The hymen (plural: hymens) is a thin fold of mucous membrane which extends across the vaginal opening, usually with some form of internal defect, which permits the free passage of normal menses.
It usually ruptures during coitus with the remnants, usually in the form of small tags of tissue ar...
Hyperechoic myometrial foci are sonographic observation where the myometrium contains numerous bright echogenic foci.
They can be observed in very different situations and the clinical context is vital in their interpretation.
Recognized causes include
There are several hypertensive states that can manifest in pregnancy. They include:
gestational hypertension - pregnancy induced hypertension (PIH)
They may be commoner in young primigravid as well as older multiparous women.
A hypocoiled umbilical cord to an umbilical cord with less than normal coiling. This is normally estimated by a low umbilical cord coiling index (usually less than 0.2 2).
single umbilical artery
abnormal cord insertion(s)
non coiled umbilical cord
Hypophosphatasia refers to a rare metabolic disorder characterized by deficient serum alkaline phosphatase activity. The effects of hypophosphatasia are primarily seen in the skeletal system. The condition has marked variation in clinical expression (see subtypes).
The true incide...
Hysterectomy (plural: hysterectomies), the surgical resection of the uterus, is the most commonly performed gynecological procedure in the USA 3. It is usually performed electively.
Approximately 600,000 hysterectomies are performed in the United States annually. After Cesarean se...
Hysterosalpingogram (HSG) is a fluoroscopic examination of the uterus and the Fallopian tubes, most commonly used in the investigation of infertility or recurrent spontaneous abortions.
Infertility to assess uterine morphology and tubal patency.
Ian Donald (1910-1987) was a Scottish obstetrician who pioneered the diagnostic use of ultrasound in medicine.
Ian Donald was born in Lisgeard, Cornwall, United Kingdom on 27th December 1910 6. His father was a general practitioner. In 1925 his family moved to South Africa where he ...
Ileal atresia is a congenital abnormality where there is significant stenosis or complete absence of a portion of the ileum. There is an increased incidence in those with chromosomal abnormalities.
This article will focus on ileal atresia alone but bear in mind that some cases correspond to jej...
Immature ovarian teratomas are uncommon ovarian germ cell tumors. They differ from mature ovarian teratomas (dermoid cysts) both histologically by the presence of immature tissue, and clinically by their more malignant behavior.
They are considerably less common than mature ovaria...
Imperforate hymen is a congenital condition in which the hymen lacks a normal opening.
It happens in 0.1% of the female population, usually an isolated finding.
Primary amenorrhea with cyclic lower abdominal pain during menarche age. An imperforate hymen c...
An incarcerated uterus or trapped uterus describes an extremely rare situation where a retroverted or retroflexed gravid uterus fails to ascend into the abdominal cavity.
This is an uncommon presentation and is said to occur in 1 in 3000 pregnancies. Uncomplicated retroversion may...
Indium-111 OncoScint is a radiopharmaceutical used in SPECT imaging. It is a labeled monoclonal antibody that is directed against TAG-72, which is a tumor-associated antigen associated with ~95% of colorectal carcinomas and 100% of ovarian carcinomas 1,2. Background hepatic uptake limits sensiti...
Infertility is common, affecting 15-20% of couples, and is defined as the inability to conceive after one year of unprotected intercourse in the fertile phase of the menstrual cycle 3. It can be due to a variety of both female and male factors, and these are discussed in separate articles:
It is important to have a systematic way of approaching a case with subfertility in the exam.
Ultrasound is the initial examination of choice. Always say that you would further assess the uterus with 3D ultrasound. You may also say that in my department we would perform a sonohysterogram or HS...
Inguinal endometriosis is an unusual extrapelvic site for endometriosis.
The estimated incidence is as around 0.07% among those having endometriosis 4. There is an increased right sided predilection (around 80-90 %of reported cases) 9.
As with endometriosis in general ...
The inguinal lymph nodes (often shortened to the inguinal nodes) are a major group of lymph nodes in the lymphatic system. They are the major drainage pathway of the lower limbs, genitals, dorsal perineum and the inferior most aspect of the anterior abdominal wall.
The inguinal nodal group is s...
The internal iliac lymph nodes (often shortened to internal iliac nodes) are the lymph nodes found adjacent to the internal iliac artery and its branches and drain the regions supplied by these vessels. This encompasses a large area from the genitalia anteriorly, the psoas muscle posteriorly and...
Intramural uterine leiomyoma is the most common type of uterine leiomyoma in terms of location. They are centered primarily within the myometrium. A large intramural uterine leiomyoma can, however, have a submucosal or subserosal component.
