vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...

s, the pubic region ( la, pubis) is the most forward-facing (

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

and anterior) of the three main

region In geography, regions, otherwise referred to as zones, lands or territories, are areas that are broadly divided by physical characteristics ( physical geography), human impact characteristics ( human geography), and the interaction of humanity an ...

s making up the

coxal bone The hip bone (os coxae, innominate bone, pelvic bone or coxal bone) is a large flat bone, constricted in the center and expanded above and below. In some vertebrates (including humans before puberty) it is composed of three parts: the ilium, ischi ...

. The left and right pubic regions are each made up of three sections, a superior ramus, inferior ramus, and a body.

Structure

The pubic region is made up of a ''body'', ''superior ramus'', and ''inferior ramus'' (). The left and right coxal bones join at the

pubic symphysis The pubic symphysis is a secondary cartilaginous joint between the left and right superior rami of the pubis of the hip bones. It is in front of and below the urinary bladder. In males, the suspensory ligament of the penis attaches to the pubi ...

. It is covered by a layer of

fat In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. The term often refers specifically to triglycerides (triple est ...

, which is covered by the

mons pubis In human anatomy, and in mammals in general, the ''mons pubis'' or pubic mound (also known simply as the mons, and known specifically in females as the ''mons Venus'' or ''mons veneris'') is a rounded mass of fatty tissue found over the pubic sym ...

. The pubis is the lower limit of the

suprapubic region The hypogastrium (also called the hypogastric region or suprapubic region) is a region of the abdomen located below the umbilical region. Etymology The roots of the word ''hypogastrium'' mean "below the stomach"; the roots of ''suprapubic'' m ...

. In the female, the pubic region is anterior to the

urethral sponge The urethral sponge is a spongy cushion of tissue, found in the lower genital area of females, that sits against both the pubic bone and vaginal wall, and surrounds the urethra. Functions The urethral sponge is composed of erectile tissue; d ...

Body

The body forms the wide, strong, middle and flat part of the pubic region. The bodies of the left and right pubic regions join at the

. The rough upper edge is the

pubic crest Medial to the pubic tubercle is the pubic crest, which extends from this process to the medial end of the pubic bone. It gives attachment to the conjoint tendon, the rectus abdominis, the abdominal external oblique muscle, and the pyramidalis mu ...

, ending laterally in the

pubic tubercle The pubic tubercle is a prominent tubercle on the superior ramus of the pubis bone of the pelvis. Structure The pubic tubercle is a prominent forward-projecting tubercle on the upper border of the medial portion of the superior ramus of the ...

. This

tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projection ...

, found roughly 3 cm from the pubic symphysis, is a distinctive feature on the lower part of the

abdominal wall In anatomy, the abdominal wall represents the boundaries of the abdominal cavity. The abdominal wall is split into the anterolateral and posterior walls. There is a common set of layers covering and forming all the walls: the deepest being the ...

; important when localizing the superficial inguinal ring and the

femoral canal The femoral canal is the medial (and smallest) compartment of the three compartments of the femoral sheath. It is conical in shape. The femoral canal contains lymphatic vessels, and adipose and loose connective tissue, as well as - sometimes - a ...

of the

inguinal canal The inguinal canals are the two passages in the anterior abdominal wall of humans and animals which in males convey the spermatic cords and in females the round ligament of the uterus. The inguinal canals are larger and more prominent in males. ...

. The inner surface of the body forms part of the wall of the

lesser pelvis The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily contains the reprod ...

and joints to the origin of a part of the obturator internus muscle.

Superior pubic ramus

The superior pubic ramus is the upper of the two rami. It forms the upper edge of the obturator foramen. It extends from the body to the median plane where it joins with the ramus of the opposite side. It consists of an inner flattened part and a narrow outer prismoid portion. Medial surface Surfaces * The ''anterior surface'' is rough, directed downward and outward, and serves for the origin of various muscles. The

adductor longus In the human body, the adductor longus is a skeletal muscle located in the thigh. One of the adductor muscles of the hip, its main function is to adduct the thigh and it is innervated by the obturator nerve. It forms the medial wall of the fem ...

arises from the upper and medial angle, immediately below the crest; lower down, the

obturator externus The external obturator muscle, obturator externus muscle (; OE) is a flat, triangular muscle, which covers the outer surface of the anterior wall of the pelvis. It is sometimes considered part of the medial compartment of thigh, and sometimes c ...

, the

adductor brevis The adductor brevis is a muscle in the thigh situated immediately deep to the pectineus and adductor longus. It belongs to the adductor muscle group. The main function of the adductor brevis is to pull the thigh medially. The adductor brevis ...

