Anatomy Flashcards
What is in the pelvic viscera?
- bladder
- rectum
- pelvic genital organs
- terminal part of the urethra
What muscles form the lateral wall of the pelvic cavity?
Obturator internus
Piriformis
Another name for pelvic floor
Pelvic diaphragm
What are the 2 holes in the pelvic floor?
- Urogenital hiatus – an anteriorly situated gap, which allows passage of the urethra (and the vagina in females).
- Rectal hiatus – a centrally positioned gap, which allows passage of the anal canal.
What are the roles of the pelvic floor?
- Support of abdominopelvic viscera (bladder, intestines, uterus etc.) through their tonic contraction.
- Resistance to increases in intra-pelvic/abdominal pressure during activities such as coughing or lifting heavy objects.
- Urinary and fecal continence.The muscle fibers have a sphincter action on the rectum and urethra. They relax to allow urination and defecation.
What are the 3 main components of the pelvic floor?
- Levator ani muscles (largest component).
- Coccygeus muscle.
- Fascia coverings of the muscles.
Which nerve and branches innervate the levator ani muscle?
Branches of the pudendal nerve S2,3,4
Which muscles make up the levator ani?
3 pairs:
- pubococcygeus
- puborectalis
- iliococcygeus
Where do the levator ani muscles attach?
- Anterior – pubic bodies of the hip bone.
- Laterally – thickened fascia of the obturator internus muscle, known as the tendinous arch.
- Posteriorly – ischial spines of the hip bone.
What is the puborectalis?
Where does it attach?
What is its path?
What is the function?
The puborectalis muscle is a U-shaped sling, extending from the bodies of the pubic bones, past the urogenital hiatus, around the anal canal. Its tonic contraction bends the canal anteriorly, creating the anorectal angle (90 degrees) at the anorectal junction (where the rectum meets the anus).
The main function of this thick muscle is to maintain faecal continence – during defecation this muscle relaxes.
What is the puborectalis muscle?
What do they do?
Some fibers of the puborectalis muscle (pre-rectal fibers) form another U-shaped sling that flank the urethra in the male and the urethra and vagina in the female (in some textbooks they appear as pubovaginalis or sphincter urethrae / vaginae). These fibers are very important in preserving urinary continence, especially during abrupt increase of the intra-abdominal pressure i.e. during sneezing.
What is the pubococcygeus?
Where does it arise and insert?
The muscle fibres of the pubococcygeus are the main constituent of the levator ani. They arise from the body of the pubic bone and the anterior aspect of the tendinous arch. The fibres travel around the margin of the urogenital hiatus and run posteriomedially,attaching at the coccyx and anococcygeal ligament.
What is the iliococcygeus?
What is the function?
The iliococcygeus has thin muscle fibres, which start anteriorly at the ischial spines and posterior aspect of the tendinous arch. They attach posteriorly to the coccyx and the anococcygeal ligament.
This part of the levator ani is the actual “levator” of the three: its action elevates the pelvic floor and the anorectal canal.
Which nerves innervate the coccygeus?
Anterior ramus of S4 and S5
Other name for coccygeus?
Ischiococcygeus
