Hello everybody,how are you all? hope you you all are doing well i am too.we are in perineal region and we learned about pelvis and perineum in the last post and now we are going to learn the remaining thing.
ISCHIORECTAL FOSSA
It is a fossa present on either side of rectum and anal canal.as it is a fossa it has boundaries
| Boundaries | Structures |
|---|---|
| Laterally | Obturator internus muscle |
| Medially | Levator ani muscle and External anal sphincter |
| Base | Skin of gluteal region |
| Anterior | Perineal membrane |
| Posterior | Sacrotuberous ligamnet and Gluteus maximus muscle |
Contents of Ischiorectal fossa
- Fat
- Pudendal canal and its contents -
Pudendal nerve
Internal pudendal vessels - Inferior rectal vessels and nerve*
It has fascia surrounding muscles you can see in the diagram above and the fascia divides the Ischiorectal fosaa into three spaces
- Perianal space
- Ischirectal fossa proper
- Supra-tegmental space
CLINICAL ASPECTS OF ISCHIORECTAL FOSSA
Infection is common in this fossa.it leads to abscess formation in the ischirectal fossa.due to this abscess fistuals are formed in anal canal
INTERNAL ILIAC ARTERY
As we are learning perineal and pelvis region we have to know which artery is going to supply the pelvis region.
Abdominal aorta is which is present in abdomen is divided into two Common iliac arteries.each common iliac artery is further divided into External iliac artery and ** Internal iliac artery**.External iliac artery goes into lowerlimb and gives blood supply to lowerlimb parts.where as Internal iliac artery is the one which give blood supply to pelvic structures.this Internal iliac artery is further divided into Anterior division and Posterior division.Anterior division gives seven branches where as posterior division has three branches.you can understand by the below diagram.
| Anterior division | Posterior division |
|---|---|
| Inferior gluteal artery | Superior gluteal artery |
| Superior vesicular artery | Ilio-lumbar artery |
| Inferior vesicular artery(males)(or)Vaginal artery(in females) | Lateral sacral artery |
| Uterine artery | |
| Middle rectal artery | |
| Obturator artery | |
| Internal pudendal artery |
During development apex of urinary bladder is attached to umbilicus and it is called Urachus and its remnant is called Median umbilical ligament
The remnant distal part of Umbilical artery is Medial umbilical ligament and remnant of Proximal part of Umbilical artery is Superior vesicular artery and a branch from superior vesicular artery gives to ductus deferens.You can understand what i said by below diagram.
URINARY BLADDER
We have urinary bladder to urinate.but there is something that we don't know that is present inside urinary bladder.lets cut the urinary bladder in coronal section.
You can see in the pic,the which
Trigone which is triangular in shape is present on the posterior wall of urinary bladder and ureters opens at
top two corners of trigone.trigone is smooth because it lacks submucosa.remaining part of urinary bladder is rough.
The ridge formed between two ureters is Interureterix ridge/bar mericier and it is formed by longitudinal muscles of ureter.
The ridge formed between ureter and urethra is Uretero-urethric ridge/bell's ridge and it is also formed due go longitudinal muscles of ureter.
Uvula vesicae - formed at the apex of trigone due to median lobe of prostate in males.
Urethral crest - the muscles of trigone extend into the prostatic urethra to form the urethral crest.
Image source
NERVE SUPPLY OF URINARY BLADDER
When we want to urinate or urge to urinate then our brain actives Parasympathetic system telling that your bladder is full please urinate and here urinary bladder is supplies by S2,S3,S4 nerves.so when these nerves are stimulated it causes contraction of detrusor muscle and relaxation of internal urethral sphincter and we can urinate freely.
The filling of urinary bladder is by relaxing the detrusor muscle and contraction internal urethral sphincter so urine is stored up in urinary bladder when our bladder is not dull or no need of urination.**
Pudendal nerve(with root values S2,S3,S3) supplies to External urethral sphincter and when it contracts it holds urine volunarily before zipping off of your pant**
URETHRA
Male urethra is important to leanr compared to female urethra the reason is male urethra is long and female urethra is short.so injuries are more common seen in male urethra.
- It is 20 cms long
- It has 3 parts
| Parts of male urethra | significance | cross section of male urethra |
|---|---|---|
| Prostatic urethra(3cms) | Most dilatable and widest | Semi-lunar/horse shoe shaped |
| Membranous urethra(1.5-2) | Least dilatable amd narrowest | Star shaped |
| Penile urethra(15cms) | divided into Bulbar,Ppongy and Terminal | Trapezoid,Horizontal slit,Vertical slit |
PROSTATIC URETHRA
We learned that the trigone of urinary bladder continues down to form the Urethral crest when we cut the prostatic urethra in coronal section,then these are the structures that we see in it in posterior wall.
You can see in the pic.
This topic is not easy to understand somewhat difficult.but when we read again and again it becomes easy.next post is about abdomen or other thing i am planning.so stay tuned for it.
Thanks for reading,
With regards
Thanks for your contribution to the STEMsocial community. Feel free to join us on discord to get to know the rest of us!
Please consider delegating to the @stemsocial account (85% of the curation rewards are returned).
You may also include @stemsocial as a beneficiary of the rewards of this post to get a stronger support.
Congratulations @salomijale! You have completed the following achievement on the Hive blockchain and have been rewarded with new badge(s):
Your next target is to reach 6000 upvotes.
You can view your badges on your board and compare yourself to others in the Ranking
If you no longer want to receive notifications, reply to this comment with the word
STOPCheck out the last post from @hivebuzz:
Support the HiveBuzz project. Vote for our proposal!
Not easy to understand, however, the pictures and tables help.
This was nice.
Perineum is tough to understand because there are so many structures in perineum.thanks for your read.