Small Animal Anatomy Exam 2

The tendon of psoas minor attaches to what pelvic structure?

The pubic eminence

The tendon of psoas major attaches to what bony structure?

Lesser trochanter of the femur

What makes up the iliopsoas?

Iliacus and psoas major

Iliopsoas and psoas minor serve what function?

Major flexors of the hip

What two muscles make up the pelvic diaphragm?

Levator ani, coccygeus mm.

Following the hypogastric nn. back allows you to find what next nerve? What plexus will both of these parts feed into?

Pelvic n. (parasympathetic pairing of the hypogastric nn); pelvic plexus

What does the pelvic nerve innervate?

Urogenital organs, the rectum, and the descending colon

Between the pubic bone and the bladder is what structure?

The pubovesicle pouch.

Between the uterus/prostate and the rectum is what space?

Rectogenital pouch

On either side of the rectum (dorsal and lateral) are what openings?

Pararectal fossas

In the female dog, the rectogenital pouch communicates ventrally on either side of the uterus with what pouch between the uterus and bladder?

Vesicogenital pouch

The aorta branches into what three arteries after the deep circumflex iliac aa.?

L and R external iliacs, and the aorta continues

The external iliac aa. branch to become what arteries as they leave the abdomen through the vascular lacuna?

Femoral artery and deep femoral artery

After the external iliac aa. (moving caudally), what branches off the aorta?

Internal iliac aa. (R and L)

What are the terminal branches of the aorta?

Internal iliac aa. and median sacral a.

What small artery is given off by the internal iliac aa., and often is not filled with latex/does not remain patent?

The umbilical aa.

What are the terminal branches of the internal iliac aa.?

Internal pudendal and caudal gluteal aa.

What remains of the umbilical artery in the fetus?

The round ligament of the bladder

What two branches come off the caudal gluteal aa. as you follow them back?

Iliolumbar aa. and cranial gluteal aa.

What homologous arteries come off the internal pudendal aa. in the male and female dog?

Male: Prostatic aa.

Female: Vaginal aa.

What are the branches of the prostatic a.?

Middle rectal (is the caudal branch) and the artery of the ductus deferens (is the cranial branch).

What are the branches of the vaginal artery?

Middle rectal (is the caudal branch), uterine artery (is the cranial branch)

What artery branches off the artery of the ductus deferens/uterine artery, coming up on the caudal aspect of the bladder?

The caudal vesical a.

What does the middle rectal artery supply in the male dog?

Rectum, prostate, and urethra

What does the middle rectal artery supply in the female dog?

Rectum, vagina

Roughly following the internal pudendal artery at the level of the ischiorectal fossa, you can find what nerve?

Pudendal nerve

What nerves arise from the dorsal surface of the pudendal nerve, supplying the skin of the anus and perineum before continuing to the scrotum or labium?

Perineal nerves

The pudendal nerve branches caudally into what nerves?

Perineal nerve and dorsal nerve of the penis/clitoris

The internal pudendal artery (in the ischiorectal fossa) gives off what branch alongside the pudendal nerve?

Ventral perineal artery

What artery, branching with the ventral perineal artery from the internal pudendal, heads back cranially and dives into the external anal sphincter?

The caudal rectal artery

What does the internal pudendal artery turn into after the caudal rectal and ventral perineal aa. branch from it?

Artery of the penis/clitoris

What are the three terminal branches of the internal pudendal artery?

Ventral perineal artery, variable urethral artery, and artery of the clitoris/penis

The artery of the penis gives off three branches. What are they?

Artery of the bulb of the penis

Deep artery of the penis

Dorsal artery of the penis

What does the artery of the bulb of the penis supply?

Corpus spongiosum and penile urethra

What does the artery of the clitoris supply?

The clitoris and vesibular bulb

What is the homologue of the artery of the clitoris in males?

Artery of the penis

What two ligaments come off the bladder?

One median ligament and two lateral ligaments.

In the fetus, what did the median ligament of the bladder contain?

The urachus and umbilical arteries

What do the lateral ligaments of the bladder often contain?

Pockets of fat along with the ureter and umbilical artery

What bladder muscle is striated and confined to the pelvis, where it surrounds the pelvic urethra and serves as a voluntary sphincter to retain urine?

Urethral muscle (controls urinary incontinence!)

Toward the mouth/neck of the bladder are several openings. What are they, and what greater structure do they help compose?

The two ureter and single urethra openings combine to create the trigone of the bladder.

What are the different portions of the urethra?

Prostatic, pelvic, and penile (spongy) parts

What is the long, raised ridge along the prostatic urethra?

Urethral crest

The raised area on the urethral crest of the prostate is called what? What is its significance?

The seminal colliculus; on either side of this structure are the openings of the ductus deferens

What muscle covers the urethra and prevents urinary incontinence?

Urethralis muscle

Where does the colon turn into the rectum?

The pelvic inlet

What is the continuation of the rectum into the anus called?

Anal canal

What are the three zones of the anal canal?