They are usually asymptomatic; ...
Intrauterine blood clot can result from a number of situations in gravid, non-gravid and postpartum states. It can mimic many other pathologies.
Any condition that predisposes to an intrauterine hemorrhage can potentially result in an intrauterine blood clot.
Intrauterine contraceptive devices (IUCD) (also known colloquially as the coil) are one of the most frequently used methods of contraception throughout the world. It prevents pregnancy by:
thinning the endometrial lining
preventing sperm motility
There are two main ty...
The presence of intrauterine gas can sometimes be inferred by tiny internal echoes on ultrasound, foci of very low attenuation at computed tomography (CT) or signal voids with susceptibility artifact at MRI. The term encompasses air within the uterine cavity as well as intramyometrial air.
Intravenous leiomyomatosis (IVLM) is characterized by the extension into venous channels of histologically benign smooth muscle tumor arising from either the wall of a vessel or from a uterine leiomyoma.
Intravenous leiomyomatosis should not be confused with benign metastasizing le...
In utero bowel perforation results in a chemical peritonitis (meconium peritonitis) from peritoneal leakage of sterile meconium.
It can result from many causes which include:
in utero intestinal ischemia
Invasive mole is a tumorous growth associated with gestation and falls under the spectrum of gestational trophoblastic disease. Due to their aggressive growth characteristics, invasive moles are considered locally invasive non-metastasizing neoplasms.
An invasive mole develops in ...
The International Ovarian Tumor Analysis (IOTA) group ultrasound rules for ovarian masses are a simple set of ultrasound findings that classify ovarian masses into benign, malignant or inconclusive masses. These rules apply to masses that are not a classical ovarian mass (e.g. corpus luteum, end...
An irregular yolk sac or an abnormally shaped yolk sac is an imaging feature that can be observed in early pregnancy scanning. It may be seen in up to 17% of early pregnancy scans 1. In contrast to an irregular gestational sac, the observation of an irregular yolk sac in not thought to correlate...
An isolated cleft palate is a type of facial cleft. This is a much rarer occurrence than a cleft lip +/- palate and is thought to represent a different pathological entity.
The estimated incidence is at ~1 per 2000-2500 pregnancies 4-5. There may be a slight female predilection 4....
An isthmic ectopic pregnancy is a sub type of tubal ectopic pregnancy an accounts for ~ 12% of such cases. According to one study the rate of tubal wall disruption was higher than with an ampullary ectopic pregnancy, suggesting that in an isthmic ectopic pregnancy, the trophoblast penetrates the...
Isthmus (plural isthmi) is an anatomical term and refers to a slender structure joining two larger components. Some of these uses of the word isthmus are now rarely used or only seen in older texts and articles:
isthmus (auditory tube)
isthmus (auricle of the ear)
IUCD (intrauterine contraceptive device) related uterine perforations are one of the causes of uterine perforation. It is a rare, but serious complication of an IUCD, and is often clinically silent.
The incidence rate is reported at ~2 in 1000 2.
Juberg-Hayward syndrome (JHS), also known as the oro-cranio-digital syndrome, is a rare autosomal recessive syndrome characterized by the association of the following:
cleft lip and palate
minor vertebral and rib anomalies 4
horseshoe kidneys 4
Junctional zone is a region representing the inner myometrium and is a very important imaging feature in pelvic MR imaging for interpretation of various pathologies. In its intact state, it is usually visualized on MRI as a low T2 signal layer beneath the endometrium. At times, it can also be se...
Juvenile granulosa cell tumors of the ovary (JGCT) are a less common subtype of granulosa cell tumor of the ovary (~5% of cases). They are classified as ovarian sex cord / stromal tumors.
It typically occurs in premenarchal girls and young women. The mean age of presentation is 13...
The kissing ovaries sign refers to the appearance seen when both ovaries are located in close proximity or are touching each other in the pouch of Douglas, usually due to pelvic adhesions, and may be seen on ultrasound, CT or MRI.
This sign is most frequently associated with the severe form of ...
Klinefelter syndrome (KS) is a sex chromosomal anomaly, which in most cases is characterized by 47 chromosomes instead of the usual 46.
The estimated incidence is 0.15-0.2% of live births.
the testes are normal prior to puberty and small in post pubertal te...
Krukenberg tumor, also known as carcinoma mucocellulare, refers to the "signet ring" subtype of metastatic tumor to the ovary. The colon and stomach are the most common primary tumors to result in ovarian metastases, followed by the breast, lung, and contralateral ovary.
