Skeletal System

2.  Hip bone is made up of
three bones, which fuse
during early adult-
hood.
 The ilium bone forms
the superior portion of
the Hip bone, the
ischium bone the lower
posterior portion, and
the pubic bone (pubis)
the lower anterior
portion.

3.  Three articulation (joint)
sites are found on each hip
bone.
 The two hip bone meet
anteriorly at the pubic
symphysis joint and
converge posteriorly with
the sacrum at the sacroiliac
joints. Laterally, deep
sockets called acetabula
accept the heads of the
femurs to form the hip
joints.

4.  The right and left hip bone
form the pelvic girdle.
Together, the pelvic girdle,
sacrum, and coccyx (final 3-5
vertebrae) make up a ring of
bones called the pelvis (bony
pelvis).
 The bony pelvis protects the
soft organs of pelvic cavity
(bladder, lower colon, rectum,
and reproductive organs).
 It also provides attachment
points for many muscles that
control the movements of the
back, abdomen, and femur
bones.

5. Ilium Bone Markings.
1. Iliac Crest or Crest of Ilium: is the curved
upper ridge of the ilium. The latissimus dorsi,
quadratus lumborum, erector spine, iliacus,
tensor fasciae latae, and abdominal muscles
attach along the surface of this ridge.
2. Iliac Fossa is a broad depression located along
the anteromedial surface, inferior to the iliac
crest. It is an attachment point for the iliacus
muscle.
3. Anterior Superior Iliac Spine is a anterior
pro-jection from the iliac crest that serves as
an attachment point for the sartorius muscle
and inguinal ligament.
4. Anterior Inferior Iliac Spine is a projection
below the anterior superior iliac spine that is
as an attachment point for the rectus femoris
muscle.

6. Pubic Bone Markings.
a. Symphysis pubis or pubic symphysis is the
cartilaginous joint between the two pubic
bones.
b. Body of pubis is the flatten, medial end of the
pubis that lies adjacent to the symphysis
c. Inferior Pubic Ramus is a thin, flat,
downward extension that runs diagonally from
the medial pubis to the ischial ramus. The
adductor brevis, adductor magnus, and gracilis
muscles attach to this ramus.
d. Superior Pubic Ramus is a band of bone that
runs along the superior aspect of the pubis.
The surface of this ramus is an attachment site
for the pectineus muscle.
e. Pubic crest is a short, superiomedial ridge
that runs extends horizontally from the
symphysis to the pubic tubercle. It is an
attachment point for the abdominal muscles.
f. Pubic tubercle is a projection from the lateral
end of the pubic crest and serves as an
attachment point for the inguinal ligament.

7. Ischium Bone Marking
a. Ramus of Ischium is a
thin, flat, anterior
extension of the ischium
that joins with the
inferior ramus of the
pubic bone. The
adductor magnus
muscle attaches along
its surface.

8. Interdivisional Bone Markings
a. Obturator foramen is a large
opening enclosed by the
pubic and ischial rami.
b. Acetabulum is a large,
rounded depression on the
external (lateral) surface of
the os coxa. It is formed by
portions of the ilium, ischium,
and pubic bones and accepts
the head of the femur to form
the hip joint.

9. Ilium Bone Markings.
a. Iliac Crest or Crest of Ilium is the
curved upper ridge of the ilium. It is
an attachment point for the
latissimus dorsi, quadratus
lumborum, erector spine, iliacus,
tensor fasciae latae, and abdominal
muscles.
b. Iliac Tubercle or Tubercle of the
iliac Crest is a prominent bulge on
the outer lip of the iliac crest, near
its midpoint. This area is an
attachment site for the iliotibial tract
or band.
c. Anterior Superior Iliac Spine or
ASIS is a projection from the anterior
portion of the iliac crest. The
sartorius muscle and inguinal
ligament attach to this elevation.

