Pelvis Flashcards
Sacrum: Description
The sacrum is an element of the bony pelvis
Location: forms the posterior aspect of the pelvic ring
Function: transmission of force between the pelvis and the spinal column
Sacrum: Gross anatomy
Inverted triangle in shape
Formed by the fusion of 5 sacral vertebrae
Concave anterior
Sacrum: Features
- Sacral prominence
- Superior articular processes with associated facets
- Sacral body
- Alar wings laterally
- Median sacral crest
- Sacral canal (triangular in shape)
- Termination of the sacral canal is at the sacral hiatus
- First four nerve roots exit via the paired anterior and posterior foramen
- The fifth sacral nerves exit via the sacral hiatus
Sacrum: Articulation
- Superiorly with the L5 vertebrae via the sacral prominence and the body of L5 and via the superior articular facets with the inferior articular facets of the L5 vertebrae
- Laterally the sacrum articulates with the ilium via the sacroiliac joints (mixed fibrous/synovial joints)
- Sacrococcygeal – inferiorly the sacrum articulates with the first coccygeal segment
Sacrum: Ligaments
- Lumbosacral
- Iliolumbar
- Sacroiliac ligaments
- Sacrospinous
- Sacrotuberous
- Sacrococcygeal ligaments
Sacrum: Neurovasculature
Blood supply:
- Iliolumbar arteries (Posterior division of the internal iliac arteries)
- Lateral sacral arteries (post. Div. int. iliac)
- Median sacral artery from the aorta
Venous drainage:
- Via the internal and external vertebral plexuses to the median and lateral sacral veins
Lymphatics:
- Perirectal and internal iliac nodes
Sacrum: Variants
- Lumboralisation of the S1
- Sacralisation of the L5
- Sacral agenesis
Hip bone: Description
The hip bone is a large paired flat bone of the pelvis.
Function: Forms the lateral and anterior aspects of the bony pelvis
Ilium
Superior part of the hip bone
Made up of a body and wing separated by the arcuate line
Forms the sacroiliac joint with the sacrum via the articular surface
Forms the superior aspect of the acetabulum
Anterior and posterior, superior and inferior iliac spines
Forms most of the greater sciatic notch
Ischium
Posterior inferior part of the hip bone
Made up of a body and a ramus
Forms the lower acetabulum
Forms the posterior part of the obturator foramen
Forms the lower part of the greater sciatic notch and all of the lesser sciatic notch with the ischial spine between them
Inferiorly is the ischial tuberosity
Pubis
Anteromedial body with a superior and inferior ramus
Forms the anterior aspect of the obturator foramen
Symphysial surface of the body of the pubis forms the pubic symphysis
Pubis tubercle located superior and lateral to the pubic symphysis
Forms the anterior aspect of the acetabulum
Sacroiliac Joint: Description
Paired symmetrical synovial and fibrous joint between the ilium and the sacrum
Location: S1-S3 level oblique plane
Movement: little movement, main function is transfer of weigh between the axial and lower appendicular skeletons.
Sacroiliac joint: Articulation
- Formed by the irregular articular facets of the ilium and the sacrum.
- The upper 1/3 is a syndesmosis
- The lower 2/3 is articular cartilage
Sacroiliac joint: Ligaments
- Has a capsule (due to its synovial element)
- Interosseous sacroiliac ligaments
- Anterior sacroiliac ligaments
- Posterior sacroiliac ligaments
- Iliolumbar ligaments
- Sacrospinous and sacrotuberous ligaments
Sacroliac joint: Relations
- Anterior: Internal and external iliac veins and arteries join, ureters, lumbosacral trunk and obturator nerve, piriformis attaches to the anterior capsule
- Posterior: sciatic nerve
- Superior: iliolumbar ligaments
- Inferior: Greater sciatic foramen
- Lateral: ilium
- Medial: sacral alar
Sacroiliac joint: Neurovasculature
Arterial:
- Iliolumbar
- Superior gluteal
- Superior lateral sacral arteries
Venous: same named veins
Innervation: Branches of the lumbar and sacral plexus
Sacroiliac joint: Variant
Accessory sacroiliac joints
Pubic symphyisis
The pubic symphysis is a midline secondary cartilaginous joint between the articular surfaces of the pubic bodies
Movement: minimal shift and rotation, may widen during pregnancy and child birth
Pubic symphysis: Gross anatomy
- Wedge-shaped fibrocartilaginous interpubic disc situated between two layers of hyaline cartilage which line the articular sufaces of the pubis
- Width narrows with age from 10 to 3mm
Pubic Symphysis: Ligaments
- Superior and inferior pubic ligaments
- Anterior and posterior pubic ligaments
- Suspensory ligament of the penis
- Pubocervical ligament
Pubic symphysis: Muscles
- Adductor longus and brevis
- Rectus abdominis and pyramidalis
Symphysis pubis: Relations
Anterior – proximal penile/clitoral shafts
Inferior – Urethra, deep dorsal vein of the penis/clitoris
Posterior – Bladder, retropubic fat, Prostate and prostate venous plexus
Pubic symphysis: Neurovasculature
Blood supply:
Obturator and inferior epigastric arteries
Innervation:
Pudendal nerve
Levator ani: Description
The lavator ani also known as the muscular pelvic diaphragm is the musculotendinous sheet that forms the majority of the pelvis floor.