This article lists a series of labeled imaging anatomy cases by system and modality.
CT head: non-contrast axial
CT head: non-contrast coronal
CT head: non-contrast sagittal
CT head: angiogram axial
CT head: angiogram coronal
CT head: angiogram sagittal
CT head: venogram axial
The labia majora (singular: labium majus) form the anteroinferior most part of the vulva, they are continuous with the mons pubis anteriorly and the perineum posteriorly. The labia are apposed in the midline forming the, externally-visible, pudendal cleft.
The labia majora have ...
The labia minora (singular: labium minus) are small glabrous cutaneous folds lying between and just superior to the labia majora. At their posterior margin the labia may be conjoined by a thin cutaneous fold of skin, the frenulum of the labia (also known as the fourchette or posterior commissure...
A large for date uterus is a clinical observation based on uterine fundal height, which may result in referral for ultrasound assessment, usually in mid to late pregnancy.
constitutionally large fetus
Large loop excision of the transformation zone (LLETZ) is a gynecological procedure. It is currently one of the most commonly used approaches to treat high grade cervical dysplasia - cervical intraepithelial neoplasia.
Leiomyolipomas are rare benign tumors of the uterus, similar to leiomyomas, except that they contain bulk fat.
Leiomyolipomas are typically found in postmenopausal women, on a background of additional leiomyomas 1.
The majority are asymptomatic and discover...
Leiomyomas of the uterine cervix are an unusual variation in terms of location for a uterine leiomyoma.
They are rare and account for ~5% (range 0.6-10%) of uterine leiomyomas 1,4.
Clinical symptoms of cervical leiomyomas, including hypermenorrhea, dysmenor...
Lethal multiple pterygium syndrome (LMPS) is a lethal sub type of the multiple pterygium syndrome.
It is primarily characterized by the presence of pterygia (or wings) present in two or more body areas overlying predominantly the large joints. Accompanying joint contractures are almo...
The levator ani muscle, also known as the muscular pelvic diaphragm, is the musculotendinous sheet that forms the majority of the pelvic floor, supports the pelvic viscera, and aids in urinary and fecal evacuation as well as maintaining continence.
The levator ani has three main ...
Lipiodol® (also known as ethiodized oil) is an oil-based iodinated contrast medium that was historically used for myelography and hysterosalpingography. It was later superseded by newer, less hazardous, agents, and now is used primarily as a therapeutic agent. Guerbet is now the sole manufacture...
A longitudinal vaginal septum is a congenital abnormality of the vagina where a septum divides it into two parallel cavities.
Usually asymptomatic unless obstructed and if obstructed it may cause cyclic pelvic pain. Amenorrhea may occur if both cavities are obstructed 1.
A long philtrum is a clinical or imaging observation where the philtrum (middle part of the upper lip) is longer than normal.
It can be associated with a number of anomalies which include
Cornelia de Lange syndrome
A long umbilical cord has been variably defined. Considering the mean length of the umbilical cord at ~50-70 cm 1, a long cord in absolute terms is usually taken as one that is over 70 cm in length at term 1-3.
increased incidence of umbilical cord knots
increased incidence of ...
Lower vaginal atresia is a type of vagina atresia where the the lower 3rd of the vagina fails to develop.
Patients may present with primary amenorrhea with progressive cyclical abdominal pain.
It is usually not considered a type of Mullerian duct anomaly. It o...
Low-lying placenta occurs when the placenta extends into the lower uterine segment and its edge lies too close to the internal os of the cervix, without covering it. The term is usually applied when the placental edge is within 0.5-5.0 cm of the internal cervical os 1. Some alternatively give th...
Low set ears is a descriptive term used to given a depressed or abnormally low positioning of the pinna by two or more standard deviations below the population average.
Low set ears can be associated with a number of anomalies which include:
aneuploidic / chromosomal s...
Lymphoma of the uterine cervix is generally uncommon and when it does occur tends to present as cervical involvement with added background multi-organ disease rather than isolated primary cervical lymphoma 1. It is often considered part of the spectrum of uterine lymphoma.
In the ...
Macroglossia means an enlarged tongue. It may be absolute (greater than the 95th centile) or relative (enlarged compared with oral cavity).
Recognized associations include:
tends to be a relative macroglossia
may also have intermi...
Male pseudohermaphroditism (MPH) is a variation of gender development.
Patients with male pseudohermaphroditism have 46 XY karyotype and may manifest as a female phenotype with various degrees of undervirilization secondary to partial androgen insensitivity.
A malignant mixed germ cell tumor of the ovary is a subtype of ovarian germ cell tumor. These are not to be confused with malignant mixed Müllerian tumors of the ovary.
