Small and Large Animals Male and Female Pelvic Viscera PDF Fall 2024

took Small and Large animals Male and Female Pelvic Viscera Cristian Dezdrobitu, DVM, MSc, PhD 1  Pelvic canal Pelvic outlet Pelvic inlet 2 Pel...

took Small and Large animals Male and Female Pelvic Viscera Cristian Dezdrobitu, DVM, MSc, PhD 1  Pelvic canal Pelvic outlet Pelvic inlet 2 Pelvic inlet Dorsal boundary: promontory of the sacrum Lateral boundary: arcuate line of the ilium Ventral boundary: pecten of the pubis 3 Pelvic outlet Dorsal boundary: first caudal vertebra Lateral boundary: sacrotuberous ligament (absent in cats), mm. of the pelvic diaphragm (coccygeus, levator ani) Ventral boundary: ischiatic arch 4 Pelvic Diaphragm Primarily muscles: Coccygeus More lateral muscle Short and thick Levator ani More medial muscle Thinner and more extensive Partly covered by the coccygeus m. Tone in both muscles retains the pelvic viscera in the pelvic canal. 5 6 Lateral view of left ischiorectal fossa Levator ani m. Coccygeus m. Superficial gluteal m. External anal sphincter m. Internal obturator m. Courtesy of Drs Ray Wilhite, Dan Hillmann and Joe Rowe Ischiorectal fossa Space excluded from the pelvic cavity by the pelvic diaphragm and normally occupied by fat (12) Located between the anus and the ischiatic tuberosity Lateral wall- ischial tuber (1) and sacrotuberous/sacrosciatic ligament (2) comp teth Medial wall- pelvic diaphragm (3,4) Vessels and nerves in the ischiorectal fossa Internal pudendal vessels Pudendal nerve 8 Caudal aspect of the 9canine  Muscles of the rectum and anal canal Internal anal sphincter Located deep to the anal sacs Caudal thickened part of the anal canal Composed of smooth muscle- ANS innervation External anal sphincter Located superficial to the anal sacs Courtesy of Drs Ray Wilhite, Dan Hillmann and Joe Rowe Striated muscle, therefore voluntary - somatic innervation Chief guardian of the lumen of the anal canal Rectococcygeus m. Stabilizes the anal canal and rectum On the ventral surface of the tail 10 Smooth m. Clinical Application: Perineal Hernia Failure of the pelvic diaphragm - Protrusion of pelvic or abdominal viscera through a weakened or ruptured pelvic diaphragm - Unilateral or bilateral - Straining can lead to stress on the pelvic diaphragm, leading to breakdown, internal organs enter hernial sac - Most occur between levator ani, external anal sphincter, and internal obturator mm. 11  12 https://metro-vet.com/perineal-hernias/  Rectum Continuation of colon Begins at the pelvic inlet Anal canal Continuation of rectum to anus 3 zones Columnar- longitudinal folds Intermediate- between the columnar and cutaneous zones Cutaneous- fine hairs, has openings of the paranal sinus Anus External opening of the anal canal 13  Paranal sinuses (anal sacs) Paired Ducts- found inside edge of the anus Between internal and external anal sphincter Anal glands are located within the wall of the anus and within the wall of the anal sacs 14  Paired Approximately 1 cm in diameter Located between the internal and external anal sphincters at approximately 3:00-4:00 and 8:00-9:00 using the face of a 15 clock Perineum Perineum wall Surrounds the anus and vulva and covers the pelvic outlet Perineal region Between the tail and the scrotum (male)/udder (female) Perineal body (center) Between the anus and the dorsal commissure of the vulva Sometimes tears during parturition 16 17  Peritoneal Reflections Pararectal fossa (16) Located lateral to the mesorectum Rectogenital pouch (17) Between the rectum and the genital fold (male)/the cranial portion of the vagina (female) Vesicogenital pouch (18) Between the urinary bladder and the cranial portion of the vagina (female)/prostate and genital fold (male) Pubovesical pouch (19) Between the urinary bladder and the pubis 18  