10. d. Anterior Inferior Iliac Spine or
AIIS is a projection below the
anterior superior iliac spine that
serves as an attachment point for the
rectus femoris muscle.
e. Posterior Superior Iliac Spine is a
projection from the posterior of the
crest. It is an attachment point for
the posterior sacroiliac ligament and
multifidus muscle.
f. Posterior Inferior Iliac Spine is a
curvature found inferior to the
posterior superior iliac spine. The
two spines are separated by a small
notch. A ligament that binds the
ilium to the sacrum attaches here.

11. g. Posterior gluteal line is a short, ridge on the
external surface of the ilium. It runs vertically
between the iliac crest and greater sciatic
notch, just anterior to the posterior spines.
The line is the anterior attachment point for
the gluteus maximus muscle and posterior
attachment point for the gluteus medius
muscle.
h. Anterior gluteal line is a long, posteriorly
curved ridge that spans the midportion of the
external ilium. The ridge serves as the anterior
attachment point for the gluteus medius
muscle and superior attachment point for
gluteus minimus muscle.
i. Inferior gluteal line is a slight ridge that runs
diagonally across the external surface of the
ilium from the anterior inferior iliac spine to
the greater sciatic notch. It is the inferior
attachment point for the gluteus medius
muscle and superior attachment point for the
gluteus minimus muscle.

12. Pubic Bone (Pubis) Markings
a. Body of pubic bone is the flatten,
medial end of the pubis that lies
adjacent to the symphysis.
b. Inferior pubic ramus is a thin, flat
extension from the medial pubis that
joins the ischial ramus.
c. Superior pubic ramus is a band of
bone that runs along the superior
aspect of the pubis. It is an attachment
point for the pectineus muscle.
d. Pubic tubercle is a projection from
the lateral end of the pubic crest that
serves as an attachment point for the
inguinal ligament.

13. Ischium Bone Markings
a. Ischial tuberosity is a roughened, curved
eminence located at the junction of the
posterior and inferior borders of the
ischium. It serves as an attachment point
for the sacrotuberous ligament and the
hamstring muscles, quadratus femoris
muscle, and inferior gemellus muscle.
b. (Inferior) Ramus of Ischium is an
anterior extension from the ischial
tuberosity that joins the inferior ramus of
the pubic bone. The adductor magnus and
obturator externus muscles attaches to
this portion of the ischium.
c. Ischial Spine is a sharp projection from
the posterior margin of the ischium. It is
an attachment point for the sacrospinous
ligament.
d. Lesser Sciatic Notch is a small
indentation located inferior to the spine.

14. Interdivisional Bone Markings.
a. Greater Sciatic Notch is a large
indentation located below the
posterior inferior iliac spine.
b. Obturator Foramen is a large
anterior opening enclosed by the
pubic and ischial rami.
c. Acetabulum is a large, rounded
depression on the external surface
of the os coxa. The acetablum is
formed by portions of the ilium,
ischium, and pubic bones and
accepts the head of the femur to
form the hip joint.

15. Ilium Bone Markings.
a. Iliac Crest or Crest of Ilium is the
curved upper ridge of the ilium. It is
an attachment point for the
latissimus dorsi, quadratus
lumborum, erector spine, iliacus,
tensor fasciae latae, and abdominal
muscles.
b. Anterior Superior Iliac Spine or
ASIS is a projection from the anterior
portion of the iliac crest. The
sartorius muscle and inguinal
ligament attach to this elevation.
c. Anterior Inferior Iliac Spine or
AIIS is a projection below the
anterior superior iliac spine that
serves as an attachment point for the
rectus femoris muscle.

16. d. Posterior Superior Iliac Spine is a
projection from the posterior of the
crest. It is an attachment point for
the posterior sacroiliac ligament
and multifidus muscle.
e. Posterior Inferior Iliac Spine is a
curvature found inferior to the
posterior superior iliac spine. The
two spines are separated by a small
notch. A ligament that binds the
ilium to the sacrum attaches here.
f. Iliac Fossa is a broad depression
located along the anteromedial
surface, inferior to the iliac crest. It
is an attachment point for the iliacus
muscle.