These tumors are rare. They most commonly affect adolescent women of reproductive age 1.
They are ma...
Malignant mixed Mullerian tumors (MMMTs), sometimes referred to as a carcinosarcoma, are uncommon malignancies that can occur anywhere along the female genital tract.
It is comprised of both epithelial (carcinomatous) and stromal (sarcomatous) components.
Implicated risk factors inc...
Malignant mixed Mullerian tumors (MMMT) of the ovary, also known as carcinosarcoma of the ovary, are a rare type of mixed ovarian tumor with both epithelial and stromal components.
They are very rare and account for less than 1% of all ovarian cancers. Most women are post-menopaus...
Malignant mixed Mullerian tumor (MMMT) of the uterus, also known a uterine carcinosarcoma, is the commonest (up to 50%) uterine sarcoma. They are thought to account for 2-8% of all malignant uterine cancers 1-2. The uterus is the commonest site for malignant mixed Mullerian tumors 1.
Malignant neoplasms involving the uterus account for a significant proportion of all female cancers.
They can be classified as:
endometrial carcinoma : commonest: >90% of all uterine malignancies
endometrioid carcinoma of the uterus: commonest histological type, ~80%
papillary serous carcino...
Malignant ovarian lesions can have typical sonographic features, and thus ultrasound is the imaging of choice for initial evaluation of suspected ovarian neoplasm.
The features of malignant ovarian neoplasm on ultrasonography include:
mass >10 cm with locula...
Massive ovarian edema (MOO) is a very rare disease characterized by a tumor-like, usually unilateral, enlargement of the ovary.
It characteristically presents in young women ~ 6 to 33 years (mean age ~21 years 4).
Most patients present with intermittent pe...
Maternal hydronephrosis in pregnancy often results as a physiological phenomenon due to the presence of the fetus.
It is estimated that up to 90% of women have some degree of asymptomatic dilatation of the renal calyces, the renal pelves and the upper two-thirds of the ureters du...
Ovarian dermoid cyst and mature cystic ovarian teratoma are terms often used interchangeably to refer to the most common ovarian neoplasm. These slow-growing tumors contain elements from multiple germ cell layers and are best assessed with ultrasound.
Although they have very simil...
Mayer-Rokitansky-Küster-Hauser syndrome (MRKH), also known as Müllerian agenesis, is a congenital anomaly characterized by vaginal agenesis associated with, in the majority of cases, a spectrum of other genitourinary tract abnormalities. MRKH syndrome belongs to class I Mullerian duct anomalies....
McKusick Kaufman syndrome (MKS) is an autosomal recessive multiple malformation syndrome primarily characterized by
hydrometrocolpos - vaginal atresia
congenital heart disease
Meconium pseudocyst formation is a complication that can occur with meconium peritonitis.
It occurs when the extruded meconium becomes walled off within the peritoneal space.
May be seen as a rim calcified mass within the abdomen.
Megalencephaly (MEG) is a disorder characterized by an abnormally large brain. It is primarily a proliferative disorder of embryonic origin. It may involve all or part of the cerebral hemispheres and can be bilateral or unilateral. It is often associated with polymicrogyria or agyria.
Meigs syndrome is defined as the presence of ascites and pleural effusion in association with a benign, usually solid ovarian tumor. In the vast majority (80-90%) of cases, the primary tumor is an ovarian fibroma. Other primary tumors include:
Mendelson syndrome or peptic pneumonia refers to acute chemical pneumonitis caused by the aspiration of stomach contents in patients under general anesthesia.
This syndrome develops rapidly (2-12 hours after aspiration) and within hours the patient may become
Menouria (Youssef syndrome) is an uncommon condition in which a vesicouterine fistula results in cyclic hematuria. Vesicouterine fistulas are the rarest of all urinary fistulas, accounting for just 4% of all such fistulas 3. It occurs most commonly after cesarean section.
Mesomelia refers to a shortening of the middle (intermediate) portion of a limb.
mesomelia-synostoses syndrome (MSS) or mesomelic dysplasia with acral synostoses1
Ellis van-Creveld syndrome 2
Mesonephric carcinoma of the cervix is an extremely rare histological sub type of cervical cancer. It falls under the sub group of adenocarcinoma of the cervix. This is a slightly confusing entitiy since some authors have used this term as synonymous with clear cell carcinoma of the cervix 6.
Metastases to the myometrium is an uncommon situation but has been occasionally reported with extrauterine cancers such as breast cancer 4 (considered commonest primary site) and colon cancer (e.g. sigmoid colon 3).
