HLTH1008 Chap.3 Pelvic Floor, Perineum and Gluteal Region
Pelvic Floor, Perineum and Gluteal Region
This chapter moves from the floor of the pelvis to the buttock. It defines the pelvic diaphragm, its four functions and the causes of pelvic floor weakness, using a case of stress incontinence.
It then divides the perineum into urogenital and anal triangles and superficial and deep pouches, traces the pudendal nerve through both sciatic foramina, and sets out the attachments, actions and nerves of the three gluteal muscles, the deep lateral rotators and the trochanteric bursae. The chapter ends with practice on the pudendal nerve and the parts of levator ani, two of the shortest high-yield answers in the course.
Its nerves link directly to the plexus chapter, where their roots are set out in full.
What this chapter covers
- 01
Levator ani and ischiococcygeus
- 02
Functions of the pelvic floor
- 03
Causes of pelvic floor weakness
- 04
Perineal triangles and pouches
- 05
Course and supply of the pudendal nerve
- 06
Gluteus maximus, medius and minimus
- 07
Deep lateral rotators of the hip
- 08
Trochanteric bursae and lateral hip pain
Worked example · free
Matching gluteal muscles to their nerves
- +1The superior gluteal nerve arises from L4 to S1.
- +1It supplies gluteus medius, gluteus minimus and tensor fasciae latae.
- +1Gluteus maximus is supplied by the inferior gluteal nerve, L5 to S2, so it is spared.
- +1The weakened muscles are the hip abductors, so single-leg stance becomes unstable.
Key terms
- Levator ani
- The main muscle of the pelvic floor, formed by puborectalis, pubococcygeus and iliococcygeus.
- Perineal membrane
- The sheet that separates the superficial and deep perineal pouches.
- Pudendal nerve
- A mixed nerve from S2 to S4 that supplies the perineum and the external sphincters.
- Piriformis
- A lateral rotator of the hip that passes through the greater sciatic foramen.
- Trochanteric bursa
- The largest bursa on the greater trochanter, lying over its posterior facet.
- Iliotibial band
- A thickened band of fascia lata into which gluteus maximus and tensor fasciae latae insert.
- Ischiorectal fossa
- A fat-filled space beside the anal canal in the anal triangle of the perineum.
- Superior gluteal nerve
- The nerve from L4 to S1 that supplies gluteus medius, gluteus minimus and tensor fasciae latae.
- Anal triangle
- The posterior part of the perineum, containing the anal canal and ischiorectal fossae.
- Inferior gluteal nerve
- The nerve from L5 to S2 that supplies gluteus maximus.
Pelvic Floor, Perineum and Gluteal Region FAQ
What weakens the pelvic floor?
The course lists hormonal change in pregnancy and childbirth, surgery, a chronic cough or chronic constipation, being overweight, inactivity and ageing. It adds that pelvic floor exercises improve strength, which is why they are the usual first approach to symptoms such as leaking on coughing.
Which muscles are in the superficial perineal pouch?
Ischiocavernosus, bulbospongiosus and the superficial transverse perineal muscle, with the erectile tissue. The pouch lies between the perineal membrane and the superficial perineal fascia, while the deep pouch holds the urethra, the external urethral sphincter and, in females, the vagina.
How do gluteus maximus and minimus produce pure extension?
Gluteus maximus extends and laterally rotates the hip, while gluteus minimus can medially rotate it. When both contract, the opposing rotations cancel and the hip extends without turning, an example the Week 3 answers use to show how muscles combine.
Where does the pudendal nerve run?
It leaves the pelvis through the lower part of the greater sciatic foramen, below piriformis, re-enters through the lesser sciatic foramen with the internal pudendal artery, and runs forward in the pudendal canal beside the ischiorectal fossa to supply the perineum and the external sphincters.
What is greater trochanteric pain syndrome?
It is the name the hip lecture gives to trochanteric bursitis, inflammation of one of the bursae over the greater trochanter, and it is one of the common causes of lateral hip pain. The largest of these bursae lies over the posterior facet of the trochanter.
Exam move
Draw the pelvic floor from above and label its parts from front to back, then write its four functions and the causes of weakness under the drawing. Trace the pudendal nerve with a finger on a pelvis model through both sciatic foramina. For the gluteal region, make a table of origin, insertion, action and nerve for the three glutei and piriformis, and test yourself on the gluteal station labels.
Add the gluteal nerves to the table with their roots, and link each to the movement lost when it is injured, so that this chapter connects to the gait signs in the hip chapter.
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