ANATOOOMMMY Flashcards
What type of joint is the sacroiliac joint?
Synovial plane joint
What type of joint is the pubic symphysis?
Secondary cartilaginous joint
With regards to the female pelvis and normal vaginal delivery: What is the narrowest diameter of the pelvic inlet?
13cm-Pelvic inlet (Anteroposterior)
With regards to the female pelvis and normal vaginal delivery: What is the narrowest diameter of the pelvic outlet?
11cm-Inferior opening
What are the walls of the pelvic cavity?
Anteroinferior wall
2 x lateral walls
Posterior wall
What is the anteroinferior wall formed by?
Bodies & rami of the pubic bones & pubic symphysis
Which muscle is present in the posterior wall of the pelvis?
PIRIFORMIS
What nerve network lies on the piriformis?
SACRAL PLEXUS
What is the perineal body?
Fibromuscular node that is the anchor point for several muscles
What is the anococcygeal body?
Musculotendinous intersection of the 2 halves of the levator ani muscles
What 2 muscles make up the majority of the pelvic floor?
Coccygeus
Levator ani (3 paired separate muscles)
What are 2 functions of the pelvic diaphragm/floor?
1)Support of abdominopelvic viscera (through their tonic contraction)
2)Urinary & faecal continence
What is the innervation of the pelvic diaphragm/ floor?
Sacral plexus-Pudendal nerve (S2-4)
What is a cystocele?
Cystocele =Prolapsed bladder – into vaginal canal
What is a cystocele?
Cystocele =Prolapsed bladder – into vaginal canal
What is a rectocele?
Rectocele =Posterior vaginal prolapse (tissue between rectum & vagina weakens)
Why is an injury to the pelvic floor (common) during childbirth potentially damaging?
Can get stress incontinence & pelvic prolapse
Why may an episiotomy minimise long term damage?
Can prevent severe perineal tearing/injury & speed up a delivery
Why is a mediolateral episiotomy preferable to a midline episiotomy?
Less risk for anal muscle tears (No midline tear)
What structures can be palpated when performing a DRE (part of the clinical examination of the abdomen)?
Male=Prostate & rectum
Female=Cervix, rectum, uterus & ovaries
Branches of the right & left ..?.. distribute blood to most of the pelvic organs, perineum & gluteal region except the ..?.., ..?.. & upper part of the rectum
Internal iliac artery
Testis
Ovaries
Venous drainage of the pelvic structures is complex & involves interplay between what circulations?
Portal & systemic circulation
This has clinical significance especially in some pathologies e.g. liver cirrhosis, pelvic cancers
There are many ..?.. plexuses formed in relation to pelvic organs (for example: rectal, prostatic) – some of these have clinical significance (e.g. ..?.. venous plexus)
- Venous
- Prostatic
What organ systems are included within the pelvis and perineum?
- The Terminal Portion of the GI tract
- The Urinary System
- Male and Female Reproductive Systems
- The Nerve Supply to the Above Organs from the Sacral Plexus
- Elements of the Musculoskeletal System related to the Bony Pelvis, SI Joints, muscles and ligaments
Pelvis as a ‘region’ the internal cavity of this is continuous with what superiorly?
Abdomen- with organ systems passing from one to another in line with normal physiological activity
In obstetric medicine what dimensions of the pelvis determine whether a baby can be safely delivered vaginally?
Differences in the horizontal & vertical dimensions of the pelvis
Which part(s) of the rectum drain(s) into the portal circulation?
Upper 2/3rds via the superior rectal vein
Which part(s) of the rectum drain(s) into the systemic circulation?
Distal portion (lower 1/3)
What is the significance of understanding the venous drainage of the rectum?
Metastases & infection spread routes/ Portal HT
Why might haemorrhoids be associated with cirrhosis of the liver?
Scarring of liver prevents the free passage of blood-pressure on veins increased as needs to find alternative route
What makes the prostate a very vascular organ?
The veins along the sides and base of the prostate join to form the prostatic venous plexus.
With which venous plexus does the prostatic venous plexus communicate with on its posterior side & why is this important (think about how prostate cancer spreads)?
