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ANATOMY - PELVIC WALLS AND FLOOR GENITALIAM AND FEMALE EXTERNAL Sa2023Amir.Your first Med school exam - don’t worry you have Allah to talk to with all your stresses !Intended learning outcomes ﻢ ﺣﺮﻟٱ ﻦٱ ﻢﺴﺑ • (bi-smi llāhi r-raḥmāni r-raḥīmi) In the name of Allah the most compassionate the most merciful. 1 2 3 Describe the Describe the Relate the anatomical anatomical changes in fundal arrangement of arrangement of height during the pelvic walls & the perineum and pregnancy to floor HIGH YIELD female external anatomical genitalia landmarksDESCRIBE THE ANATOMICAL ARRANGEMENT OF THE PELVIC WALLS & FLOORWhat is the function of the pelvic walls and floor? - Support your abdominal organs (abdominopelvic viscera) - through their contractions. This is why its important in pregnancy. - Resistance to increases in abdominal pressure – during lifting heavy objects or coughing - Urinary and faecal continence (control of movement) - Muscle fibres have a role in relaxing your rectal and urethral sphincters . Thus allowing urination and defecationAnatomy of the pelvic walls and floor internalORIGIN, INSERTION, INNERVATION AND ACTION Levator Ani- 3 paired muscles Puborectalis, pubococcygeus, iliococcygeus Coccygeus is not classed in levator ani group but makes up pelvic floor. CIPP = coccygeus, illiococcygeus, pubococcygeus, puborectalis BLOOD SUPPLY– inferior gluteal, inferior vesical and pudendal arteries ALL INNERVATED BY: Superior surface - nerve to levator ani (S3-4) Inferior surface - pudendal nerve (S2-4) Pudendal nerve - Mixed nerve originating from S2-S4 Sensory function: external genitalia, skin around anus, anal canal and perineum Motor function: pelvic muscles, external urethral sphincter and external anal sphincter Pathway: Originates from the sacral plexus passes through the greater sciatic foramen Hooks around ischial spine Enters perineum through lesser sciatic foramenLevator Ani - PUBORECTALIS– Mainting faecal incontinence Pubo – pubis Rectalis – rectum ORIGIN andINSERTION – Posterior surface of the pubis. Forms a U-shaped sling around the anal canal and inserts back into the posterior surface of the pubis. ACTION – Contraction causes anal canal to bend anteriorly. Thus creating an anorectal angle aiding faecal continence. This action can be voluntarily inhibited during defecation. INNERVATION – nerve tolevatorani andpudendal nerve BLOOD SUPPLY– inferior gluteal, inferior vesical and pudendal arteries PRE-RECTALISFIBRES Are fibres from your puborectalis muscles so also form a U-shaped sling around the urethra in both males and females. These fibres therefore play a role in urinary incontinence especially in sudden increases In pressure – sneezing, sudden laughter or coughing.PUBOCOCCYGEUS ■ PUBOCOCCYGEUS Pubo – Pubis Coccygeus - coccyx ORIGIN and INSERTION – Originates from the posterior surface of the pubis. The fibres then decussate (form an X) and insert into the coccyx. ACTION – It forms the bulk of your levator ani so is involved in stability and support of abdominal organs. INNERVATION – Nerve to levator Ani and Pudendal nerveILLIOCOCYGEUS ILLIOCOCCYGEUS Illio – illiacis (hip bone) Coccygeus - coccyx ORIGIN AND INSERTION– originates from ischial spine and inserts into your coccyx, perineal body and anococygeal ligament ACTION – elevates the pelvic floor and anorectal canal INNERVATION – nerve to levator ani and branches of the pudendal nerve BLOOD SUPPLY – inferior gluteal, inferior vesical and pudendal arteries Annococcygeal ligament/body/raphe - extends between the pelvis and sphincter is formed from the fibres of the levator ani and external analCOCCYGEUS Coccygeus Coccy – coccyx ORIGIN and INSERTION – Originates from ishial spines and inserts into the coccyx ACTION – supports abdominal organs (pelvic viscera) and flexes the coccyx INNERVATION – Anterior rami of S4 and S5 BLOOD SUPPLY – inferior visceral, inferior gluteal and pudendal arteries.Extra bits you need to know: Piriformis key landmark in the gluteal