Kaan Yücel M.D., Ph.D.
26. February.2013 Tuesday
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1.INTRODUCTION TO OSTEOLOGY
Osteology (Gk, osteon, bone, logos, science)
branch of medicine concerned with the development and diseases of bone tissue
The human skeleton
206 bones in adults
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The skeletal system may be divided into
2 functional parts:
The axial skeleton
• head (cranium or skull)
• neck (hyoid bone and cervical vertebrae)
• trunk (ribs, sternum, vertebrae, and sacrum)
The appendicular skeleton
• Limbs
including those forming the shoulde & pelvic girdles
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Bone
one of the hardest structures of the animal body
calcification of its extracellular matrix
some elasticity
results from the organic matter
great rigidity
results from their lamellous structures and tubes of inorganic calcium
phosphate
color in a fresh state
pinkish-white externally, deep red within.
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sparse cells surrounded by an extracellular network/matrix
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Osteoblasts
secrete proteins into the matrix.
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Mature bone is composed of proteins and minerals.
60% the weight of the bone mineral
Rest - water & matrix.
90% of the matrix proteins collagen 1/3 of the bone weight
very strong
forms bone, cartilage, skin, and tendons.
High resolution image of cortical
bone and single collagen fibril (inset)
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Minerals of the matrix
Mainly calcium phosphate & calcium carbonate
Embedded in the protein network
Provide hardness and compressive strength.
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Matrix maintained by osteocytes
Haversian systems or osteons
concentric rings of osteocytes arranged around a central blood vessel.
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Principal types of bone cells
1.
2.
3.
4.
Osteogenic cells
Osteoblasts
Osteocytes
Osteoclasts
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Periosteum
membrane surrounding the bone tissue
provides a route for the vasculature and nerve supply.
participates in bone growth and repair.
Endosteum
lines the marrow cavity
active during bone growth, repair, and remodeling
covers trabeculae of spongy bone
lines the inner surfaces of the central canals
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The skeleton is composed of cartilages and bones.
Cartilage
resilient, semirigid form of connective tissue
forms parts of the skeleton where more flexibility is required.
articulating of bones participating
in a synovial joint capped with
articular cartilage
provides smooth, low-friction, gliding surfaces for
free movement
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Blood vessels do not enter cartilage avascular
Diffusion
bone /cartilage in the skeleton
changes as the body grows
younger a person the more cartilage
bones of a newborn are soft and flexible because mostly composed of cartilage.
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The skeleton is composed of cartilages and bones.
The amount and kind of extracellular fibers in the matrix
depends on the type of cartilage.
Heavy weightbearing areas or areas prone to pulling forces
More collagen fibers, less flexible cartilage.
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Functions of cartilage
1. support soft tissues
2. provide a smooth, gliding surface for bone articulations at joints
3. enable the development and growth of long bones.
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Types of cartilage
1. Hyaline
most common, matrix w/ moderate amount of collagen fibers articular surfaces of bones
2. Elastic
large number of elastic fibers external ear
3. Fibrocartilage
limited number of cells & ground substance amidst substantial amount of collagen fibers intervertebral discs
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Bones function as
supportive structures for the body
protectors of vital organs
reservoirs of calcium and phosphorus
levers on which muscles act to produce movement
containers for blood-producing cells
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TYPES OF BONES
according to their shape gross anatomy
1) Long bones
2) Short bones
tubular humerus in the arm
cuboidal
tarsus (ankle) carpus (wrist)
3) Flat bones
protective functions
flat bones of the cranium protect the brain
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Classification of Bones
4) Irregular bones
various shapes other than long, short, or flat
bones of the face
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Classification of Bones
5) Sesamoid bones
patella or knee cap
protect the tendons from excessive wear
often change the angle of the tendons as they pass to their attachments.
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Long bones develop by replacement of hyaline cartilage plate
endochondral ossification
a shaft diaphysis - two ends epiphyses
Metaphysis
a part of the diaphysis adjacent to the epiphyses.
Diaphysis encloses the marrow cavity.
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2 types of bones according to histological features
compact bone & spongy (trabecular) bone
relative amount of solid matter
# & size of the spaces they contain
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All bones have a superficial thin layer of compact bone
around a central mass of spongy bone
except where the spongy bone is replaced by a medullary (marrow) cavity.
