Canine Pelvis

List the Clinical Relevancies of the Pelvis

• Spaying / Neutering

• Pelvic Fractures

• Femoral Head Osteotomy

• Micturition Disorders

• Fecal Incontinence

• Repro Disorders

• Perineal Urethrostomy (PU)

• Perineal Hernia/Tumors

• Anal Sac Infection/Ruptire/.Tumor

• Inguinal Hernia

• Mammary Tumors

What are the anatomical landmarks for a perineal urethrostomy?

Bulbourethral glands, retractor penis muscle, and ischiocavernosus muscle

What nerve is at risk when performing any anal sac surgeries?

Caudal Rectal Nerve

What mammae are the most affected by mammary tumors in non-spayed bitches?

Abdominal (4th) and Inguinal (5th) mammae

What bones compose the pelvic girdle (hemipelvis/os coxae)

Ilium, Pubis, Ischium

What are the two symphysises that make up the pelvic symphysis?

• Pubis Symphysis

• Ischial Symphysis

What is the orientation of the long axis of the pelvis?

Caudoventral with 45 degree angle

What disorders are commonly diagnosed using radiographs of the pelvis?

• Hip & Iliosacral joint luxation

• Fractures

• Hip Dysplasia

• Perineal Hernia

• Urinary Problems

What is included in a right lateral radiograph of the pelvis?

Stifle joints to the level of the proximal crus

In what situation would you use a flexed position for a V/D radiograph?

Fractures of the pelvis or dogs who are not able to extend their femurs

True or False: The dogs pelvis is box shaped and are less divergent laterally compared to the cat.

False

What are the bony boundaries of the pelvis inlet?

Dorsal: Promontory of the sacrum

Ventral: Pecten of the pubis

Lateral: body or shaft of the ilium along the arcuate line

What are some structures that pass through the pelvic inlet?

• Hypogastric nerve

• Internal Iliac Artery

• Descending Colon

• Median Iliac Artery

What are the borders of the pelvic outlet?

Dorsal: 1st caudal vertebrae

Ventral: Ischial Arch

Lateral: sacrotuberous ligaments and muscles of pelvic diaphragm

True or False: Cats have a sacrotuberous ligament

FALSE

Perineum

The area between the base of the tail and just below the vulva or slightly above the scrotum

Pelvic Diaphragm

Bilateral pelvic muscular wall that keeps the internal organs such as intestines, prostate, female repro. Tract, and urinary bladder in place

What muscles make up the pelvic diaphragm?

Coccygeus muscle (outer)

Levator ani muscle (inner)

What is the clinical relevance of the pelvic diaphragm?

Perineal hernias occur from the failure of the muscles of the pelvic diaphragm (coccygeal and levator ani), thats causes hernia Timon of pelvic or abdominal viscera

What muscle is used in repairs of perineal hernias?

Internal Obturator muscle via reinforcement of the other pelvic diaphragm muscles

What can happen in sequence with failure of the pelvic diaphragm? What are some clinical signs?

Retroflexion of urinary bladder

• strain in defecation

• Difficulty passing urine

• Enlargement of perineal region

List possible contents in perineal hernias.

• Intestine

• Urinary Bladder

• FAT

What innervates the external anal sphincter and what kind of innervation is this?

Caudal rectal nerve (somatic motor)

What can we expect with damage to the caudal rectal nerve?

Fecal Incontinence

Ischiorectal Fossa

Wedge-shaped space between the tail and hip muscles or between pelvic diaphragm and the pelvic bones or between the ischium and rectum

What is contained within the ischiorectal fossa?

• Sacrotuberous Ligament

• Blood Vessels

  • Caudal Gluteal

  • Internal Pudendal

  • Caudal Rectal

• Nerves

  • Sciatic, Pudendal, Caudal Rectal

• Muscles

  • Pelvic Diaphragm (levator ani, coccygeus), external anal sphincter m, internal Obturator m, tail muscles

What is the clinical significance of the ischiorectal fossa?

• Surgical repair of perineal hernia

• Surgical removal of infected anal sacs

  • Caudal rectal artery and nerve

Rectum

Continuation of descending colon in the pelvic cavity

Anal Canal

Terminal part of the rectum; location of the paranal sinus or anal sacs

Location of the Paranal Sinus

Between the external and internal anal sphincter muscles

Where do the ducts of anal sacs empty?

Cutaneous zone of the anal canal (4&8 o’clock)

What is the function of the anal sacs?

Secrete territorial marker

What are the three zones of the anal canal?

1. Cutaneous Zone (outer most)

2. Intermediate Zone (anocutaenous line)

3. Columnar Zone (Inner most)

What anatomical structure prevents the backflow of urine in the bladder?

Intramural part of the ureter that closes while filling

What muscle makes up the urinary bladder wall?

Destrousor muscle (smooth muscle)

What is the location of the urinary tract in females and males?

Females: below the repro tract

Males: below the rectum

What are the two urinary bladder spinchters and what is their innervation?

• External Urethral Sphincter (urethral muscle)

  • Pudendal Nerve (somatic)

• Internal Urethral Spincter

  • Hypogastric nerve (sympathetic)

What is the innervation of the detrusor muscle of the bladder wall?

Pelvic and Hypogastric nerves 

How many ligaments suspend the bladder? What are they?

Three

• Left and Right Lateral Ligament of the Urinary Bladder

  • contains umbilical artery or round ligament of the bladder

• Median Ligament of the Urinary Bladder

  • no fetal structure associated

What is the dorsal area of the bladder that is recognized by a triangular zone called?

Trigone of the Bladder

What is the clinical significance of the trigone of the bladder?

Transitional cell carcinoma commonly develops here

True or False: 50% of cases of urinary incontinence in female dogs happens at less than 1 year of age

TRUE

What is a patent urachus?

the tube that connects the fetal urinary bladder with the allantois remains after fetal life

What are the autonomic nerves affecting the pelvic viscera?

Pelvic Nerve (parasympathetic) and Hypogastric nerve (sympathetic)

What are the somatic nerves affecting the pelvic viscera?

Pudendal nerve and its branches

• Caudal rectal nerve

• Perineal branches (superficial - sensory; deep - motor)

• Dorsal Nerve of the Penis/Clitoris

What effect does the pelvic nerve have on micturition?

Voiding (parasympathetic)

What effect of the hypogastric nerve have on micturition?

Storage (sympathetic) with pudendal

What effect does the caudal rectal nerve have on micturition?

Storage and voluntary control of voiding (somatic)

True or False: The somatic and sympathetic divisions promote bladder filling while the parasympathetic promotes voiding.

TRUE

What neurologic exam would we perform to assess the integrity of the pudendal nerve?

Perineal Reflex

What two arteries supply the urinary bladder?

Cranial Vesical Artery and Caudal Vesicle Artery

What three arteries supply the rectum?

• Cranial Rectal Artery

• Middle Rectal Artery

• Caudal Rectal Artery

FATE

Feline Aortic Thromboembolism (aka Saddle Thrombus)

• blood clot that occurs at the branch-point of external and internal iliac arteries blocking blood flow to both hind limbs causes lack of pulses, pain, paralysis, and poikilothermis

ID the pouch A

Pararectal Fossa

ID pouch B

Rectogenital Pouch

ID pouch C

Vesicogenital Pouch

ID pouch D

Pubovesical Pouch