17. g. Iliac tuberosity is a roughened area
located inferior to the crest and
posterior to the iliac fossa. The
posterior sacroiliac ligaments and
the sacrospinalis and multifidus
muscles attach here.
h. Auricular surface is a L-shaped or
ear-shaped roughened surface
situated inferior to the tuberosity.
This area articulates with auricular
surface of sacrum to form the
sacroiliac joint.
i. Arcuate line is a curved ridge that
forms the inferior boundary of the
iliac fossa. It also delinates the
boundary between the body and the
wing (large expanded portion; ala) of
the ilium.

18. Pubic Bone (Pubis) Markings.
a. Symphysis pubis or pubic
symphysis is the cartilaginous
joint between the two pubic
bones
b. Body of pubis is the flatten,
medial end of the pubis that lies
adjacent to the symphysis.
c. Inferior pubic ramus is a thin,
flat extension from the medial
pubis that joins the ischial
ramus. The adductor brevis,
adductor magnus, and gracilis
muscles attach along this
surface.

19. d. Superior pubic ramus is a band of
bone that runs along the superior
aspect of the pubis. It is an
attachment point for the pectineus
muscle.
e. Pectineal line is a sharp ridge that
runs along the superior margin of the
superior pubic ramus. This area,
which is also called the pecten pubis,
is an the attachment point for the
pectineus muscle.
f. Pubic crest is a short, superiomedial
ridge that runs extends horizontally
from the symphysis to the pubic
tubercle. It is an attachment point for
the abdominal muscles.
g. Pubic tubercle is a projection from
the lateral end of the pubic crest that
serves as an attachment point for the
inguinal ligament.

20. Ischium Bone Markings.
a. Ischial tuberosity is a roughened,
curved eminence located at the junction
of the posterior and inferior borders of
the ischium. It supports the weight of the
body when sitting and serves as an
attachment point for the sacrotuberous
ligament and the hamstring muscles,
quadratus femoris muscle, and inferior
gemellus muscle.
b. (Inferior) Ramus of Ischium is an
anterior extension from the ischial
tuberosity that joins the inferior pubic
ramus. The adductor magnus and
obturator externus muscles attach to this
surface.
c. Ischial Spine is a sharp projection from
the posterior margin of the ischium. It is
an attachment point for the sacrospinous
ligament.
d. Lesser Sciatic Notch is a indentation
located below the spine.

21. Interdivisional Bone Markings.
a. Greater Sciatic Notch is a
large indentation located
below the posterior inferior
iliac spine.
b. Obturator Foramen is a
large anterior opening
enclosed by the pubic and
ischial rami.

22.  The femur extends from the hip to the knee and is the
longest and strongest bone in the body.
 Forming the midportion of the femur is a long
cylindrical shaft, which arches or curves anteriorly.
 At its proximal end, the spherical head of the femur
articulates with the acetabulum of the hip bone to
form the hip joint.
 Distally, the femur articulates with the medial and
lateral condyles of the tibia to form the knee joint.
 The patella bone covers the anterior portion of the
femur’s distal articular surface and helps protect the
knee joint from injury.

23. Bone Markings.
a. Shaft is the cylindrical,
anteriorly arched body of the
femur.
b. Head is a prominent, smooth,
ball-shaped structure on the
proximal end of the bone. The
head articulates with the
acetabulum of the hip bone to
form the hip joint.
c. Fovea of Femur Head is a
small, pit-like depression on the
medial surface of the head,
which is also called the fovea
capitis. It is as an attachment
site for the ligamentum teres.

24. d. Neck is a pyramid-shaped expanse
that connects the head to the shaft.
This region is a frequent site of
fractures, especially in the elderly.
e. Greater trochanter is a large,
irregular-shaped process located
lateral to neck and superior to shaft.
It is an attachment point for the
gluteus medius, gluteus minimus,
piriformis, obturator, and gemellus
muscles.
f. Lesser trochanter is a medial
prominence located just inferior to
neck. It is the insertion point for the
iliacus and psoas major muscles.
g. Intertrochanteric line is an anterior
ridge that obliquely spans the
distance betweeen the greater and
lesser trochanters. It is the
attachment point for the articular
capsule and iliofemoral ligament.

