Bony Pelvis and pelvic Wall

Question 1

what are the components of the pelvic girdle?

Answer 1

• Sacrum
• Coccyx
• Right and left Os Coxae (hip bones)

Question 2

what is the Os Coxae? and how does it articulate with other bones

Answer 2

The hip bones:

• compose of ilium, ischium, and pubis
• articulate anteriorly with eath other at the pubic symphysis
• articulate posteriorly with the sacrum (S1-S3) at the sacroiliac joints

the hip bone will fuse together after birth at the acetabulum

Question 3

Characteristics of the sacrum and coccyx

Answer 3

Sacrum consists of 5 vertebrae that fuse together by the age of 25

Coccyx consists of 3-5 vertebrae

Sacrococcygeal symphysis includes a fibrocartilaginous disc
-occurs at the sacrococcygeal joint

Question 4

Bony features of the Pelvic girdle

Answer 4

1) in infants and children each hip bone consists of three seperate bones united by a tri-radiate cartilage at the acetabulum, a cup like depression in the lateral surface of the hip bone articulates with the head of the femur
- after puberty the three bones fuse together

2) the concavity between the ischial spine and the ischial tuberosity is the lesser sciatic notch
3) the larger concavity, the greater sciatic notch is superior to the ischial spine and is formed in part by the ileum
4) THe pubis is an angulated bone with a superior ramus which helps form the acetabulum, and an inferior ramus, this contributes to the bony borders of the obturator foramen
5) the pubic arch is formed by the right and left ischiopubic rami, which meet at the pubic symphysis

Question 5

what are the two divisions of the pelvic region

Answer 5

Pelvis major (false pelvis) located above the pelvic brim

Pelvis minor (true pelvis) located inferior to pelvic brim

Question 6

what makes up the pelvic brim?

Answer 6

also known as the pelvic inlet and makes the lineal terminalis:

• pubic crest
• pecten pubis
• arcuate line
• margin of ala
• promontory

Question 7

what are the boundaries of the pelvis minor?

Answer 7

sacrum
coccyx
inner surface of the ischium and pubis
small part of the ilium

Question 8

what makes up the lumbosacral joint?

Answer 8

• Intervertebral disc between L5 vertebrae and the sacrum, plus the two zygapophysial joints between the articular processes of L5 and S1
• iliolumbar lumbar ligament stabilizes the L5 vertebra on the sacrum by anchoring its transverse processes to iliac crest thus limiting the motion of L5 vertebrae

Question 9

what makes up the sacrococcygeal joint?

Answer 9

• occurs between S5 vertebra and the coccyx, this atypical intervertebral joint contains an intervertebral disc
• allows for posterior movement of the coccyx during defecation or childbirth

-Anterior and posterior sacroccygeal ligaments help stabilize this articulation

Question 10

what are the characteristics of the pubic symphysis

Answer 10

located along the anterior midline between the two ox coxae

the pubic bones are united by a fibrocartilaginous disc and neumerous ligamentous fibers including a strong arcuate (inferior pubic) ligament and a superior pubic ligament

the subpubic angle is less in males and greater in females
-in females the distance between the ischial tuberosities is greater than in males to provide additional space necessary for childbirth

Question 11

Characteristics of the sacroiliac joint

Answer 11

Is a synovial joint between the lateral surface of the sacrum (S1-S3) vertebrae) and the internal surface of the ilum, posterior to the iliac fossa

several ligaments stabilize the joint

• interosseous sacroiliac
• posterior sacroiliac
• iliolumbar
• sacrotuberous
• sacrospinous

Question 12

what is the orientation of the pelvic girdle when an individual is in the anatomical position:

Answer 12

right and left anterior superior iliac spines and the anterior aspect of the pubic symphysis line in the same vertical plane

Question 13

What are the components of the walls and floor of the pelvic cavity

Answer 13

the pelvic cavity has an antero-inferior wall, two lateral walls, a posterior wall, and a floor

Question 14

what makes up the antero-inferior wall of the pelvic cavity?

Answer 14

Formed by the bodies and rami of the pubic bones and the pubic symphysis

it bears the weight of the urinary bladder

Question 15

what makes up the lateral walls of the pelvic cavity

Answer 15

formed by the two hip bones

• each of which contain the obturator foramen closed by the obturator membrane
• obturator internus muscles cover the lateral pelvic walls and their tendons pass through the lesser sciatic foramena to attach to the greater trochanter
• medial surface of the obturator muscles are covered by obturator fascia which is thickened centrally as a tendinous arch that provides attachment for the pelvic diaphragm

Question 16

what makes up the posterior wall of the pelvic cavity

Answer 16

Consists of a bony wall and roof in the midline formed by the sacrum and coccys

the posterolateral walls are formed by the ligaments associated with the sacroiliac joints and piriformis muscles

Question 17

What makes up the pelvic floor of the pelvic cavity

Answer 17

The pelvic floor is formed by the pelvic diaphragm which includs the coccygeus and levator ani muscles and their fascias

the pelvic diaphragm seperates the true pelvis from the region known as the perineum which contains the anal canal and the external genitalia

Question 18

Priformis: orgin, insertion, pathway, action, and innervation

Answer 18

Orgin: lateral masses of S2-S4 vertebrae and the sacrotuberous ligament

INsertion: greater trochanter of the femur

exits the pelvis via the greater sciatic foramen

Action: lateral rotator of thigh

INnervation: nerve to piriformis (S1-S2)

Question 19

Obturator internus: origin, insertion, pathway, action, and innervation

Answer 19

Origin: anterolateral wall of the pelvis minor and obturator membrane

insertion: greater trochanter

exits the pelvis via the lesser sciatic foramen

action: lateral rotator of the thigh
innervation: nerve to the obturator internus (L5-S1)

Question 20

what muscles make up the pelvic floor? and what does this muscle separate and what is its innervation?

Answer 20

the pelvic floor is formed by the diaphram which is composed of:
Levator ani
-puberorectalis
-pubococcygeus
-iliococcygeis
INNervation: superior surface is the S3-S4
inferior rectal nerve on the inferior surface
Actions: support pelvic viscera, resists inferior thrust, raises pelvic flood to increase pressure

Coccygeus (ishiococcygeus)

• INN: S4-S5
• helps pull the coccyx forward

the pelvic diaphragm seperates the true pelvis from the perineum

Question 21

what are the three layers of the Pelvic fascia?

Answer 21

1) diaphragmatic fascia
2) Visceral facscia
- first two are anchored to the pelvic brim

3) Parietal fascia (continuous with the abdominal fascia

Question 22

What are the three types of Urinary incontinence:

Answer 22

Overflow

• urethral blockage
• bladder unable to empty properly

Stress:

• relaxed pelvic floor
• increased abdominal pressure

Urge:

• Bladder over sensitivity form infection
• Neurologic disorder

Question 23

what muscle can tear during childbirth

Answer 23

the Pubococcygeus the puborectalis muscles

-these support the urethra and anal canal