The
pubic symphysis is the midline
cartilaginousCartilage is a stiff yet flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
jointA joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...
(secondary cartilaginous) uniting the
superior ramiThe superior pubic ramus is a part of the pubic bone which forms a portion of the obturator foramen.It extends from the body to the median plane where it articulates with its fellow of the opposite side...
of the left and right
pubic bonesThe android pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis.It is covered by a layer of fat, which is covered by the mons pubis.It is divisible into a body, a superior ramus and an inferior ramus....
. It is located anterior to the
urinary bladderIn anatomy, the urinary bladder is the organ that collects urine excreted by the kidneys prior to disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...
and superior to the external genitalia; for females it is above the
vulvaThe vulva refers to the external genital organs of the female. This article deals with the human vulva, although the structures are similar for other mammals....
and for males it is above the
penisThe penis is an external sexual organ of certain biologically male organisms, in both vertebrates and invertebrates....
. In males, the
suspensory ligament of the penisIn males, the suspensory ligament of the penis is attached to the pubic symphysis, which holds the penis close to the pubic bone and supports it when erect....
attaches to the pubic symphysis. In females, the pubic symphysis is intimately close to the
clitorisThe clitoris is a sexual organ that is present only in female mammals. In humans, the visible button-like portion is located near the anterior junction of the labia minora, above the opening of the urethra and vagina. Unlike the penis, which is homologous to the clitoris, the clitoris does not...
and is slightly movable for the birth of children.
Symphysis pubis is a
non-synovialSynovial membrane is the soft tissue that lines the non-cartilaginous surfaces within joints with cavities...
amphiarthrodial-Types:In amphiarthroses, the contiguous bony surfaces are either:* A symphysis: connected by broad flattened disks of fibrocartilage, of a more or less complex structure, as in the articulations between the bodies of the vertebrae. An example is the sternocostal joint.* A syndesmosis: united by an...
joint and comes from the Greek word "symphysis" meaning growing together.
The
pubic symphysis is the midline
cartilaginousCartilage is a stiff yet flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
jointA joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...
(secondary cartilaginous) uniting the
superior ramiThe superior pubic ramus is a part of the pubic bone which forms a portion of the obturator foramen.It extends from the body to the median plane where it articulates with its fellow of the opposite side...
of the left and right
pubic bonesThe android pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis.It is covered by a layer of fat, which is covered by the mons pubis.It is divisible into a body, a superior ramus and an inferior ramus....
. It is located anterior to the
urinary bladderIn anatomy, the urinary bladder is the organ that collects urine excreted by the kidneys prior to disposal by urination. A hollow muscular, and distensible organ, the bladder sits on the pelvic floor...
and superior to the external genitalia; for females it is above the
vulvaThe vulva refers to the external genital organs of the female. This article deals with the human vulva, although the structures are similar for other mammals....
and for males it is above the
penisThe penis is an external sexual organ of certain biologically male organisms, in both vertebrates and invertebrates....
. In males, the
suspensory ligament of the penisIn males, the suspensory ligament of the penis is attached to the pubic symphysis, which holds the penis close to the pubic bone and supports it when erect....
attaches to the pubic symphysis. In females, the pubic symphysis is intimately close to the
clitorisThe clitoris is a sexual organ that is present only in female mammals. In humans, the visible button-like portion is located near the anterior junction of the labia minora, above the opening of the urethra and vagina. Unlike the penis, which is homologous to the clitoris, the clitoris does not...
and is slightly movable for the birth of children.
Anatomy
Symphysis pubis is a
non-synovialSynovial membrane is the soft tissue that lines the non-cartilaginous surfaces within joints with cavities...
amphiarthrodial-Types:In amphiarthroses, the contiguous bony surfaces are either:* A symphysis: connected by broad flattened disks of fibrocartilage, of a more or less complex structure, as in the articulations between the bodies of the vertebrae. An example is the sternocostal joint.* A syndesmosis: united by an...
joint and comes from the Greek word "symphysis" meaning growing together. The anterior width of the symphysis pubis is 3-5 mm greater than its intrapelvic posterior width. This joint is connected by
fibrocartilageWhite fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions; to the former of these constituents it owes its flexibility and toughness, and to the latter its elasticity...
and may contain a fluid filled cavity, the center is
avascularThe blood vessels are the part of the circulatory system that transport blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart, the capillaries, which enable the actual exchange of water and chemicals between the blood and...