Function: supports the pelvic viscera and aided in urinary and faecal continence
Levator ani: Gross anatomy
Pubococcygeus:
- From the inner surface of the pubis merging medially to form the perineal body
Iliococcygeus:
- From the inner tip of the coccyx to the ischial spine.
Puborectalis:
- From the body of the pubis forming a sling around the rectum
- Coccygeus is not formally part of lavatory ani however it is an important element of the pelvic floor. It is between the sacrospinous ligament/ischial spine and the lateral border of the coccyx and sacrum.
Levator ani: Neurovasculature
Arterial supply:
- Inferior gluteal artery
Venous drainage:
- Inferior gluteal veins
Innervation:
- Pudendal nerve (internal surface)
- Branches of S3,4 (external surface)
Levator ani: Variant
- Thinning or aplasia of one side is common ~50%
Piriformis: Description
The piriformis muscle is a muscle of the gluteal region
Gross anatomy:
Flat muscle, pyramidal in shape
Piriformis: Gross anatomy
Flat muscle, pyramidal in shape
Origin: Sacrum
Course: exits the pelvis via the greater sciatic foramen
Insertion: Greater trochanter of the femur
Piriformis: Neurovasculature
Arterial supply: Superior and inferior gluteal arteries, lateral sacral artery
Innervation: Nerve to piriformis (sacral plexus)
Lymphatics:
- Internal iliac
Piriformis: Relations
Structures passing through the greater sciatic foramen pass above or below the piriformis:
Passing above:
- Superior gluteal nerve and vessels
Passing below (PIN PINS):
- Posterior cutaneous nerve of the thigh
- Inferior gluteal vessels and nerves
- Nerve to quadratus femoris
- Pudendal nerve
- Internal pudendal vessels
- Nerve to obturator internus
- Sciatic nerve
Piriformis: variants
- Fusion with gluteal muscles
- Pierced by the fibular nerve
Psoas muscle: Description
The psoas major muscle is on the muscle of the posterior abdominal wall.
Location: Posterior the retroperitoneum in the iliopsoas compartment
Action: lateral flexion of the trunk, stabilisation and flexion of the hip
Psoas muscle: Gross anatomy
Enclosed by the psoas fascia.
Fuses with the iliacus muscle to form the iliopsoas.
Passes through the retro-inguinal space
Origin: vertebral bodies, discs and transverse processes of T12 to L5
Insertion: Lesser trochanter of the femur
Psoas muscle: Neurovasculature
Innervation: L1-L3 nerve roots
Arterial supply: Lumbar, iliolumbar, deep circumflex iliac, external iliac and femoral arteries
Venous: Same named veins
Lymphatics: Para-aortic
Psoas muscle: Variants
Asymmetry of the psoas muscle
Psoas minor muscle
Inguinal ligament: Description
The inguinal ligament is a ligament that marks the transition from the pelvis to the lower limb
Function: Support of the inferior aspect of the anterior abdominal wall, allows the passage of structures from the pelvis to the superficial anterior pelvis
Inguinal ligaments: Gross anatomy
Formed from a thickening of the lower border of the aponeurosis of the external oblique. Extends from the anterior superior iliac spine to the pubic tubercle.
Some fibres attach elsewhere:
- Superior pubic ramus – Lacunar ligament
- Pecten pubis – pectineal ligament
- Crossing the midline – reflected inguinal ligament
The upper surface gives origin to the external spermatic fascia
The ligament is continuous with the fascia lata of the thigh.
