19. Pelvis and Perineum Flashcards
1
Q
What are the 3 Bony Constituents of the Pelvic Girdle?
A
- Hip Bones
- Sacrum
- Coccyx
2
Q
What are the 3 Sections of the Hip Bones?
A
- Ilium
- Ischium
- Pubis
3
Q
What is the Hip Bone also known as?
A
Os Innominatum
Coxa Bone
4
Q
How can the Hip Bone be described?
A
It is like a Propeller:
- Acetabulum at the Hub,
- One Blade is the Iliac Bone,
- The other Blade is the Ischium and Pubis,
- Perforated by the Obturator Foramen.
5
Q
What Bones is the Sacro - Iliac Joint between?
A
Between the Ilium of the Hip Bones and the Sacrum
6
Q
What Type of Joint is the Sacro - Iliac Joint?
A
Synovial Joint
7
Q
What Bones is the Pubic Symphysis between?
A
Between the Pubis Bodies of the Two Hip Bones
8
Q
What Type of Joint is the Pubic Symphysis?
A
Secondary Cartilaginous Joint
9
Q
What are the 2 Parts of the Pelvis?
A
- Greater/False Pelvis
- Lesser/True Pelvis
10
Q
Where is the Greater Pelvis located?
A
Situated Above and In Front of the Pelvic Brim.
Found Superior to the Pelvic Inlet.
11
Q
What does the Greater Pelvis contain?
A
Contains the Inferior Parts of the Abdominal Organs.
Occupied by portions of the Small and Large Intestines.
12
Q
Why is the Greater Pelvis called the False Pelvis?
A
Because it is more Closely Associated with the Abdominal Cavity
13
Q
Where is the Lesser Pelvis located?
A
The Lesser Pelvis is located between the Pelvic Inlet and Pelvic Outlet
14
Q
What does the Lesser Pelvis contain?
A
- Bladder
- Internal Reproductive Organs
- The Perineum
15
Q
Why is the Lesser Pelvis called the True Pelvis?
A
Because it contains the Pelvic Organs
16
Q
What separates the Greater from the Lesser Pelvis?
A
The Pelvic Brim/Inlet forms the Superior Margin of the Lesser Pelvis,
Separating it from the Greater Pelvis.
17
Q
What are the borders of the Pelvic Brim?
A
Anterior Border:
- Upper Margin of the Pubic Symphysis
Posterior Border:
- The Pectineal Line of the Pubis
- The Arcuate Line of the Ilium
- Sacral Promontory Posteriorly
18
Q
What are the borders of the Pelvic Inlet?
A
Anterior:
- Pubic Symphysis
Lateral:
- Arcuate Line on the Inner Surface of the Ilium
- Pectineal Line on the Superior Pubic Ramus.
Posterior:
- Sacral Promontory
- Sacral Ala
19
Q
What does the Pelvic Inlet separate?
A
The Pelvic Inlet marks the Boundary between the Greater Pelvis and Lesser Pelvis.
20
Q
What is the Sacral Promontory?
A
The Anterior Margin of the Superior Sacrum.
21
Q
How is the Pelvic Inlet related to Childbirth?
A
The Pelvic Inlet determines the size and shape of the Birth Canal.
22
Q
What attaches to the Pelvic Inlet?
A
The Prominent Ridges of the Pelvic Inlet are key areas of Muscle and Ligament Attachment.
23
Q
Where is the Pelvic Oulet located?
A
The Pelvic Outlet is located at the End of the Lesser Pelvis,
And the Beginning of the Pelvic Wall.
24
Q
What are the borders of the Pelvic Outlet?
A
Anterior Border:
- The Pubic Arch
- Pubic Symphysisthe
- Inferior Border of the Ischiopubic Rami.
Lateral Border:
- The Ischial Tuberosities and the Inferior Margin of the Sacrotuberous Ligament.
Posterior Border:
- The Tip of the Coccyx.
25
What is the Sub - Pubic Angle?
The Angle beneath the Pubic Arch is known as the Sub - Pubic Angle,
Is of a Greater Size in Women.
26
What are the 4 Varieties of Pelvic Shapes?
