Anatomy I: Pelvis

Question 1

Greater (“[]”) pelvis vs lesser (“[]”) pelvis]

Greater pelvis contains []

Lesser pelvis is []

Answer 1

Greater (“false”) pelvis vs lesser (“true”) pelvis Greater pelvis contains inferior abdominal viscera – above the pelvic brim

Lesser pelvis is completely enclosed in the pelvic girdle

Question 2

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Question 3

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Question 4

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Question 5

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Question 6

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Question 7

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Question 8

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Question 9

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Question 10

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Question 11

The acetabulum is about [] ilium, [] ischium and [] pubis.

Answer 11

The acetabulum is about two-fifths ilium, two-fifths ischium and one-fifth pubis.

Question 12

The obturator foramen is surrounded by [] and [].

Answer 12

The obturator foramen is surrounded by pubis and ischium.

Question 13

The greater sciatic notch is a notch in the posterior borders of both the [] and the [].

Answer 13

The greater sciatic notch is a notch in the posterior borders of both the ilium and the ischium.

Question 14

The pelvic brim (inlet) is the upper edge of the skeletal wall of the pelvic cavity.

1. []
2. []
3. []

Answer 14

The pelvic brim (inlet) is the upper edge of the skeletal wall of the pelvic cavity.

1. the pubic portion: the pubic crest and the pecten of the pubis
2. the iliac portion: the arcuate line of the ilium
3. the sacral portion: the sacral promontory, which is the upper edge of the body of the first sacral vertebra, and the parts of the upper edge of the sacrum that are lateral to the sacral promontory at each side.

Question 15

The pubic arch is formed by the []. The pubic arch is generally much [] in females than in males.

Answer 15

The pubic arch is formed by the ischiopubic rami. The pubic arch is generally much wider in females than in males.

Question 16

The sacroiliac joints are very stable [] between the ala of the ilium and the sacrum.

Answer 16

The sacroiliac joints are very stable synovial joints between the ala of the ilium and the sacrum.

The auricular (ear-shaped) surface on the ala of the ilium is the iliac portion of the sacroiliac joint.

Question 17

Answer 17

Question 18

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Question 19

Lumbosacral joints are between []and [] and consist of an intervertebral disc between the bodies of the vertebrae and zygapophysial (facet) joints between the articular processes. The interlocking facet joints prevent the lumbar vertebrae from sliding down the anterior aspect of the sacrum.

Answer 19

Lumbosacral joints are between L5 and S1 and consist of an intervertebral disc between the bodies of the vertebrae and zygapophysial (facet) joints between the articular processes. The interlocking facet joints prevent the lumbar vertebrae from sliding down the anterior aspect of the sacrum.

Question 20

The pubic symphysis is a [] joint that consists of a fibrocartilaginous disc between the bodies of the pubic bones

Answer 20

The pubic symphysis is a cartilaginous joint that consists of a fibrocartilaginous disc between the bodies of the pubic bones

Question 21

Ligaments of the Sacroiliac Joint

Answer 21

1. The interosseous sacroiliac ligaments are the major ligaments that span between the sacrum and ileum and mediate the transfer of the body weight from upper body to the pelvis. These ligaments are extensive and occupy an area approximately 10 cm2 . The anterior and posterior sacroiliac ligaments are continuations of these ligaments.
2. The iliolumbar ligament extends from the transverse process of L5 to the ilea.
3. The sacrotuberous and sacrospinous ligaments tie together the sacrum and the ischium.
   a. The sacrotuberous ligament crosses between the caudal part of the sacrum and the coccyx and attaches to the ischial tuberosity. This is the longer and more posterior of the two.
   b. The sacrospinous ligament attaches to the caudal part of the sacrum and the coccyx and to the ischial spine. This is the shorter and more anterior of the two. The portion near the sacral attachment is overlapped by the longer sacrotuberous ligament.