25. h. Medial condyle is a large,
rounded, knob-like projection at
the mediodistal end of the femur.
It articulates with the medial
condyle of the tibia.
i. Medial epicondyle is a small,
medial protrusion superior to the
articular surface of the medial
condyle. It is an attachment point
for the tibial (medial) collateral
ligament.
j. Adductor tubercle is a small
elevation on the superior surface
of the medial condyle. It serves as
an attachment point for the
adductor magnus muscle.
k. Lateral condyle is a large
rounded projection at the
laterodistal end of the bone. It
articulates with the lateral
condyle of tibia

26. l. Lateral epicondyle is a
small, lateral protrusion
superior to the articular
surface of the lateral condyle.
It is an attachment point for
the fibular (lateral) collateral
ligament.
m. Patellar surface is the
smooth surface that covers
the anterior portion of the
femur condyles. This area
articulates with the posterior
surface of the patella.

27. Bone Markings
a. Shaft is the cylindrical, anteriorly
arched body of the femur.
b. Head is a large, smooth, ball-
shaped structure on the proximal
end of the bone. It fits into the
socket (acetabulum) of the of the
hip at the hip joint.
c. Fovea of the femur head is a
small, pit-like depression on the
medial surface of the head. It is as
an attachment site for the
ligamentum teres. This short,
narrow, ligamentous band
transmits arteries to the head of
the femur and helps attach the
head to the acetabulum of the hip
bone.

28. d. Neck is a pyramid-shaped expanse that
connects the head of the femur to the
shaft. it extends laterally from the head
at a downward angle of approximately
125 degrees, and is a frequent site of
fractures.
e. Greater trochanter is a large,
irregular-shaped process located
lateral to neck and superior to shaft. It
is an attachment point for the gluteus
medius, gluteus minimus, piriformis,
obturator, and gemellus muscles.
f. Lesser trochanter is a medial
prominence located just inferior to
neck. It is the insertion point for iliacus
and psoas major muscles.

29. g. Intertrochanteric crest is a thick
ridge that runs obliquely along the
base of the posterior neck from
the greater trochanter to the
lesser trochanter. It marks the
junction between the neck and
shaft.
h. Quadrate tubercle is a small
elevation on the intertrochanteric
crest that serves as an attachment
point for quadratus femoris
muscle.
i. Pectineal line is a slight ridge
located inferior to the posterior
surface of the lesser trochanter. It
is an inferior (distal) attachment
site for the pectineus muscle.

30. j. Linea aspera is a vertical ridge that
runs along the midline of the
femur's posterior surface. The
medial and lateral lips of the linea
aspera are attachment sites for the
adductor, vastus lateralis, vastus
medialis, and biceps femoris (short
head) muscles.
k. Gluteal tuberosity is a roughened,
vertical elevation that extends from
the top of the linea aspera to the
base of the greater trochanter. It is
an insertion point for the gluteus
maximus muscle.
l. Medial condyle is a large rounded
projection at the mediodistal end of
the bone. It articulates with medial
condyle of tibia at the knee joint.

31. m. Lateral condyle is a large
rounded projection at the
laterodistal end of the bone.
It articulates with the lateral
condyle of tibia at the knee.
n. Intercondylar fossa is a
large notch between the
posterior condyles that
provides space for the
cruciate ligaments that help
attach the femur to the tibia
at the knee.
o. Medial epicondyle is a
protrusion above the medial
condyle. It is an attachment
point for the tibial (medial)
collateral ligament that helps
attach the femur to the tibia
at the knee.

