1 - Pelvic Vasculature & Perineum Flashcards
Internal Iliac Artery
Anatomical definition
Location
Branches
- Anatomical Definition
- Branch of common iliac;
- Location
- Enters true pelvis to supply pelvic viscera, walls, perineum, and gluteal region
- Branches
- Posterior Division
- Anterior Division
Internal Iliac Artery
Posterior Division:
Iliolumbar Artery
Lateral Sacral Artery
Superior Gluteal Artery
- Iliolumbar Artery
- Sends branches to iliac foss and lower lumbar region
- Lateral Sacral Artery
- Descends anterior to sacrum; branches to anterior sacral foramina to supply radicular branches to anterior spinal artery
-
Superior Gluteal Artery
- Large artery
- Passes posteriorly between lumbosacral trunk (ant. rami of L4,L5) and anterior ramus of S1
- Exits pelvis via greater sciatic foramen (superior to piriformis muscle) to supply gluteal muscles
Internal Iliac Artery
Anterior Division (variable branching)
Obturatory Artery - Surgical Complication?
Umbilical Artery
- Obturartor Artery
- Passes with obturator nerve on later wall of pelvis, then through obturatory foramen
- Clinical: 25% of obturator arteries originate from Inferior Epigastric Artery; beware of this variation when repairing inguinal hernia; may also arise directly from external iliac artery
- Umbilical Artery
- Patent, proximal part gives off 2-3 superior vesical arteries (upper urinary bladder supply)
- Obliterated distal part forms medial umbilical ligament that courses toward umbilicus; represents obliterated fetal umbilical artery
Internal Iliac Artery
Anterior Division (variable branching)
Inferior Vesical Artery
Vaginal Artery
- Inferior Vesical Artery
- Supplies base of urinary bladder, prostrate, and seminal vesicles
- Found ONLY in MALES
- Equivalent to vaginal artery in females
- Vaginal Artery
- Passes to sides of vagina
- Found only in femalesEquivalent to inferior vesical artery in males
Internal Iliac Artery
Anterior Division (variable branching)
Middle Rectal Artery
Uterine Artery (Clinical)
- Middle Rectal Artery
- May arise from Inferior Vesical Artery in males
- Often absent, especially in females
- Uterine Artery
- Crosses superior to ureter (lateral to cervix) to enter broad ligament of uterus
- May be damaged during hysterectomy; ligate and sever the artery, NOT the ureter
- “Water under the bridge”
- May have a vaginal branched (not confused with vaginal artery)
Internal Iliac Artery
Anterior Division:
Inferior Gluteal Artery
Internal Pudendal Artery
- Inferior Gluteal Artery
- Passes posteriorly between anterior rami of S1 and S2 (or S2 and S3)
- Passes between piriformis muscle / coccygeus muscles
- Passes through greater sciatic foramen
- Can arise from posterior branch
- Internal Pudendal Artery
- Main blood supply to structures of perineum
- Passes between piriformis and coccygeus, leaves via greater sciatic forman
- Passes through lesser sciatic formane to enter perineum
- Does NOT pass through the diaphragm; would be potential site of weakness
Perineum-Anal Triangle
Perineum
Boundaries
- Perineum
- Region inferior to pelvic diaphragm
- Diamond shaped
- Boundaries:
- Anterior to Posterior: Pubic Symphysis to Tip of Coccyx
- Lateral: Pubic arches, ischial rami, ischial tuberosities, sacrotuberous ligament
Perineum-Anal Triangle
Urogenital Triangle
- Anterior triangle
- Contains urogenital structures: Root of Penis/Vulva, Urogental Diaphragm
Perineum-Anal Triangle
Anal triangle
- Posterior triangle
- Contrains: Anal canal, adjacent external anal sphincter in midline; surrounded by fat filled wesge shaped space–the ischioanal fossa
- Borders:
- Posterior - Tip of Coccyx
- Lateral - Sacrotuberous Ligament
- Anterior - Imaginary Transverse Line through Ischial Tuberosities
Contents of Anal Triangle
Ischioanal Fossa
Borders, Contents
- Borders (wedge shaped)
- Base - Located superficially at skin surrounding anus
- Lateral - Obturator Internus Muscle
- Medial - Levator Ani
- Contents
- Much fat, allowing distension of anal canal while cutting turds
- Pudendal Nerve / Internal Pudendal Artery and Vein
-
Pudendal Canal (Alcock’s Canal)
- Pudendal Neurovascular Bundle
- Within Obturator Internus Fascia
Contents of Anal Triangle
Pudendal Nerve
Origin
Innervation Type/Locations
Passage
Branches
- Origin
- Formed from Anterior Rami of S2-S4 of Sacral Plexus
- Type
- Somatic Nerve (voluntary) not autonomic
- Locations
- Somatic Innervation to most of perineum
- Passage
- Passes out of main pelvic cavity via inferior part of greater sciatic foramen to enter gluteal regions; descends posterior to ischial spine and passes through lesser sciatic foramen to enter pudendal canal
- Branches
- Inferior Rectal Nerve - Ext. Anal Sphincter/Lower half anal canal
- Perineal Nerve
- Dorsal N. of Penis / Clitoris
Contents of Anal Triangle
Branches of Pudendal Nerve:
Inferior Rectal Nerve
Perineal Nerve
Dorsal N. of the Penis/Clitoris
- Inferior Rectal Nerve
- Innervates External Anal Sphincter and suppl sensory fibers to mucous membrane of lower half of anal canal
- Perineal Nerve
- Motor branches to muscles in superficial and deep perineal pouches and cutaneous branches to posterior scrotum and labia
- Dorsal N. of the Penis/Clitoris
- Sensory to respective organ
What is the innervation for the External Anal Sphincter/supplies sensory fibers to mucous membrane of lower half of anal canal?
