Pelvis and Perineum Anatomy

• The study notes below are a summary of the provided document.

Introduction

• This document is a study guide for the pelvis and perineum covering anatomy, structure, function, and clinical significance.

Skeletal Components of the Pelvis

• The pelvis connects the spine to the lower limbs acting as attachments for muscles and ligaments for locomotion.
• It is comprised of Hip Bone (os coxae or innominate bones), ilium, ischium, pubis, sacrum, and the coccyx.
• Hip bones are formed by the fusion of the ilium, ischium, and pubis during development.
• The iliac crest, a key landmark, includes the anterior superior iliac spine for muscle attachment and clinical assessments.
• The ischial tuberosity bears the body's weight when sitting and is a site for hamstring muscles to join.
• The two pubic bones meet at the inter cartilageinous pubic symphysis, it allows slight movement and it reinforced by ligaments.
• The sacrum is a triangular bone at the spine base, formed by five fused sections and it connects to hip bones via sacroiliac joints for weight equilibrium.
• The coccyx, or tailbone, has four fused vertebrae, and functions as muscle and ligament attachments of the pelvic floor.
• These bones makeup the pelvic girdle and work by supporting the body, protect pelvic structures, and promote movement.

Ligamentous Components of the Pelvis

• Ligaments are key stabilisers of the pelvis, promoting joint support and bone connection.
• Sacroiliac Ligaments stabilise the sacroiliac joints joining sacrum and ilium.
• The anterior Sacroiliac ligament assists in the front section of the sacroiliac joint.
• The posterior Sacroiliac ligament reinforces the rear of the joint.
• The interosseous Sacroiliac ligament is contained deep in with the joint, it is the most supportive ligament in that zone.
• The sacrospinous ligament extends out from the sacrum to ischial spine, it transforms major sciatic indentation to the greater sciatic opening, this is a passway for nerves and blood vessels.
• The sacrotuberous ligament stretches out from the sacrum to the ischial tuberosity, it helps to form the lesser sciatic foramen, it controls sacral revolution and reinforces the pelvis.
• The lumbar (L5) vertebrae is secured to the iliac crest, reinforcing the spinal linkage with the hips.
• Pubic Symphysis- the fibrocartilaginous joint located between the pubic bones is reinforced by public ligaments.
• The superior Pubic ligament strengthens the highest area of the pubic symphysis.
• The inferior Pubic ligament offers assistance across the lower borderline of the pubic symphysis.

Pelvic Inlet

• The pelvic inlet marks the border across greater with the abdominal viscera and lesser with the pelvic organs.
• Anterior border is the pubic crest.
• Lateral boundary by the pectineal line and also the arcuate line of the ilium.
• Posterior is the sacral point.

Pelvic Outlet

• The pelvic outlet makes up the inferior opening across the smallerpelvic area.
• It offers pathways, these include the rectum, vaginal passage , in females only, and channels in the urinary tract and it is involved in maintaining the body core and during delivery.
• The pelvis forms a diamond shape controlled via the placement of bones and ligamnets.
• Females have a broader pelvis ideal for baby delivery.
• Males posses a narrower shape with a narrower outlet.

Clinical Significance of Pelvis

• Abnormal or contracted pelvis is identified during pre natal examinations for birthing guidance.
• Fractures to the pelvis from trauma can cause damage to organs, blood vessels and nerves.
• Injuries to the public ligaments causes pelvic organ prolapse, along with urinary and bowel related complications.
• The spinal Ilia articulation bears loads and provides weight shifting from the axial spine along the lower body.
• Sciatica from sacral pressure along the sacrotuberous spine may cause pressure on nerves or vessels.
• Forcep or cesarean intervention may be required when delivery obstructions occur in vaginal births.

Mechanical Differences Between Male and Female Pelvis

• Male : Narrower broader bone heavier built skeleton.
• Male has a heart shaped pelvic inlet.
• Female: Wider rounder lighter bone structure.
• Female has a oval inlet shape. wider arch of the pubis .
• Female has a flexible coccyx.
• Wider greater sciatic alignment.

Female During Pregnancy

• Relaxin hormone loosens joints and allows flexibilities, most notably the public symphysis for child birth passage.
• Lumbar curve is increased to balance loads.
• The sacrum back tilts open up the pathway for passage.
• Fetal load places increased load on supportive muscles.

Lumbosacral Joint

• The articulation between the lumbar spine and first sacral vertebrae.
• Includes both cartilage and moving components for mobility and stability as well as weight stabilisation.
• Key point is the intervertebral disc is between each vertebrea.
• Key supports are the annulus, a Fibrosus, and shock distributing properties from nucleus pulposus.
• Synovial gliding actions come from the zygapophoseal alignment.
• Articular cartilage aids with smooth gliding motions.
• Illiolumbar ligaments give support from excessive movement potential.
• Some movements: bending, rotating and tilting.
• Transfer upper weight from lumbar down too sacrum, to the pelvis, down to femur bones.
• Shock reduction from activity.
• The L5 and S1 are reinforces by the ligaments disc and gliding facet joints in the spine, allowing safe controlled loading.

