3.4.1. ANATOMY LAB Pelvis Wall and Vessels Flashcards
Function of the SI joint
The sacroiliac joint or SI In humans, the sacrum supports the spine and is supported in turn by an ilium on each side. The joint is a strong, weight bearing synovial joint with irregular elevations and depressions that produce interlocking of the two bones
What is the SI joint
joint (SIJ) is the joint in the bony pelvis between the sacrum and the ilium of the pelvis, which are joined by strong ligaments.
Function of the Symphysis Pubis
The main motions of the symphysis pubis are superior/inferior glide and separation/compression. The functions of the joint are to absorb shock during walking and allow delivery of a baby.
The sacrotuberous ligament contains what?
The sacrotuberous ligament contains the coccygeal branch of the inferior gluteal artery.
Main function of the sacrospinous ligament
Sacrospinous ligament - Its main function is to prevent posterior rotation of the ilium with respect to the sacrum.
Stress to the sacrospinous ligament causes what?
Laxity of this ligament along with the sacrotuberous ligament allows for this posterior rotation to occur. Stresses to these ligaments occur most often when leaning forward or getting out of a chair
Discuss etiology and treatment for an entrapped pudendal nerve at the sacrospinous and sacrotuberous ligaments
If the pudendal nerve becomes entrapped between sacrotuberous ligament and the sacrospinous ligament causing perineal pain, the sacrotuberous ligament is surgically severed to relieve the pain.
What is the pelvic inlet?
The pelvic inlet or superior aperture of the pelvis is a planar surface which defines the boundary between the pelvic cavity and the abdominal cavity
What is the pelvic outlet
The pelvic outlet: A diamond-shaped area, best appreciated when viewed from below. The boundaries of the pelvic outlet are: the pubic symphysis, right and left rami of the pubic arch, the ischial tuberosities, the sacrotuberous ligaments, and the tip of the coccyx.
What is a gynecoid pelvis? Discuss what makes it unique
Gynecoid pelvis - a type of pelvis characteristic of the normal female and associated with the smallest incidence of fetopelvic disproportion. It is the ideal pelvic type for childbirth
- the inlet is nearly round
- the sacrum is parallel to the posterior aspect of the symphysis pubis
- the sidewalls are straight
- the ischial spines are blunt and do not encroach on the space in the true pelvis.
What is an android pelvis?
Android pelvis - The android or male pelvis is more robust, narrower, and taller than the female pelvis. The angle of the male pubic arch and the sacrum are narrower as well.
What is the interspinous distance?
26 cm in females between the anterior superior iliac spines
10 - 11 cm betwee nthe ischial tuberosities
Discuss pelvic fracture
The pelvis can be like a brittle ring – difficult to break in just one place - and thus, pelvic fractures often come in pairs: When you see a pelvic fracture, always look for the other fracture
Innervation by the Obturator nerve
The Obturator nerve is responsible for the sensory innervation of
- the skin of the medial aspect of the thigh.
It is also responsible for the motor innervation of the
- adductor muscles of the lower extremity(external obturator.,adductor longus, adductor brevis, adductor magnus,gracilis)
- the pectineus
Innervation by the sciatic nerve
Lateral rotator group except the piriformis and quadratus femoris and the posterior compartment of the thigh
Innervation by the Pudendal Nerve?
Pudendal - The pudendal nerve is a somatic nerve in the pelvic region which is a large branch of the sacral plexus (L4-5, S1-4) that innervates the external genitalia of both sexes, as well as sphincters for the bladder and the rectum
Innervation by the Superior Gluteal nerve
Superior Gluteal - The superior gluteal nerve is a nerve that originates in the pelvis and supplies the gluteus medius, the gluteus minimus, and the tensor fasciae latae muscles.
Innervation by the Inferior gluteal nerve
Inferior gluteal - The inferior gluteal nerve is the main motor neuron that innervates the gluteus maximus muscle.
Discuss the levator ani nerves
Levator ani nerves - The levator ani forms the main part of the pelvic diaphragm, the cranial layer of the pelvic floor. It is primarily supplied by direct branches of the sacral plexus (S3-S5). To a small degree the pudendal nerve contributes to its innervation as well.
Discuss the internal iliac artery and what precedes it
Arteries of the pelvis branch from the common iliac arteries, the terminal branches of the aorta. The common iliac divides into the external and internal iliac aa. While both of these arteries traverse the pelvis, we will concentrate on the internal iliac a. since it provides many branches inside the pelvis.