Vertebral venous plexus
Can affect bones & be route of further spread
Describe the course of:
1) Ilioinguinal nerve
2) Genitofemoral nerve?
1) The ilioinguinal nerve originates from L1 and enters the inguinal canal at the superficial inguinal ring to supply skin at the root of the penis in the male and the labia in the female.
2) The genitofemoral nerve originates at L1-2 and enters at the deep inguinal ring.
What structure(s) in the male are supplied by the genital branch of the genitofemoral nerve & what is the clinical significance of this?
Scrotal skin & cremaster muscle
Clinical significance =Cremaster reflex-assess testicular torsion
Where does the pudendal nerve arise from?
The sacral plexus
From which segmental level(s) does the pudendal nerve arise?
S2-4
What is the course of the pudendal nerve?
Follows the course of the pudendal artery to innervate the skin and the muscles of the perineum.
The pudendal nerve travels from pelvis to perineum, via the gluteal region.
This arrangement is essential to understand in bilateral pudendal nerve block for pain relief during childbirth, particularly for an instrumental (e.g. forceps) assisted vaginal birth.
What bony landmarks are used when performing a pudendal nerve block during labour?
Ischial spines
Where does the autonomic nerve supply to the pelvis originate from?
The pelvic plexus (or inferior hypogastric)
Where do the sympathetic fibres originate from?
The sympathetic fibres originate from L1 and L2 via the hypogastric nerve and terminal aspect of the sympathetic trunk. These fibres hitchhike on the arterial supply to reach their target organs.
Sympathetic fibres (from L1-2) provide what & what do they supply in male compared to female?
They provide sympathetic supply to all internal pelvic organs.
In a male they supply the vas deferens, seminal vesicles, prostate and epididymis.
In a female they supply the ovaries, uterus, fallopian tubes and vagina.
Where do Parasympathetic fibres in the pelvis originate from & what do they supply and innervate?
The pelvic splanchnic nerves (S2 to S4). In addition to providing parasympathetic supply to all the internal pelvic organs, they innervate erectile tissues in both male and female.
What fibres innervate erectile tissues in both male & female?
Parasympathetic fibres from pelvic splanchnic nerves (S2-4)
What is the difference between splanchnic nerves in the thorax & pelvis?
In the thorax the greater, lesser and least splanchnic nerves are sympathetic
In the pelvis the pelvic splanchnic nerves are parasympathetic
After rectal surgery, why are some men unable to ejaculate?
Autonomic nerve damage- Pelvic splanchnic nerves (part of ANS)
Lymphatic drainage of the pelvis tends to follow what?
The arterial supply
There are four primary nodes present in the pelvis receiving the lymphatic drainage of the pelvic organs. (They are variable in number, size and location) What are they?
- External iliac
- Internal iliac
- Sacral
- Common iliac
What 4 categories can the male reproductive organs be grouped into?
1)The External Genitalia
2)The Gonads – Where gametes or sex cells are produced and also the site for the production of male sex hormones
3)The Tube System – For transporting the sperm from the gonads
4)The Accessory Glands – These support the sperm and lubricate the copulatory organs.
What is the role of the accessory glands?
They support the sperm & lubricate the copulatory organs
The gonads (testis) are located where?
Outside the abdomino-pelvic cavity but remain intimately connected to the structures located there.
Where are gametes or sex cells produced in males (also site for the production of male sex hormones)?
The gonads
What are the male reproductive organs?
- Testis
- Vas Deferens or Ductus Deferens
- Seminal glands
- Prostate
- Epididymis
- Bulbourethral glands
During embryological development the testis move from where to where?
The internal abdominal cavity, through the anterior abdominal wall, and lie as part of the external genitalia in the scrotum.
What is the name of the canal that the testis passes through during development?
Inguinal canal
What are the deep and superficial openings of the inguinal canal called?
Inguinal Rings
The inguinal canal carries a group of structures known as what in the male?
Spermatic cord.
What are the main contents of the spermatic cord?
