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Anatomy Made
Easy “MSS”
The Pelvis and Lower
Extremity
By Lana Rashdan
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Hip Bones
Hip Bones
Pelvis
Pelvis
The pelvis is made up of
The pelvis is made up of
two hip bones, the sacrum
two hip bones, the sacrum
and coccyx.
and coccyx.
It is more stable than the
It is more stable than the
shoulder girdle, with less
shoulder girdle, with less
freedom.
freedom.
Coccyx
Coccyx
‫ض‬
‫ض‬2‫ع‬1‫ئءءءذذذاعتتع‬
1
‫ذصذصضض‬
Sacrum
Sacrum
Pelvic girdle is bigger when we compare it with the
shoulder girdle
It has to bear weight of human being.
The pelvic articulates with the axial skeleton by the
sacrum.
 Sacrum :
Located in the middle and articulates with two iliac
bones.
Hip
bone
The Hip Bone
The hip bones are made
up of 3
These bones are different
bones (ilium superiorly ,
ischium posteriorly and pubis
anteriorly)
connected together with
cartilage, and later fuse
together at the age of 16 - 18
They all meet at the
acetabulum.
Ilium
Ischium
Acetabulum
Pubis
Can be
palpated
Ilium
(Lateral View Left hip Bone)
Gluteal Surface
(posteriolateral
surface)
Anterior
Gluteal Line
Posterior
Gluteal Line
Inferior
Gluteal Line
Greater
Sciatic
Notch
Ilium (Medial View)
Iliac Tuberosity
Arcuate Line
Auricular Surface
In the posterior
aspect) an ear
shaped part that
articulates with the
ala of the sacrum
laterally at the sacro –
iliac joint
pelvic brim
Upper flat area.
The ilium is a large flaring bone that forms the superior region of the
coccyx bone.
 It consists of a body and a superior wing-like portion called the ala.
The ilium is limited superiorly by the crest that we can palpate it
from the anterior to the posterior.
 The iliac crest has two ends one anterior called the anterior
superior iliac spine and one posterior called posterior superior iliac
spine ( the inferior two spines are not parts of the crest )
The crest is thicker anteriorly compared with posteriorly.
There is a split border that has two margin one medial and one
lateral but the most aspect of it is the presence of iliac tubercle (a
roughed area in the medial aspect and posterior to it is the iliac fossa)
 anterior superior iliac spine allows the insertion of external and
internal oblique muscles which make the anterior abdominal
wall, these muscles come from lumbar fascia but superiorly
they take origin from the ribs which are floating and 8th, 9th
and 10th ribs and if you go anterior these muscles, they fuse
together with aponeuroses and these aponeuroses are thin.
 In the lateral view of iliac there are three lines:1. posterior gluteal line
2. Anterior gluteal line
3. Inferior gluteal line
 The gluteus muscles attach to the ilium between these lines.
 In the aspect of the iliac crest, we have the internal lip and the
external lip. And these two lips are important for the insertion of the
muscles.
 There is a depression occurs where the ilium meets the ischial body
and this depression is called the greater sciatic notch (it is inf. to the
post. inf. iliac spine and sup. to ischial body.
Ischium
The part that human beings set on
 An irregular area that has a U-shape.
 The ischium forms the posterioinferior part of the hip bone
Participates in forming one third of acetabulum fossa.
 The thick body articulates with the ilium, and the thinner ramus
articulates with the pubis
Pubis
an opening (usually closed by an obturator
membrane that contains an opening called
obturator canal where
the obturator nerve pass).
Pubis
Iliopectineal Line
Arcuate Line
Pectineal Line
Pubic Tubercle
The Iliopectineal line is a compound line of the arcuate line
from the ilium and the pectineal line from the pubis
V-shape.
The two bones of pubic fused together at pubic crest to form pubic
symphysis ( a wide anterior bone that comes closed by adhesion fused
between both pubic crests in a cartilaginous ligament (so it is less
movable than any other joint compared with synovial joint).
 The pelvic brim is formed by the sacral promontory behind the
iliopectineal lines laterally , and the symphysis pubis anteriorly .
The pectineal line of the pubis: is a ridge on the superior ramus of the
pubic bone, forms part of pelvic prime and in combination with the
arcuate line it makes the iliopectineal line.
