A pelvic digit, pelvic finger, or pelvic rib is a rare

congenital abnormality A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can r ...

in humans, in which

bone tissue A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, an ...

develops in the

soft tissue Soft tissue is all the tissue in the body that is not hardened by the processes of ossification or calcification such as bones and teeth. Soft tissue connects, surrounds or supports internal organs and bones, and includes muscle, tendons, ligam ...

near the

pelvis The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...

, resembling a

rib In vertebrate anatomy, ribs ( la, costae) are the long curved bones which form the rib cage, part of the axial skeleton. In most tetrapods, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the ches ...

finger A finger is a limb of the body and a type of digit, an organ of manipulation and sensation found in the hands of most of the Tetrapods, so also with humans and other primates. Most land vertebrates have five fingers ( Pentadactyly). Chambers ...

and often divided into one or more segments with pseudo-articulations. Pelvic digits are typically

benign Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malign ...

and asymptomatic, and are usually discovered accidentally. Approximately 41 cases have been reported. The pelvic digit was first reported by D. Sullivan and W.S. Cornwell in 1974. Pelvic digits may be located at any level of the pelvis, the lower ribs, or even the anterior abdominal wall. It is theorized that pelvic digit anomalies arise during the

mesenchymal Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood or bone. The interactions between mesenchyme and epithelium help to form nearly every o ...

stage of bone growth, within the first six weeks of

embryogenesis An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...

. Their formation may result from a failure of the

primordium A primordium (; plural: primordia; synonym: anlage) in embryology, is an organ or tissue in its earliest recognizable stage of development. Cells of the primordium are called primordial cells. A primordium is the simplest set of cells capable o ...

of the

coccyx The coccyx ( : coccyges or coccyxes), commonly referred to as the tailbone, is the final segment of the vertebral column in all apes, and analogous structures in certain other mammals such as horses. In tailless primates (e.g. humans and othe ...

to fuse to the

vertebral column The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordata, ...

, leading to the independent development of a proto-rib structure.

References

External links

Radiographs of a pelvic digit
* *{{cite journal, doi=10.1007/s002560050168, title=The pelvic digit: Five new examples of an unusual anomaly, year=1996, last1=Granieri, first1=G. F., last2=Bacarini, first2=Lamberto, s2cid=19362429, journal=Skeletal Radiology, volume=25, issue=8, pages=723–726, pmid=8958617 *"The Pelvic Digit – A Rare Developmental Anomaly"] in ''Acta Radiologica'' Congenital disorders Supernumerary body parts Pelvis

See also

References

External links