Pelvis / perineum problem set Flashcards
____________ refers both to the area of the surface of the trunk between the thighs and the buttocks, extending from the coccyx to the pubis, and to the shallow compartment lying deep (superior) to this area but inferior to the pelvic diaphragm. Contains the anus and external genitalia.
perineum
list the functions of the pelvic girdle X7
1) ”bear the weight of the upper body when sitting and standing
2) transfer that weight from the axial to the lower appendicular skeleton for standing and walking and
3) provide attachment for the powerful muscles of locomotion and posture and those of the abdominal wall, withstanding the forces generated by their actions.
4) contain and protect the pelvic viscera (e.g. parts of the urinary reproductive and digestive systems),
5) provide support of the abdominopelvic viscera and gravid uterus,
6) provide attachment for the erectile bodies of the external genitalia, and
7) provide attachment for the muscles and membranes that assist the functions listed above by forming the pelvic floor and filling gaps that exist around it.”
identify the three bones that compose the adult pelvic girdle
Right and left Coxal bones (ilium, ischium and pubis)
and sacrum
What is formed by:
- promontory and ala of the sacrum (superior surface of its lateral part, adjacent to the body of the sacrum).
- a right and left linea terminalis (terminal line) together form a continuous oblique ridge consisting of the:
o arcuate line on the inner surface of the ilium.
o pecten pubis (pectineal line) and pubic crest, forming the superior border of the superior ramus and body of the pubis.
pelvic brim (also defines the pelvic inlet)
how do the subpubic angles and obturator foramen differ between males and female
subpubic angle in males is more narrow/ wide in females
obturator foramen in males is round and females is oval
What is bound by the following description
- pubic arch anteriorly.
- ischial tuberosities laterally.
- inferior margin of the sacrotuberous ligament (running between the coccyx and the ischial tuberosity) posterolaterally.
- tip of the coccyx posteriorly
pelvic outlet
what is defined by the following description
- superior to the pelvic inlet.
- bounded by the iliac alae posterolaterally and the anterosuperior aspect of the S1 vertebra posteriorly.
- occupied by abdominal viscera (e.g., the ileum and sigmoid colon).
greater pelvis
what is defined by the following description
- between the pelvic inlet and pelvic outlet.
- bounded by the pelvic surfaces of the hip bones, sacrum, and coccyx.
- that includes the true pelvic cavity and the deep parts of the perineum (perineal compartment), specifically the ischio-anal fossae.
- that is of major obstetrical and gynecological significance
.
lesser pelvis
what two types of joints are associated with the anterior and posterior sacroiliac joint
Anterior – synovial
Posterior – syndesmosis: immovable joined by fibrous connective tissue
what ligament transfers the weight of the upper body from the axial skeleton to the two ilia
interosseous sacroiliac ligament
what are the three ligaments that pull the ilia medially to compress the sacrum between them
- interosseous ligaments
- posterior sacro-iliac ligaments
- iliolumbar ligaments
what type of joint and what type of cartilage forms the pubic symphysis
secondary cartilaginous joint
fibrocartilage
contrast the terms spondylolysis and spondylolisthesis
Spondylolysis is a fracture of the pars interarticularis at L5 lumbar vertebra
Spondylolisthesis is bilateral fracture of the pars interarticularis and anterior displacement of the affected vertebra. of L5
- inverted napoleon hat
- grading scale 1-5
Remember the pars interarticularis is a region of the lamina that connect the facet joints
what three muscles compose the levator ani and help form the pelvic floor
levator ani muscles include
- pubococcygeus m.
- puborectalis m.
- iliococcygeus m.
what is another name for the pelvic floor
pelvic diaphragm
what other muscles help form the pelvic floor
coccygeus (ischiococcygeus) muscle
what muscle helps form the lateral pelvic wall
obturator internus muscle
what muscle helps form the posterior pelvic wall
piriformis muslce
what is the anterior gap between the medial borders of the levator ani muscles of each side that give passage to the urethra and in females the vagina
urogenital hiatus
The peritoneum passes over the fundus of the uterus and descends the entire posterior aspect of the uterus onto the posterior vaginal wall before reflecting superiorly onto the anterior wall of the inferior rectum (rectal ampulla).
The “pocket” thus formed between the uterus and the rectum is the _________________
rectouterine pouch
lateral extensions on each side of the rectum of the rectouterine pouch (“pocket”) are the ________________
pararectal fossa
what are the spinal root origins of the pudendal nerve
S2, S3, S4
2,3,4 keep your poop off the floor (innervated the anal and urethral sphincters)
what two foramen does the pudendal nerve pass through
greater sciatic foramen and lesser sciatic foramen
what is the sensory distribution of the pudendal nerve
sensory
- peri-anal skin
- skin of posterior scrotum/ labium majus
- skin of labium minus
- skin of penis/clitoris
what is the motor distribution of the pudendal nerve
another way asking same question: what are the muscles innervated by the motor component of the pudendal nerve
motor
- levator ani
- external anal sphincter
- external urethral sphincter
- superficial and deep transverse perineus muscle
- bulbospongiosus m
- ischiocavernosus m.