The acetabulum is not rounded completely.
In anatomical position of the pelvic, the hip opening is oriented
anterior not superior (the post. Sup. Iliac spin is on the same line with
ischial tuberosity and ant. Sup. Iliac spine is on the same line with
pubic symphysis).
Acetabular fossa is non-articular space with the head of the femur, it
fixed in their ligamentum fovea. Ligamentum fovea comes from the
fovea capitis of the femur head. This fovea capitis is the site into
which the blood vessels enter into the head of the femur. So any
movement or any cutting in that fovea capitis or the foveal ligament
might put this part of bone in danger because of lack of
vascularization.
the acetabular notch is completed by the presence of interacetabular
ligament that prevents the head of femur from dislocation downward.
True and False Pelvis
Sacral promontory +
Arcuate Line +
Pectineal Line =
Linea Terminalis.
The Pelvic Brim is the
edge of the pelvic
inlet.
Above the pelvic
brim  False Pelvis
Beneath the pelvic
brim  True Pelvis
Pelvic
Brim
False and True Pelvis
Contain organs from the abdomen.
The intestines (ileum and sigmoid)
Some reproductive organs, pelvic
colon, rectum, some of the urinal
system.
Orientation of The Pelvis
The anterior superior iliac
spine and the symphysis
pubis are in the same
vertical plane.
The pelvic inlet is directed
antero-superiorly.
(The inlet is when you look at the pelvis from
above. When you do that, you are actually
looking at the False pelvis)
The pelvic outlet is directed
postero-inferiorly.
(the outlet is when you look at the pelvis
(inferior view), you’ll be looking at the true
pelvis)
Pelvic Ligaments
Iliolumbar Ligament
From the transverse processes of the 5th lumbar
vertebra to the iliac crest
Inguinal
Ligament
From the ASIS
to the pubic
tubercle
Anterior Longitudinal
Ligament
Covering the bodies of the vertebrae
Lumbosacral
Ligament
Anterior
Sacro-iliac
Ligament
Covering the
sacro-iliac joint.
Pelvic Ligaments
Sacrotuberous
Ligament
Sacrospinous
Ligament
Obturator
Ligament
Sciatic Nerve passes
through it
The Sacrospinous
and Sacrotuberous
ligaments create the
Greater and Lesser
Sciatic Foramina
from the greater and
lesser sciatic notches,
respectively.
Posterior
Sacroiliac
Ligament
Sacrotuberous
Ligaments
Sacrospinous
Ligaments
Cover the
Posterior Inferior
Iliac Spines (so
they cannot be
palpated)
Ligaments at the Sacro-iliac Joint
Most anteriorly:
Anterior Sacroiliac
Ligament
Intermediate:
Interosseous Sacroiliac
Ligament
Strong ligament that holds the
sacroiliac joint, coming from the
posterior part of the sacrum to the
border between the PSIS and the
PIIS
Most posteriorly:
Posterior Sacroiliac
Ligament
***Structures that hold the pelvic girdle :
1. Illiosacral joint
2. Muscles that come from posterior aspect of abdomen and they go
to the anterior aspect of the thigh.
3. Muscles that are located in gluteal region and these muscles go
downward to the posterior aspect of the thigh.
4. Iliolumbar ligament and that comes from the transverse process of
the lumbar number 5 into the superior posterior border of the iliac
crest.
***Structures that hold the pelvic girdle :
5. Two ligaments that run from
 the Sacrum into the ilium (which the anterior sacroiliac ligament
and the posterior sacroiliac ligament that comes from the sacrum
into the auricular surface of the ilium)
 the Sacrum into the ischium:
A. From the Sacral into the ischial spine = (sacrospinal ligament)
>>> smaller and more anterior >>>creates greater sciatic
foramen
B. From the Sacral into the ischial tuberosity = (sacrotuberous
ligament)>>> creates lesser sciatic foramen.
And these ligaments have two important functions:
 To hold the pelvic girdle to the axial skeleton.