1. Gynecoid (Female)
2. Android (Male)
3. Anthropoid
4. Platypelloid
27
List the Main Features of the Female Pelvis:
1. Bones are Lighter and Thinner.
2. False Pelvis is Shallow.
3. Pelvic Cavity is Wide and Shallow.
4. Pelvic Inlet is Round and Oval.
5. Pelvic Outlet comparitively Large.
6. Subpubic Angle Large.
7. Coccyx more Flexible and Straighter.
8. Ischial Tuberosities more Everted.
28
List the Main Features of the Male Pelvis:
1. Bones are Heavier and Thicker.
2. False Pelvis is Deep.
3. Pelvic Cavity is Narrow and Deep.
4. Pelvic Inlet is Heart Shaped and Smaller.
5. Pelvic Outlet comparitively Small.
6. Subpubic Angle more Acute.
7. Coccyx Less Flexible and More Curved.
8. Ischial Tuberosities more Everted.
29
How does the the Foetal Head enter the Pelvic Inlet?
1. The Foetal Head enters the Pelvic Inlet Transverse.
2. As the Baby Descends, its head rotates 90 Degrees.
3. The head will be Flexed and U-shaped.
4. The Head then Extends During Delivery.
30
What is the Ideal/Common Position for the Foetal Head?
The Occiput Anterior Fetal Position is a Cephalic Presentation,
In which the Fetus is Face Down, facing the Mother's Spine.
This is the Ideal Position for Childbirth.
31
How Wide is the Pelvic Inlet and Outlet?
Pelvic Inlet is 13 cm Wide,
Pelvic Outlet is only 11 cm Wide.
32
What is the Widest Portion of the Pelvic Outlet?
12.5 cm from top to bottom
33
Why does the Foetus have to Rotate?
1. The Fetus has to Rotate in order to get through the Pelvic Canal.
2. This is as the Pelvic Inlet is Wider than the Pelvic Oulet.
3. In order to fit through the Pelvic Outlet at its Widest Dimension
4. The Fetus must rotate so it presents its head to the Widest Dimension of the Pelvic Cavity,
At each Point of the Pelvic Cavity that it Passes through.
34
What is the Largest part of the Foetal Head?
The largest part of the Fetus is the Skull,
So the Baby’s Head Rotates First,
And the Shoulders and the Rest of the Body follow.
35
Where does the True Pelvis Project?
The True Pelvis projects Posteriorly into the Gluteal Region.
36
What does the True Pelvis contain?
Contains the Pelvic Organs.
37
How can the Pelvic Organs be Palpated?
Not Palpable Abdominally,
Must be Examined Vaginally/Rectally
38
What Angle does the Pelvic Inlet make with the Horizontal?
55 - 60 Degrees
39
What is the Angle of the Pelvic Inlet called?
Pelvic Inlet Angle is called Anterior Pelvic Tilt
40
What is the Obstetric Significance of the Anterior Pelvic Tilt?
The Mother can be repositioned during Childbirth.
41
Which structures does Anterior Pelvic Tilt align?
Brings the Pubic Tubercle into the same Vertical Plane as the ASIS,
And the same Horizontal Plane as the Ischial Spine.
42
What Angle does the Pelvic Outlet make with the Horizontal?
10 - 15 Degrees
43
What is the Axes of the Pelvic Cavity?
Axes describes the direction in which the Fetus progresses as it passes through the Birth Canal.
Hypothetic Curved Line joining the Center Point of each of the Four Planes of the Pelvis,
Marking the Center of the Pelvic Cavity at every level.
44
How would you Perform a Manual Pelvimetry?
Compare the Size of the Pelvic Cavity with a Clenched Fist
45
Where are the Common Sites of Fracture of the Pelvis?
1. Breaks across the Top of One Ilium
2. Cracks to the Pubic Ramus on one side,
3. Or cracks in the Sacrum.
46
How is the Pelvis similar to a Pretzel?
Because the Pelvis is Shaped like a Pretzel,
When one Part of the Pelvic area is Fractured
It is likely that you will have a Fracture in another area of the Pelvis as well.
47
What are the Complications of a Frature to the Pelvis?
1. Bleeding:
- Especially of the Iliac Artery,
- May be Profuse due to Injury to Local Blood Vessels.
2. Hematuria:
- Blood in the Urine,
- Due to Injury to the Bladder or Urethra.
