Peen and related structures

1. Peen and related structures Haddy Cosh and Amy Wood

2. Testicles • Derive from intermediate mesoderm • Development: • High on posterior abdominal wall, drop down via gubernaculum • Coverings: • Skin • Dartos • External Spermatic Fascia • Cremasteric Fascia (Cremasta muscle, genitofemoral nerve, s2 reflex) • Internal spermatic fascia • Tunica vaginalis • Testicles Some Damn Englishman Called It The Testes

3. Spermatic Cord • Arteries • Testicular (Torsion) • Ducts deferens artery • Cremasteric artery • Nerves • Genital • Autonomic • Illioinguinal • The rule of 3’s: • Coverings: • Internal spermatic fascia • Cremasteric fascia • External spermatic fascia • Veins: • Pampiniform plexus (visible – varicocoele) • Ductus deferens • Lymphatics

4. Ductus Deferens • Runs from? • Tail of Epidydimis to ejaculatory duct • Capable of peristalsis, controlled by which nervous system? • Sympathetic • Arterial supply: • Branches of vesical and testicular arteries

5. Prostate • Location? • Surrounds urethra, between bladder and levatorani muscles • Produces? • Prostatic fluid (20% seminal fluid) = Citric acid, prostaglandins, proteolytic enzymes • Zones? • Central, Transitional, Peripheral (most glandular so carcinoma site) • Lobes? • Anterior, posterior, median, 2 X lateral • Arterial supply: • Middle rectal and inferior vesical arteries • Venous supply: • Runs to prostatic venous plexus  vertebral veins • Valveless plexus, route of cancer spread

6. Seminal Vesicles • Accessory gland which produces? • Alkaline fluid rich in fructose, Prostaglandin E and semen clotting factors • Arterial supply? • Inferior vesicle and middle rectal • Venous supply? • Vesical and prostatic venous plexi • What do you need to warn men about vasectomies? • May be fertile for a couple of weeks as sperm can sill be in the vesicles

7. Penis • Structure? • 2 X Corpus cavernosum (most erectile tissue) • 1 X Corpus spongiosum • Arterial supply • Internal iliac  Internal pudendal  Deep and dorsal penile arteries (Through Alcock’s canal LOL) • Venous supply • Superficial and deep dorsal veins  venous plexus  vertebral plexus • Problems: • Priapism • Persistant, painful, non-stimulated erection for +4 hours • Prepuce: • Phimosis / Paraphimosis

8. Erection and Ejaculation • ERECTION: (Point = Parasympathetic = Cavernous Nerve = S234) • Straightening of coiled helicine arteries, relaxation of smooth muscle  blood flow to corpus cavernosum • Bulbospongiosus and Ischiocavernosus muscles compress venous plexi (blood remains in penis) • Flaccid penis: Arterio-venous anastomoses allow blood to bypass corpus cavernosum

9. EMISSION (Shoot = Sympathetic = Secretion = L1,2) • Internal urethral sphincter closes • Peristalsis of vas and seminal vesicles • Smooth muscle of prostate relaxes  • Ejaculate squeezed into penile bulb

10. EJACULATION (Score = Somatic = Pudendal = S2-4) • Contraction squeezes base of penis  ejaculation • Although brought about by somatic system, there is no control

11. Lymph drainage routes • Testicles  • Para Aortic nodes (~L2) • Prostate  • Internal Iliac nodes • Seminal Vesicles  • Internal / External Iliac & sacral nodes • Ductus deferens  • Internal Iliac • Glans of penis  • Deep inuinal • Corpus cavernosum  • Internal iliac

12. Per rectal examinations If you don’t put your finger in it, you stick your foot in it! • What can you feel (7)? • Walls of anal canal • Walls of inferior rectum • Bones: Sacrum, Coccyx • Sacral Lymph nodes • Prostate • Inferior bladder - possible • Seminal vesicles – possibly

13. Catheterisation • Indications (4) • Inability to void bladder (urinary retention) • Spinal injury • Incapacitated • Surgery • Difficulties (4) • Navicular fossa (mucosal fold superiorly) • Angle at penile bulb and membranous urethra • Prostate (crest / enlarged lobes) • Sphincters – nervous patient

14. Catheterisation contd.. • Procedure: • See http://almostadoctor.co.uk/content/osces/skills-and-procedures/catheterization