32. p. Adductor tubercle is a small elevation on
the superior surface of the medial condyle.
The vertical fibers of the adductor magnus
muscle attach to this prominence.
q. Lateral epicondyle is a small protrusion
above the lateral condyle. It is an attachment
point for the fibular (lateral) collateral
ligament that helps attach the femur to tibia
at the knee.
r. Lateral supracondylar line is an inferior
extension of the lateral lip of the linea aspera
that ends at the lateral epicondyle. The ridge
is an attach-ment site for the vastus lateralis,
piriformis, and biceps femoriss.
s. Medial supracondylar line is an inferior
extension of the medial lip of the linea aspera
that terminates just above the adductor
tubercle. It serves as attachment point for
inferior portions of vastus medialis and
adductor magnus muscles

33. Introduction.
 The patella is a triangular shaped
bone that covers and protects the
distal surface of the anterior femur.
 It is located directly anterior to a
groove between the femur condyles
called the patellar surface. Two facets
(or depressions) on the posterior side
of the patella articulate with the
medial and lateral femur condyles.
 The patella is embedded in the
quadriceps tendon, which makes it
the largest sesamoid bone in the body.
It functions to displace the tendon
away from the femurotibial joint
surface. This increases the lever arm
of the tendon and the tension applied
to the tibia when the knee extends

34. Bone Markings.
a. Base is the broad, convex superior
margin of the patella, which serves
as an attachment point for the
quadriceps tendon.
b. Apex is the pointed inferior
margin of patella. This region
serves as an attachment point for
the patellar ligament, which is an
inferior extension of the
quadriceps tendon.
c. Lateral articular facet is the
larger of two shallow depressions
on the posterior surface of the
patella, which articulates with the
lateral condyle of femur
d. Medial articular facet is the
smaller of two shallow depressions
on the posterior surface of the
patella, which articulates with the
medial condyle of femur.

35.  The tibia and fibula are the bones that
support the leg. The larger tibia or
shine bone is located medial to the
fibula and bears most of the weight.
 At the superior (proximal) end of the
tibia, a pair of flattened condyles
articulate with the rounded condyles at
the distal end of the femur to form
the knee joint or tibiofemoral joint.
 The tibia and fibula articulate at two
sites. At the knee, a superior (proximal)
tibiofibular joint is formed by the
lateral tibial condyle and head of the
fibula. At the ankle, an inferior (distal)
tibiofibular joint is formed by the lower
fibula and a lateral concavity (notch) on
the lower tibia.
 A socket formed by the distal ends of
the tibia and fibula articulates with the
superior portion of the talus (foot
tarsal) bone to form the ankle joint.

36. Tibia Bone Markings.
a. Lateral condyle is a lateral expansion
of the tibia's proximal end.
b. Medial condyle is a medial expansion
of the tibia's proximal end. The
posterior of the medial condyle
provides attachment for the
semimembranosus muscle.
c. Intercondylar eminence is an elevated
area between the condyles. Anterior
and posterior cruciate ligaments and
the central tips of the medial and lateral
menisci are attached to the depressions
of condyle
d. Tibial tuberosity is a raised,
roughened area on the anterior surface
of the bone, just inferior to the
condyles.

37. e. Tibial shaft or body is the long, cylindrical
midsection of the bone.
f. Anterior crest, border or margin is a
anterior ridge located just under the skin.
g. Interosseous border or margin is the
tibia's sharp-edged lateral margin that
provides attachment for the interosseous
membrane of the leg.
h. Medial malleolus is a prominent
downward projection at the distal end of
the tibia, on the medial side. It articulates
with the talus bone to form the medial
portion of the ankle joint.
i. Fibular notch is an concavity at the distal
end of the tibia, on the lateral side. It
articulates with the fibula to form the
inferior tibiofibular joint.

38. Fibula Bone Markings.
a. Head of fibula is a small knob-like extension
from the proximal end of the fibula that
articulates with the lateral condyle of tibia. The
head is an attachment site for the soleus, bicep
femoris, fibularis longus, and extensor digitorum
longus muscles and the fibular (lateral)
collateral ligament.
b. Shaft of fibula or body is the elongated
midsection of the bone.
c. Interosseous border or margin is the sharp-
edged medial margin of the fibula that serves as
the attachment site for the interosseous
membrane, which binds the fibula to the tibia.
d. Lateral malleolus is a pyramidal-shaped,
downward projection from the distal end of the
fibula. The medial malleolus, which extends
more inferiorly than the lateral malleolus,
articulates with the tibia and the talus bones of
the foot to form the lateral portion of the ankle
joint. Several ligaments attach the lateral
malleolus to the tibia, talus, and calcaneus bones