What is the urogenital triangle?
The urogenital triangle is the area bound by a triangle with one vertex at the pubic symphysis and the two other vertices at the [ischial tuberosities] of the pelvic bone.
Vertices of the anal triangle
Vertices of the anal triangle: one vertex at the coccyx bone and the other two at the two ischial tuberosities of the pelvic bone
What makes up the pelvic diaphragm?
The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus muscle, and associated connective tissue which span the area underneath the pelvis.
3 functions of the pelvic diaphragm?
- It is important in providing support for pelvic viscera (organs), e.g. the bladder, intestines, the uterus (in females), and in maintenance of continence as part of the urinary and anal sphincters. 2. It facilitates birth by resisting the descent of the presenting part, causing the fetus to rotate forwards to navigate through the pelvic girdle. 3. It helps maintain optimal intra-abdominal pressure
What is the urogenital diaphragm?
layer of the pelvis that separates the deep perineal sac from the upper pelvis, lying between the inferior fascia of the urogenital diaphragm (perineal membrane) and superior fascia of the urogenital diaphragm
Discuss the UG Hiatus
the gap between the anteromedial borders of the pelvic diaphragm (pubococcygeus muscle) through which the male urethra or female urethra and vagina and the (deep) dorsal vein of the penis or clitoris pass; outside of these traversing structures, the urogenital hiatus is closed by the perineal membrane.
O/I, Innervation and Action for the Obturator Internus
Origin - Ischiopubic ramus and obturator membrane Insertion - Medial aspect of the greater trochanter Nerve - Nerve to obturator internus Action - Abducts and laterally rotates the extended hip and abducts the flexed thigh at the hip and stabilizes the hip during walking
Piriformis O/I Action Innervation
Origin - Sacrum Insert - Greater Trochanter Nerve - Nerve to the piriformis (L5, S1, and S2) Action - External rotator of the thigh
Coccygeus Origin/Insertion, Action, Innervation
Origin - Sacrospinous ligament and ischial spine Insert - Lateral margin of coccyx and related border of sacrum Nerve - sacral nerves: S4, S5, or S3 - S4 Action - Pull coccyx forward after defecation, closing in the back part of the outlet of the pelvis
3 parts of the levator ani group
- pubococcygeus 2. iliococcygeus 3. puborectalis
O/I for Pubococcygeus
Origin - back of the pubis and from the anterior part of the obturator fascia Insert - Coccyx and sacrum
O/I for iliococcygeus
Origin - Ischial spine and from the posterior part of the tendinous arch of the obturator fascia Insert - coccyx and anococcygeal raphe
O/I for puborectalis
Origin - Lower part of the pubic symphysis, superior fascia of the urogenital diaphragm Insert - Midline sling posterior to rectum
Which of the levator ani inhibits defecation?
puborectalis
Which of the levator ani controls urine flow?
pubococcygeus
Which if the levator ani contracts during orgasm?
pubococcygeus
Innervation for the levator ani
Nerve - Levator ani nerve, inferior rectal nerve and the coccygeal plexus
What is the tendinous arch of the levator ani
a thickened portion of the obturator fascia on themedial aspect of the obturator internus (muscle) that extends in an arching line from the pubis posteriorly to the ischial spine and gives origin to part of the levator ani muscle
What is the gut and how is pain related to it?
The gut is a midline structure innervated by autonomics arising from both the left and right sides. Thus, pain from the intestines will often initially be referred to the midline of the abdomen – in the epigastric, periumbilical, or pubic area – depending on if the etiology (origin of the pathology) is derived from the foregut, midgut, or hindgut.
When does pain in the gut change?
until the irritant contacts the parietal peritoneum of the body wall (e.g., the internal lining of the peritoneal cavity), it is perceived as a deep, dull, ache that cannot be well localized. When it does contact the peritoneum of the body wall, the pain then can be localized by the patient to that specific area.
Discuss pain from the kidney
Pain from a kidney, on the other hand, will often be referred to the side and upper back. Sensory afferents also travel up the vagus nerve and can be involved in reflex arcs, such as those causing vomiting. Pain fibers travel with the sympathetics.
Discuss the sacral plexus
L4 & L5 Lumbosacral trunk L4, L5, S1, S2, & S3 Sciatic nerve S2, S3, S4 Pudendal nerve
Where does parasympathetic innervation rise in the sacral plexus?
Arising from S2, S3, S4
Draw out the branches of the internal iliac artery?
What is the distinction between the greater and lesser pelvis?