Also forms the posterior wall of the inguinal canal
Inguinal ligament: Relations
Anterior: Superficial epigastric arteries
Posterior: Retroinguinal space, femoral artery, vein and nerve, iliopsoas
Lateral: iliac wing, circumflex iliac vessels
Medial: Pubic symphysis
Inguinal ligament: Neurovasculature
Arterial:
Superficial and inferior epigastric arteries
Superficial circumflex iliac arteries
Venous:
Superficial and inferior epigastric veins draining into the femoral system
Lymphatics:
Superficial iliac nodes
Innervation:
Iliohypogastric nerves
Sacrospinous ligament: Gross anatomy
Triangular in shape
Attachments: The base is attached to the anterior sacrum (S2-S4) and the apex is attached to the ischial spine.
Sacrospinous ligament: Relations
- Anterior: coccygeus
- Posterior Sacrotuberous ligament
- Superior: forms the lower border of the greater sciatic foramen
- Inferior: Forms the superior border of the lesser sciatic foramen
Sacrotuberous ligament
Gross anatomy:
Also triangular in shape
Attachments: Broad origin from the sacrum and coccyx, apex inserts into the medial aspect of the ischial tuberosity with fibres extending to the ischial ramus called the falciform ligament
Provides extensive insertion of the gluteus maximus muscle
Sacrotuberous ligament: Relations
Forms the medial boundary of the greater sciatic foramen
Forms the posterior boundary of the lesser sciatic foramen
Anterior division of internal iliac: Description
The internal iliac artery is the primary blood supply to the pelvis, pelvic viscera, external genitals, perineum, buttocks and medial thigh
Anterior division of internal iliac artery: Gross anatomy
Origin: The bifurcation of the common iliac artery at the level of the pelvic brim
Course: Posteromedial toward the greater sciatic foramen.
Termination: Divides into the anterior and posterior division just prior to the greater sciatic foramen
Branches of the anterior division of internal iliac artery
Rule of 3’s: 3 bladder, 3 muscular, 3 female
ISO POG MUV
- Superior vesicular
- Inferior vesicular
- Obliterated umbilical
- Inferior gluteal
- Obturator
- Internal pudendal
- Middle rectal
- Uterine
- Vaginal
Anterior division of internal iliac artery: Variants
- Persistent sciatic artery
- Obturator artery origin from the external iliac
Posterior division of internal iliac artery: Gross anatomy
Origin: The internal iliac artery divides into anterior and posterior divisions at the superior border of the greater sciatic foramen
Course: Posterior towards the great sciatic foramen
Posterior division of internal iliac artery: Branches
Iliolumbar artery – with lumbar and ilial branches – ilium, iliacus, L5/S1 foramen
Lateral sacral artery – with superior and inferior branches – supplies the sacrum and piriformis
Superior gluteal artery – superficial and deep braches – supplies the gluteal muscles
Posterior division of internal iliac artery: Variants
- Persistent sciatic artery
- Superior and inferior branches of the lateral sacral origin directly from the posterior division of the internal iliac artery
- Superior gluteal may arise directly from the internal iliac
Venous drainage of the left testis: Description
The venous drainage of the testis and the epididymis is via the pampiniform plexus to the testicular veins.
Functions: return of deoxygenated blood, themoregulation of the testis.
Venous drainage of the tesis: Gross anatomy
The pampiniform plexus is a venous network of approximately 10 veins. The network surrounds the testicular artery in the spermatic cord and lies anterior to the ductus deferens.
The pampiniform plexus ascends to form four veins at the level of the superficial inguinal ring. Forming a single testicular vein at the level of the deep inguinal ring. It ascends through the inguinal canal within the spermatic cord.
Testicular veins
Course: The testicular veins ascend in the retroperitoneum on the psoas major muscle.
Tributaries: in addition to the pampiniform plexus there are multiple small tributaries from the retroperitoneal, abdominal wall and renal capsular veins.
Termination: The left testicular vein drains into the left renal vein, the right testicular vein drains into the inferior vena cava at the level of ~L2
Tersticular vein variants
The right testicular vein drains into the right renal vein
Duplication is common
Sacral plexus
Sacral plexus (2010)
The sacral plexus is formed by the anterior rami of the L4 to S4 and its branches.
