Anatomy of the Mare

Comprehensive vocabulary flashcards covering the anatomical structures, histology, hormonal adaptations, and clinical management of the mare's reproductive tract based on ANSC 4402.

Open mare

An equine reproductive status indicating a mare that is not pregnant.

Maiden mare

A mare that is being prepared for breeding or is being bred for the very first time.

In foal

Equine terminology indicating that a mare is pregnant.

Wet mare

A mare that currently has a nursing foal by her side.

Equine reproductive aging

The physiological reproductive decline in mares, where fertility begins to decrease at $12$ years of age.

Mesovarium

The thick peritoneal attachment securing the mare's ovaries to the dorsal abdominal wall near the level of the $5^{\text{th}}$ lumbar vertebra, allowing significant ovarian mobility during transrectal palpation.

Equine ovarian tissue layers

The reversed anatomical arrangement of the mare's ovary relative to other domestic species, characterized by an outer medulla and an inner cortex.

Ovulation fossa

The distinct, singular depression on the equine ovary where the cortex reaches the surface and through which all mature follicles ovulate.

Granulosa cell tumor

A generally benign ovarian neoplasm that typically affects only one ovary and secretes hormones that cause behavioral changes and infertility, leaving the contralateral ovary to function normally once surgically excised.

Mesosalpinx

The portion of the broad ligament that suspends the oviduct and blends with the mesovarium to create a large but shallow ovarian bursa.

Infundibulum (Equine)

The funnel-shaped cranial end of the oviduct lined with fimbria that acts like a "baseball mitt" over the ovulation fossa during estrus to catch the released ovum.

Ampulla (Equine)

The expanded portion of the oviduct lined with fimbria near the infundibular junction, serving as the site of fertilization near the ampullary-isthmic junction (AIJ).

Isthmus (Equine)

The narrower, highly muscular caudal section of the oviduct responsible for the transport of spermatozoa and the developing embryo.

Uterotubal junction

The physiological boundary between the oviduct and the uterine horn that selectively allows only fertilized embryos to enter the uterus.

Bicornuate uterus (Mare vs. Cow)

A uterus consisting of two horns and a single body; the mare exhibits a larger uterine body and less defined horns compared to the bovine uterus.

Uterine edema ("Orange-sectioned" appearance)

The distinct ultrasonographic wagon-wheel or sliced-citrus appearance of the mare's uterine horn during estrus, caused by fluid accumulation within the endometrial mucosal folds.

Equine cervix mucosal folds

The longitudinal mucosal folds extending along the length of the mare's cervix, distinct from the annular cartilaginous rings of a cow and allowing straightforward passage of an insemination pipette.

Vaginal fornix

The circumferential recess in the cranial vagina that surrounds the lobed, protruding external portion of the equine cervix.

Cervical os

The central lumen or opening of the cervix that relaxes and opens during estrus under estrogen dominance and tightens/firms during diestrus and pregnancy under progesterone.

Transverse fold

A mucosal remnant of the hymen situated cranial to the external urethral orifice in the vagina, occasionally palpated as a narrowing or wall of tissue in maiden mares.

Equine vestibule

The caudal segment of the reproductive tract housing the external urethral opening at its cranial border, possessing a floor that slopes steeply downward to ensure drainage.

Insemination pipette orientation

The procedural technique of angling the pipette upward upon entering the vulva to clear the sloping vestibule, and then leveling it horizontally once past the vestibule.

Winking

An estrous behavioral display wherein rhythmic labial contractions of the vulva repeatedly expose the clitoris.

Normal vulvar conformation

Perineal alignment in which the vulva is vertically positioned parallel to the anus and entirely ventral to the pelvic floor (ischium).

Wind-sucking (Pneumovagina)

The involuntary aspiration of air into the reproductive tract caused by poor vulvar conformation, commonly seen in performance mares and leading to vaginitis, endometritis, and subfertility.

Caslick procedure

A corrective minor surgery where the mucocutaneous junction of the dorsal $\frac{1}{3}$ of the vulvar labia is resected and sutured or stapled together to prevent aspiration of air and feces.