QuestionSBA
QuestionChoice
This is a nerve bundle formed by the anterior rami of the L4-L5 lumbar nerves and is a root which contributes to the sacral plexus.
10014282
e
Lumbosacral trunk
QuestionChoice
The prostate is innervated by the prostatic plexus arising from the inferior hypogastric plexus. This inferior hypogastric plexus is formed by the contributions from the pelvic and sacral splanchnic nerves and superior hypogastric plexus.
10014278
a
Inferior hypogastric plexus
QuestionChoice
This provides sensory innervation to the skin overlying the coccyx.
10014281
d
Coccygeal plexus
QuestionChoice
The Lumbar plexus (L1-4) spreads over the anterior surface of the psoas major muscle. It innervates muscles of the posterior abdominal wall, thigh, skin of the labia, inguinal region, thigh and scrotum.
10014279
b
Lumbar plexus
QuestionChoice
The Sacral plexus (L4, L5) lies on the anterior surface of the piriformis muscle. It mostly supplies the gluteal and lower limb muscles.
10014280
c
Sacral plexus
Concept
Chapter
## Summary

The prostate gland is located inferior to the neck of the bladder, and posterior to the ampulla of the rectum.

## Anatomy

It is known for being the size of a walnut, but can be subject to increase in later life - either as a part of a benign prostatic hyperplasia (BPH) process, or as a result of malignancy.

The prostate has four zones, three of main anatomical importance.

- **Central** zone - this encloses the ejaculatory ducts
- **Transitional** zone - this encloses the prostatic urethra and is the site of BPH
- **Peripheral** zone - this is the main bulk of the prostate, and is the area felt on digital rectal examination

The **fibromuscular stroma** is the tissue found at the apex of the prostate. It contains muscle fibres and connective tissue, but no glandular tissue.

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## Relations

- Anteriorly: Pubic symphysis
- Posteriorly: Ampulla of the rectum separated by the fascia of Denonvilliers
- Superiorly: External urethral sphincter and bladder neck
- Laterally: Levator ani muscles

## Blood supply

It receives blood supply from several sources (bilaterally):
- Inferior vesicular artery
- Pudendal artery
- Middle rectal artery

The veins around teh prostate form a plexus which drain to the internal iliac veins. They also connect to the vertebral venous plexus.

## Function

- The prostate produces seminal fluid which is released during ejaculation.
- During urintation the muscles int eh central zone conotract closing off the seminal ducts preventing retrograde flow.
- The prostate converts testosterone to its active form, dihydrotestosterone.

## Clinical points
- Because of it's relation to the rectum, the prostate can be palpated through a digital rectal exam. However, it is important to remember that the more anterior parts (transitional zone and fibromuscular tissue) cannot be palpated.
- Because of the close relation between the prostate and the bladder neck,  possible complications of prostate surgery are incontinence and retrograde ejaculation.
- The connections between the prostate venous plexus and the vertebral venous plexus explains why prostate cancer commonly metastasises to the vertebral column.
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Prostate gland
Topic
237
Pelvic Anatomy
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Topic
237
Pelvic Anatomy
What is the nervous supply of the annotated structure?

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a