3. The Lower Intestine or Rectum may also be Torn or Ruptured.
4. Damage to Reproductive Organs
5. Infection
6. Venous Thrombosis
48
What is Symphysial Diastasis?
Separation of Normally Joined Pubic Bones.
Dislocation of the Bones, but Without a Fracture.
49
Who commonly suffers from Symphysial Diastasis?
Can occur spontaneously in at least 1 in 800 Vaginal Deliveries.
Common in Pregnant Women.
50
What are the Important Features of the Iliac Bone?
1. Iliac Crest
2. Tubercule of Iliac Crest
3. Wing/Ala of Ilium
4. Anterior Superior Iliac Spine (ASIS)
5. Anterior Inferior Iliac Spine (AIIS)
6. Posterior Superior Iliac Spine (PSIS)
7. Posterior Inferior Iliac Spine (PIIS)
51
What is the Importance of the Level of the Iliac Crest?
Top of Iliac Crest also marks the level of the Fourth Lumbar Vertebral Body (L4).
A Lumbar Puncture may be performed above and below L4 as well as Epidural.
52
What level is the Iliac Tubercule found at?
The Iliac Tubercle is found at L5.
53
What is the Widest Part of the Iliac Crest?
Iliac Tubercule
54
Which Muscles are connected to the Iliac Crest?
Gives Partial Origin to:
- Internal Oblique Muscle
-Transversus Abdominis Muscle
Provides Insertion for:
- External Oblique Muscle
55
Which Muscles attach to the ASIS?
Inguinal Ligament
Sartorius Muscle
56
What Vertebral Level is the PSIS?
L5/S1
57
What is the Gluteal Surface of the Ilium?
The Gluteal Surface of the Ilium faces Posterolaterally,
Lies below the Iliac Crest.
Marked by Three Curved Lines.
58
Where are the Gluteal Lines located?
Posterior Aspect of the Wing/Ala of Ilium.
On the Gluteal Surface of the Ilium
59
What are the 3 Gluteal Lines?
1. Posterior Gluteal Line
2. Anterior Gluteal Line
3. Inferior Gluteal Line
60
What do the Gluteal Lines divide?
The Gluteal Lines divide the Gluteal Surface into 4 Regions.
61
Where does the Inferior Gluteal Line originate?
The Inferior Gluteal Line originates just Superior to the Anterior Inferior Iliac Spine.
62
Where does the Inferior Gluteal Line End?
Curves Inferiorly across the Bone to End near the Posterior Margin of the Acetabulum.
63
Where does the Rectus Femoris Muscle attach?
The Rectus Femoris Muscle attaches to:
- Anterior Inferior Iliac Spine
- Roughened patch of Bone between the Superior Margin of the Acetabulum,
- And the Inferior Gluteal Line.
64
Where does the Anterior Gluteal Line originate?
The Anterior Gluteal Line originates from the Lateral Margin of the Iliac Crest,
Between the Anterior Superior Iliac Spine and the Tuberculum of the Iliac Crest.
65
Where does the Anterior Gluteal Line run?
Arches Inferiorly across the Ilium,
To Disappear just Superior to the Upper Margin of the Greater Sciatic Foramen.
66
Where does the Gluteus Minimus Muscle originate?
The Gluteus Minimus Muscle Originates from between the Inferior and Anterior Gluteal Lines.
67
Where does the Posterior Gluteal Line run?
The Posterior Gluteal Line descends almost Vertically from the Iliac Crest,
To a position near the Posterior Inferior Iliac Spine.
68
Where do the Gluteus Medius/Maximus Muscle originate?
The Gluteus Medius Muscle attaches to Bone between the Anterior and Posterior Gluteal Lines
The Gluteus Maximus Muscle attaches Posterior to the Posterior Gluteal Line.
69
Which Muscle occupies the Iliac Fossa?
Iliacus Muscle:
Flat, Triangular Muscle.
70
What is the Origin of the Iliacus Muscle?
Iliac Fossa of the Pelvis
71
What is the Insertion of the Iliacus Muscle?
Lesser Trochanter of the Femur.
72
What is the Action of the Iliacus Muscle?
Flexes the Thigh at the Hip Joint.
