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What is the Pelvis?

The pelvis or pelvic girdle is a basin-shaped complex bone placed right between the abdomen and pelvic region that's thighs. The pair of hip bones (coxal bone) join the lower limbs and the spine. They are connected to the sacrum rearwards, attached anteriorly, and associated with the two femurs at the hip bones. The passage surrounded by the bony pelvis, termed the pelvic cavity, is a particular body division below the abdomen and essentially contains and supports the urinary bladder, intestines, and other internal reproductive organs. 


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The bony pelvis has a rift in the centre in mammals which is significantly larger in females compared to males helping them with reproduction. 

Pelvis Anatomy

The pelvic region of the torso is the lower part, between the things and the abdomen. The area comprises multiple structures: the pelvic cavity, the perineum, the bony pelvis, and the pelvic floor. The bony pelvis is the portion of the skeleton buried in the pelvic region of the body. It is divided into two sections, the pelvic spine and the pelvic girdle. 

The pelvic bone consists of the coccyx and sacrum. The pelvic girdle, composed of ring-oriented appendicular hip bones (ilium, pubis, and ischium), attaches the pelvic area of the spine to the lower limbs. 

  • The pelvic cavity is a little part of the space encircled by the bony pelvis. The pelvic area is delineated by the pelvic brim, at the above and the pelvic floor at the below. The cavity is also defined as a place completely enclosed by the pelvic skeleton, which is parted into:

  • the false (or greater) pelvis, over the pelvic brim

  • the true (or lessen) pelvis, under the pelvic brim

  • The pelvic floor is also known as the pelvic diaphragm (placed right below the pelvic cavity)

  • The perineum (placed below the pelvic floor)


Pelvic Bone

The pelvic skeleton is created in the back pelvic area by the coccyx and the sacrum, anteriorly and either side by a pair of hip bones. 

Singly coxal bone consists of three segments, pubis, ilium, and ischium. During adolescence, these segments are separate bones linked by the triradiate cartilage. And throughout puberty, they blend to form an individual bone.


Pelvic Cavity

The pelvis bones surround the pelvic cavity and essentially hold reproductive organs and the rectum. A disparity is created between the true pelvis inferior to the terminal line and the false pelvis above it. 

The superior pelvic aperture or the pelvic inlet that leads into the true pelvis is joined by the cape, the iliopubic eminence, the top portion of the pubic symphysis, the pecten of the pubis, and the arcuate line of the ilium. The pelvic socket is the section within the pubic arch, the coccyx, and the ischial tuberosities.


Pelvic Floor

The muscle of the pelvic floor has two essentially contradictory purposes. The first is to seal the abdominal and pelvic cavities and endure the weight of the visceral organs. The second is to regulate the openings of the rectum and urogenital organs that penetrate the pelvic floor and make it more vulnerable. The pelvic floor consists of several connective tissues and overlapping muscles to manage both tasks. 

The pelvic diaphragm is constituted of the coccygeus muscle of the pelvic floor and the levator ani, which appears between the coccyx and the ischial spine and the symphysis and the anococcygeal ligament. It spreads between the anal hiatus and the tip of the coccyx, which leaves a gap for the urogenital openings and the anal. Hence a second closing means is needed because of the expanse of the genital gap, which is broader in females. 

The urogenital diaphragm constitutes a profound intersecting perineal, which originates from the lower ischial and pubic rami and stretches to the urogenital break. The urogenital diaphragm is strengthened posteriorly by the shallow intersecting perineal.

The anus and urethra are closed by the urethral sphincters and the external anal. In contrast, the urethra is encircled by the bulbospongiosus that envelops the corpus spongiosum in males and shrinks the vaginal introitus in females. And, the ischiocavernosus muscle, present right below the surface of the perineum, compresses blood into the clitoris and the corpus cavernosum penis.


Variation

Modernised humans are, to a great extent, identified by bipedal movement and healthy brains. Since the pelvis is essential to both childbirth and locomotion, two opposing demands have defied natural assortment: a broad birth canal and movement efficiency, an "obstetrical dilemma." The gynaecoid pelvis, better known as the female pelvis, has emerged to its greatest width for reproduction. In contrast, the male pelvis isn’t necessitated by the obligation to give birth and consequently are absolute for bipedal movement.


Differences Between Male and Female Pelvis

Male Pelvis

Female Pelvis

Smaller and leaner with thicker and heavier bones.

Bigger and broader with thinner, lighter, and denser bone.

Structures to assist a big body with robust muscle structure.

Structured to assist the objective of childbearing and easier delivery.

The greater (or false) pelvis is profound.

The greater (or false) pelvis is superficial.

The pubic arch is lean (v-shaped) and is less than 90 degrees.

The pubic arch is broader, more than 90 degrees. 

The acetabulum is bigger and faces sideways.

The acetabulum is tinier and faces towards the head.

The coccyx is inflexible and is swelled inwards

The coccyx is elastic and straighter.

The pelvic inlet is tinier and heart-shaped.

The pelvic inlet is big and oval.

The pelvic outlet is leaner.

The pelvic outlet is broader.

The greater sciatic point is leaner, and the obturator foramen is spherical.

The greater sciatic point is broader, and the obturator foramen is elliptical.

The sacrum is longer, leaner, and more scooped.

The sacrum is smaller, broader, and less scooped.


Did You Know?

  • Pelvis bone provides support to the spinal cord.

  • High-speed accidents or falls from great heights are the most common cause of pelvis fracture.

  • There are differences between the male and female pelvis. That female pelvis is bigger and broader than that of the male pelvis. 

  • The principal difference between male and female pelvis is the pelvis ligament, which is present in the female body and help in an easier birth process.

  • Severe injuries to the pelvic bone can be life-threatening.

  • During pregnancy, the body secretes hormones that soften pelvis ligaments for an easier birth.

  • There are four muscles of the pelvic floor, namely, pubococcygeus, coccygeus, iliococcygeus, and puborectalis muscles.

FAQs (Frequently Asked Questions)

Q1.What is the pelvis meaning? Name its components.

Ans: The pelvis meaning is a complex bowl-shaped bone that supports the spinal cord and protects parts of internal reproductive organs. 

There are three main components of the pelvis;

  • Sacrum

  • Hip Bones (coxal bone)

  • Tail bone

Q2.What is the primary function of the pelvis?

Ans: The primary functions of the pelvis are:

  • Locomotion, as body weights, transfers through the pelvic girdle to lower limbs.

  • Reproduction, as the human neonate is bound to pass through the birth canal.

  • Support abdominal organs held by the pelvis and the pelvic floor.

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