When evaluating soft tissues around the spine, you want imaging with high soft-tissue contrast to distinguish ligaments from surrounding structures. MRI uses magnetic properties of tissues to create detailed images and offers multiple sequences that highlight ligaments, discs, and surrounding soft tissue, making tears or inflammation easy to see. CT provides excellent detail of bone but relatively limited soft-tissue contrast, so ligaments aren’t as clearly delineated. X-ray mainly shows bone alignment and degenerative changes with little soft-tissue information, and nuclear medicine focuses on function rather than detailed anatomy. Therefore, MRI is the best choice for assessing ligaments around the spine.

GnRH from the hypothalamus signals the anterior pituitary to secrete the gonadotropins FSH and LH. The anterior pituitary is the gland responsible for producing and releasing these hormones in response to GnRH, forming a key link in the hypothalamic-pituitary-gonadal axis. The posterior pituitary doesn’t release FSH or LH (it releases oxytocin and vasopressin), and the adrenal cortex isn’t involved in producing these gonadotropins.

The main idea here is distinguishing joints by the tissue that binds them. In the pelvis, cartilaginous joints are those held together by cartilage rather than a synovial capsule. The pair that fits this is the pubic symphysis and the sacrococcygeal joint. The pubic symphysis is a secondary cartilaginous joint (a symphysis) with a fibrocartilaginous disc between the pubic bones, allowing only slight give to absorb forces. The sacrococcygeal joint is also a cartilaginous joint (a symphysis) between the sacrum and coccyx, permitting limited movement that can become more rigid with age. Other pelvic joints are not cartilaginous: the sacroiliac and lumbosacral joints are primarily synovial joints, though they have strong ligaments; the hip and knee are classic synovial joints; and the pubic arch and acetabulum are bony structures rather than joints themselves.

Blockage of the vaginal outflow tract at the vaginal opening. When the opening is completely closed, menstrual blood cannot exit, leading to primary amenorrhea and potential pelvic distention or pain that can look like delayed puberty because menses do not appear. Imperforate hymen is a hymenal membrane that covers the entire vaginal opening, so it directly blocks the introitus. On exam you may notice a tense, bulging hymen, sometimes with a bluish hue, indicating trapped blood behind it. The other conditions don't directly block the opening. A transverse vaginal septum sits across the vagina internally, so while it can obstruct flow, the vaginal opening itself remains patent. Mullerian agenesis involves absent or underdeveloped uterus with a normally formed vagina, so there isn’t an outflow obstruction at the entry. Ovarian cysts affect the ovaries and can cause pain or mass effects, but they do not block the vaginal opening.