Function: Innervation of the pelvis, perineum and lower limb
Branches of the sacral plexus
Sacral plexus forms on the anterior belly of the piriformis from the s1 to s4 nerve roots
SLIP DSP
- Superior gluteal nerve (L4-S1)
- Lumbosacral trunk (L4-L5)
- Inferior gluteal nerve (L5 – S2)
- Posterior femoral cutaneous (S1 -3)
- Direct branches to muscles – nerve to piriformis, nerve to obturator internus, nerve to quadratus femoris, nerves to the gemelli
- Sciatic (L4-S3)
- Pudendal (S2-S4)
Sacral plexus: Relations
- Anteromedial: common iliac artery and vein, ureter
- Anterior: lateral sacral artery and vein
Sacral plexus: Variants
- Common peroneal and tibial parts of the sciatic nerve fail to unite and course into the lower limb separately
- Additional caudal nerve root contribution to the sacral plexus
Pudendal N: Gross anatomy
Origin: S 2- 4
Course: Through the greater sciatic foramen, back through the lesser sciatic foramen
Runs along the wall of the obturator internus, in the pudendal canal
Terminates into braches for the skin and muscle of the peritoneum
Pudendal N: Innervates
- External anal sphincter
- External urethral sphincter
- Skin of perineum
Lymphatic drainage of the uterus and ovaries
The lymphatic drain of the uterus and ovaries generally follows with blood supply to these organs.
Ovaries: Vasculature
- Ovarian arteries from the abdominal aorta
- Right ovarian vein to the inferio vena cava
- Left ovarian vein to the left renal vein
Uterus: vasculature
the ovarian and uterine arteries unite and form an anastomotic network, venous drainage uterine veins into the internal iliac veins
Ovaries: Lymphatic drainage
- pre and para-aortic lymph node
Uterus: lymphatic drainage
- Uterus fundus – pre and para-aortic lymph nodes due to the anastomotic network
- Uterus body and cervical – predominantly to the internal and external iliac chains however there is some drainage to the superficial inguinal nodes via the round ligament
Lymphatic efferent channels
- Superficial inguinal nodes drain to the external iliac nodes
- The internal iliac and external iliac node drain to the common iliac nodes
- The common iliac nodes drain in the para-aortic nodes
- The para-aortic nodes drain to the cistern chyli which continues as the thoracic duct in the thorax
- The thoracic duct drains to the junction of the left subclavian and internal jugular veins
Anal canal: Description
The anal canal is the section of the gastrointestinal tract between the rectum and the anal verge.
Function:
- Control of defecation
Anal canal: Gross anatomy
- Approximately 4cm in length
Origin: anorectal angle (the right angle turn at lavator ani)
Termination: The anal verge
- Dentate line – separates the anal canal into an upper and lower part. These parts differ in structure and neurovascular supply. The dentate line is formed by the anal columns (of Morgani), which are a series of anal sinuses that drain the anal glands. It is located at approximately the middle of the anal canal.
- Above the dentate line the epithelium is a mucous membrane and below the dentate line the epithelium is a stratified squamous cells.
- Anal sphincters – divided into internal and external. Internal is a continuation of the inner rectal muscle, thickened muscular ring, composed of visceral muscle. External skeletal muscle with deep, superficial and subcutaneous parts
- The anal margin is the 5cm of skin around the anal verse
Anal canal: Relations
- Laterally – inchioanal fossa
- Anterior – bulbospongiosus, perineal body, vagina
- Posterior – tip of the coccyx
Anal canal: Neurovasculature
Blood supply:
- Above the dentate line: superior and middle rectal arteries. (Superior from the inferior mesenteric, middle rectal from the internal iliac artery) and median sacral artery.
- Below the dentate line: inferior rectal artery a branch of the internal pudendal artery
Venous drainage:
- Above the dentate line: superior rectal vein to the inferior mesenteric vein (portal system)
- Below the dentate line: inferior and middle rectal veins to the internal iliac veins
Lymphatic drainage:
- Above the dentate line: internal iliac nodes
- Below the dentate line: superficial inguinal nodes
Innervation:
- Above the dentate line: inferior hypogastric plexus
- Below the dentate line: Inferior rectal branches of the pudendal nerve (S2-4)
Anal canal: Variant anatomy
Imperforate anus
Rectum: Description
The rectum is a part GI system in the hind gut
Location: between the anus and the sigmoid colon in the ishiorectal fossa, at the level of S3 the sigmoid loses its mesentery and becomes the rectum.