Possible differential considerations include
Metastases to the ovary are relatively common with a documented incidence of 5-30% of all malignant ovarian masses.
These may be incorrectly grouped under Krukenberg tumors, which are signet cell containing tumors that form only 30-40% of all ovarian metastases.
Metastases to the uterine cervix is an extremely uncommon with near to nothing publications in radiological literature at the time of writing. Generally, invasion of the uterine cervix (i.e. from vaginal and primary uterine malignancies) are excluded in its definition. There have been occasional...
Metastases to the uterus is a rare occurrence accounting for less than 10% of all cases of metastases to the female genital tract from extragenital cancers 3. The endometrium is reported to be even less frequently affected by metastases.
Uterine metastases however can occur from a number of si...
Metastases to the vagina are more common than primary vaginal malignancies and account for >80% of vaginal tumors.
Metastases usually spread from contiguous sites most commonly, with lymphatic and hematogenous metastases also recognized.
Tumors that metastasize to the vagina include...
Microphthalmia essentially means small eyes. It is characterized by a small eye within a small orbit. It can be unilateral or bilateral. It is sometimes defined as a globe with a total axial length (TAL) that is at least two standard deviations below the mean for age.
Midfacial hypoplasia is a type of congenital facial anomaly and can be feature of a number of congenital syndromic anomalies. These include:
chromosome 1p36 deletion syndrome 2
chromosome 18q deletion syndrome
fetal alcohol syndrome
fetal valproate s...
A missing IUCD is considered when the retrieval strings of certain types of intrauterine contraception devices (IUCD) cannot be seen on physical examination.
The possibilities are
expulsion of IUCD
migration of IUCD
detachment of IUCD thread
uterine perforation in IUCD
Mixed gonadal dysgenesis (MGD) is a type of gonadal dysgenesis characterized by gonadal asymmetry, and/or sex chromosomal mosaicism, as well as retained Müllerian ducts.
Depending on the chromosomal composition, patients may have testes and/or streak gonads.
A monochorionic monoamniotic (MCMA) twin pregnancy is a subtype of monozygotic twin pregnancy. These fetuses share a single chorionic sac, a single amniotic sac and, in general, a single yolk sac.
It accounts for the minority (~5%) of monozygotic twin pregnancies and ~1-2% of al...
A monochorionic twin pregnancy is a type of monozygotic twin pregnancy where the twins share a single chorion. Depending on the sharing of the amnion this can be divided into two types.
monochorionic monoamniotic (MCMA) pregnancy: single amnion
monochorionic diamniotic (MCDA) pregnancy: two am...
A mono nostril falls under the midline facial defects which arise from cleavage anomalies. It can occur as part of many underlying conditions such as
holoprosencephaly: particularly alobar holoprosencephaly
Several other facial anomalies can be associated ...
A monozygotic (MZ) twin pregnancy results from the division of single zygote following fertilisation and shares similar genetic materials. These twins are therefore always of the same gender.
MZ twins account for approximately 30% of all twin pregnancies 1. The estimated incidence...
The mons pubis (plural: montes pubis) refers to the rounded protuberant skin-covered soft tissue overlying the symphysis pubis (in both sexes). It is most prominent in adult females.
In females it forms the most superior part of the vulva and it is also called the mons Veneris (plural: montes V...
MR defecography is a dynamic study for evaluation of the pelvic floor and pelvic organ prolapse.
There are four phases of evaluation:
Method of evaluation
Many variations in the techniques described below exist.
MRI reporting guidelines for cervical cancer help maintain uniformity of reports and assessment of important imaging staging criteria.
The tumor should be measured in three orthogonal planes. Tumors with a maximum diameter >4 cm are usually not amenable to primary radical surgery.
Mucinous carcinoma of the cervix is an uncommon histological subtype of cervical cancer. It falls under the group of adenocarcinoma of the cervix.
As a general rule any mucin-producing tumor will produce very high T2 signal 1.
An enhancing lesion, irregular margin, ...
The Müllerian ducts (or paramesonephric ducts) are paired ducts of mesodermal origin in the embryo. They run laterally down the side of the urogenital ridge and terminate at the Müllerian eminence in the primitive urogenital sinus.
In the female, they will develop to form the Fallopian tubes, u...
Müllerian duct anomalies (MDAs) are congenital abnormalities that occur when the Müllerian ducts (paramesonephric ducts) do not develop correctly. This may be as a result of complete agenesis, defective vertical or lateral fusion, or resorption failure.
MDAs are estimated to occur...