, and the upper part of the gracilis take origin. * The ''posterior surface'', convex from above downward, concave from side to side, is smooth, and forms part of the anterior wall of the pelvis. It gives origin to the

levator ani The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis. It is attached to the inner surface of each side of the ...

and obturator internus, and attachment to the

puboprostatic ligament The pubovesical ligament is a ligament that extends from the neck of the urinary bladder to the inferior aspect of the pubis bones. Structure The pubovesical ligament is the continuation of the detrusor muscle and the adventitia surrounding t ...

s and to a few muscular fibers prolonged from the bladder. Borders * The ''upper border'' presents a prominent tubercle, the

(

pubic spine The pubic tubercle is a prominent tubercle on the superior ramus of the pubis bone of the pelvis. Structure The pubic tubercle is a prominent forward-projecting tubercle on the upper border of the medial portion of the superior ramus of the ...

), which projects forward; the

inferior crus The superficial inguinal ring is bounded below by the crest of the pubis; on either side by the margins of the opening in the aponeurosis, which are called the crura of the ring; and above, by a series of curved intercrural fibers. * The inferio ...

of the

subcutaneous inguinal ring The inguinal canals are the two passages in the anterior abdominal wall of humans and animals which in males convey the spermatic cords and in females the round ligament of the uterus. The inguinal canals are larger and more prominent in males. Th ...

(external abdominal ring), and the inguinal ligament (Poupart's ligament) are attached to it. Passing upward and laterally from the pubic tubercle is a well-defined ridge, forming a part of the pectineal line which marks the brim of the

: to it are attached a portion of the

inguinal falx The conjoint tendon (previously known as the inguinal aponeurotic falx) is a sheath of connective tissue formed from the lower part of the common aponeurosis of the abdominal internal oblique muscle and the transversus abdominis muscle, joining th ...

(conjoined tendon of obliquus internus and transversus), the lacunar ligament (Gimbernat's ligament), and the reflected inguinal ligament (triangular fascia). Medial to the pubic tubercle is the crest, which extends from this process to the medial end of the bone. It affords attachment to the

, and to the

rectus abdominis The rectus abdominis muscle, ( la, straight abdominal) also known as the "abdominal muscle" or simply the "abs", is a paired straight muscle. It is a paired muscle, separated by a midline band of connective tissue called the linea alba. It exte ...

and pyramidalis. The point of junction of the crest with the medial border of the bone is called the angle; to it, as well as to the

symphysis A symphysis (, pl. symphyses) is a fibrocartilaginous fusion between two bones. It is a type of cartilaginous joint, specifically a secondary cartilaginous joint. # A symphysis is an amphiarthrosis, a slightly movable joint. # A growing togethe ...

, the superior crus of the subcutaneous inguinal ring is attached. The ''medial border'' is articular; it is oval, and is marked by eight or nine transverse ridges, or a series of nipple-like processes arranged in rows, separated by grooves; they serve for the attachment of a thin layer of cartilage, which intervenes between it and the interpubic fibrocartilaginous lamina. The ''lateral border'' presents a sharp margin, the obturator crest, which forms part of the circumference of the obturator foramen and affords attachment to the obturator membrane. Lateral portion Surfaces * The ''superior surface'' presents a continuation of the pectineal line, already mentioned as commencing at the

. In front of this line, the surface of bone is triangular in form, wider laterally than medially, and is covered by the pectineus. The surface is bounded, laterally, by a rough eminence, the

iliopectineal eminence Medial to the anterior inferior iliac spine is a broad, shallow groove, over which the iliacus and psoas major muscles pass. This groove is bounded medially by an eminence, the iliopubic eminence (or iliopectineal eminence), which marks the point o ...

, which serves to indicate the point of junction of the ilium and pubis, and below by a prominent ridge which extends from the

acetabular notch The acetabular notch is a deep notch in the acetabulum of the hip bone. The acetabular notch is continuous with a circular non-articular depression, the acetabular fossa, at the bottom of the cavity: this depression is perforated by numerous aper ...

to the pubic tubercle. * The ''inferior surface'' forms the upper boundary of the obturator foramen, and presents, laterally, a broad and deep, oblique groove, for the passage of the obturator vessels and nerve; and medially, a sharp margin, the obturator crest, forming part of the circumference of the obturator foramen, and giving attachment to the obturator membrane. * The ''posterior surface'' constitutes part of the anterior boundary of the

. It is smooth, convex from above downward, and affords origin to some fibers of the obturator internus.