Function: Storage of stool and defecation
Rectum: Gross anatomy
Muscular tube which is the continuation of the sigmoid colon, it is continues with the anus inferiorly
Angulated course due compression from puborectalis
Rectum: Neurovasculature
Arterial supply:
Superior and middle rectal arteries branches of the IMA and internal iliac arteries
Venous drainage:
Same named veins, superior and middle into the portal system
Innervation:
Upper rectum: Inferior mesenteric plexus
Mid and lower: Superior and Inferior hypogastric plexus
Lymphatics:
Perirectal nodes in the ishiorectal fossa
Inferior mesenteric nodes
Internal iliac group
Rectum: Relations
Anterior: Vagina or prostate
Posterior: tip of the coccyx
Lateral: ishiorectal spaces
Medial: lumen
Superior: sigmoid colon
Inferior: Anus
Rectum: Variants
Imperforate rectum
Rectal prolapse
Fallopian tubes: Description
The fallopian tubes are paired hollow tubes that are part of the female reproductive system located between the ovaries and the uterus
Function: convey ovulated eggs to the endometrial canal
Fallopian tubes: Gross anatomy
Tubular ~10-12cm in length
Dividable into (Four inches across is impossible):
- Fimbria – finger like projections draping over the ovaries
- Infundibulum – funnel segment
- Ampulla – widest and longest segment
- Isthmus – narrowest segment
- Intersitial segment – section within the myometrium
Location: within the mesosalpinx
Fallopian tubes: Relations
- Medial: cornu of the uterus
- Lateral: walls of the pelvis
- Posterior: Iliac arteries
- Inferior: right and left adnexa
- Superior: interabdominal cavity
Fallopian tubes: neurovasculature
Arteries supply:
- Uterine and ovarian arteries
Venous drainage:
- Uterine and ovarian veins
Lymphatics:
- Predominantly the para-aortic nodes like the ovaries
Innervation:
- Ovarian and uterine plexus (T11-L1)
Fallopian tube: variants
- Absent
- Fallopian tubes duplication
- Cyst
Uterus: Description
The uterus is a primary reproductive organ of females
Function:
Gestation of an embryo to birth
Location: Extraperitoneal pelvis, peritoneum drapes over the fundal uterus
Uterus: Gross anatomy
Inverted pear shaped, most of the bulk is myotrium -> smooth muscle
Typically 7.5cm in length, can grow to 40 in length during pregnancy
Consists of:
- Body
- Isthmus between the body and the cervix
- Cervix at the base
- Rounded fundus superiorly above the plane of the insertion of the fallopian tubes
- Cornu laterally
- Endometrial cavity internally which is lined with endometrial tissue
Uterine ligaments
- Pubocervical
- Uterosacral
- Transverse cervical
- Broad ligament
- Round ligament
- Suspensory ligament of the ovaries
- Ovarian ligament
Uterus: Neurovasculature
Blood supply:
Uterine arteries, branches of the anterior division of the internal iliac arteries
Venous drainage:
Uterine veins into the internal iliac veins
Lymphatics:
- Fundus: para-aortic nodes
- Body/cervix: internal and external iliac nodes, superficial inguinal nodes via the round ligament
Innervation:
Inferior Hypogastric plexus, uterovaginal and ovarian plexus
Uterus: Relations
- Posterior: Rectum and pouch of Douglas
- Anterior: Urinary bladder, uterovesical pouch
- Lateral: the adexal spaces, multiple vessels, the ovaries, broad ligament
- Superior: the intraabdoinal cavity
- Inferior: vagina
Uterus: Variants
- Bicornate
- Arcuate
- Septated
- Unicornated
- Agenisis
- Anteverted
- Retroverted
- Uterus didephys
Ovary: Description
The ovary is the female gonad
Location: Paired organs in the adnexa bilaterally
Function: Ovulation and hormone production (estrogen and progesterone)
Ovary: Gross anatomy
- Ovoid in shape
- 1 to 10cc in volume
- Outer capsule surrounding an outer cortex and inner medulla
Ovary: Ligaments
- Located within the mesovarium of the broad ligament
- Attached to the uterus by the ovarian ligament
- Attached to the wall of the uterus by the suspensory ligament of the ovary, this ligament contains the ovarian neurovasculature
Ovary: Neurovasculature
Arterial supply:
- Ovarian artery (origin aorta)
Venous drainage:
- Pampiniform plexus to the ovarian veins (right vein to the inferior vena cava, left vein to the left renal vein)
Innervation:
- Ovarian plexus from the aortic, renal, superior and inferior hypogastric plexuses
Lymphatics:
- Para-aortic
Ovary: Relations
- Anterior – broad ligament, mesovarium, ovarian vessels, obliterated umblical artery
- Posterior – ureter, internal iliac vessels, pelvic wall
- Superiorly – external iliac vessels
- Inferiorly – levator ani
- Medially – ovarian ligament