Sarcoiliac Joint

• Uniquely has both cartilaginous joint and moving sections: The sacroiliac joint joins the sacrum with the ilium bone providing rotation and stabilization.
• Synovial fluid filled with cartilage pads.
• Fibrous support by interlocking articulations with a multitude of ligaments.
• It is an important joint transferring the spines weight to the hips.
• Mobility is limited, but required rotation between parts .
• Some shock capacity during loading .
• Aids to manage centre position.

Pubic Symphysis

• Has a fibro cartilage structure allowing flexibility and movement and pelvic stability.
• Made up of secondary cartilaginous joint.
• The parts are linked with sections of fibrocartage, a wedge-shaped shock pad.
• Boney articulations connect surfaces with a thin lining of hyaline-cartilage with fibers connecting.
• There are superior and inferior ligament parts with a degree of movement allowance, approximately one to two mm.
• Nerves are proprioreceptors for sensing the body's self position, these include inguinal and pudendal locations.
• Is a shock absorbent buffer.
• Some shifts for movement, small though they maybe.
• Expands during pregnancy allowing the joints some give with relaxin hormones.

Openings

• Allow pathways into the perineum and allow nerves and arteries an free flow .
• Pelvic inlet is with the abdominals.
• Vessels are of the abdominal aorta origin.
• Ureters and muscles have passage throughout .
• Pelvic outlets allow the pudendal vasculature out, also muscles from membrane wall.
• Greater sciatic allows many major structures through.
• Lesser sciatic for pudendal.

Anatomical Walls of the Pelvic Cavity

• Shaped like a funnel inside the pelvic are, containing connective and other soft tissues.
• The anterior wall is for the public bone articulations, connecting components of the public symphysis.
• Back walls are for protection, and load transmission through the lower segment..
• The sides have bones like hips ischium sections connected with obturator sections, these reinforce core stability .
• Inferior wall is lined with tissue membranes.
• A strong base floor must support with muscles.

Pelvic Diaphragm

• Made of filament and ligaments to support the core anatomy of the pelvis.
• The parts of the Levariani control the anus passage.
• The posterior diaphragm aids with core stability and pelvic positioning.
• Sex specific parts are controlled by muscle tissues, and anal, vagina control mechanisms.

Pelvic Ligaments

• Sacrospinous: runs Sacrum to coccyx bone to ischial locations
• Sacrotuberous: runs sacrum ischial tuberosities.
• Illiolumbar : L5 linkage and iliac sections and some nerve branching.
• Anterior helps stabilises of a joint alignment.
• The uterosacral sections assists females.
• Critical for support, sacral integrity and organ management.

Peritoneal Pouches

• The abdomen cavities are of spaces in between parts and anatomical arrangements.
• Pockets are created from reflections of a membrane covering abdominals regions.
• They are often of clinical significance, resulting in build up, fluids in those zones .
• Sex specifics make some areas exclusive.
• Pouch is deep between the female anatomy
• Anterior vagina regions and the uterus.
• The rear section, douglas section, that has a fold running though .
• It is typical for fluids in female to be there as its low and more common for fluid build up.
• Infection and endometriosis may result.
• needle implementation is easy through this.

Pelvic Viscera

• Include organs for digestive, reproductive and urinary.
• Sagittal planes is as viewed from sides.
• Bladder to recum in male
• Bladder the uterus then out to rectum..
• frontal displays the bladder.
• Prostate seminal then deferens
• Female has uterus with vagina.
• Transversley viewing is for the body regions and the bladder.
• uterus, vagina then the vaginal canal.

Perineum

• Regions under the core diaphragm, this includes.
• bladder is in smaller area
• The urinary passages in men is in prostate with a deep.
• Penile positions.
• Females are shorter passages , directly in membrane openings and vagina.
• Lower region digestive section transition to the anal passage with internal components.
• The male system have testes, and cord parts, to vasculature cords.
• Both seminal vesical, and prostates.
• Females have an expansion going out of of the cervix to passageway to the vagina outer regions.
• A series of passages for menstruation and child brith are in sequence .
• The lower regions include vaginal exterior openings, these are attached with to the core passages of reproduction.

The Iliac Artery

• Vessels to parts in core. It runs to areas like pelvic , gluteal and more lower extremity.
• Origins are at key connection at L5/ s1 where common artery separates into the iliac parts.
• The arterial supplies the bladder, vaginally region for females too,.
• and rectum, , prostate ..
• Nerves in lower sections.
• Thigh is at gluteals sections.

Pelvis and Perineum Venous

• The pelvic area vessels have a interconnected network that transports blood cells to the core organ systems and support areas .

Pelvis Lymphatics

• Vessels for immune purpose within the pelvic cavity.
• Nodes connect to internal and external regions.
• Key nodes connect to iliac channels.
• Pathways connect both pelvic and abdominal vasculature tracts.
• Perineum has its own unique superficial and deep connection for filtration purposes.

Sacral

• Nerve alignment that provides motor and sensory to the pelvis , perineum gluteaus , leg and foot area .
• L4 and L5 provide rami that intersect vertebral bodies.
• This allows connection within piriformis muscle and vertebral cavities.
• This supply's the glutes, outer skin, back of leg ,and lower area .
• Sciatica as its called.
• Provides innervation to the external genitalia region and helps with core support regions.
• Motor parts control the outer most regions of the anus and helps posture .
• Pelvic helps regulate bladder or digestion.