This is the location of neuron somas (cell bodies) that innervate the smooth muscle to cause contraction of the urinary bladder. ______
ganglia of the outer and submucosa of the urinary bladder (parasympathetic terminal ganglia)
This is the location of neuron somas (cell bodies) that innervate blood vessels in the wall of the urinary bladder ______
ganglia of the pelvic portion of the sympathetic ganglia of the pelvic plexus (collateral ganglia)
This is the location of neuron somas (cell bodies) that are activated by stretch of the urinary bladder detrusor muscle fibers._________
dorsal root ganglia of S2, S3, S4
This is the location of somas (cell bodies) that initiate and interrupt micturition._______
anterior gray column of the 2nd, 3rd, and 4th sacral segments of the spinal cord
what spinal roots form the pudendal nerve
S2-S4
What meets this description
Bordered by the: Pubic symphasis, ischiopubic rami, and line between the ischial tuberosity
urogenital triangle????????
What meets this description
Bordered by the: line between the ischial tuberosities, coccyx, bilateral lines between the coccyx and ischial tuberosities
the anal triangle ????????
what meets this description
Bordered by the: Midline raphe from the perineal body to coccyx and anococcygeal ligament, posterior border of the urogenital diaphragm, inferior border of gluteus maximus
perineum ????????
what meets this description
Bordered by the: pubic symphysis, inferior ischiopubic rami, bilateral lines from ishchial tuberosities to the coccyx and coccyx
??????/
what fascia fills the ischiorectal fossae
the adipose layer or camper’s fascial layer
in terms of muscle, what is the difference between the internal anal sphincter and external anal sphincter
Internal anal sphincter is smooth muscle and innervated by autonomic nervous system,
external anal sphincter is skeletal muscle and innervated by somatic nervous system – aka voluntary control- pudendal nerve innervates
name the three muscle of the superficial perineal compartment
- bulbospongiosus m.
- ischiocavernosus m.
- superficial transverse perineus m.
what are the sources of sensory innervation of the dartos muscle
sensory:
- genital branches of genitofemoral n
- ilioinguinal n
- perineal branch of posterior femoral cutaneous n
- posterior scortal branch of pudendal n
what are the sources of motor innervation of the dartos muscle
postganglionic sympathetic nerve fibers of genital branch of genitofemoral n
and
posterior scrotal n
with what fascia is the external perineal fascia continous
Buck’s fascia of penis and muscular fascia of external oblique m.
to what structures is colle’s fascia attached
ischiopubic rami to the external perineal fascia of the posterior border of the urogenital triangle to the perineal membrane to the deep transversus perineal muscle
list the osseofascial boundaries of the superficial perineal compartment
Ischiopubic rami to the external perineal fascia, and perineal membrane.
what portion of the male urethra is most prone to traumatic injury
membranous urethra
what route is taken by blood and urine which escapes in an injury to the male urethra (membranous urethra injury)
Extravasating blood and urine escape into the superficial perineal cleft, then pass into the scrotum deep to the dartos muscle and into the penis superficial to Buck’s fascia. Also the anterior abdominal wall deep to Scarpa’s fascia.
what is the embryological origin of the regions superior and inferior to the pectinate line
superior to pectinate line: hindgut (endoderm derived)
inferior to pectinate line: proctoderm (ectoderm derived)
what is the histological difference in terms of epithelial tissue type of the regions superior and inferior to pectinate line
superior: simple columnar epithelium (non keratinized)
inferior: keratinized stratified squamous epithelium
what is the white line and the type of epithelial tissue superior and inferior to the white line
Ancutaneous line (white line) separates non keratinized superior from keratinized (inferior) epithelium
what is the arterial and venous blood supply to the regions superior and inferior to the pectinate line
blood supply to the inferior
- inferior rectal artery and vein
- sometimes a middle rectal vessel anastomoses with superior and inferior vessels
superior blood supply:
- superior rectal artery and vein
what is the type of innervation to the regions superior and inferior to the pectinate line
innervation superior to the pectinate line = parasympathetic (S2-4) and sympathetic (T12-L2)
innervation to the inferior portion= somatic
(S2-4 via pudendal nerve-> inferior rectal nerve)
describe in further the innervation to the superior portion of pectinate line
PARASYMPATHETIC
- preganglionic nerve fibers originate in S2-4
and synapse with post ganglionic nerve fibers in the rectal (pelvic) ganglia
- post ganglionic nerve fibers innervate the INTERNAL ANAL SPHINCTER
SYMPATHETIC
- preganglionic nerve fibers originate in T12- L2
and pass through sympathetic chain ganglia to synapse with postganglionic neurons in the prevertebral ganglia
- post ganglionic nerve fibres travel via superior rectal nerves or abdominal peri-aortic plexus-> superior hypogastric plexus-> inferior hypogastric plexus to innervate the INTERNAL ANAL SPHINCTER
describe the inferior pectinate line innervation
somatic innervation
- efferent (motor) fibers originate S2-4 regions and travel via pudendal nerve -> inferior rectal nerve to external anal sphincter
- afferent (sensory) fibers travel from region below the pectinate line to S2-4 region via inferior rectal nerve-> pudendal nerve
aka S2-4 ->pudendal nerve-> inferior rectal nerve
compare internal and external hemorrhoids
External:
- hard, subcutaneous
- dark due to thrombosis in EXTERNAL VENOUS PLEXUS
- bout of burning pain/pruritis in anal region
- INFERIOR TO PECTINATE LINE (SOMATIC PAIN)
internal
- moist/dark
- prolapsed veins of the internal venous plexus!!!!
- blood/mucus in stool
- typically painless due to visceral innervation !!!!!!!!!!