- Laterally – obturator vessels and nerves
Ovary: Variants
- Agenesis
- Ectopic location
- Thyroid tissue in ovary
Epidydimys
The epididymis are folded tubular structures that located in the scrotum
Function: transport, collection and maturation of sperm
Location: between the vas deferens and the rete testis on the posterior aspect of the testis
Epidydimys: Gross anatomy
- ~6cm long however 6m of tubing
Dividable into:
- Head
- Body
- Tail
- Drains the rete testis via efferent ductules
- Epididymus drains into the vas deferens
Epidydymis: Relations
- Anterior: testicles
- Posterior: posterior wall of the scrotum
- Lateral lateral wall of the scrotum
- Medial: scrotal septa
Epididymis: Vasculature
Arterial supply:
- Deferential artery a branch of the superior vesicular artery
- Testicular artery
Venous drainage:
- Pampiniform plexus
Lymphatics;
- Para-aortic nodes
Epididymis: Variants
- Epididymal cyst
- Appendix of the epidymal head
- Spermatocyte
- Patent process vaginalis
Testis: Description
The testes are the male gonads
Location: within the scotum
Function: Production of sperm and testosterone
Testis: Gross anatomy
- 12-20ml adult
- Ovoid in shape
- Covered in a tough membrane called the tunica albuginea with the tunica vaginalis covering exteriorly.
- Tight junctions between Sertoli cells form a blood testis barrier
Production and maturation of sperm
- Seminiferous tubules
- Tubuli recti
- Rete testis (within the medistinum testis)
- Efferent ductules (10-15) in number
- Head of the epididymis uniting to form a single duct
- Vas deferens
Testis: Neurovasculature
Arterial:
Testicular arteries from ~L2 level abdominal aorta
Venous:
Pampiniform plexus draining into the testicular veins
Innervation:
Spermatic plexus from the para-aotic ganglion
Lymphatics:
Para-aortic
Testis: Variants
- Asymmetry in size
- Polyorchidism
- Agenesis
- Cryptorchidism
- Testicular appendix
- arrest of testicular descent
- both testes in one scrotal sac
Ductus deferens
Paired 30-45cm muscular tubes.
Origin: Continuation of the tail of the epididymus
Course:
- Runs in the spermatic cord
- through in the inguinal canal
- into the abdominal cavity running extra-peritoneal
- laterally through the pelvis
- passing anterior the ureters
- inferior to the bladder
Termination: unites with seminal vesicles to form the ejaculatory duct within the prostate
Ductus deferens: vasculature
Arterial: deferential artery from the superior vesical artery
Venous: veins of the ductus deferens drain into the pelvic venous plexus
Lymphatic drainage:
Drains to the external and internal iliac nodes
Ducus deferens: Variants
Agenesis of the ductus deferens
Spermatic cord: Gross anatomy
Origin: deep inguinal ring
Course: through the inguinal canal
Termination: at the posterior border of the testis
Spermatic cord: Contents
3 arteries, 3 nerves, 3 other things:
- 3 arteries: deferential artery, testicular artery, cremasteric artery
- 3 nerves: genital branch of the genitofemoral, cremasteric nerve, sympathetic nerves
- 3 other things: ductus deference, pampiniform plexus, lymphatic vessels
Spermatic cord: Layers
- External spermatic fascia from the external oblique
- Cremaster fascia from the internal oblique
- Internal spermatic fascia from the transversalis fascia
Prostate gland: Description
The prostate gland is part of the male reproductive system.
Location: Surrounding the proximal urethra
Function: Ejaculation
Prostate gland: Gross anatomy
Inverted pyramidal shape
Composed of 70% glandular and 30% fibromuscular tissue
The base of the prostate is in continuity with the bladder
The prostate is compose of three zones:
- Peripheral zone – largest in volume, surrounds the posterior aspect and distal urethra
- Central zone – Surround the ejaculatory ducts, most common area from BPH
- Transition zone - Surrounds the Proximal ureter
Structures within the prostate gland
Membranous urethra
Ejaculatory ducts
Prostate gland: Neurovasculature
Arterial supply:
Inferior vesicular artery (a branch of the internal iliac artery)
Venous drainage:
Prostatic venous plexus to the internal iliac veins
Lymphatic drainage:
Internal iliac nodes
Innervation:
Inferior hypogastric plexus
Prostate gland: Relations
- Anterior – retropubic space, pubic symphysis
- Posterior – rectovesicular fascia, rectum
- Lateral – Prostatic venous plexus
- Medial – membranous urethra
- Superior – urinary bladder
- Inferior – urogenital membrane
Male urinary bladder: Description
The urinary bladder is a hollow muscular organ that is part of the urinary tract.