Urinary Bladder and related structures Lateral ligaments of the bladder In the fetus – each ligament contains the caudal portion of the ureter and a portion of the umbilical artery In the adult – each ligament contains the caudal portion of the ureter and the round ligament of the bladder which is the remnant of the umbilical artery Median ligament of the bladder In the fetus – contains portions of the umbilical arteries and urachus In the adult – usually does not contain any structures (fetal structures regress) 19  Urinary Bladder Full bladder Distensible storage organ, confined within the pelvic cavity when contracted The neck will remain fixed within the pelvic cavity when distended 3 portions Apex Body Neck 4. Os penis 5. Cecum Dorsal View 6. Fundus of stomach 7. Left kidney 20 Dyce 4th ed. Fig. 14-8 8. Urinary bladder  Urinary Bladder Ventral Views Trigone Triangle bounded by the ureteric and urethral openings Courtesy of Drs Ray Wilhite, Dan Hillmann and Joe Rowe Dorsally located Urethral crest Located in the pelvic urethra Folds that converge at the exit * from the urinary bladder 21 Urinary bladder and ureters Dyce 4th ed. Fig. 5-31 Dyce, Sack, and Wensing's Textbook of Veterinary Anatomy FIG. 15.7 The canine bladder made visible by the introduction of air. The arrow indicates the terminations of the ureters in the dorsal wall of the bladder, superimposed here on the air-filled lumen. 22 1, Caudal end of bladder; 2, ureters; 3, shaft of ilium; L7, seventh lumbar vertebra.  Urinary bladder / detrusor muscle Smooth muscle, arranged in three sheets, squeezes and empties the bladder Innervation: Physiologic smooth muscle sphincter at the neck of the bladder is under sympathetic tone Parasympathetic stimulation causes the smooth muscle of the bladder to contract and the sphincter to relax resulting in evacuation of the bladder Sensory innervation via pudendal n. Urethralis m. Skeletal muscle Surrounds the pelvic urethra Acts as a voluntary sphincter Innervated by pudendal n. 23 Female urethra Found on the pelvic floor Opens ventrally Junction of the vestibule and vagina Suburethral diverticulum (12’) Cow and sow- blind pouch ventral to urethral opening Urethralis/urethral m. Surrounds the urethra External urethral sphincter/ Median section of bovine pelvis innervated by pudendal n. 24 Male urethra 2 parts Pelvic urethra Penile urethra Colliculus seminalis Elevated region on the urethral crest Opening of the deferent ducts and many prostatic openings Urethralis/urethral m. Surrounds the pelvic urethra Voluntary sphincter/innervated by pudendal n. 25 26 Blood supply, innervation, and lymphatics of the pelvic viscera 27 Blood supply Aorta External iliac a. (bilateral) Internal iliac a. (bilateral) Median sacral Median sacral a. Unpaired Continuation of the aorta Supplies blood to the sacrum and then becomes the median caudal artery which supplies the caudal 28 (coccygeal) vertebrae  Internal iliac a. Umbilical a. Gives off the cranial vesical a. In the fetus, carries blood to the placenta Remnant is the round ligament of the urinary bladder Found in the lateral ligament of the urinary bladder 29 30 Internal iliac a. terminal branches Color code Red- female 1. Internal pudendal a. Blue- male Black – both genders Vaginal/prostatic a. Uterine a./artery of the ductus deferens Caudal vesical a. Middle rectal a. Continues lateral to the coccygeus m. and accompanies the pudendal n. (ischiorectal fossa) Terminates as 3 branches Ventral perineal a. (it supplies a caudal rectal a.) Urethral a. (variable) Artery of the clitoris/penis 31  branches from the middle recta l MALE DOG 32  Structures supplied by the prostatic artery Prostate Ductus deferens Epididymis Urinary bladder Urethra (pelvic) Ureter *Rectum Rectum * * * * Urinary bladder * Courtesy of Dr. Terri