Inferior pubic ramus

The inferior pubic ramus is a part of the pelvis and is thin and flat. It passes laterally and downward from the medial end of the superior ramus; it becomes narrower as it descends and joins with the

inferior ramus of the ischium The ischium () form ...

below the obturator foramen. Surfaces * Its ''anterior surface'' is rough, for the origin of muscles—the gracilis along its medial border, a portion of the

Obturator externus The external obturator muscle, obturator externus muscle (; OE) is a flat, triangular muscle, which covers the outer surface of the anterior wall of the pelvis. It is sometimes considered part of the medial compartment of thigh, and sometimes c ...

where it enters into the formation of the obturator foramen, and between these two, the adductores brevis and magnus, the former being the more medial. * The ''posterior surface'' is smooth, and gives origin to the obturator internus, and, close to the medial margin, to the Constrictor urethrae. Borders * In the female pelvis, the ''medial border'' is thick, rough, and everted, and presents two ridges, separated by an intervening space. The ridges extend downwards, and are continuous with similar ridges on the

inferior ramus of the ischium The ischium () form ...

; ** to the external ridge is attached the

fascia of Colles The membranous layer of the superficial fascia of the perineum (Colles' fascia) is the deeper layer ( membranous layer) of the superficial perineal fascia. It is thin, aponeurotic in structure, and of considerable strength, serving to bind down th ...

** to the internal ridge is attached the inferior fascia of the

urogenital diaphragm Older texts have asserted the existence of a urogenital diaphragm, also called the triangular ligament, which was described as a layer of the pelvis that separates the deep perineal sac from the upper pelvis, lying between the inferior fascia of ...

* The ''lateral border'' is thin and sharp, forms part of the circumference of the obturator foramen, and gives attachment to the obturator membrane.

Other animals

Mammals

Non-

placental Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguishe ...

mammals possess osteological projections of the pubis known as

epipubic Epipubic bones are a pair of bones projecting forward from the pelvic bones of modern marsupials, monotremes and fossil mammals like multituberculates, and even basal eutherians (the ancestors of placental mammals, who lack them). They first o ...

bones. These evolved first among derived cynodonts, and evolved as a means of support for muscles flexing the thigh, facilitating the development of an erect gait. However, these prevent the expansion of the torso, preventing pregnancy and forcing the animal to give birth to larval young (the modern

marsupial Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a ...

"joeys" and monotreme "puggles"). Placentals are unique among all mammals, including other

eutheria Eutheria (; from Greek , 'good, right' and , 'beast'; ) is the clade consisting of all therian mammals that are more closely related to placentals than to marsupials. Eutherians are distinguished from noneutherians by various phenotypic tra ...

ns, in having lost epipubic bones and having been able to develop proper

pregnancy Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...

. In some groups, remnants of these pre-pubic bones can be found as

os penis The baculum (also penis bone, penile bone, or ''os penis'', ''os genitale'' or ''os priapi'') is a bone found in the penis of many placental mammals. It is absent from the human penis, but present in the penises of some primates, such as the ...

es.

Dinosaurs

The clade

Dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

ia is divided into the

Saurischia Saurischia ( , meaning "reptile-hipped" from the Greek ' () meaning 'lizard' and ' () meaning 'hip joint') is one of the two basic divisions of dinosaurs (the other being Ornithischia), classified by their hip structure. Saurischia and Ornithis ...

and Ornithischia based on hip structure, including importantly that of the pubis. An opisthopubic pelvis is a condition where the pubic bone extends back towards the tail of the animal, a trait that is also present in birds. In a propubic pelvis, however, the pubic bone extends forward towards the head of the animal, as can be seen in the typical saurischian pelvic structure pictured below. The acetabulum, which can be thought of as a "hip-socket", is an opening on each side of the pelvic girdle formed where the ischium, ilium, and pubis all meet, and into which the head of the femur inserts. The orientation and position of the acetabulum is one of the main morphological traits that caused dinosaurs to walk in an upright posture with their legs directly underneath their bodies.Martin, A.J. (2006). Introduction to the Study of Dinosaurs. Second Edition. Oxford, Blackwell Publishing. pg. 299-300. . The ''prepubic process'' is a bony extension of the pubis that extends forward from the hip socket and toward the front of the animal. This adaptation is thought to have played a role in supporting the abdominal muscles. Ornithischia pelvis structure.svg, Ornithischian pelvic structure (left side) Saurischia pelvis structure.svg, Saurischian pelvic structure (left side).

Additional images

File:Skeletal pelvis-pubis.svg, The sacrum and pelvic bone, with parts labelled. The pubic bone consists of the body and superior pubic ramus (4), and the inferior pubic ramus (3), which join at the

. The gap between them is the obturator foramen. File:Gray235.png, Right hip bone. External surface. File:Gray236.png, Right hip bone. Internal surface. File:Gray237.png, Plan of ossification of the hip bone. File:Gray321.png, Symphysis pubis exposed by a coronal section. File:Gray404.png, Left levator ani from within. File:Gray436.png, The obturator externus. File:Gray341.png, Left hip-joint, opened by removing the floor of the acetabulum from within the pelvis. File:Slide16A.JPG, Pubis

References

External links

* - "The Male Pelvis: Hip Bone" {{Authority control Bones of the pelvis