Location: extraperitoneal within the true pelvis
Function: storage of urine and micturition
Male urinary bladder: Gross anatomy
- Triangular shape with a posterior base, anterior apex and an inferior neck.
- Becomes ovoid when full of urine
- Lined with tough trabeculated transitional cell epithelium except at the trigone
- The trigone is a triangular area of smooth mucosa located between the ureteric orificies and the urethral orifaces
- The urethra orinates from the neck of the bladder
- Ureters insert posteriorly and follow a short course within the wall of the bladder
Male urinary bladder: Muscles
- Detrusor muscle
- Internal urethral sphincter
Urinary bladder: Neurovasculature
Arterial supply:
Superior and inferior vesicular arteries (branches of the anterior division of the internal iliac arteries)
Venous drainage:
Into the interal iliac veins via:
Male: Vesical and prostatic venous plexus
Female: Vesical and uterovaginal plexus
Innervation:
Vesicular nerve plexus supplied by the Inferior hypogastric plexus (and pelvic splanchnic nerves)
Lymphatics:
Internal iliac nodes
Urinary bladder: Male relations
- Anterior: pubic symphysis
- Posterior: rectovesical pouch and rectum
- Inferior: prostate, levator ani
- Superior: peritoneum
- Laterally: ischiorectal fossa
Urinary bladder: Female relations
- Anterior: pubic symphysis
- Posterior: vesiculouterine pouch, uterus, cervix, vagina
- Lateral: ischiorectal fossa
- Superior: uterus and peritoneum
- Inferior: Perineal membrane
Urinary bladder: variants
Double bladder, septation, agenesis, uterocele
Male urethra: Description
The male urethra is a fibromuscular tube the from the neck of the bladder to the external urethral meatus.
Function: transportation of urine and semen
Male urethra: Gross anatomy
18-20cm in length.
Origin: Internal urethral orifice
Dividable into parts: (Prime minister, big prick)
- Prostatic urethra – Neck of bladder through the internal urethral sphincter, travels through the transitional zone of the prostate, ejaculatory ducts enter
- Membranous urethra – Passes through the urogenital diaphragm, though the external urethral sphincter
- Bulbar – Transverses the root of the penis, receives the bulbourethral glands
- Penile – longest portion, within the corpus spongiosum, distally it dilates as the fossa navicularis
Male urethrea: Neurovasculature
Arterial supply:
- Internal Pudendal artery
- Urethral artery (internal pudendal)
- dorsal artery of the penis (internal pudendal)
Venous drainage:
- Internal Pudendal veins
- Internal iliac veins
Lymphatics:
- Internal iliac nodes and deep inguinal nodes
Nerves:
Pudendal nerves
Male urethra: Sphincter
- Internal urethra sphincter
- External urethral sphincter
Male urethra: Variants
- Urethral valves
- Urethral Stricture
- Hypospadius
Female urethra: Gross anatomy
4cm in length
Origin: Neck of the bladder
Course: Transverse the deep and superficial perineal pouches to exit midline between the labia minora in the vestibule
Female urethra: Muscles
Internal urethral sphincter
External urethral sphincter -> compressor urethrae, urethrovaginal muscle, sphincter urethrae
Female urethra: Relations
Superior: Urinary bladder
Anterior: Clitoris
Posterior: Vagina
Lateral: puborectalis
Female urethra: Neurovasculature
Nerves:
Pudendal nerve S2-4
Artery:
Internal pudendal artery and vaginal artery
Venous drainage:
Internal pudendal vein and vaginal veins
Lymphatics:
Internal iliac nodes
Female urethra: Variants
Urethral agenesis
Penis:Description
The most distal part of the male urogenital system
Function: urination, reproduction
Penis: Gross description
Divided into 3 sections:
Skin:
- Loosely connected to the tunica albuginea
- distally folded to form the prepuce (foreskin) at the corona of the penis
- the frenulum is a median fold of skin at the urethral aspect of the glans running between the orifice and the deep surface of the prepuce
Root:
Consists of three cylindrical structures of erectile tissue:
- penile crura (paired) attach to the pubic arch. These join towards the symphyseal border and continue as the corpora cavernosa
- the bulb of the penis is a median structure found between the crura and is attached to the perineal membrane. It narrows to continue as the corpus spongiosum. The urethra pierces its deep aspect to traverse the bulb as the bulbar urethra and continues to the corpus spongiosum.
