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Learning ObjectivesAt the end of the lecture, the students should be able

to :

Describe the bony structures of the pelvis.

Describe in detail the hip bone, the sacrum, and thecoccyx.

Describe the boundaries of the pelvic inlet and outlet.

Identify the structures forming the pelvic walls.

Identify the articulations of the bony pelvis.

List the major differences between the male and female

pelvis.

List the different types of female pelvis.

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BONY PELVI SIt provides a strong, stable

connectionbetween the trunkand lower extremities.

I ts Main Functions are: Transmit the weight of the

body from the vertebralcolumn to the femurs.

Contain, support and protectthepelvic viscera.

Provide attachment to trunkand lower limb muscles.

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Pelvic GirdleI ts bones are large & heavy.

Bearing weight is their most

important function.

The total weight of the upper

body rests on the pelvis.

I t is composed of (4) Bones:

TwoH ipBones.

Sacrum.

Coccyx.

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Hip Bone

I t is a large irregular

bone.

I t is formed by the

fusion ofthree boness:

I l ium

Ischium

Pubis.

They are joined at thedeep socket

(Acetabulum)

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I l ium

TheUpper F lattened Partof the hip bone.

I t Possesses:

I l iac Crest: it is an important anatomical

landmark below the waist.

I t runs between the Anter ior and Poster ior

Super ior I li ac Spines.

Below are the corresponding Anter ior and

PosteriorI nfer ior I li ac Spines.

The outer sur face is rough and has gluteal lines.

On the inner sur face:

I l iac Fossa (forms false pelvis).Aaur icular sur face(for articulation with the

sacrum).

I li opectin ial Line:runs Downwards & Forwards

(separates between the False & the True pelvis) .

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Pubis

Forms the Anter ior & infer ior

partof the hip bone.

I t has:

Body; bears the Pubic Crest and

Pubic Tubercle.

Two pubic Rami:Superior &Inferior;

Bounding theObturator Foramen;

whichis closed partiall y by the

obturator membrane.

Leaving theObturator canalfor

passage of blood vessels & nerves

into the thigh.

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IschiumForms theI nferior and Poster iorpartof the hip bone.

I t has:

I schial Tuberosity:

I t is a roughened area that r eceives body

weight in sitti ng.

I schial Spine:

Superior to the tuberosity, it is

important especial ly in obstetr ic.

Greater sciatic notch:

Allows sciatic nerve & vessels to pass

from pelvis to thigh.

Lesser sciatic notch: allow vessels &

nerves to pass from pelvis to per ini um.

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Articulations

of H ip Bone

1. Symphysis Pubis: A Carti laginous joint between

the two pubic bones.

(2) Sacroiliac Joints

Strong synovial joints, betweenthe auricular sur faces of i l ium and

sacrum.

Transmit the weight of the body

from vertebral column to the bonypelvis.

(3)H ip Joint:

The outer surface articulates at

the acetabulum with the head offemur.

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Sacrum

A Single Wedgeshaped bone(consists of F ive rudimentaryvertebrae fused together) ,forming.

Sacral Promontory:

The anter ior and uppermargin

I t is til ted forward formingthelumbosacral angle.

The anter ior and poster iorsurfaces possess on each side

(4 ) Sacral Foramina.The fused vertebralforamina form theSacralCanal.

I ts lower limit i s theSacral

Hiatus.

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Coccyx

Consists of (4)

vertebrae fused

together forming a

singleTriangular

piece.

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Articulations of SacrumLumbsacral joint:

The upper border,

articulates with the 5th

Lumber vertebra.

Sacrococcygeal joint:

The infer ior part articulates

with the Coccyx

Sacroil iac joints:

Lateral articulation with the

H ip bones.

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Orientation of

the PelvisI t is the Correct Positionof the bony pelvis relative

to the trunk:

1.The front of the

Symphysis pubisand theAnter ior Super ior il iac

spinesl ie in the same

vertical plane.

2. The pelvic sur face of

theSymphysis pubisfacesupward and backward.

3.The anter ior sur face of

theSacrumis directed

forward and downward.

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Subdivisions of the PelvisIt is divided by the

Pelvic Brim (PelvicInlet) into:

True pelvis.

False pelvis.

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False pelvis L ies superior tothe pelvic brim.

Enclosed by theFossaeof the il iac

bones. Forms the inferiorregion of theabdominal cavity.

Houses the

Inferiorabdominal organs

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True PelvisLiesinferiortothe pelvic brim.

Encloses the

pelvic cavity.Contains thepelvic organs.

I t has :

InletOutlet.

Pelvic walls

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Pelvic I nlet (pelvic Br im)

Bounded by:

Sacral promontory

Symphasis pubes.

I l iopectineal l ines.

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Pelvic Outl et

Bounded by:

Coccyx

Ischialtuberosities.

Pubicarches.

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Pelvic Walls

Formed by bones andligaments.

L ined with muscles, and

covered with fascia.

Anter ior Wall :

Poster ior sur faces of bodies of

pubic bones.

Pubic rami.

Symphasis pubes.

Poster ior Wall :

Sacrum and Coccyx

Pir iformis muscles, and their

cover ing of par ietal pelvic fascia

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Lateral Pelvic WallHipbonebelow the

pelvic inlet.

Obturatormembrane.

Sacrotuberus andsacrospinusligaments.

Obturator internus

muscleand cover ingfascia.

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False pelvis deep shallow

Pubic arch Morerounded&pubicangle

greaterPelvic inlet Heart

shapedOval orrounded

Pelvicoutlet

Larger

Ischialtuberosities

Turned in Everted

Ischialspines

Shorter&fartherapart

Pelvic cavity Roomer

Male FemaleFemale & Male

pelvis

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Length Shorter

Breadth Wider

Curvature Less Curved

Sacrum

MF

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MaleFemale

Pelvic Inlet

Pelvic Outlet

Pelvic Cavity

Pubic Arch

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Types of Obstetr ical Female Pelvis

(1) Gynaecoid.

(2) Anthropoid.

(3) Android.

(4) Platypelloid.

(1)

(2)

(3)

(4)

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