Flexion of the Trunk at the Hip.
External Rotation of the Thigh at the Hip.
73
What is the Innervation of the Iliacus Muscle?
Femoral Nerve.
Nerve Roots: L2 - L4
74
How is the Iliac Bone useful in Haematology?
A Bone Marrow Biopsy/Transplant or Needle Aspiration is usually done from the Iliac Bone.
75
What are the Important Features of the Pubic Bone?
1. Body
2. Superior Rami
3. Obturator Foramen
4. Inferior Rami
6. Pubic Arch
7. Pubic Crest
8. Pectineal Line
9. Pubic Tubercule
76
What Structures attach to the Pubic Tubercule?
Inguinal Ligament
77
What Structures attach to the Pubic Crest?
Conjoint Tendon
Rectus Abdominis
Abdominal External Oblique
78
What Structures attach to the Pectineal Line?
Pectineus Muscle
Pyramidalis Muscle
79
What forms the Lower Border of the Obturator Foramen?
Inferior Ramus
Ramus of the Ischium
80
What Structure fills the Obturator Foramen?
Obturator Canal:
- Passageway formed in the Obturator Foramen by part of the Obturator Membrane.
- Connects the Pelvis to the Thigh.
81
Which Structures pass through the Obturator Canal?
Obturator Artery
Obturator Vein
Obturator Nerve
82
Which Muscle Originates from the Medial Aspect of the
Obturator Foramen?
Obturator Internus
83
Where does the Obturator Internus Muscle Insert?
Inserts on the Medial Aspect of the Greater Trochanter
84
What are the Important Features of the Ischial Bone?
1. Body
2. Ischial Spine
3. Ischial Tuberosity
4. Ischial Ramus
85
What is the Vertebral Level of the Ischial Spine?
S4
86
Which group of Muscles arise from the Ischial Tuberosity?
1. Hamstring Muscles
2. Superficial Transverse Perineal Muscle
3. Ischiocavernosus Muscle
87
Which Muscles/Ligaments attach at the Ischial Tuberosity?
1. Adductor Muscles of the Thigh
2. Hamstring Muscles of the Thigh
3. Sacrotuberous Ligaments
88
What Weight does the Ishial Tuberosity have to take?
The Ischial Tuberosity takes the body weight when sitting.
89
What does the Ischial Spine separate?
The Ischial Spine separates the Greater and Lesser Sciatic Notches.
90
Which Artery/Nerve winds around the Ischial Spine?
Pudendal Nerve
Internal Pudendal Artery
91
Why is the Ischial Spine important in Obstetric Practice?
1. Can serve as the Landmark for Pudendal Anaesthesia.
It is the location where you can undertake a Pudendal Nerve Block.
2. Determine the Extent of Foetal Descent using your fingers.
Can see if the Entire Baby Head is in the Pelvis.
Measure it using your fingers (e.g. 1/5th, 3/5th etc.)
92
What are the Base Attachments of the Sacro - Tuberous Ligament?
Base Attachments:
- Posterior Superior Iliac Spine
- Posterior Sacroiliac Ligaments (with which it is partly blended),
93
What are the Tip Attachments of the Sacro - Tuberous Ligament?
Tip Attachements:
- Lower Transverse Sacral Tubercles
- Lateral Margins of the Lower Sacrum and Upper Coccyx.
94
What is the Base Attachments of the Sacro - Spinous Ligament?
Base Attachment:
- Outer Edge of the Sacrum and Coccyx
95
What is the Tip Attachment of the Sacro - Spinous Ligament?
Tip Attachement:
- Spine of the Ichium
96
How do the Tuberous/Spinous Ligaments change the Pelvic Outlet?
Convert the Sciatic Notches into Foramina.
Convert the Pelvic Outlet into a Diamond Shape.
97
What are the Functions of the Sacro - Tuberous Ligaments?
- To stop the Distal Sacrum from being Displaced Posteriorly.
- Contributes to the Strength of the Pelvis
- Inhibits Nutation (rocking/swaying)
- Provides an Attachment point for Muscles.
98
Which Muscles does the Sacro - Tuberous Ligament
provide Attachment for?
Gluteus Maximus
Long Head of the Biceps Femoris
99
What is the Sacrum made up of?