Columnar zone

Intermediate zone

Cutaneous zone

What lies beneath/deep to the external anal sphincter?

The anal sacs/paranal sinuses

Deep to the paranal sinus (anal sacs) are what muscles?

Internal anal sphincters

What is the significant difference between the external and internal anal sphincters?

External is skeletal muscle, while internal is smooth muscle

What are the ridges and depressed areas between the ridges of the anus called?

Anal columns; anal sinuses

What is the sparsely-furred area around the anus called?

Cutaneous zone

Between the mucous membrane and cutaneous zone of the anal canal is what region?

Intermediate zone (anocutaneous line)

What muscle continues the longitudinal smooth muscle of the rectum to the ventral surface of the tail?

Rectococcygeus muscle

What are each crus of the penis composed of?

Corpus cavernosum penis, supplied by deep artery of the penis, and its tunica albuginea (thick covering)

On what landmark does each crus of the penis attach?

Ischiatic tuberosity

What is the white tissue that covers the lateral sides of the penis?

Tunica albuginea

What erectile tissue is inside of the tunica albuginea?

Corpus cavernosum

What muscles are most lateral on the penis, originating from the ischium and covering the corpus cavernosum?

Ischiocavernosus muscles

What is the region of the penis covered by the ischiocavernosus muscles called? (hint: Formed by the crura and bulb of the penis)

The root of the penis

Where is the body of the penis?

From the ends of the ischiocavernosus muscles to the beginning of where the os penis starts.

What is the erectile tissue that erects from the prepuce called?

Glans penis

What are the two parts of the glans penis?

Bulbus glandis and pars longa glandis

What is the erectile tissue within the bulb of the penis?

Corpus spongiosum

What artery supplies the corpus spongiosum penis?

Artery of the bulb of the penis

A thin layer of what tissue surrounds the entire length of the penile urethra?

Corpus spongiosum penis

What is the muscle that covers the bulb of the penis?

Bulbospongiosus muscle

Describe how the fibers of the bulbospongiosus muscle are oriented on the penis.

They are transverse proximally, covering the bulb, but then turn longitudinally as they move distally onto the body of the penis.

What strap-like muscle runs down the ventral side of the penis? What does it do?

Retractor penis m.; retracts penis into the prepuce

What is the external preputial orifice?

The exit site of the penis from the prepuce

What is the space called where the prepuce reflects back on the penis itself?

Fornix

What is the groove in the os penis?

Urethral groove

What are the two parts of the glans of the penis?

Bulbus glandis and pars longa glandis

How does the os penis form?

It forms about a month after birth as an ossification of the fused distal ends of the corpora cavernosa penia. The expanded, rough, truncate base of the bone originates in the tunica albuginea of the corpora cavernosa penia.

What does the urethral groove surround?

The urethra and corpus spongiosum

What does the dorsal artery of the penis supply?

The prepuce, corpus spongiosum penis, and pars longa glandis.

Where is the cervix located?

It forms a small, palpable enlargement just caudal to the short body of the uterus.

Where is the vagina located?

Between the uterine cervix and the vestibule

What is the most cranial part of the vagina (closest to the cervix) called? Hint: there’s one in males, too!

Fornix

What cavity extends from the vagina to the vulva?

The vestibule

What structure projects from the floor of the cranial part of the vestibule? The urethra opens on this structure.

Urethral tubercle

The urethral tubercle is at the level of what body structure?

Ischial arch

What are the two elongated masses of erectile tissue located in the floor and ventrolateral wall of the vestibule?

Vestibular bulbs

Vestibular bulbs are homologous to what structures in the male dog?

Bulbs of the penis

What is the female homologue of the penis?

The clitoris

In what space is the clitoris located?

Fossa clitoridis

The dorsal wall of the fossa clitoridis is homologous to what male structure?

The prepuce

What is included in the vulva?

The two labia and rima pudendi

Where do the labia of the vulva fuse above and below the rima pudendi?

At the dorsal and ventral commissures

What artery originates from the pudendoepigastric trunk, before emerging from the superficial inguinal ring?

External pudendal artery

What artery runs cranially to the deep surface of the inguinal mamma and supplies the mammary branches, as well as the prepuce in the male dog? (Extra hint: It appears as a direct continuation of the external pudendal artery, dorsal to the superficial inguinal lymph node)

Caudal superficial epigastric artery

What is L1 also called?

Cranial iliohypogastric nerve

What is L2 also called?

Caudal iliohypogastric nerve

What is L3 also called?

Ilioinguinal

What is L4 also called?

Lateral cutaneous femoral nerve

What nerve often courses along the caudal aspect of the last rib?

T13

What artery and vein pairing leave the superficial inguinal ring caudal and medial to the structures that extend to the testis?

External pudendal a. and v.

What nerve arises from the ventral branches of the third and fourth lumbar nerves?

Genitofemoral n.

What nerve passes through the inguinal canal with the spermatic cord and innervates the cremaster muscle, skin covering the inguinal region & proximal medial thigh, and part of the prepuce in males?

Genitofemoral n.