Inferior Rectal Nerve (branch of Pudendal)
Contents of the Anal Triangle
Internal Pudendal Artery
Branches
- Internal Pudendal Artery
- Branch of internal iliac artery
- Courses w/pudendal nerve
- Branches
- Inferior Rectral Artery
- Courses w/Inferior Rectal Nerve through ischioanal fossa to supply lower half of anal canal
- Branches to penis/clitoris
- Inferior Rectral Artery
Perineum-Urogenital Triangle
Location of Urogenital Triangle / Boundaries
- Location:
- Anterior part of perineum
- Lies below part of pelvic diaphragm which has acentral urogenital gap; allows for passage of urethra in males/females, and vagina in females
- Boundaries:
- Posterior: Imaginary line between ischial tuberosities
- Lateral: Inferior Rami of Pubis and Ramus of Ischium
Perineum-Urogenital Triangle
Urogenital Diaphragm
Location?
Function?
Layers?
Major structures which pass through?
- Location
- Inferior to pelvic diaphragm
- Attached to inferior rami of pubis and rami of ischium
- Function
- Prevent herniation (prolapse) or bladder, prostate, and uterus
- Layers
- Superficial Fascia, Muscle, Inferior Fascia
- Major Structures
- Urethra (both sexes)
- Vagina
Perineum-Urogenital Triangle
Layers of Urogenital Diaphragm
Superior Fascial Layer
Deep Perineal Pouch*
Inferior Faschial Layer (Perineal Membrane)
*own card
- Superior Fascial Layer
- Deep Perineal Pouch
- Males - Striated Muscles / Bulbourthral Glands
- Branches of Pudendal N, Int. Pudendal Vessels
- Inferior Faschial Layer (Perineal Membrane)
- Thick fascial layer
- Superior/Inferior layers fuse ant / post to form an enclosed fascial space
Perineum-Urogenital Triangle
Deep Perineal Pouch Muscular Contents:
Deep Transverse Perineal Muscle
External Urethral Sphincter
- Deep Transverse Perineal Muscle
- Action: Stabolize perineal body; reinforce pelvic diaphragm
- Innervation: Pudendal Nerve
- External Urethral Sphincter
- Surrounds urethra in urogenital diaphragm
- Action: Voluntary sphincter of urethra; controls flow of urine
- Innervation: Somatic innervation by Perineal Branch of Pudendal Nerve
Perineum-Urogenital Triangle
Deep Perineal Pouch Male Non-Muscular Contents:
Membranous Urethra (clinical)
Bulbourethral Glands
What A, V, N branches?
- Membranous Urethra
- Thinnest, shortest, narrowest, least dilatable part of urethra
- Clinical: Subject to tear during insertion of catheter
- Bulbourethral Glands
- Posterior to membranous urethrea
- Ducts pass through inferior fascia layer or urogenital diaphragn and open into spongy (penile) urethra in bulb of penis
- Secretes lubricant during sexual arousal
- Internal Pudendal Artery, Vein, Nerve branches
Perineum-Urogenital Triangle
Deep Perineal Pouch Female Non-Muscular Contents:
3x structures that pass through urogenital diaphragm?
- Urethra
- Vagina
- Internal Pudendal neurovascular bundle