Body:
- the corpora cavernosa (right and left) and the corpus spongiosum (median)
- the urethra courses through the corpus spongiosum and opens at the tip of the penis (glans) via the meatus
- two suspensory ligaments support the body - fundiform and triangular ligaments
Penis: Neurovasculature
Arterial supply:
- Artery of the bulb of the penis – corpus spongiosum and the bulbourethral glands
- Caversonal artery (internal pudendal) -> corpus cavernosum
- Dorsal artery of the penis – corpus cavernosum and penile skin
Venous drainage:
- deep dorsal vein (unpaired) drains the corpus cavernosum and corpus spongiosum
- superficial dorsal vein (unpaired) drains the prepuce and penile skin
Lymphatic drainage:
- Inguinal and iliac nodes
Innervation:
- pudendal nerve and pelvic plexusi (S2-4)
Penis: Variants
- hypospadias
- epispadias
- phleboliths in the corpus cavernosum
Ischiorectal fossa: Description
Is a fat filled paired triangular space of the perineum
Location: surrounding the rectum/anus
Function: Allows movement of the anus with defecation
Ischiorectal fossa: Boundaries
- Roof: lavator ani
- Floor: Perineal fascia
- Medial: external anal sphincter and anal canal
- Lateral: Obturator internus and ischial tuberosity
Ischiorectal fossa: Contents
- Ischioanal fat pad
- Pudendal canal
- Inferior rectal braches of the pudendal nerve
- Lymphatics
Ischiorectal fossa: Neurovasculature
Lymphatics:
- Drain to the internal iliac chain and the inguinal nodes
Nerves:
- Perineal nerve
- Internal rectal nerve
Sciatic foramen: description
The great sciatic foramen is one the major foramen of the pelvis
Function:
It transmits piriformis and the neurovasculature of the gluteal region
Sciatic foramen: Boundaries
- Superior: Sacroiliac ligament
- Inferior: Sacrospinous ligament
- Medial: sacrotuberous ligament
- Lateral: Greater sciatic notch
Sciatic foramen: Contents
Piriformis muscle
Above piriformis:
Superior gluteal vessels
Superior gluteal nerve
Below piriformis:
Pin Pins
- Pudendal nerve
- Inferior gluteal vessels and nerve
- Nerve to obturator internus
- Posterior femoral cutaneous nerve
- Internal pudendal vessels
- Nerve to quadratus femoris
- Sciatic nerve
Lesser sciatic foramen: Boundaries
Lesser sciatic notch
Sacrospinous ligament
Sacrotuberous ligament
Lesser sciatic foramen: Contents
Obturator internus and nerve to obturator internus
Pudendal nerve and (internal) vessels
Perineum: Description
Diamonds shaped space between the pubis/ischial tuberosities/coccyx
Function: Transmits the urethra, anus and vagina in females
Urogenital triangle
-Contains the perineal membrane attachment to bulb and cura of penis
The membrane divides the superficial and deep perineal pouches
Superficial: bulb of penis /root clitoris
Deep: external urethral sphincter / vagina in women
Anal triangle
- Contains the anus and its sphincter
- Ischiorectal fossa
- Anococcygeal body
Perineum: relations
- Bounded by the pubis anteriorly
- The ischial tuberosities anterolaterally
- Sacrotuberous ligaments posterolaterally
- Coccyx posteriorly
Perineum: Neurovasculature
Arterial supply:
Internal pudendal artery
Venous drainage:
Internal pudendal vein
Lymphatics:
Internal iliac nodes
Nerves:
Pudendal nerve (S2-4)
Inguinal canal:description
A passage from the abdomen to the superficial tissue of the anterior abdominal wall
Function: to allow the passage of structures from the abdomen
Inguinal canal: Gross anatomy
- Superior wall: Internal oblique and transversus abdominus
- Anterior wall: aponeurosis of external oblique and internal oblique
- Lower wall: Inguinal ligament and the lacunar ligament
- Posterior wall: conjoint ligament and transversalis fascia
Inguinal canal: Transmits
Deep inguinal ring: o shaped opening in the transversalis fascia
Superficial inguinal ring: v shaped opening in the external oblique fasica
The spermatic cord in males or the round ligament in females and the ilioinguinal nerve in both
Inguinal canal: Relations
Posterior: retroinguinal passage
Inguinal canal: Variants
Indirect inguinal hernia