Exam V: Pelvic Structures Flashcards
Function, Contents, and Associated Structures of the Pelvis
Function: contains and supports the bladder, rectum, anal canal, and reproductive tracts, gateway to other areas of the body
Contents: bladder, prostate, uterus, uterine tubes, fallopian tubes, vas deferens, sigmoid colon, rectum, vagina, ovaries, seminal vesicle, ejaculatory duct, ureters, urethra
Related structures: external genitalia, scrotum, sacrum, pelvic bones
4 Parts of the Pelvis
The Pelvis is composed of 4 parts
os coxae x2/ innominate bones
sacrum
coccyx
Pelvic Inlet and Outlet Components
Inlet: Promontory: S1 Ala: wings of sacrum Sacroiliac joint Linea terminalis made of arcuate line, pectin pubis, and pubic crest pubic symphysis
Outlet:
Pubic symphysis, pubic arches, ischial tuberosity, coccyx and sacrotuberous ligament
Pelvic Bone Components
- Ilium
- Ischium
- Pubis
Pelvic Joints and Ligaments
Lumbosacral Joint – symphysis (secondary cartilaginous); intervertebral disc, iliolumbar ligament
*L5-S1 most frequent site of disc herniation
Two zygapophyseal (facet) joints (plane synovial)- between superior and inferior articular facets
Sacroiliac – compound joint, plane synovial & syndesmosis; anterior/posterior sacroiliac lig., sacrotuberous & sacrospinous ligaments
Sacrococcygeal – sacrococcygeal ligament
Pubic symphysis – secondary cartilaginous, superior/inferior pubic (arcuate) ligament
Obturator membrane within the obturator foramen
Histology of Pubic Symphysis
Composed of fibrocartilage covered in hyaline cartilage
Direction of Pubic Bones Within the Body
The pubic bones are directed inferiorly in anatomic position
The sacrotuberous and sacrospinous ligaments stabilize the sacrum and prevent upward tilting of the inferior sacrum
Maintain the posture of the pelvis when standing; limits upward tilting of sacrum
Ischial tuberosity to sacrum = sacrotuberous ligament
Sacrum to spinous process = sacrospinous ligament
L5 to S1 Forward Sliding
Area of most frequent slippage
Articular processes and liolumbar ligaments prevent it from forward slipping
Spondylolisthesis
Forward moving of vertebral body
L5 moving on top of S1 from fracture or too much pressure = Meyerding Grade 1
Scotty dog collar: pars interarticularis fracture
Difference Between Male and Female Pelvic Structure
Male pelvis is heart shaped and female are more circular
Males have narrower pelvic angle than female
Ischial spines are wider in females than in males
Greater sciatic notch is wider in females than in males
Conjugate Line Diameter
anterior/posterior diameter, superior border of pubic symphysis to middle of sacral promontory
True Conjugate Diameter
from back of pubic symphysis to promontory, slightly shorter than conjugate, narrowest region between pubic symphysis and promontory (inlet)
Diagonal Conjugate Diameter
from bottom of pubic symphysis to sacral promontory, the only diameter that can be measured per vaginam
Oblique Diameter
sacroiliac joint to the iliopubic eminence on the opposite side
Transverse Diameter
at inlet and outlet; outlet=between the ischial tuberosities
maximum diameter of inlet is transverse