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Muscles - Coggle Diagram

- - - - course and distribution: passes around lateral aspects of anal canal, insertion into perineal body
  - - - origin: median raphe on ventral surface of bulb of penis; perineal body
        
        course and distribution: surrounds lateral aspects of bulb of penis and most proximal part of body of penis, inserting into perineal membrane, dorsal aspect of corpus spongiosum and corpora cavernosa, and fascia of bulb of penis
        
        action: support and fixes perineal body/pelvic floor; compresses bulb of penis to expel last drops of urine/semen; assists erection by compressing outflow via deep perineal vein and pushing blood from bulb into body of penis
    - - origin: perineal body
        
        course and distribution: passes on each side of lower vagina, enclosing bulb and greater vestibular gland; inserts into pubic arch and fascia of corpora cavernosa of clitoris
        
        action: supports and fixes perineal body/pelvic floor; "sphincter" of vagina; assists in erection of clitoris; compresses greater vestibular gland
  - - - course and distribution: embraces crus of penis or clitoris, inserting onto inferior and medial aspects of crus and to perineal membrane to perineal body
  - - - origin: internal surface of ischiopubic ramus and ischial tuberosity
        
        course and distribution: passes along inferior aspect of posterior border of perineal membrane to perineal body
    - - origin: internal surface of ischiopubic ramus and ischial tuberosity
        
        course and distribution: passes along superior aspect of posterior border of perineal membrane to perineal body and external anal sphincter; in females, often replaced by smooth muscle blending with perineal body
  - - - course and distribution: surrounds urethra superior to perineal membrane; in males, it also ascends anterior aspect of prostate; in females, some fibers also enclose vagina
- - - - insertion: linea alba, pubic tubercle, and anterior iliac crest
  - - - insertion: inf. borders of 10-12th ribs, linea alba, and pecten pubis via conjoint tendons
  - - - insertion: linea alba with aponeurosis of internal oblique, pubic crest, and pecten pubis via conjoint tendon
  - - - vertical muscle of the anterior abdominal wall
    - - insertion: xiphoid process and 5-7th costal cartilage
- - - - passes inferolateral
        
        lies lateral to lumbar vertebrae
        
        deep to inguinal ligament
    - - inferior attachment: strong tendon to the lesser trochanter of the femur
    - - with iliacus: thigh flexion
        
        flexes vert. column laterally
        
        trunk balance
  - - - lies adjacent to lumbar transverse processes
        
        broader inferiorly
    - - inferior attachments: iliolumbar ligament and internal lip of iliac crest
  - - - lateral side of inferior part of psoas major
    - - inferior attachment: lesser trochanter and psoas major tendon
- - - - proximal attachment: pelvic surfaces of ilium and ischium; obturator membrane
        
        distal attachment: greater trochanter
      - innervation: nerve to obturator internus (L5, S1, and S2)
      - action: externally rotates the thigh, assists in holding the head of the femur in the acetabulum
  - - - proximal attachment: pelvic surface of S2-S4 segments; superior margin of greater sciatic notch and sacrotuberous ligament
        
        distal attachment: greater trochanter
      - innervation: anterior rami of S1 and S2
      - action: externally rotate and abduct the thigh; assists in holding the head of the femur in the acetabulum
  - - - ischiococcygeus
        
        proximal attachment: ischial spine
        
        distal attachment: inferior end of the sacrum and coccyx
        
        innervation: branches of S4 and S5 spinal nerves
        
        action: forms small part of pelvic diaphragm that supports pelvic viscera; flexes coccyx
    - - puborectalis, pubococcygeus, and iliococcygeus
      - proximal attachment: body of pubis; tendinous arch of obturator fascia; ischial spine
        
        distal attachment: perineal body; coccyx; anococcygeal ligament; walls of the prostate or vagina, rectum, and anal canal
      - innervation: nerve to levator ani (branches of S4), inferior anal nerve, and coccygeal plexus
      - action: forms most of pelvic diaphragm that supports the pelvic viscera, and resists increases in intra-abdominal pressure