- Ductus deferens
- Testicular artery
- Testicular lymph vessel
- Testicular veins (pampiniform plexus)
- Genital branch of the genitofemoral nerve
- Cremasteric artery
The ovoid testes are suspended in the scrotum by what?
The spermatic cords
What is the tough outer fibrous layer of the testis called?
Tunica Albuginea
What are the two layers of tunica vaginalis?
Visceral tunic (tunica vaginalis propria) and a parietal tunic (tunica vaginalis communis)
What material is present between the two layers of tunica vaginalis?
Serous fluid
What are 2 pathologies associated with the tunica vaginalis & what causes each of these?
Hydroceles
-Type of scrotal swelling that occurs when fluid collects in the thin sheath that surrounds the testical
-Caused by serous fluid collection around testical-injury or inflam
Haematoceles
-Collection of blood in layers
-Caused usually by injury to the testes – rupture or torsion
How is the testis supplied with blood?
Testis is supplied by a branch of the abdominal aorta called the testicular artery.
At what vertebral level do the testicular arteries arise from the abdominal aorta?
L2-3
What route do the testicular arteries take?
These arteries travel retroperitoneally and cross two important structures(Ureter & Genitofemoral nerve) near the pelvic brim before they travel through the inguinal canal.
What structures do the testicular arteries cross?
- Ureter
- Genitofemoral nerve
What is the term used for the 8-12 anastomosing veins associated with the testis & what is the function of these veins?
Pampiniform venous plexus
- They drain testes/epididymis
Into which vein does the right testicular vein drain into?
The right testicular vein drains into IVC
Into which vein does the left testicular vein drain into?
The left testicular vein drains into L Renal vein
What is a varicocele & what causes it?
Enlargement of veins caused by defective valves
Is a pathology specific to the venous drainage of the testis
Is testicular torsion an emergency presentation? If so why?
YES, requires urgent resolution through an operation and internal fixation (orchidopexy) of the testis to the scrotum to prevent this happening in the future
What is happening to cause testicular torsion and what is the risk of this?
Blood supply has been completely cut off from one of the testis, therefore it is at risk of necrosis within a few hours
Which two lymph node groups receive lymph from the testis?
Retroperitoneal LNs and Para-aortic LNs
What structures make up the tube system?
- Epididymis
- Vas deferens
- Seminal glands (vesicles)
- Prostate gland
- Bulbourethral (Cowper’s) glands
What is the epididymis attached to & what does it store?
Attached to the body of the testis
Stores sperm that is produced by the testis
What is the vas deferens and where does it arise from?
Muscular tube arises from the tail of the epididymis
What is the course of the vas deferens?
Arises from the tail of the epididymis, traverses the inguinal canal and enters the pelvis by crossing over the external iliac vessels. It terminates by joining the duct of the seminal gland to form the ejaculatory duct.
What 2 structures join to form the ejaculatory duct?
Vas deferens terminates by joining the duct of the seminal gland to form the ejaculatory duct
What are the paired structures are located on either side of the posterior surface of the bladder?
Seminal glands (Vesicles) (note their relation to the ureter, the vas deferens and the prostate gland)
What secretions are produced by the seminal vesicles?
Alkaline liquid component of semen
Where is the prostate gland located?
Fused to the inferior part (neck) of the bladder and surrounds the prostatic urethra.
What secretions are produced by the prostate?
Proteins in a prostatic fluid
Why might an enlarged prostate gland cause retention of urine?
Blocks urine outflow
What is the clinical significance of drainage from the prostatic venous plexus?
Spread to spine or spread to liver
What are the small, paired structures located in the urogenital diaphragm which empty into the penile/spongy urethra?
Bulbourethral (Cowper’s) glands
What secretions are produced by the bulbourethral glands?
Clear colourless mucoid product released prior to ejaculation – neutralise acidic secretions of the vagina & urethra
Where is the perineum located & what can it be divided into?
The perineum lies inferior to the pelvic diaphragm and is the most inferior portion of the trunk. It can be divided into two triangular areas.
What bony landmarks create the boundaries of the perineum?