 To provide an openings within the posterior cavity and we call it
pelvic outlet
Male Vs. Female Pelvis
Female
Male
Flat, wide, short alae
Longer, higher alae
Distance from midline is
broad and shallow
Narrow and deep
Obtuse subpubic angle
Acute subpubic angle
Pelvis brim is bigger
Pelvis brim is smaller
Round pelvis brim
Heart-shaped pelvis brim
Bigger pelvic inlet
smaller pelvic inlet
Broader sciatic notch
Narrower sciatic notch
Femur
It articulates proximally with
the hip and distally with the
tibia and fibula.
Longest and largest
bone (weight bearing)
Long neck, prone to
fracture.
Anterior:
Intertrochanteric Line
Posterior:
Intertrochanteric Crest
Patella: sesamoid bone
Head fits in the
acetabulum.
All parts in the picture are
required.
Popliteal
fossa
 Femur doesn’t have a surgical neck.
 The anatomical neck of the femur is longer than the anatomical neck of the
humerus ; that is why it is more vascularized (lateral circumflex artery and
medial circumflex artery that come from the femoral artery).
 So the neck of the femur is more prone to fracture.
 Fovea capitis: is a depression on the head of the femur, it is the entrance of
the obturator artery branch that irrigate the whole articular surfaces together
with acetabular fossa and the head of the femur as well.
 The head of the femur practically will receive vascularization from the
femoral artery as well from the obturator artery.
 necrosis of the head and the neck occurs only if these arteries have been
blocked.
 Adductor tubercle: it's an elevation for the (adductor Magnus muscle)
which leaves a gap; and that's why we call it the adductor canal.
Tibia and Fibula
Intercondylar
Eminence will fill in the
Intercondylar Fossa
present in the inferior
aspect of the femur.
Intercondylar
Eminence provide
attachment for the
Cruciate Ligaments of
the knee joint.
Tibia  weight-bearing
Fibular Notch
Present in the distal portion of
Tibia (at the distal tibiofibular
joint)
can be palpable
Foot
Talus articulates with the
Tibia and Fibula anteriorly.
Calcaneus articulates posteriorly
(It is the biggest)
Proximal group:
Talus and Calcaneus
Intermediate:
Navicular
Distal bones: Cuneiforms
and Cuboid
7 tarsals
5 metatarsals
14 phalanges
(talus is keystone)
runs obliquely from one
side of the foot to the other
(cuboid is keystone)
Foot
Achilles Tendon
Dorsal Surface
Large tendon in the
posterior aspect of the
foot, attaches to the
calcaneus.
The foot has many arches.
there are three arches :
1-lateral longitudinal
2-medial longitudinal
3-transverse.
The foot has a dome
shape that not the whole
foot would touch the
ground, except people
with flat feet.
Plantar Surface
Fracture of The Femur’s Neck
In grade 3 and 4  Displaced
Fracture. Ends of the bone go in
opposite directions (out of
alignment)
Fracture because:
The neck is long
Weight-bearing bone (your
weight pressures the neck of the
femur)
Displaced and not open because:
Muscles and ligament surrounding
the neck of the femur are strong,
so it is unlikely that the fracture
would be open.
To learn more about types of
fractures:
http://www.thehealthsite.com/dis
eases-conditions/all-fractures-are
not-the-same/
Displaced
Traction
Traction is one of the
methods used in
treatment of
fractures.
Uses weights in
different ways to
regain alignment of
fractured bones.
General Notes
Iliac crest is divided into:
Inner lip (directed anterio-medially)
Outer lip (posterio-lateral
Obturator canal is a small gap made by the incomplete coverage of the
Obturator Membrane superiorly.
Auricular surface of ilium + auricular surface in sacral ala = Sacro -iliac Joint
Ischium
Medial surface  Smooth
Lateral surface  roughened (Ischial Tuberosity)  you’re sitting on it!
PIIS cannot be palpated like the ASIS because it is covered by the
Sacrotuberous ligament.
The patella is a sesamoid bone that practically has two facet; each one is for each condyle of the femur,
one for the medial and on for the lateral condyles.
Surface of the patella: the anterior aspect is more roughened than the posterior aspect.
There is hyaline cartilage on the condyles of the femur for articulation with
the articular surfaces on the tibia  Knee Joint
Weight - bearing bones are the femur and tibia.
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