Clark Evans 7th ed. Fig. 4-39 FEMALE DOG 34  Structures supplied by the vaginal artery Uterus (horns, body, cervix) Vagina Urinary bladder Urethra Ureter * Rectum Rectum * * * * Urinary bladder * * Courtesy of Dr. Terri Clark Dyce 4th ed. Fig. 5-64 & Evans 7th ed. Fig. 4-38 Internal iliac a. terminal branches 2. Caudal gluteal a. Larger than the internal pudendal a. Follows with the sciatic n. lateral to the coccygeus m. The main blood supply to the biceps femoris, semimembranosus and semitendinosus mm. Iliolumbar a. – arises close to the origin of the caudal gluteal a. or directly from the internal iliac a. – iliopsoas, sartorius, tensor fascia latae and middle gluteal mm. Cranial gluteal a. Main blood supply to the middle and deep gluteal mm. 36 37  Innervation Pelvic plexus (27) Hypogastric n. (2) Caudal mesenteric ganglia and plexus Supplies SNS to the pelvic viscera Pelvic n. (21) S1-S3 PSNS to the pelvic viscera 38  Genitofemoral n. (L3-L4) i Somatic innervation to the cremaster m. Sensory to skin of the proximal medial aspect of the thigh, inguinal region 39  Pudendal n. (S1-S3) Gives rise to the caudal rectal n., perineal n. and dorsal n. of the penis/clitoris. Somatic motor innervation to the muscles of the pelvic viscera (i.e. external urethral sphincter, external anal sphincter, etc.) and the perineum (muscles of the penis and clitoris, scrotum, etc.). Sensory to the pelvic viscera, rectum, anus, scrotum/vulva, penis, clitoris, perineum, and internal and external reproductive organs 40 Lymphatics (locations in relation to the canine) Medial iliac ln. (4,4’,4’’) Located between the deep circumflex iliac a. and the external iliac a. Drainage received from the dorsal aspect of the abdomen, the pelvis, pelvic limb, genital tract and caudal aspect of the urinary and digestive systems Internal iliac ln. (old term ‘’Hypogastric’’) (5) Located between the internal iliac a. and the median sacral a. Drain the musculature in the area, pelvis, lumbar, sacral and caudal vertebrae, genital system, caudal digestive and urinary systems Sacral ln. (6,7) Not present about half the time and not easily differentiated from the hypogastric ln. when they are present. They will lie ventral to the sacrum. Drains similar structures as the hypogastric ln. 41  (4’) (4’’) 42  CAT Medial Iliac ln. ORIGINAL - PhD Thesis Cristian DEZDROBITU 43  Lymphedema Massive swelling of the right rear limb Normal lymphangiogram Medial iliac lymph node Popliteal lymph node Lymphatic vessels Popliteal lymph node Lymphangiogram of a dog with lymphedema 44 https://veteriankey.com/surgery-of-the-hemolymphatic-system/ Lymphatics con’t Inguino-femoral lymph center (old term Superficial inguinal) Lie in the fat that fills the furrow between the abdominal wall and the medial surface of the thigh. In the female it is a few mm. cranial to the vaginal process and in the male it lies along the dorsolateral border of the penis The external pudendal vessels lie lateral to it or between them (if two nodes are present) Drains the ventral half of the abdominal wall (including abdominal and inguinal mammary glands), prepuce, scrotum. 45  Lymphatics con’t The inguino-femoral lymph center comprises in dog, the scrotal lymph nodes - palpable on the dorsolateral surface of the penis, 1 centimeter cranial to the spermatic cord, close to the lower part of the preputial cavity, embedded in fat tissue in bitch, the mammary lymph nodes - one, two or three normally palpable and placed on the dorso-lateral margin of the last mammary gland, 2-3 centimeters from the cranial margin of the pubis bone 46 ORIGINAL - PhD Thesis Cristian DEZDROBITU ORIGINAL - PhD Thesis Cristian Mammary ln. DEZDROBITU FEMALE CAT MALE DOG MALE DOG Inguino-femoral lymph center: mammary (female) scrotal ln. and scrotal (male) lymph nodes 47