over the coccyx
S4 and S5
How many sacral sympathetic ganglia are there
Three or four
The anterior primary of each sacral nerve receives postganglionic fibers via
A gray ramus communicans
The gray ramus communicans sends what kind of fibers to the anterior primary rami of each sacral nerve?
Postganglionic sympathetic fibers
The sacral plexus is formed by the anterior primary rami of
L4,L5, S1-S3, and part of S4
How does L4, L5 contribute to the Sacral plexus
Via the lumbosacral trunk
Where is the sacral plexus formed?
On the anterior surface of the piriformis muscle
What fibers make up the nerve to the quadratus femoral and gemellus inferior
L4,L5,S1 nerves
The nerve to the quadratus femoris and gemellus inferior exit the pelvis through
The greater sciatic foramen
What muscles contribute to the lateral rotation and adduction of the thigh
Nerve to the quadratus femoris and gemellus inferior
The nerve to obturator internus and gemellus superior is fibers from
L5, S1,S2
THe nerve to the obturator internus and gemellus superior exits the pelvis through the
Greater sciatic foramen
The nerve to obturator internus re enters the pelvis via the
Lesser sciatic foramen to supply obturator internus
What muscles contribute to lateral rotation and abduction of the thigh
Nerve to obturator internus and gemellus superior
The pudendal nerve contains fibers from
S2,S3,S4
The pudendal nerves course is
Leaves pelvis via greater sciatic foramen, arches around the ischial spine, and into the perineum via the lesser sciatic foramen
The pudendal nerve travels in the
Pudendal canal, inferior to the pubic symphysis to reach the dorsal side of the Penis or Clitoris
The inferior rectal nerves are a branch of
The pudendal nerve
The inferior rectal nerves carries sensory info from
The skin around the anus and the inferior 2/3 of the anal canal
The inferior rectal nerves is the motor supply to
External anal sphincter
The perineal nerve is a branch of the
Pudendal nerve
The deep branches of the perineal nerve supply what four muscles
External anal sphincter
Bulbosponsiosus
Ischiocavernosus
Superficial transverse perineus
The superficial branches of the perineal nerve supplies
Sensory fibers
Males- posterior sacrum, urethral mucosa, bulb of penis
Females- labium majus, external urethral orifice, vestibule
What is the terminal branch of the pudendal nerve
The dorsal nerve of the penis/clitoris
What does the dorsal nerve of the penis/clitoris motor supply
Deep transverse perineus
Urethral sphincter muscles
The dorsal nerve sensory fibers supply
Males- corpus cavernosum, glans penis, skin covering the penis
Females- corpus cavernosum, clitoris
What supplies the levator ani and coccygeus muscles
Muscular branches of S4
The pelvic splanchnic nerve contains fibers from
S2,S3,S4
The nerve to piriformis contains fibers from
S1,S2
The superior gluteal nerve is made up of fibers
L4,L5,S1
The superior gluteal nerve leaves the pelvis via
Greater sciatic foramen, superior to the piriformis and splits into superior and inferior branches
The superior gluteal nerve superior branches supply
Gluteus medius and minimus
The inferior branches of the superior gluteal nerve supply
Gluteus medius, gluteus minimus, tensor fascia late
The inferior gluteal nerve fibers are from
L5,S1,S2
The inferior gluteal nerve leaves the pelvis via the
Greater sciatic foramen inferior to piriformis,
What muscles does the inferior gluteal nerve supply
Gluteus Maximus
The perforating cutaneous nerve contains fibers from
S2,S3
The perforating cutaneous nerve travels
Through the sacrotuberous ligament, ultimately reaching lower medial aspects of the buttocks
The perforating cutaneous nerve may also be formed by a branch off of
The pudendal nerve or be absent
The posterior cutaneous nerve of the thigh is made up of
Anterior division of S2,S3
Posterior divisions of S1,S2
The posterior cutaneous nerve of the thigh travels
Exits pelvis through greater sciatic foramen, descends through posterior thigh and inferior to the leg where it will communicate with the SURAL NERVE
The posterior cutaneous nerve of the thigh supplies the skin on the
Posterior and medial thigh
What is the largest nerve in the human body
Sciatic nerve
What is the size of the sciatic nerve
2 cm in diameter
What are the two nerves that combine to make up the sciatic nerve
Tibial nerve and common fibular nerve
The tibial nerve is formed by the
Anterior divisions of L4-S3
Is located medial
The common fibular nerve is made up of
Posterior divisions L4-S2
The sciatic nerve exits the pelvis in a common shealth through the
Greater sciatic foramen, below the piriformis
The sciatic nerve travels posterior aspect of the
Adductor Magnus, approx. 2/3 of the way to the knee, where it splits into common fibular and tibial