5 Fused Vertebrae (with their Costal Elements)
Separated by 4 Transverse Ridges (Inter - Vertebral Discs).
100
What are the Important Features of the Sacral Bone?
1. Sacral Promontory
2. Sacral Ala
3. Transverse Lines
4. Ventral Sacral Foramina
5. Apex of the Sacrum
6. Sacral Canal
7. Body of the Sacrum
8. Superior Articular Process
9. Median Sacral Crest
10. Intermediate Sacral Crests
11. Lateral Sacral Crest
12. Dorsal Sacral Foramina
13. Sacral Hiatus
101
Which Structures arise from the Dorsal & Ventral Foramina?
S1 - S4 Sacral Nerves come from the Dorsal & Ventral Foramina
102
Which Structures arise from the Sacral Hiatus?
S5 Emerges from the Sacral Hiatus
103
How are the Intermediate Sacral Crests formed?
The Intermediate Sacral Crests are formed by,
The Fusion of the Sacral Articular Processes.
104
Which Ligaments attach to the Intermediate Sacral Crests?
Posterior Sacroiliac Ligaments
105
How are the Transverse Processes formed?
The Transverse Processes of the Five Sacral Bones Fuse,
To form the Lateral Sacral Crests.
106
Which Ligaments attach to the Transverse Processes?
Posterior Sacroiliac Ligaments
Sacrotuberous Ligament
107
What is the Median Sacral Crest?
The Midline of the Dorsal Surface of the Sacrum,
Bears a projection of Bone known as the Median Sacral Crest.
This Crest is Palpable.
108
How is the Median Sacral Crest formed?
Formed by the Fusion of Sacral Spines of S1 to S4.
109
Which Structures cross the Ala of the Sacrum?
Medial to Lateral
1. Sympathetic Trunk
2. Lumbosacral Trunk
3. Iliolumbar Artery
4. Obturator Nerve
110
Which Structures cross the Pelvic Brim?
Internal Iliac Artery
Ureter
111
What is the Lumbosacral Angle?
Angle between L5 and S1:
- Where the Lumbar Spine Ends and the Sacral Spine Begins.
- L5 - S1 is the Joint that connects these Bones.
112
What is the Lumbosacral Angle Vulnerable to and Why?
Vulnerable to Misalignment, Wear and Tear, Injury.
L5 is prone to Slipping Off.
This is because the top of the Sacrum is Positioned at an Angle in most people.
It is one of the two most Common sites for Back Surgery.
113
How do the Sacro - Iliac Joints direct Body Weight?
The Slope of the Sacro - Iliac Joints is such that Body Weight forces the Sacrum Downwards.
114
What prevents the Body Weight forcing Sacrum through Iliac Bones?
Interosseous Sacroiliac Ligament:
- Forms the major connection between the Sacrum and the Ilium.
- Strongest Ligament in the Body.
- Prevents Anterior and Inferior Movement of the Sacrum.
115
Which Muscle arises from the Pelvic Surface of the Sacrum?
Piriformis Muscle
116
Which Muscle Group arises from Posterior Surface of the Sacrum?
Erector Spinae Muscles:
1. Iliocostalis
2. Longissimus
3. Spinalis
117
Where does the Median Sacral Artery arise from?
The Median Sacral Artery originates from the Posterior Surface of the Aorta,
Just superior to the Aortic Bifurcation at Vertebral Level L4 in the Abdomen.
118
Where does the Median Sacral Artery run?
Descends in the Midline,
Crosses the Pelvic Inlet,
Courses along the Anterior Surface of the Sacrum and Coccyx.
119
At which Vertebral Level does the Dura Mater Terminate?
L1/L2 at the Conus Medalluris
120
At which Vertebral Level does the Filum Terminale terminate?
S2
121
What is the Pelvic Diaphragm?
The Cranial Layer of the Pelvic Floor.
Supports the Pelvic Organs.
Closes off the Pelvic Outlet
While allowing passage for the Rectum, Vagina and Urethra.
122
What are the 3 Important Muscles within the Pelvic Cavity?
1. Levator Ani Muscles
2. Piriformis
3. Obturator Internus
123
Which 3 Muscles make up the Levator Ani complex?
