Essentials of Anatomy and Physiology

The Muscular System 159

Clitoris

Urethra

Vagina

Ischium

Central

tendon

Anus

Gluteus

maximus

Anococcygeal

ligament

Coccyx

Ischiocavernosus

Bulbospongiosus

Transverse perineus

Levator ani

External

anal

sphincter

Coccygeus

Figure 7–13. Muscles of the female pelvic floor.

QUESTION:In women, what organs are directly supported by this “floor” of muscles?

Table 7–7 MUSCLES OF THE PELVIC FLOOR

Muscle Function Origin Insertion

Levator ani

Coccygeus

Ischiocavernosus

Bulbospongiosus

Transverse perineus

(superficial and deep)

External anal sphincter

Supports pelvic organs, especially dur-

ing defecation, urination, coughing,

and forced exhalation; constricts

anus, urethra, and vagina

Supports pelvic organs, especially dur-

ing defecation, urination, coughing,

and forced exhalation

Erection of clitoris in female, penis in

male

Assists urination; erection in female;

erection and ejaculation in male

Assists urination in female; urination and

ejaculation in male

Closes anus

• pubis and ischium


• ischium


• ischium and pubis


• central tendon of
  perineum


• ischium


• anococcygeal
  ligament
  
  
  • coccyx, anal canal,
    urethra
  
  
  • coccyx and sacrum
  
  
  • clitoris or penis
  
  
  • fasciae, pubic arch,
    clitoris, or penis
  
  
  • central tendon of
    perineum
  
  
  • central tendon of
    perineum
  
  
  
  

STUDY OUTLINE

Organ Systems Involved in Movement

1. Muscular—moves the bones.


2. Skeletal—bones are moved, at their joints, by mus-
   cles.


3. Nervous—transmits impulses to muscles to cause
   contraction.


4. Respiratory—exchanges O 2 and CO 2 between the
   air and blood.
   5. Circulatory—transports O 2 to muscles and removes
   CO 2.

Muscle Structure

1. Muscle fibers (cells) are specialized to contract,
   shorten, and produce movement.


2. A skeletal muscle is made of thousands of
   muscle fibers. Varying movements require contrac-