region ORIGIN - from the anterior surface of the sacrum. INSERTS - The fibres travel inferiorly and laterally through the greater sciatic foramen to insert onto the greater trochanter of the femur. Actions - Lateral rotation and abduction of hip Innervation: Nerve to piriformis. ObturatorInternus The obturator internus forms the lateral walls of the pelvic cavity. Origin-from the pubis and ischium at the obturator foramen. Inserts - It travels through the lesser sciatic foramen, and attaches to the greater trochanter of the femur. ■ Actions: Lateral rotation and abduction. ■ Innervation: Nerve to obturator internus.Post Fajr walkPERINEUMWhat is the perineum and its function? Anatomical definition: The perineum is the region between the pubic symphysis and the coccyx . The muscles within the perineum sit under the pelvic floor. It has a function of protecting and supporting your urogenital (uterus, vagina, rectum and bladder) and gastrointestinal systems . Therefore, it plays a role in micturition, defecation, sexual intercourse and childbirth Clinically: region between the external genitalia and anusBorders Anatomical borders Anteriorly – Pubic symphysis Anterolateral – inferior pubic rami and ischial rami Lateral – ischial tuberosity Posterolateral – sacrotuberous ligament Posterior – coccyx Surface border Anteriorly – mons pubis in females, base of penis in males Laterally – medial surface of thighs Posteriorly – intergluteal cleftAnal and Urogenital triangles The perineum is divided in half by the ischial tuberosities forming 2 triangles. Anteriorly is the urogenital triangle. Posteriorly is the anal triangle. The anal triangle in both males and females is the same. The urogenital triangle in males and females differ. Anal triangle contents Ischioanal fossa spaces lateral to the anus. This fossae contains fat and connective tissue for expansion of the anal canal during defecation. Anococcygeal ligament/body Pudendal nerve Internal pudendal artery and Internal pudendal vein Anal canal/aperture - opening of the anus Muscles – External anal sphincter – Gluteus maximus muscle – Levator ani muscle – Coccygeus muscleUrogenital triangle contents The contents of the male and female urogenital triangle differ. ■ Posterior scrotal nerves / Posterior labial nerves ■ Urethra ■ Vagina ■ Bulbourethral gland / Bartholin's gland ■ Muscles – Superficial transverse perineal muscle – Ischiocavernosus muscle – Bulbospongiosus muscle ■ Crus penis / Clitoral crura ■ Bulb of penis / vestibular bulb ■ Urogenital diaphragm ■ Muscular perineal body ■ Superficial and Deep perineal pouch ■ Blood vessels and lymphaticsMuscles origin and insertion Superficial transverse perineal muscle Origin – ischial tuberosity Inserts – perineal body Ischiocavernosus muscle Origin – ishial tiberosity Insert – ishial rami Bulbospongiosus muscle Origin - Male: Perineal body, median perineal raphe Female: Perineal body Insert - Male: Perineal membrane, dorsal aspect of corpus spongiosum and corpora cavernosa, fascia of bulb of penis Female: Pubic arch, fascia of corpora cavernosa and clitoris Urogenital triangle layers The urogenital triangle is much stronger in structure then the anal triangle due to its many layers. Superficial to deep: Skin– where the urethral and vaginal orifices open into Perinealfascia – continuation of abdominal fascia – Deep fascia: covers the superficial perineal muscles and protruding structures (penis and clitoris) – Superficial fascia ■ Superficial layer – campers fascia of anterior abdominal wall ■ Deep layer scarpas fascia of anterior abdominal wall Superficial perineal pouch – a potential space between the perineal membrane and superficial perineal fascia. It contains – Erectile tissues from the penis and clitoris – Ischiocavernosus, bulbospongiosus and superficial transverse perineal muscles. – Greater vestibular glands (Bartholion glands) **student read in own time unless have time to explain** Perinealmembrane – a layer of tough fascia, which is perforated by the urethra and