1. Pubococcygeus
2. Puborectalis
3. Iliococcygeus
124
Which Muscle forms the Pelvic Diaphragm?
Levator Ani forms the main part of the Pelvic Diaphragm.
125
What is the Innervation of the Levator Ani Muscles?
All 3 Components of the Levator Ani are innervated by the:
- Branches of the Sacral Plexus
- Pudendal Nerve
126
How are the Levator Ani Muscles attached to the Pelvis?
Anteriorly:
- Pubic Bodies of the Pelvic Bones
Laterally:
- Thickened Fascia of the Obturator Internus Muscle,
- Tendinous Arch
Posteriorly:
- Ischial Spines of the Pelvic Bone.
127
What is the Origin of the Puborectalis Muscle?
Posterior Surface of the Pubis
128
What is the Insertion of the Puborectalis Muscle?
Midline Sling Posterior to the Rectum
129
What is the Origin of the Pubococcygeus Muscle?
Back of the Pubis
From the Anterior Part of the Obturator Fascia
130
Where does the Pubococcygeus Muscle run?
Directed Backward almost Horizontally,
Along the side of the Anal Canal towards the Coccyx and Sacrum.
131
What is the Insertion of the Pubococcygeus Muscle?
Coccyx
Sacrum
132
What are the most Medial Fibres of the Pubococcygeus?
They form the:
- Pubovaginalis in Females
- Puboprostaticus in Males
133
What is the Origin of the Iliococcygeus Muscle?
Inner Side of Ischium
Posterior Part of Tendinous Arch of the Obturator Fascia
134
What is the Insertion of the Iliococcygeus Muscle?
Coccyx
Anococcygeal Body
135
How is the Obturatur Internus connected to the Levator Ani?
Medial Surface of the Obturator Internus Muscle is covered with Fascia,
From which arises the Levator Ani Muscle (Pelvic Diaphragm) which supports the Pelvic Organs.
136
What is the Ischiococcygeus Muscle?
Triangular - Shaped Sheet of Muscle,
Located Posterior to the Levator Ani Muscles in the Pelvic Floor,
Forms a part of the Pelvic Diaphragm.
137
Which Ligament forms the Gluteal Surface of the Ischiococcygeus?
Sacrospinous Ligament
138
What is the Major Nerve Supply of the Levator Ani Muscle?
- Sacral Plexus (S3-S5)
- Pudendal Nerve (S2-S4)
139
What is the Minor Nerve Supply of the Levator Ani Muscle?
Coccygeal Plexus
Inferior Rectus Nerve
Perineal Nerve
140
What is the Consequence of Damage to Levator Ani Nerves?
1. Pudendal Neuralgia:
- Cause of Pain, Discomfort and Numbness in your Pelvis or Genitals.
- Can make it Hard to sit down, use the Bathroom or have Sex.
2. Prolapse and Urinary/Fecal Incontinence.
141
What are the Most Common causes of Damage to the Pelvic Floor?
Childbirth
Obesity
142
How can Pelvic Floor Damage lead to Prolapse?
Pelvic Diaphragm is covered with Fascia,
Which is condensed into Ligaments in some parts,
Damage to these Fascial Supports also predisposes to Pelvic Organ Prolapse.
143
Give an Example of a Fascial Support Ligament:
Sacrospinous Ligament
144
What are the other Functions of the Pelvic Floor?
1. Resistance to increases in Intra - Pelvic/Abdominal Pressure,
- During activities such as Coughing or Lifting Heavy Objects.
2. Urinary and Fecal Continence:
- The Muscle Fibres have a Sphincter Action on the Rectum and Urethra.
- They can also relax to allow Urination and Defacation.
3. Facilitates Birth:
- By Resisting the Descent of the Presenting Part,
- Causing the Fetus to Rotate Forwards to Navigate through the Pelvic Girdle.
- Helps Movement of the Foetal Head.
145
Which Muscle completes the Pelvic Floor Posteriorly?
Piriformis
146
What is the Origin of the Piriformis Muscle?
Internal Surface of the Sacrum
147
What is the Insertion of the Piriformis Muscle?
Superior Border of the Trochanter of the Femur (Greater Trochanter)
148
Which Surgical Procedure is associated with the Sacrospinous?