Question 22

Ligaments of the Pubic Symphysis

Answer 22

The superior pubic ligament extends across the pubic symphysis as far laterally as the pubic tubercles.

The inferior (arcuate) pubic ligament is a thick band of fibers that cross on the inferior part of the pubic arch, forming the apex of the arch.

Question 23

Ligaments of the Lumbosacral Joint

Answer 23

In addition to the facet joints that stabilize the lumbosacral joint, it is further stabilized by the iliolumbar ligaments.

Question 24

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Question 25

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Question 26

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Question 27

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Question 28

The [] is the passage between the pelvic cavity and the gluteal region.

Answer 28

The greater sciatic foramen is the passage between the pelvic cavity and the gluteal region.

Question 29

The skeletal boundary of the greater sciatic foramen is the []; the ligamentous boundary consists of parts of both the [] and the [].

Answer 29

The skeletal boundary of the greater sciatic foramen is the greater sciatic notch of the pelvic bone; the ligamentous boundary consists of parts of both the sacrotuberous ligament and the sacrospinous ligament.

Question 30

The lesser sciatic foramen is the passage from the [] and to the [].

Answer 30

The lesser sciatic foramen is the passage from the gluteal region and to the perineum.

Question 31

The skeletal boundary of the lesser sciatic foramen is the l[]; the ligamentous boundary consists of parts of both the [] and the [].

Answer 31

The skeletal boundary of the lesser sciatic foramen is the lesser sciatic notch of the ischium; the ligamentous boundary consists of parts of both the sacrotuberous ligament and the sacrospinous ligament.

Question 32

Sciatic Foramina

Answer 32

1. Greater Sciatic Foramen
2. Lesser Sciatic Foramen

Question 33

Contents of the Greater Sciatic Foramen

Answer 33

a. piriformis muscle
b. the two gluteal arteries
c. the internal pudendal artery
d. almost all of the branches of the sacral plexus of nerves
e. the pudendal nerve (innervation of the perineum)

Question 34

Contents of the Lesser Sciatic Foramen

Answer 34

a. tendon of the obturator internus muscle
b. the internal pudendal artery
c. pudendal nerve

Question 35

The [] and the [] pass from the pelvic cavity into the gluteal region through the greater sciatic foramen and then from the gluteal region into the perineum through the lesser sciatic foramen.

Answer 35

The internal pudendal artery and the pudendal nerve pass from the pelvic cavity into the gluteal region through the greater sciatic foramen and then from the gluteal region into the perineum through the lesser sciatic foramen.

Question 36

Muscles of the Pelvic Wall

Answer 36

1. Piriformis
   a. Originates from the front of the sacrum
   b. Inserts in the greater trochanter of the femur
   c. Acts to laterally rotate thigh
   d. Innervated by L5, S1, S2
2. Obturator Internus Muscle
   a. Originates from the bone surrounding obturator foramen and internal surface of obturator membrane
   b. Inserts in the greater trochanter of the femur
   c. Acts to laterally rotate thigh
   d. Innervated by nerve to obturator internus from sacral plexus

Question 37

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Question 38

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Question 39

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Question 40

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Question 41

Muscles of the Pelvic Diaphragm

Answer 41

1. Levator ani muscle. The levator ani muscle comprises the floor of the pelvic cavity. It is composed of three parts and, like the thoracic diaphragm, has apertures to allow passage of viscera and vessels.
   a. puborectalis - body of pubis to wall of anal canal, loops around the rectum.
   b. pubococcygeus - body of pubis and obturator internus fascia to coccyx
   c. iliococcygeus - obturator internus fascia, ischial spine to coccyx

Acts to support pelvic contents

Innervated by S4 and S5

2. Coccygeus muscle.

Origin: ischial spine

Insertion: coccyx and inferior sacrum

Acts to support pelvic contents

Innervated by S4 and S5

Question 42

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Question 43

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Question 44

Answer 44