- Pubic symphysis
- Ischial tuberosities
- Coccyx
Which bony prominences separate each of the triangles (anal & urogenital triangles)?
Ischial Tuberosities
What provides support to the organs of the perineum?
Muscles of the perineum and fascial planes (there are some anatomical variations between the male and female perineal muscles)
What are 2 important muscle attachment areas in the perineum?
Perineal & anococcygeal bodies
What are the potential consequences if the perineal body is damaged/ruptured during childbirth?
Incontinence issues
What 2 layers of fascia are important as additional support for the pelvic organs within the perineum?
These are the superior & deep fascia, making up the pelvic diaphragm.
Which structures pierce through the pelvic diaphragm?
- Rectum
- Urethra/Vagina
Is the urethra longer in males or females and why is this?
The urethra is longer in males compared to females due the number of structures it has to traverse
What are the 3 parts of the male urethra?
- Prostatic
- Membranous
- Spongey
Enlargement of the prostate puts what structure at risk of becoming narrowed?
URETHRA
What does the male external genitalia comprise of?
Testes, scrotum and penis
What is the penis & what is it the common outlet for?
The penis is the male organ of copulation and is the common outlet for both urine and semen.
What does the penis comprise of?
Left and right corpus cavernosa and single corpus spongiosum. The terminal aspect of the penis is the glans penis, covered by the prepuce (foreskin) and provides transit for the urethra via the external urethral meatus.
The corpus cavernosa is covered by a fascial layer called what?
Buck’s Fascia
The urethra is transmitted through the corpus ..?..
SPONGIOSUM
The majority of the erectile tissue in the penis is in the corpus ..?..
CAVERNOSUM
What is the function of umbilical veins in the foetal circulation?
Carries oxygenated blood from the placenta into the growing foetus
What structure (ligament) does the umbilical vein persist as in adult?
Round ligament/ligamentum teres (of the liver)
What is the function of umbilical arteries in the foetal circulation?
Carry deoxygenated & nutrient deficient blood from the fetus to the placenta
At what stage of labour does the placenta physiologically separate from the uterine wall?
3rd stage
What are four functions of the placenta?
- Gaseous Exchange
- Foetal nutrition & excretion
- Foetal protection & immunity
- Endocrine (hormone production) bHCG
Breast tissue undergoes cyclical changes in activity controlled by what?
Controlled by hormones involved with the ovarian cycle.
What remains one of the major causes of carcinoma within the female population?
Breast cancer
Although screening programmes, chemotherapy and earlier surgical intervention have reduced the morbidity and mortality from breast cancer.
Due to the vascularity and good lymphatic drainage of the breast, malignant cells can quickly spread either to the opposite breast, or to other sites in the body (bone, lung, brain)
Which group of lymph nodes first receives lymph from the lateral part (quadrant) of the breast tissue?
Axillary nodes
Why does lymphatic drainage of the breast assume great importance to the surgeon?
Because cancer of the breast spreads mostly along lymphatics to the regional nodes and beyond.
The mammary gland is extremely vascular. They are supplied by branches of what?
Subclavian & axillary arteries
The axillary tail of the breast is an extension of the breast tissue into the axilla, and is important to appreciate in what?
The spread of breast cancer
The breasts deep surface is related to what muscles?
- Pectoralis Major
- Pectoralis Minor
- Serratus Anterior
Breast extend vertically from where to where & horizontally from where to where?
Vertically from the 2nd rib to the 6th rib
Horizontally from the lateral border of sternum to the mid- axillary line.
How many lobules does each breast consist of?
Each breast consists of 15-25 lobes with tubulo-acinar glands (parenchyma) and stroma (connective tissue).
Breasts (mammary gland) are what type of glands and what is the role of them?
Highly modified exocrine glands lying in the superficial fascia of the pectoral region. They form important accessory organs of the female reproductive system and provide nutrition to the new-born in the form of milk.
Which group of lymph nodes drains the ovary?
Para-aortic LNs
The lymphatic drainage of the internal pelvic organs largely follows the ..?.. supply and venous drainage
Arterial
What structures is not uncommon to be damaged during a CS or hysterectomy (removal of the uterus)?