Sacro - Spinous Fixation Surgery:
- Correcting Vaginal Prolapse
149
Describe Sacro - Spinous Fixation Surgery:
Operation to attach the Top of the Vagina or Cervix,
To a Pelvic Ligament such as Sacrospinous Ligament with a Stitch.
150
What is Sacro - Spinous Fixation intended to Treat?
Primary intention to treat Prolapse of the Uterus or the Vault (top) of the Vagina.
Can also help Correct Prolapse of the Bladder or Bowel.
151
How does the Piriformis leave the Pelvic Cavity?
Through the Greater Sciatic Foramen.
152
Which Structure is found on the Anterior Aspect of the Piriformis?
Sacral Plexus
153
Which 2 Structures leave the Pelvis Above the Piriformis?
Superior Gluteal Nerve
Superior Gluteal Artery
154
What are the 2 Arteries that leave the Pelvis Below the Piriformis?
1. Inferior Gluteal Artery
2. Internal Pudendal Artery
155
What are the 6 Nerves that leave the Pelvis Below the Piriformis?
1. Sciatic Nerve
2. Inferior Gluteal Nerve
3. Posterior Femoral Cutaneous Nerve (S1-S3)
4. Pudendal Nerve
5. Obturator Internus Nerve
6. Quadratus Femoris Nerve
156
How is the Sciatic Nerve related to the Piriformis?
Sciatic Nerve lays Inferior to Piriformis,
Though in 12% of people, the Common Fibular Portion may exit through the Muscle.
157
Which important Neurovascular structures emerge from
The Greater Sciatic Foramen?
Superior Gluteal Nerves and Vessels Superior to Piriformis
Inferior Gluteal Nerves and Vessels Inferior to Piriformis.
158
What is the only structure that leaves the Pelvis through
the Lesser Sciatic Foramen?
Obturator Internus
159
Which Artery and Nerve wind around the Ischial Spine,
And Where do they Enter the Perineum?
Pudendal Nerve
Internal Pudendal Artery
Enter the Perineum below the Pelvic Diaphragm
160
What is the Space between the Obturator Internus & Levator Ani?
Wedge Shaped Space:
- Ischioanal Fossa
161
What is the Clinical Significance of the Ischioanal Fossa?
Susceptible to Formation of Abscesses.
If left untreated, they can cause Fistulous Connections within the Anal Canal.
162
What is Alcock's Canal?
Pudendal Canal
163
Which Structures pass through the Pudendal Canal?
1. Internal Pudendal Artery
2. Internal Pudendal Veins
3. Pudendal Nerve
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What is the Perineum?
Part of the Trunk that is Caudal to the Pelvic Diaphragm.
165
What can the Perineum be Divided into?
Divided by a Line drawn between the Ischial Tuberosities into 2 Triangles:
1. Anal Triangle
2. Uro - Genital Triangle
166
Which Structures form the Boundaries of the Perineum?
Anterior Boundary:
- Pubic Symphysis
Anterolateral Boundary:
- Ischio - Pubic Ramus
Posterolateral Boundary:
- Sacrotuberous Ligament
Posterior Boundary:
- Coccyx
- Ischial Tuberosity
167
What are the Structural Components of the Anal Triangle?
1. Ischioanal Fossa
2. Anococcygeal Body
3. Anal Canal
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Which Ligaments are Found in the Anal Triangle?
Sacrotuberous Ligament
Sacrospinous Ligament
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What Neurovascular Structures are Found in the Anal Triangle?
Pudendal Nerve
Internal Pudendal Artery
Internal Pudendal Vein
170
List the Anal Mucles Found in the Anal Triangle:
1. Sphincter Ani Externus Muscle
2. Gluteus Maximus Muscle
3. Obturator Internus Muscle
4. Levator Ani Muscle
5. Coccygeus Muscle
171
What 3 Membranes divide Perineum into Superficial & Deep Spaces?
1. Superficial Fascia
2. Perineal Membrane
3. Deep Perineal Fascia
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What is the Perineal Membrane?
Triangular Ligament
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What are the Attachments of the Perineal Membrane?
Ischial Tuberosity
Ischiopubic Rami of the Pelvis
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What does the Perineal Membrane Separate?
