Bony Pelvis And Pelvis Wall Flashcards
Name bony feature of the ilium, ischium, pubis, and pelvic brim
Ilium: crest, ASIS, AIIS, PSIS, gluteal lines, iliac fossa, arcuate line (border between greater and lesser pelvis)
Ischium: body, ramus, spine, tuberosity
Pubis: symphysis, tubercle, body, superior and inferior pubic rami, pectineal line
Pectineal and arcuate line demarcate pelvic brim
When is the pelvic bone in anatomical position?
When the ASIS and anterior pubis is in the same vertical plane
Strong extensive ligaments connecting the sacrum and ilium and separates the hip bones?
What ligaments prevent rotation of the sacrum/coccyx and create the greater and lesser sciatic foramina?
Sacroiliac L (anterior/posterior)
Sacrotuberous and sacrospinous L
Pelvic injuries:
Anteroposterior compression causes fractures of ____.
Lateral forces squeeze ____ and ____ together breaking both.
Weak areas?
Pelvic rami
Acetabulum and ilia
Pubic rami, acetabulum, sacroiliac joints, and ala
Define the area of the lesser/true pelvis
Define the area of the greater (false) pelvis
What bone bears most the abdominal weight?
Superiorly by pelvic brim (pelvic inlet), inferiorly by muscular pelvic diaphragm, laterally and anteriorly by lower half of hip bones, posteriorly by sacrum and coccyx
Superior to pelvic brim, occupied by abdominal viscera
Pubic bone
What is the normal male pelvis?
Female pelvis?
Android pelvis: thick and heavy, deep greater pelvis, narrow and deep lesser pelvis, heart shaped pelvic inlet, small pelvic outlet, narrow pubic arch and subpubic angle, round obturator foramen, narrow greater sciatic notch
Gynecoid pelvis: thin and light, shallow greater pelvis, wide and shallow lesser pelvis, oval pelvic inlet, large pelvic outlet, wide pubic arch and subpubic angle, oval obturator foramen, wider 90 degree greater sciatic notch
Obturator internus M:
Origin
Insertion
Innervation
Action
Ilium/ischium surface (inside surface); obturator membrane
Greater trochanter
Obturator N
Rotates thigh laterally
Piriformis M:
Origin
Insertion
Innervation
Action
S2-4 surface, superior margin of greater sciatic notch; sacrotuberous L
Greater trochanter
S1-S2
Rotates thigh laterally
Coccygeus M
Origin
Insertion
Innervation
Action
Ischial spine
Inferior end of sacrum and coccyx
S4-S5
Support pelvic viscera, flex coccyx
Four muscle of the pelvic diaphragm with origin
What is the action of the last three and what are they called?
Coccygeus M: ischial spine
- Iliococcygeus M: tendinous arch
- Pubococcygeus M: pubis
- Puborectalis M: pubis
- Elevate the anal canal; levator ani
What is the function of the levator ani and what muscles does it contain?
What is the tendinous arch of the levator ani?
Elevates the anal canal
Iliococcygeus, pubococcygeus, puborectalis
Tendinous arch of levator ani is a thickening of obturator (part of endopelvic) fascia between ischial spine and body of pubis
What makes up the anorectal angle?
What is its function?
Puborectalis M
Maintain fecal continence (with sphincters)
Relaxes during both urination and defecation
Distinct from external and internal anal sphincter
What is the urogenital (levator) hiatus and how does it form?
What muscles are susceptible to tearing during birth?
Passageway for rectum, urethra, and vagina; formed by anterior gap between levator ani muscle
Pubococcygeus and puborectalis most susceptible to tearing during birth being most medial and large part of levator ani
Where is the ischiorectal fossae?
What is it filled with?
How is it divided?
Where is the perineal membrane?
Inferior to pelvic floor
Filled with fat
Diamond shaped and divided into two triangles (urogenital, anal)
Perineal membrane spans between rami; layer of fat is superior to membrane and external genitalia is inferior to membrane
Describe the ischiorectal fossae
Location?
Action?
Contents?
Fat-filled space around anorectum
Fossa extends anteriorly above perineal membrane
Allows moment of pelvic diaphragm and expansion of anal canal
Contains neurovasculature to anal canal and some perineum
Where is the anal canal?
What are anal columns?
Anal valves?
Anal sinuses?
Begins at the level when the rectum perforates the levator ani
Longitudinal rides
Folds at the base of columns
Small recess adjacent valves, exude mucus facilitating defecation
Describe the internal anal sphincter
External anal sphincter
Inner circular smooth M. (Involuntary), keeps tonic contraction except when feces fill the rectum, 55-85% of resting anal tone
Skeletal M. (Voluntary), 15-30% of resting anal tone; 3 parts: subcutaneous, superficial, deep (puborectalis)
Enlarged and collapsed varicosity of normal venous anatomy
Clinical consequence of _____.
What causes internal and its bright red blood?
External?
Hemorrhoids
Portal hypertension
Prolapse of rectal mucosa; due to weakened muscularis mucosa (bright red due to abundant arteriovenous anastomoses within internal rectal venous plexus)
External venous plexus covered with epidermis (painful)
What is above the pectinate line?
Nerves, veins, hemorrhoids classification, destination of lymph, embryological origin
Nerves: inferior hypogastric plexus (visceral)
Veins: primarily superior rectal V.
Hemorrhoids classification: internal hemorrhoids (not painful)
Destination of lymph drainage: internal iliac lymph nodes, inferior mesenteric
Embryological epithelial origin: endoderm
What is below the pectinate line?
Nerves, veins, hemorrhoids classification, destination of lymph, embryological origin
Nerves: inferior rectal nerves (somatic)
Veins: primarily inferior rectal veins
Hemorrhoids classification: external hemorrhoids (painful)
Destination of lymph drainage: superficial inguinal lymph nodes
Embryological epithelial origin: ectoderm
