Anatomy workbook 1 - introduction Flashcards
True pelvis
- Also known as greater pelvis
- Supports lower abdominal organs
- Little obstetric value
False pelvis
- Also known as lesser pelvis
- Inferior to true pelvis
- Contains pelvic cavity and viscera
Sacroiliac joint
- Diarthrodial joint (synovial)
Pubic symphysis
- Secondary cartilaginous joint
Features of the male pelvis (android)
- Thick and heavy bone composition
- Lesser and greater pelvis (tall narrow)
- Pelvic inlet (heart shaped)
- Pelvic outlet (small)
- Acute sub pelvic angle (less than 90°)
- Acetabulum (Close, less flexible, curved)
Features of female pelvis
- Light and thin bone composition
- Greater and less pelvis (wide and shallow)
- Pelvic inlet (oval)
- Pelvic outlet (large)
- Subpubic angle (greater than 90°)
- Acetabulum (further apart, more flexible and straight)
Walls of the pelvic cavity
- 2 lateral walls
- Antero-inferior wall
- Posterior wall
Muscle making up posterior wall of pelvis
Coccygeus muscle
Margins of the pelvic inlet
- Posterior (sacral promotory)
- Lateral (iliopectineal line)
- Anterior (pubic symphysis)
Boundaries of the pelvic inlet
- Posterior (sacral promontory)
- Lateral (iliopectineal line)
- Anterior (pubic symphysis
Boundaries of the pelvic inlet
- Anterior (pubic symphysis)
- Lateral (iliopectineal line)
- Posterior (sacral promontory)
Boundaries of the pelvic outlet
- Anterior (pubic arch)
- Lateral (ischial tuberosity + sacrotuberous ligaments)
- Posterior (tip of coccyx)
Perineal body
- fibromuscular structure in midline of perineum
- Anchor point for several structures
Anococcygeal body
- Fibrous ligament from tip of coccyx to external anal sphincter
Separate components of the levator ani muscle
- Pubococcygeus
- Illiococcygeus
- Puborectalis
Structures that support majority of the pelvic floor
- Coccygeus
- Levator ani
Functions of the pelvic floor
- Basically a diaphragm (like thoracic)
- Support abdomino-pelvic viscera
- Increase intra pelvic/abdominal pressure
- Urinary and faecal continence
Innervation of the pelvic floor
- Pudendal nerve (S2-4)
- Anterior rami of S4-5 (sacral plexus)
Cystocele
- Herniation of urinary bladder into vagina
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Rectocele
- Herniation of rectum through posterior wall of vagina
Function of the mediolateral episiotomy
- Controlled tearing of pelvic floor to avoid damage to external anal sphincter
- Speeds delivery time (prevents foetal distress)
Function of the mediolateral episiotomy
- Controlled tearing of pelvic floor to avoid damage to external anal sphincter
- Speeds delivery time (prevents foetal distress)
Long-term complications of childbirth on pelvic floor
- Urinary and faecal incontinence
Function of the DRE (M and F)
- Male (palpate prostate)
- Female (palpate cervix and vagina)
Vessel supplying majority of the pelvic organs, perineum and gluteal region
Internal iliac arteries
Superior and inferior vesicular arteries
- Supplies bladder, seminal gland and prostate (M)
- Branch of internal iliac artery
Uterine artery
- Supplies the round ligament of uterus, ovaries, uterus, cervix and Fallopian tubes
- Branch of internal iliac artery
Uterine artery
- Supplies the round ligament of uterus, ovaries, uterus, cervix and Fallopian tubes
- Branch of internal iliac artery
Gonadal arteries
- AKA testicular/ ovarian artery
- Supplies testes/ ovaries
- Branch of abdominal aorta
Difference in origin of the superior, middle and inferior rectal arteries
- Superior (inferior mesenteric artery)
- Middle and inferior (internal iliac artery)
Internal pudendal artery
- Main artery of perineum
- Branch of internal iliac a.
Obturator arteries
- Supplies muscles in medial compartment of thigh
- Branch of internal iliac artery
Difference in venous drainage of the rectum
- Superior third → superior rectal vein → porto-venous circulation
- Middle and inferior thirds → inferior rectal vein → systemic circulation
Which plexus does the prostatic venous plexus communicate with on its posterior side
Internal vertebral venous plexus
How does prostate cancer spread
- Rapidly metastasises
- Bone ( vertebral), lungs, liver
Ilioinguinal nerve
- L1 origin
- Enters inguinal canal at superficial inguinal ring
- Supplies skin at base of penis and labia
Genitofemoral nerve
- L1-2
- Enters at deep inguinal ring
- Supplies upper thigh and anterior scrotum (assists in cremasteric reflex)
Pudendal nerve
- S2-4 roots of sacral plexus
- Follows pudendal artery and innervations perineum
Clinical significance of the ischial tuberosity
- Palpated tranvaginally
- Located when performing bilateral pudendal nerve block
Origin of the sympathetic nervous in the pelvis
- L1-2 via hypogastric nerve and distal aspect of the sympathetic trunk
- ‘Hitchhike’ arterial supply to reach organs
Origin of parasympathetic nervous system in pelvis
- S2-4 of the pelvic splanchnic nerves
- Additionally innervates erectile tissues in both male and females
After rectal surgery, why are some men unable to ejaculate
- Damage to the autonomic nervous system
External iliac lymph nodes drain:
- Pelvic structures
- Anterior and middle pelvic organs
- Inguinal lymph nodes
Internal iliac lymph nodes drain:
- Gluteal region
- Deep perineum
- Inferior pelvic viscera
Common iliac lymph nodes
- Drains external, internal and sacral lymph nodes