Due to the close proximity of the ureter and bladder to the female reproductive organs, it is not uncommon that either can be damaged
What does the expression “water under the bridge” reminds us of?
An important anatomical relation to the ureter to remember during the ligation of uterine artery.
The uterine artery crosses over the ureter at what level and area?
Level of ischial spine, junction of cervix and lateral part of fornix of vagina.
Ovarian veins: the ascending course of the left and right are different – into which vessels do these paired vessels drain?
Left = Left renal vein
Right = IVC
What vessel does the ovarian artery freely anastomose with?
Uterine artery.
At what vertebral level do the ovarian arteries originate? In what ligament does it pass within as it descends?
L2/3
As it descends the artery passes within the suspensory ligament to supply the ovaries via the broad ligament.
Ovarian artery why does it correspond to the male testicular artery?
Branches directly from the abdominal aorta
What 2 major branches from the aorta provide the blood supply to the gonads & genitalia?
The ovarian (gonadal) and internal iliac arteries.
What are the two ligaments associated with the ovary?
1) From uterus to ovary = Ovarian ligament
2) Ovary to lateral pelvic wall = Suspensory ligament of ovary
What is a cornual ectopic pregnancy?
Pregnancy occurring outside of the uterine cavity in the uterine horns-the place where the fallopian tubes & the uterus meet
What is meant by a tubal (ectopic) pregnancy?
Fertilized egg attaches outside of the uterus
An ectopic pregnancy is an uncommon, but important clinical diagnosis to be aware of an requires urgent surgery due to the risk of blood loss
Fertilization occurs in which part of the uterine tube?
Ampulla
Which part of the uterine tube is longest and widest?
Ampulla
What are the 4 parts of the uterine tubes?
1) Infundibulum
2) Ampulla
3) Isthmus
4) Intramural or uterine part
Is the uterus a fixed structure?
The uterus is supported, but has ability to move, especially when increasing in size during pregnancy.
Is the cervix a fixed structure?
In the pelvis the cervix is a fixed structure, supported by strong ligaments to prevent movement.
Apart from pelvic fascia, what other structure in the pelvis is also an important support of the uterus?
Broad ligament
What nerve provides sensory innervation of the penis?
Dorsal nerve of the penis, a branch of the pudendal nerve
Where does the urethra opening to in females?
Opening to the anterior aspect of the urogenital triangle directly in front of the vagina
..?.. and ..?.. urethra sphincters are important in regulation of urinary ..?..
Internal
External
Continence
Where is the internal/vesical urethral sphincter located?
Neck of the bladder
Is the internal/vesical urethral sphincter voluntary or involuntary & what is its innervation?
Involuntary
Sympathetic=T11-L2
Parasympathetic=S2-4
Is the internal/vesical urethral sphincter voluntary or involuntary & what is its innervation?
Involuntary
Sympathetic=T11-L2
Parasympathetic=S2-4
Where is the external urethral sphincter found in females?
Distally & inferiorly to the bladder neck between the vaginal orifice & clitoris
Which ligament (part of the pelvic fascia, which is one of the main supports of the uterus) is called the cardinal ligament of the uterus?
Transverse cervical ligament
Attachments & origins of:
- Ligament of ovary
- Suspensory ligament of ovary
- Round ligament of uterus
- Broad ligament
Ligament of ovary-uterus to ovary
Suspensory ligament of ovary-ovary to pelvic wall
Round ligament of uterus-both sides of uterus to mons pubis
Broad ligament- lateral aspect of the uterus to the lateral pelvic wall
Is the external urethral sphincter found in males voluntary or involuntary? What is its innervation?
Voluntary
Deep branch of perineal nerve (S 2-4)
The uterus and cervix are firmly anchored in position in the pelvis by a number of …?..
Ligamentous attachments.
Through which vaginal fornix you can access the rectouterine pouch? What is the clinical significance of this?
Posterior- common site of pathology spread -site where infection & fluids typically collect – access via surgical incision of vaginal fornix
What are the fornices of the vagina? How many are they?