https://www.youtube.com/watch? the vagina in the female. The role of the membrane is to provide attachment for the muscles of the external genitalia. v=FGwQv3Ru3AA Deep perinealpouch – a potential space between the deep fascia of the pelvic floor (superiorly) and the perineal membrane (inferiorly). It contains – urethra, external urethral sphincter, and the vagina in the female. – In males, it also contains the bulbourethral glands and the deep transverse perineal muscles.Extra bits to know about The Perineal Body The perineal body is an irregular fibromuscular mass. It is located at the junction of the urogenital and anal triangles – the central point of the perineum. This structure contains skeletal muscle, smooth muscle and collagenous and elastic fibres. It acts as a point of attachment for muscle fibres from the pelvic floor and the perineum itself: ■ Levator ani (part of the pelvic floor). ■ Bulbospongiosus muscle. ■ Superficial and deep transverse perineal muscles. ■ External anal sphincter muscle. ■ External urethral sphincter muscle fibres. In women, it acts as a tearresistant body between the vagina and the external anal sphincter, supporting the posterior part of the vaginal wall against prolapse. In the male, it lies between the bulb of penis and the anus. Common Q about its significance in child birth - It is the site of episiotomy Female External Genitalia Functions and important structures - Assists in micturition by directing the flow of urine - Protects the internal reproductive system from infection - A sensory tissue during sexual intercourse Clitoris – formed of erectile corpora cavernosa tissue that fills with blood during sexual stimulation (the same tissue and mechanism that occurs in males during an erection) Mons pubis – subcutaneous fat. In DR you'll notice it is the part that bears most of the pubic hair. Labia majora – external skin folds. Hair baring. Labia Minora – internal hairless skin folds. Anteriorly fused to form the clitoris. Posteriorly merge to form a fold of skin called the fourchette. Vestibule – enclosed by the labia minora. Contains vaginal and urethral openings. Bartholionglands/greatervestibularglands – secrete lubricating mucus from small ducts during sexual arousal. Skenes glands/lesservestibulargland – secrete a fluid during sexual arousal Pudendalcleft – the opening between the labia majora.Anatomical changes seen in pregnancy Fundal height – measurement from the top of the mother uterus to her pubic symphysis Gestational age Fundal height landmark 12-14 weeks Pubic symphysis 16 weeks Between umbilicus and pubic symphysis 20-22 weeks Umbilicus 36 weeks Xiphoid process of sternumExam style questions 1. What complications can occur if your pudendal nerve is damaged Sensory – innervates the external genitalia of both sexes and the skin around the anus, anal canal and perineum Motor– innervates various pelvic muscles, the external urethral sphincter and the external anal sphincter.LabelLabel ■ Anatomical borders ■ Anteriorly – Pubic symphysis ■ Anterolateral – inferior pubic rami and ischial rami ■ Lateral – ischial tuberosity ■ Posterolateral – sacrotuberous ligament ■ Posterior – coccyx ■ Surface border ■ Anteriorly – mons pubis in females, base of penis in males ■ Laterally – medial surface of thighs ■ Posteriorly – intergluteal cleftName the 3 muscles in the urogenital triangle ■ Muscles – Superficial transverse perineal muscle – Ischiocavernosus muscle – Bulbospongiosus muscle Name the 4 muscles in the anal triangle – External anal sphincter – Gluteus maximus muscle – Levator ani muscle – Coccygeus muscleName 3 male and 3 female contents of the urogential triangle The contents of the male and female urogenital triangle differ. ■ Posterior scrotal nerves / Posterior labial nerves ■ Urethra ■ Vagina ■ Bulbourethral gland / Bartholin's gland ■ Muscles – Superficial transverse perineal muscle – Ischiocavernosus muscle – Bulbospongiosus muscle ■ Crus penis / Clitoral crura ■ Bulb of penis / vestibular bulb Break!!! & Time For Any Questions!!!