THE SKELETAL SYSTEM
Focus on the Pelvic Girdle and lower limb
General anatomical terms to know
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Process
Ramus
Trochanter
Tuberosity
Tubercle
Crest
Line
Spine
Head
Neck
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Condyle
Trochlea
Facet
Fossa
Sulcus
Foramen
Canal of meatus
Fissure
Sinus
Appendicular Skeleton
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126 bones
Includes
 bones
of the limbs (appendages)
 Supporting bones of the pectoral
and pelvic girdles (connect limbs to
axial skeleton)
Pelvic Girdle
Includes sacrum, coccyx and coxal (hip) bones
Function: transfers weight of the upper body to the legs;
designed for stability and locomotion
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more massive than the pectoral girdle
more firmly attached to the axial skeleton
Sacroiliac joint = articulation of hip bone with sacrum
Hip joint = articulation of hip bone with femur (acetabulum)
The Coxal Bones (2; hip bones)
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TWO coxal bones
Each hip bone results from the fusion of three separate
components which fuse together:
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2.
3.
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The ilium
The ischium
Pubis symphisis
The ilium, ischium and pubis together form a deep socket
called the acetabulum which articulates with the head of
the femur
The Ilium
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Largest, most superior component of the coxal bone
Broad curved surface provides large surface area for
attachment of muscles, tendons and ligaments
Iliac crest = “the hip”
Iliac spine can be seen is especially thin people
The ilium – superior portion of the hip
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Iliac crest (superior)
ASIS = anterior superior iliac spine
PSIS = posterior superior iliac spine
Iliac fossa = wide depression
Ala = the other side of the iliac fossa
Arcuate line (medial)
Sacral articulation
Anterior, posterior and superior gluteal lines
(attachments for gulteal muscles)
Greater sciatic notch
The Ischium
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Most Inferior and strongest part of the coxal bone
Ischial tuberosity (inferior surface) supports the body’s
weight when sitting; attachment site for hamstrings
Ischial Spine: separates the greater and lesser sciatic
notch.
Obturator foramen – passageway for nerves and blood
vessels from abdominal cavity to lower limbs
Lesser Sciatic Notch- smooth notch covered with cartilageattachment for tendons
Pubis
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Most anterior part of the coxal bone
Also called pubic bone
Acetabulum:
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Latin for little cup of vinegar
Deep socket formed were the ilium, ischium and
pubis bones articulate
Accepts the head of the femur to form the hip joint
Ball and socket joint
Male vs Female
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Differences in shape and size result from variations in
body size and muscle mass
 Female
pelvis: Smoother, lighter in mass and less prominent
markings
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Some differences are adaptations for child-bearing (to
support the weight of the fetus and to ease passage of baby
during birth)
 Female
pelvis: broad, low pelvis, larger pelvic outlet, broader
pubic angle
Male vs Female
Male vs Female Pelvis
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Female pelvis:
 Pelvic
weight- bones of the pelvis are lighter and thinner
 Pelvic inlet(brim)- rounded and oval shaped
 Pelvic outlet- rounded and larger
 Subpubic angle- female greater than 80 degrees
 Ischial spines- greater distance between the ischial spines
 Lesser pelvic cavity- shorter and wider in females- this is why
females tend to have broader hips.
Male vs Female
Bones of the Lower Limbs
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Thigh = femur
Leg = tibia and fibula
Foot = tarsals, metatarsals and
phalanges
The Femur
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Heaviest strongest bone in the body
Structures to know: greater and lesser trochanters,
intertrochanteric crest, gluteal tuberosity, lateral and
medial condyles, intercondylar fossa (notch), patellar
surface
Head of femur articulates with acetabulum of pelvis girdle
Neck of femur = common fracture site
Slants medially to join with the leg bones which brings the
knees in line with the center of gravity
Head- articulates with the acetabulum
 Neck- weakest part of the femur-common
area for fractures
 Greater trochanter- insertion of gluteus
muscles
 Lesser trochanter- insertion of the psoas
muscle
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Epicondyles- attachment of ligaments and
muscles
 Trochlear groove(patellar groove)articulates with the patella
 Condyles- articulate with the condyles of the
tibia- distribute weight to the knee
 Intercondylar fossa: separates the condyles
of the femur- attaches the cruciate ligaments
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Intertrochanteric crest
The Femur
Greater trochanter
neck
head
Lesser
trochanter
Gluteal
tuberosity
Intercondylar
Fossa (notch)
Medial condyle
Patellar
surface
Lateral condyle
Guess Who??
The Leg
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Two bones connected by interosseous membrane
 Tibia
(shin) = larger, medial bone
 Forms
knee joint with femur
 Medial malleolus forms the ankle
 Fibula
= thin and stick-like
 No
part in forming knee joint
 lateral malleolus forms the ankle
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Structures to know: medial and lateral condyles, intercondylar eminence,
tibial tuberosity, medial and lateral malleolus, tibiofibular joints, anterior
crest,
The Leg
The Foot
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Two important functions:
Support of body weight
 Serves as a lever to propel our body forward
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Tarsals (7 bones)
Calcaneous = heel bone
 Talus = “ankle” lies between the tibia and the calcaneous
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Metatarsals (5 bones) = sole of foot
Phalanges (14 bones) = toes
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Each toe has 3 phalanges except the big toe which has 2
The Foot
Arches of the Foot
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3 arches
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Two longitudinal (medial and lateral)
One transverse
Ligaments bind the foot bones together
Tendons help hold the bones firmly in the arched position
Weak arches = “flat feet” or “fallen arches”
Can you identify the following: