Pelvis: Anatomy

Structure of the Bony Pelvis

Bones

The pelvis is a ring-like structure that surrounds and protects the pelvic cavity.  The pelvis is composed of the following bones:

• 2 “hip bones,” which consist of 3 bones each; these 3 bones are separated at birth, joined by hyaline cartilage Hyaline cartilage A type of cartilage characterized by a homogeneous amorphous matrix containing predominantly type II collagen and ground substance. Hyaline cartilage is found in articular cartilage; costal cartilage; laryngeal cartilages; and the nasal septum. Cartilage: Histology, and fuse completely in late adolescence:
  • Ilium:
    • Largest of the 3 bones 
    • Makes up the superior part of the acetabulum
    • The anterior superior iliac spine Anterior Superior Iliac Spine Chronic Apophyseal Injury, anterior inferior iliac spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy, iliac crest, and posterior superior iliac spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy are anatomical physical examination landmarks.
  • Ischium:
    • Inferior aspect of the pelvis and posteroinferior aspect of the acetabulum
    • The inferior bony projection is the ischial tuberosity Ischial Tuberosity Chronic Apophyseal Injury, which is the location of insertion of the proximal hamstrings.
  • Pubis:
    • Anteromedial portion of the pelvis
    • Joins as the pubic symphysis Pubic Symphysis A slightly movable cartilaginous joint which occurs between the pubic bones. Vagina, Vulva, and Pelvic Floor: Anatomy in the anteromedial direction
  • Acetabulum:
    • Formed from parts of the ilium, ischium, and pubis
    • Cup-shaped socket of the hip joint Hip joint The hip joint is a ball-and-socket joint formed by the head of the femur and the acetabulum of the pelvis. The hip joint is the most stable joint in the body and is supported by a very strong capsule and several ligaments, allowing the joint to sustain forces that can be multiple times the total body weight. Hip Joint: Anatomy (forms the acetabulofemoral joint with the head of the femur Head of the femur The hemispheric articular surface at the upper extremity of the thigh bone. Hip Joint: Anatomy)
• Sacrum Sacrum Five fused vertebrae forming a triangle-shaped structure at the back of the pelvis. It articulates superiorly with the lumbar vertebrae, inferiorly with the coccyx, and anteriorly with the ilium of the pelvis. The sacrum strengthens and stabilizes the pelvis. Vertebral Column: Anatomy:
  • Butterfly-shaped bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Bones: Structure and Types formed by the fusion of the 5 sacral vertebrae
  • Articulates with the 2 hip bones posteriorly
  • Each side articulates with the ilium via the sacroiliac joints.
• Coccyx Coccyx The last bone in the vertebral column in tailless primates considered to be a vestigial tail-bone consisting of three to five fused vertebrae. Vertebral Column: Anatomy:
  • Terminal end of the spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy
  • Inferior to the sacrum Sacrum Five fused vertebrae forming a triangle-shaped structure at the back of the pelvis. It articulates superiorly with the lumbar vertebrae, inferiorly with the coccyx, and anteriorly with the ilium of the pelvis. The sacrum strengthens and stabilizes the pelvis. Vertebral Column: Anatomy
  • An attachment for various muscles, tendons, and ligaments of the pelvis

Joints

There are 4 primary joints within the pelvis:

• Sacroiliac:
  • Synovial joint Synovial joint Jaw and Temporomandibular Joint: Anatomy
  • Composed of the articular surfaces of the sacrum Sacrum Five fused vertebrae forming a triangle-shaped structure at the back of the pelvis. It articulates superiorly with the lumbar vertebrae, inferiorly with the coccyx, and anteriorly with the ilium of the pelvis. The sacrum strengthens and stabilizes the pelvis. Vertebral Column: Anatomy and ilium
  • Transmits weight from the vertebral spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy to the hip bones and lower limbs
• Sacrococcygeal:
  • Cartilaginous joint
  • Composed of the base of the coccyx Coccyx The last bone in the vertebral column in tailless primates considered to be a vestigial tail-bone consisting of three to five fused vertebrae. Vertebral Column: Anatomy and oval surface at the apex of the sacrum Sacrum Five fused vertebrae forming a triangle-shaped structure at the back of the pelvis. It articulates superiorly with the lumbar vertebrae, inferiorly with the coccyx, and anteriorly with the ilium of the pelvis. The sacrum strengthens and stabilizes the pelvis. Vertebral Column: Anatomy
• Pubic symphysis Pubic Symphysis A slightly movable cartilaginous joint which occurs between the pubic bones. Vagina, Vulva, and Pelvic Floor: Anatomy:
  • Cartilaginous joint
  • Composed of the left and right superior rami of the pubic bones
• Lumbosacral joint:
  • Located between lumbar spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy (L5) and sacrum Sacrum Five fused vertebrae forming a triangle-shaped structure at the back of the pelvis. It articulates superiorly with the lumbar vertebrae, inferiorly with the coccyx, and anteriorly with the ilium of the pelvis. The sacrum strengthens and stabilizes the pelvis. Vertebral Column: Anatomy
  • Stabilized by the iliolumbar ligaments

Ligaments

The bony pelvis is primarily stabilized by the following ligaments:

• Anterior and posterior sacroiliac ligament: supports the sacroiliac joint
• Sacrotuberous ligament:
  • Runs from sacrum Sacrum Five fused vertebrae forming a triangle-shaped structure at the back of the pelvis. It articulates superiorly with the lumbar vertebrae, inferiorly with the coccyx, and anteriorly with the ilium of the pelvis. The sacrum strengthens and stabilizes the pelvis. Vertebral Column: Anatomy to ischial tuberosity Ischial Tuberosity Chronic Apophyseal Injury
  • Forms the lesser sciatic foramen
• Sacrospinous ligament:
  • Runs from sacrum Sacrum Five fused vertebrae forming a triangle-shaped structure at the back of the pelvis. It articulates superiorly with the lumbar vertebrae, inferiorly with the coccyx, and anteriorly with the ilium of the pelvis. The sacrum strengthens and stabilizes the pelvis. Vertebral Column: Anatomy to ischial spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy
  • Creates the greater sciatic foramen
• Ligaments of the hip joint Hip joint The hip joint is a ball-and-socket joint formed by the head of the femur and the acetabulum of the pelvis. The hip joint is the most stable joint in the body and is supported by a very strong capsule and several ligaments, allowing the joint to sustain forces that can be multiple times the total body weight. Hip Joint: Anatomy

Pelvic Cavity

The pelvic cavity is bound by the bones of the pelvic girdle and primarily contains reproductive organs, urinary organs, and the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy. As the peritoneal cavity Peritoneal Cavity The space enclosed by the peritoneum. It is divided into two portions, the greater sac and the lesser sac or omental bursa, which lies behind the stomach. The two sacs are connected by the foramen of winslow, or epiploic foramen. Peritoneum: Anatomy rests in the pelvic cavity, spaces from this region are also considered to be part of the space of the pelvic cavity. By using bony landmarks and ligaments, the pelvis can be divided into various openings, foramina, and spaces.

Openings of the pelvis

• Pelvic inlet:
  • Superior aperture of the pelvis
  • Boundary between the pelvic and abdominal cavities
• Pelvic outlet:
  • Inferior aperture of the pelvis 
  • Lower circumference of the lesser pelvis

Foramina of the pelvis

• Greater sciatic foramen:
  • Connects the pelvis to the gluteal region Gluteal region The gluteal region is located posterior to the pelvic girdle and extends distally into the upper leg as the posterior thigh. The gluteal region consists of the gluteal muscles and several clinically important arteries, veins, and nerves. The muscles of the gluteal region help to move the hip joint during walking, running, standing, and sitting. Gluteal Region: Anatomy
  • Separated from lesser sciatic foramen by the sacrospinous ligament
• Lesser sciatic foramen: connects the pelvis to the posterior thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy
• Obturator foramen:
  • Connects the pelvis to the thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy
  • Almost completely covered by the obturator membrane 

Peritoneal spaces of the pelvis

The pelvis has multiple spaces related to the caudal end of the peritoneal cavity Peritoneal Cavity The space enclosed by the peritoneum. It is divided into two portions, the greater sac and the lesser sac or omental bursa, which lies behind the stomach. The two sacs are connected by the foramen of winslow, or epiploic foramen. Peritoneum: Anatomy and the peritoneal folds Peritoneal Folds Peritoneum: Anatomy found within the viscera:

• Rectovesical pouch:
  • Exists only in males
  • Located between the upper posterior part of the urinary bladder Urinary Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters (ureter), and is held there until urination. Urinary Tract: Anatomy and the upper middle part of the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy
• Rectouterine pouch of Douglas Pouch of Douglas A sac or recess formed by a fold of the peritoneum. Ovaries: Anatomy:
  • Exists only in females
  • Located between the upper posterior part of the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy and the upper middle part of the rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy
• Pararectal fossa:
  • Connects at both sides with the rectovesical/rectouterine pouch
  • Located on both sides of the intraperitoneal Intraperitoneal Peritoneum: Anatomy rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy
  • Lateral boundaries: uterosacral/sacrogenital folds (females/males)
• Vesicouterine pouch:
  • Exists only in females
  • Located between the posterior surface of the urinary bladder Urinary Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters (ureter), and is held there until urination. Urinary Tract: Anatomy and the anterior surface of the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy
• Rectovesical space:
  • Exists only in males
  • Located posterior to the lower portion of the bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess and the prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. gland, inferior to the rectovesical pouch
• Ischiorectal Ischiorectal Perianal and Perirectal Abscess fossa: triangular-shaped, on both sides of the lower rectum Rectum The rectum and anal canal are the most terminal parts of the lower GI tract/large intestine that form a functional unit and control defecation. Fecal continence is maintained by several important anatomic structures including rectal folds, anal valves, the sling-like puborectalis muscle, and internal and external anal sphincters. Rectum and Anal Canal: Anatomy and the anus
• Retropubic space of Retzius: located between the posterior surface of the pubis and the anterior surface of the bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess/ prostate Prostate The prostate is a gland in the male reproductive system. The gland surrounds the bladder neck and a portion of the urethra. The prostate is an exocrine gland that produces a weakly acidic secretion, which accounts for roughly 20% of the seminal fluid. in males

Anatomical variations of the bony pelvis

There are anatomical variations between the female (gynecoid) and male (android) pelvis.

• Gynecoid:
  • Considered the “classic female pelvis shape”
  • Generally wider than its male counterpart, with less prominent ischial spines, as an adaptation for childbirth
• Android: considered the “classic male pelvis shape”

Pelvic Floor

Overview

The pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy, also referred to as the pelvic diaphragm Pelvic diaphragm Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy, is a group of muscles that supports the abdominal and pelvic viscera. The pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy has 3 layers:

• Superficial layer:
  • Also referred to as the perineum Perineum The body region lying between the genital area and the anus on the surface of the trunk, and to the shallow compartment lying deep to this area that is inferior to the pelvic diaphragm. The surface area is between the vulva and the anus in the female, and between the scrotum and the anus in the male. Vagina, Vulva, and Pelvic Floor: Anatomy or the superficial perineal layer
  • Diamond-shaped region between coccyx Coccyx The last bone in the vertebral column in tailless primates considered to be a vestigial tail-bone consisting of three to five fused vertebrae. Vertebral Column: Anatomy and pubic symphysis Pubic Symphysis A slightly movable cartilaginous joint which occurs between the pubic bones. Vagina, Vulva, and Pelvic Floor: Anatomy
• Intermediate layer:
  • Pelvic diaphragm Pelvic diaphragm Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy
  • Separates perineum Perineum The body region lying between the genital area and the anus on the surface of the trunk, and to the shallow compartment lying deep to this area that is inferior to the pelvic diaphragm. The surface area is between the vulva and the anus in the female, and between the scrotum and the anus in the male. Vagina, Vulva, and Pelvic Floor: Anatomy from pelvic cavity
• Deep layer:
  • Urogenital diaphragm Urogenital diaphragm Vagina, Vulva, and Pelvic Floor: Anatomy
  • Separates upper pelvis from deep perineal sac

Muscles of the pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy

The muscles of the pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy have several important functions:  

• Provide physical support to the pelvic viscera and prevent pelvic organ prolapse Pelvic Organ Prolapse Pelvic organ prolapse (POP) is a general term that refers to herniation of 1 or more pelvic organs (e.g., bladder, uterus, rectum) into the vaginal canal, and potentially all the way through the introitus. Weakness and insufficiency of the pelvic floor may result in POP. Pelvic Organ Prolapse
• Maintain both urinary and fecal continence
• Assist in childbirth

Vessels and Innervation of the Pelvis

Arterial supply

Blood to the pelvis is supplied by:

• Abdominal aorta Abdominal Aorta The aorta from the diaphragm to the bifurcation into the right and left common iliac arteries. Posterior Abdominal Wall: Anatomy: bifurcates into the left and right common iliac arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
• Common iliac artery: bifurcates at the sacroiliac joint into the internal and external iliac arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
• Internal iliac artery: divides into an anterior (supplies pelvic viscera) and a posterior ( gluteal region Gluteal region The gluteal region is located posterior to the pelvic girdle and extends distally into the upper leg as the posterior thigh. The gluteal region consists of the gluteal muscles and several clinically important arteries, veins, and nerves. The muscles of the gluteal region help to move the hip joint during walking, running, standing, and sitting. Gluteal Region: Anatomy) trunk
• External iliac:
  • Gives off the inferior epigastric and deep circumflex iliac arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
  • Becomes the femoral artery Femoral Artery The main artery of the thigh, a continuation of the external iliac artery. Femoral Region and Hernias: Anatomy after passing the inguinal ligament Inguinal Ligament Femoral Region and Hernias: Anatomy

Venous drainage

The 3 main veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology of the pelvis follow the course of the arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology and are named accordingly:

• Common iliac vein:
  • Union of the external and internal iliac veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology 
  • Joins with the corresponding common iliac vein to become the inferior vena cava Inferior vena cava The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs. Mediastinum and Great Vessels: Anatomy
• Internal iliac vein: responsible for the majority of pelvic venous drainage
• External iliac vein:
  • Continuation proximally of the femoral vein
  • Primarily drains lower extremities

Innervation

The innervation of the pelvis is provided by branches from the sacral plexus, including the pudendal nerve Pudendal nerve A nerve which originates in the sacral spinal cord (s2 to s4) and innervates the perineum, the external genitalia, the external anal sphincter and the external urethral sphincter. It has three major branches: the perineal nerve, inferior anal nerves, and the dorsal nerve of penis or clitoris. Gluteal Region: Anatomy, which is formed from the sacral plexus, S2 S2 Heart Sounds– S4 S4 Heart Sounds. The pelvis receives both somatic and autonomic innervation.

• Motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology supply to:
  • External urethral and anal sphincters
  • Levator ani
  • Bulbospongiosus
  • Ischiocavernosus
• Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology innervation to:
  • Perineum Perineum The body region lying between the genital area and the anus on the surface of the trunk, and to the shallow compartment lying deep to this area that is inferior to the pelvic diaphragm. The surface area is between the vulva and the anus in the female, and between the scrotum and the anus in the male. Vagina, Vulva, and Pelvic Floor: Anatomy
  • Penis Penis The penis is the male organ of copulation and micturition. The organ is composed of a root, body, and glans. The root is attached to the pubic bone by the crura penis. The body consists of the 2 parallel corpora cavernosa and the corpus spongiosum. The glans is ensheathed by the prepuce or foreskin. Penis: Anatomy/ clitoris Clitoris An erectile structure homologous with the penis, situated beneath the anterior labial commissure, partially hidden between the anterior ends of the labia minora. Vagina, Vulva, and Pelvic Floor: Anatomy
  • Posterior scrotum Scrotum A cutaneous pouch of skin containing the testicles and spermatic cords. Testicles: Anatomy/labia
  • Anal canal
• Reflex erection Erection The state of the penis when the erectile tissue becomes filled or swollen (tumid) with blood and causes the penis to become rigid and elevated. It is a complex process involving central nervous system; peripheral nervous systems; hormones; smooth muscles; and vascular functions. Penis: Anatomy:
  • Afferent Afferent Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology pudendal nerve Pudendal nerve A nerve which originates in the sacral spinal cord (s2 to s4) and innervates the perineum, the external genitalia, the external anal sphincter and the external urethral sphincter. It has three major branches: the perineal nerve, inferior anal nerves, and the dorsal nerve of penis or clitoris. Gluteal Region: Anatomy → activates reflex arc 
  • Parasympathetic fibers in S2 S2 Heart Sounds– S4 S4 Heart Sounds roots
• Sympathetic: penis Penis The penis is the male organ of copulation and micturition. The organ is composed of a root, body, and glans. The root is attached to the pubic bone by the crura penis. The body consists of the 2 parallel corpora cavernosa and the corpus spongiosum. The glans is ensheathed by the prepuce or foreskin. Penis: Anatomy/ clitoris Clitoris An erectile structure homologous with the penis, situated beneath the anterior labial commissure, partially hidden between the anterior ends of the labia minora. Vagina, Vulva, and Pelvic Floor: Anatomy (male ejaculation)

Clinical Relevance

• Pelvic fractures Pelvic Fractures Pelvic fractures are a disruption in the cortex of a pelvic bone involving iliac wing fractures, acetabular fractures, or those causing loss of integrity of the pelvic ring (the sacrum and the 2 innominate bones). Patients often present with a history of trauma or a fall, limb length discrepancy, intense pain on palpation, and mechanical instability. Pelvic Fractures: most often occur in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship involved in high-energy impact injuries such as car accidents or falls. Because of the high-energy nature of this trauma, pelvic fractures Pelvic Fractures Pelvic fractures are a disruption in the cortex of a pelvic bone involving iliac wing fractures, acetabular fractures, or those causing loss of integrity of the pelvic ring (the sacrum and the 2 innominate bones). Patients often present with a history of trauma or a fall, limb length discrepancy, intense pain on palpation, and mechanical instability. Pelvic Fractures are often considered unstable fractures, and individuals may present with vascular compromise and concomitant injuries to the genitourinary system. Older individuals with osteoporosis Osteoporosis Osteoporosis refers to a decrease in bone mass and density leading to an increased number of fractures. There are 2 forms of osteoporosis: primary, which is commonly postmenopausal or senile; and secondary, which is a manifestation of immobilization, underlying medical disorders, or long-term use of certain medications. Osteoporosis may present with pelvic fractures Pelvic Fractures Pelvic fractures are a disruption in the cortex of a pelvic bone involving iliac wing fractures, acetabular fractures, or those causing loss of integrity of the pelvic ring (the sacrum and the 2 innominate bones). Patients often present with a history of trauma or a fall, limb length discrepancy, intense pain on palpation, and mechanical instability. Pelvic Fractures after low-impact injuries. 
• Obturator hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: herniation Herniation Omphalocele of pelvic or abdominal contents through the obturator foramen. Obturator hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias more often occurs on the right side, as the sigmoid Sigmoid A segment of the colon between the rectum and the descending colon. Volvulus colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy blocks the obturator canal on the left. This hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias often presents with bowel obstruction Bowel obstruction Any impairment, arrest, or reversal of the normal flow of intestinal contents toward the anal canal. Ascaris/Ascariasis or lancinating pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways in the medial thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy, extending to the knee, due to compression Compression Blunt Chest Trauma of the obturator nerve Obturator Nerve A nerve originating in the lumbar spinal cord (L2 to L4) and traveling through the lumbar plexus to the lower extremity. The obturator nerve provides motor innervation to the adductor muscles of the thigh and cutaneous sensory innervation of the inner thigh. Thigh: Anatomy.
• Pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy insufficiency or dysfunction: The pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy supports the abdominal and pelvic viscera. This structure separates the perineum Perineum The body region lying between the genital area and the anus on the surface of the trunk, and to the shallow compartment lying deep to this area that is inferior to the pelvic diaphragm. The surface area is between the vulva and the anus in the female, and between the scrotum and the anus in the male. Vagina, Vulva, and Pelvic Floor: Anatomy from the pelvic cavity and assists in controlling the sphincter function of the rectal, urinary, and genital tracts. Weakening of connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology and/or muscles can lead to pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy insufficiency, contributing to pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy disorders. Pelvic floor Pelvic floor Soft tissue formed mainly by the pelvic diaphragm, which is composed of the two levator ani and two coccygeus muscles. The pelvic diaphragm lies just below the pelvic aperture (outlet) and separates the pelvic cavity from the perineum. It extends between the pubic bone anteriorly and the coccyx posteriorly. Vagina, Vulva, and Pelvic Floor: Anatomy dysfunction includes pelvic organ prolapse Pelvic Organ Prolapse Pelvic organ prolapse (POP) is a general term that refers to herniation of 1 or more pelvic organs (e.g., bladder, uterus, rectum) into the vaginal canal, and potentially all the way through the introitus. Weakness and insufficiency of the pelvic floor may result in POP. Pelvic Organ Prolapse (e.g., prolapse of the uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Uterus, Cervix, and Fallopian Tubes: Anatomy), urinary incontinence Urinary incontinence Urinary incontinence (UI) is involuntary loss of bladder control or unintentional voiding, which represents a hygienic or social problem to the patient. Urinary incontinence is a symptom, a sign, and a disorder. The 5 types of UI include stress, urge, mixed, overflow, and functional. Urinary Incontinence, and fecal incontinence Fecal incontinence Failure of voluntary control of the anal sphincters, with involuntary passage of feces and flatus. Pediatric Constipation.
• Childbirth: Childbirth begins with contractions that lead to progressive cervical dilation Cervical dilation A measurement of the diameter of the cervical canal, reported in centimeters Normal and Abnormal Labor and effacement, resulting in the birth of the infant and expulsion of the placenta Placenta A highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (chorionic villi) derived from trophoblasts and a maternal portion (decidua) derived from the uterine endometrium. The placenta produces an array of steroid, protein and peptide hormones (placental hormones). Placenta, Umbilical Cord, and Amniotic Cavity through the birth canal of the pelvis. Vaginal childbirth is possible because of the anatomical differences between the bony pelvis in men and women.