; possibly due to the nature of the compressive forces passing through this joint which may lead to harmful vascular disease. The ends of both pubic bones are covered by a thin layer of
hyaline cartilageHyaline cartilage consists of a slimy mass of a firm consistency, but of considerable elasticity and pearly bluish color. It contains no nerves or blood vessels, and its structure is relatively simple....
which is attached to the fibrocartilage. The fibrocartilaginous disk is reinforced by a series of ligaments. These ligaments cling to the fibrocartilaginous disk to the point that fibers intermix with it.
Two such ligaments are the
superiorThe superior pubic ligament connects together the two pubic bones superiorly, extending laterally as far as the pubic tubercles....
and
inferiorThe inferior pubic ligament is a thick, triangular arch of ligamentous fibers, connecting together the two pubic bones below, and forming the upper boundary of the pubic arch.Above, it is blended with the interpubic fibrocartilaginous lamina; laterally, it is attached to the inferior rami of...
, these being the ligaments that provide the most stability; the posterior and anterior ligaments are weaker. The strong and thicker superior ligament is reinforced by the tendons of the
rectus abdominisThe rectus abdominis muscle is a paired muscle running vertically on each side of the anterior wall of the human abdomen . There are two parallel muscles, separated by a midline band of connective tissue called the linea alba...
,
obliques externusThe external oblique muscle is the largest and the most superficial of the three flat muscles of the lateral anterior abdomen.-Structure:...
,
gracilisThe Gracilis is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below. It arises by a thin aponeurosis from the anterior margins of the lower half of the symphysis pubis and the upper half of the pubic arch.The muscle's...
and
thigh adductors musclesIn human anatomy, the muscles of the hip joint are those muscles that cause movement in the hip. Most modern anatomists define 17 of these muscles, although some additional muscles may sometimes be considered...
. The inferior ligament in the pubic arch is known as the arcuate pubic ligament.
At the time of birth the symphysis pubis is 9-10mm in width, with thick cartilaginous end-plates. By mid-adolescence the adult size is achieved. During adulthood the end-plates decrease in width to a thinner layer. Degeneration of the symphysis pubis accompanies aging and
postpartumPostnatal is the period beginning immediately after the birth of a child and extending for about six weeks. A more correct term would be postpartum period, as it refers to the mother...
. Women have a greater thickness of this pubic disc which allows more mobility of the pelvic bones, hence providing a greater diameter of pelvic cavity during
childbirthChildbirth is the culmination of a human pregnancy or gestation period with birth of one or more newborn infants from a woman's uterus...
.
Fibrocartilage
FibrocartilageWhite fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions; to the former of these constituents it owes its flexibility and toughness, and to the latter its elasticity...
is composed of small chained bundles of thick clearly defined type I
collagenCollagen is the main protein of connective tissue in animals and the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content. It is naturally found exclusively in metazoa, including sponges. In muscle tissue it serves as a major component of endomysium...
fibers. This fibrous connective tissue bundles have cartilage cells between them, these cells to a certain extent resemble tendon cells. The collagenous fibers are usually placed in an orderly arrangement parallel to tension on the tissue. It has a low content of glycosaminoglycans (2% of dry weight). Glycosaminoglycans are long unbranched polysaccharides (relatively complex carbohydrates) consisting of a repeating
disaccharideA disaccharide is the carbohydrate formed when two monosaccharides undergo a condensation reaction which involves the elimination of a small molecule, such as water, from the functional groups only...
unit. Disaccharide a sugar (a carbohydrate) is composed of two monosaccharides. The two monosaccharides are bonded via a dehydration reaction that leads to the loss of a molecule of water. Fibrocartilage does not have a surrounding
perichondriumThe perichondrium is a layer of dense irregular connective tissue which surrounds the cartilage of developing bone. It consists of two separate layers: an outer fibrous layer and inner chondrogenic layer. The fibrous layer contains fibroblasts, which produce collagenous fibers. The chondrogenic...