Separates Deep & Superficial Perineal Spaces
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Which Female Structures does the Perineal Membrane,
provide attachment for?
Crura of Clitoris
Bulb of Vestibule
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Which Muscle covers the Crura of the Clitoris?
Ischio - Cavernosus Muscle
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Which Muscle covers the Bulb of the Vestibule?
Bulbo - Spongiousus Muscle
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Where is the Bulb of the Vestibule in relation to Crus of the Clitoris?
Bulb of Vestibule is Medial to Crus of Clitoris.
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What is the Perineal Membrane bounded by?
Bounded Posteriorly by:
- Deep Transverse Perinei Muscles
- Perineal Body
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What are the 3 Muscles found in the Superficial Perineal Space?
1. Ischiocavernosus (Lateral)
2. Bulbospongiosus (Medial)
3. Superficial Transverse Perineal Muscles
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What is the Innervation of the Superficial Perineal Space Muscles?
Perineal Nerve
182
List 3 Structures Found in the Superficial Perineal Space?
Urethra
Vagina
Clitoris
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What are the 3 Muscles found in the Deep Perineal Space?
1. Compressor Urethrae Muscles
2. Levator Ani
3. Deep Transverse Perineal Muscles
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List 3 Structures Found in the Deep Perineal Space?
Internal Pudendal Vessels
Bulbourethral Glands
Pudendal Nerve
185
Describe the Passage of Internal Pudendal Artery & Pudendal Nerve?
1. Out of the Pelvis through the Greater Sciatic Foramen
2. Winding around the Ischial Spine to Enter the Perineum through the Lesser Sciatic Foramen
3. Pass Anteriorly in Alcock’s/Pudendal Canal towards the Uro - Genital Triangle.
186
What are the Main Branches of the Pudendal Nerve?
- Inferior Rectal Nerve
Terminal Branches:
- Perianal Nerve
- Dorsal Nerve of Clitoris
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What does the Inferior Rectal Nerve supply?
Sensory Innervation: Peri - Anal Skin
Motor Innervation: Anal Sphincter
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What does the Perianal Nerve supply?
Sensory Innervation:
1. Posterior 2/3 of Labia Majora
2. Urethra
3. Vagina
Motor Innervation:
3. Perineal Muscles:
- Ischio - Cavernosus
- Bulbo - Spongiosus
- Transverse Perineal
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What is the Perineal Body?
Central Tendon of the Perineum:
- Pyramidal Fibromuscular Mass in the Middle Line of the Perineum,
- At the Junction between the Urogenital Triangle and Anal Triangle.
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Which Muscles are inserted onto the Perineal Body?
1. Bulbocavernosus Muscles
2. Superficial Transverse Perineal Muscles
3. Deep Transverse Perineal Muscles
4. A Portion of Levator Ani Muscles
5. Rectovaginal Fascia
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What is the Importance of the Perineal Body?
Contributes to Stabilisation and Support of Levator Ani.
192
When might the Perineal Body be Damaged?
Childbirth
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What are the Potential Consequences of Perineal Body Damage?
1. Faecal Incontinence
2. Faecal Urgency
3. Chronic Perineal Pain
4. Pain with Sex
5. Fistula Formation
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Where is the Perineal Body attached to the Perineal Membrane?
Attached to the Posterior Border of the Perineal Membrane.
195
How is the Superficial Perineal Fascia attached to Perineal Membrane?
Posterior Limit of the Superficial Perineal Fascia,
Also attaches to the Posterior Border of the Perineal Membrane.
196
What is an Episiotomy?
An Incision made in the Perineum during Childbirth.
In order to avoid Tearing of the Perineal Body.
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Which Structures are most likely to be Cut during an Episiotomy?
Bulbospongiosus Muscle
Superficial Transverse Muscle
Deep Transverse Muscle
198
Where might a Mid - Line Episiotomy extend to?
In a Midline Episiotomy,
The Incision is made in the Middle of the Vaginal Opening,
Straight down toward the Anus.
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What can be the Consequences of a Mid - Line Episiotomy?
Increased Risk for Tears that Extend into or through the Pelvic Muscles.
This type of injury can result in Long - Term problems including Fecal Incontinence,
Or the Inability to Control Bowel ,ovements