Superior portions of the vagina-extending into the recesses created by the vaginal portion of cervix
1) ………………Anterior……………………
2) ………………Posterior…………………..
3) ………………Right lateral………………
4) ……………… Left lateral………………….
At any surgical management of miscarriage why might it be important to know prior to instrumentation of the uterine cavity whether the uterus is anteverted or retroverted?
To plan surgical approach
What is the normal position of the uterus?
‘Anteflexed’ and ‘anteverted’.
When a CS is done which part of the uterus is opened to deliver the baby?
Lower uterine segment
The area between the cervix and uterus develops into the lower segment. When a caesarean section is required the uterus is opened at the lower segment with a transverse incision for delivery of the baby (Pfannenstiel)
As pregnancy advances the uterus physiologically has an ‘upper’ segment and a ‘lower segment’ – what area of the uterine body does the lower segment develop from?
Isthmus of the uterus
What are the 3 layers of the uterus?
- Perimetrium
- Myometrium
- Endometrium
What three structures constitute the birth canal?
- Cervix
- Vagina
- Vulva (pudendum)
The duct system for the transference of gametes is short, and leads from where?
The ovaries to the uterus, where implantation and development of the zygote occurs.
This then communicates with the exterior via the birth canal.
What is the female reproductive system made up of?
The uterus, fallopian tubes, vagina and ovaries.
Disruption to one or both of the urethral sphincter can cause the development of what in both males & females?
Urinary incontinence
What natural process weakens the urinary sphincters making incontinence more likely?
The aging process
What can make incontinence more likely in 1) Males & 2) Females?
1) In males any form of prostatic surgery to overcome urinary retention can make urinary incontinence more likely
2) In the female childbirth can weaken the ligaments supporting the pelvic floor, and can increase the risk of incontinence.
What is the vulva the collective name for?
The female external genitalia.
What nerve & what artery supply the contents of the vulva?
Pudendal nerve & Internal pudendal artery
What is the vestibule & what does it contain?
The vestibule is the area enclosed by the labia minora and contains the terminal aspects of the vagina & urethra
In females what mirrors the corpus cavernosa in the male?
The clitoris
What is the erectile tissue found within the female external genitalia?
The clitoris
What is the clitoris comprised of?
2 crura, which meet in the midline to form the body. This then projects downwards to the prepuce and glans which lies in the anterior labial commissure.
What is the equivalent of the corpus spongiosum in females?
There is NO equivalent of the corpus spongiosum in females
What is the area between the ischial tuberosities & coccyx called and what does it contain?
The anal triangle is the area between the ischial tuberosities and coccyx.
It contains the anus (terminal part of the GI tract)
Where does the anus run from & how long is it?
The anus runs from the rectum to the external environment and is approx. 4cm long.
Where does the anus run from & how long is it?
The anus runs from the rectum to the external environment and is approx. 4cm long.
What kind of control is the external anal sphincter under?
Voluntary Control
What kind of control is the internal anal sphincter under?
Involuntary control
Somatic sensation extends upwards from the external environment to where?
The inter-sphincteric groove (the ‘white line’)
What is the purpose of the ischio-anal (ischio-rectal) fossa?
These allow the anal canal to expand during defaecation.
What neurovascular bundle enters the ischio-anal (rectal) fossae through the lesser sciatic foramen?
Pudendal neurovascular bundle
Where are the ischio-anal (ischio-rectal) fossa located?
Lateral to the anal canal and inferior to the pelvic floor - 2 fat containing fossa
What structures are present in the pudendal neurovascular bundle & what structures do they supply?
Artery, vein and nerve (Pudendal)
- Urethral sphincters
- External genitalia
- Skin around anus, anal canal and perineum
How can an ischio-anal abscess form?
Anal crypts can extend laterally into the ischio-anal fossa forming abscesses within this relatively ischaemic area.
These can spread rapidly with these peri-anal abscesses requiring drainage under GA
What are the contents of the vulva?
- Mons Pubis
- Labia Majora
- Labia Minora
- Vulva vestibule
- Bartholin’s Glands
- Clitoris