. Perichondrium surrounds the cartilage of developing bone, it has a layer of dense irregular connective tissue and functions in the growth and repair of cartilage.
Hyaline cartilage
Hyaline cartilageHyaline cartilage consists of a slimy mass of a firm consistency, but of considerable elasticity and pearly bluish color. It contains no nerves or blood vessels, and its structure is relatively simple....
is the white shiny gristle at the end of long bones. This cartilage has very poor healing potential, and efforts to get it to repair itself frequently end up with a similar, but poorer fibrocartilage.
Physiology
Analysis of the pelvis shows that the skinny regions function as arches, transferring the weight of the up-right trunk from the sacrum to the hips. The symphysis pubis connects these two weight-bearing arches and the ligaments that surround this pelvic region maintain the mechanical integrity.
The Main Motions of the Symphysis Pubis are
- Superior/ inferior glide.
- Separation/ compression.
The Functions of the Joint are to
- Absorb shock absorption during walking.
- Delivery of baby.
Pregnancy
During pregnancy in the human, hormones such as
relaxinRelaxin is a peptide hormone that was first described in 1926 by Frederick Hisaw.The relaxin-like peptide family belongs in the insulin superfamily and consists of 7 peptides of high structural but low sequence similarity; relaxin-1 , 2 and 3, and the insulin-like peptides, INSL3, INSL4, INSL5...
remodels this ligamentous capsule allowing the pelvic bones to be more flexible for delivery. The non-pregnant gap of the symphysis pubis is 4-5mm but in pregnancy there will be an increase of at least 2-3mm, therefore, it is considered that a total width of up to 9mm between the two bones is normal for a pregnant woman. The symphysis pubis separates to some degree during the birthing process. In some women this separation can become a
diastasis of the symphysis pubisDiastasis symphysis pubis is the separation of normally joined pubic bones, as in the dislocation of the bones, without a fracture.- Diagnosis :...
. The diastasis could be the result of a rapid birth or a
forcepsForceps are a handheld, hinged instrument used for grasping and holding objects. Forceps are used when fingers are too large to grasp small objects or when many objects need to be held at one time while the hands are used to perform a task. The term forceps is used almost exclusively within the...
delivery or maybe even prenatal.. A diastasis of the symphysis pubis is a symptom of
pelvic girdle painPregnancy related Pelvic Girdle Pain causes pain, instability and limitation of mobility and functioning in any of the three pelvic joints. PGP has a long history of recognition, mentioned by Hippocrates...
(PGP). Overall, about 45% of all pregnant women and 25% of all women postpartum suffer from PGP
Symphysiotomy
Historically, when labor failed to progress because of the head of the fetus was too large, the mother's symphysis pubis was cut and the fetus' skull was crushed. The Caesarean section has allowed for the - largely safe - delivery of these infants (see Hope Langer, MD; NY Times Review of Books, Oct. 22, 2006)
In remote, isolated tropical areas women presenting with a large baby and small pelvis travelled for great distances for medical help; a
symphysiotomySymphysiotomy is a surgical procedure in which the cartilage of the symphysis pubis is divided to widen the pelvis allowing childbirth when there is a mechanical problem.- Introduction :...
has been suggested . This practise was carried out in Europe before the introduction of the Caesarean Section. It is still considered as an option in Third World countries .
Diseases of the Symphysis Pubis
Metabolic disease, such as renal osteodystrophy, produces widening, while ochronosis results in calcific deposits in the symphysis. Inflammatory disease, such as ankylosing spondylitis, results in bony fusion of the symphysis.
Osteitis pubisOsteitis pubis is a medical condition which is prevalent among footballers, runners and other athletes, particularly players of Australian rules football...
, the most common inflammatory disease, is treated with anti-inflammatory medication and rest. Degenerative joint disease of the symphysis, which can cause groin pain, results from instability or from abnormal pelvic mechanics
Use in forensic anthropology
The pubic symphysis have importance in the field of forensic anthropology, as they can be used to estimate the age of adult skeletons. Throughout life, the surfaces of the pubic symphysis are worn at a more or less predictable rate. By examining the wear of the pubic symphysis, it is possible to estimate the age of the person at death.
External links