Spongy bone
found @ expanded heads of long bones + fills most irregular bones.
Compact bone
forms outer shell of all bones + shafts in long bones.
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Bone Markings and Formations
 Bone markings appear wherever tendons, ligaments, and fascias are
attached or where arteries lie adjacent to or enter bones.
 Other formations occur in relation to the passage of a tendon (often
to direct the tendon or improve its leverage) or to control the type of
movement occurring at a joint.
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Bone Markings and Formations
 Surfaces of the bones are not smooth.
 Bones display elevations, depressions and holes.
 The surface features on the bones are given names to distinguish and
define them.
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Vasculature and Innervation of Bones
 Bones are richly supplied with blood vessels.
 Veins accompany arteries.
 Nerves accompany blood vessels supplying bones.
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SKULL BONES
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Skull
is supported on the summit of the vertebral column, and is of an oval
shape, wider behind than in front.
It is composed of a series of flattened or irregular bones which, with one
exception (the mandible), are immovably jointed together. It is divisible
into two parts:
(1) cranium, which lodges and protects the brain, consists of 8 bones
(2) skeleton of the face, of 14
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at the back and lower part of the cranium
trapezoid in shape and curved on itself.
pierced by a large oval aperture, the foramen magnum,
cranial cavity communicates with the vertebral canal
through the foramen magnum
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form, by their union, the sides and roof of the cranium
each bone irregularly quadrilateral in form
external surface convex, smooth
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@front of the skull. Forms the forehead.
Enters into the formation of the roofs of the orbital and nasal cavities.
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at the sides and base of the skull.
consist of the pathway to the inner ear and contributes to the
formation of the jaw with the mandible.
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at the base of the skull in front of the temporals and basilar part of
the occipital.
median portion or body, two great and two small wings extending
outward from the sides of the body, and two pterygoid processes
which project from it below.
supplies the bed for the pituitary gland.
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exceedingly light and spongy
cubical in shape
at the anterior part of the base of the cranium
between the two orbits, at the roof of the nose
contributes to each of these cavities.
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Cranial Fossae
Anterior cranial fossa
occupied by the inferior and anterior parts of
the frontal lobes of the brain
shallowest cranial fossa
Middle cranial fossa
butterfly-shaped
central part composed of the sella turcica on the
body of the sphenoid
large, depressed lateral parts on each side
Posterior cranial fossa
largest and deepest cranial fossa
formed mostly by the occipital bone
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Facial Bones
Nasal Bones
o two small oblong bones, varying in size
form in different individuals
o placed side by side @ middle & upper
part of the face
o form, by their junction, “the bridge” of
the nose.
Maxillæ (Upper Jaw)
o largest bones of the face, excepting
mandible
o form the whole of the upper jaw.
Form the boundaries of 3 cavities
o roof of the mouth
o floor and lateral wall of the nose
o floor of the orbit
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Facial Bones
Lacrimal Bone
smallest & most fragile bone of the face
at the front part of the medial wall of the orbit
Zygomatic Bone (Malar Bone)
small and quadrangular
at the upper and lateral part of the face
forms
prominence of the cheek
part of the lateral wall & floor of the orbit.
Zygomatic arch
zygomatic process of the temporal bone
temporal process of the zygomatic bone
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Facial Bones
Palatine Bone
@ back part of the nasal cavity.
contributes to the walls of three cavities
1) floor and lateral wall of the nasal cavity
2) roof of the mouth
3) floor of the orbit.
Inferior Nasal Concha
extends horizontally along the lateral wall of the nasal cavity.
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Facial Bones
Vomer
in the median plane
thin, somewhat quadrilateral in shape
forms hinder & lower part of the nasal septum.
Mandible (Lower Jaw)
largest and strongest bone of the face
serves for the reception of the lower teeth.
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Facial Bones
Hyoid Bone
shaped like a horseshoe
suspended from the tips of
the styloid processes of the
temporal bones.
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Ribs (L. costae)
curved flat bones
form most of the thoracic cage.
3 types of ribs:
 True (vertebrocostal) ribs (1st-7th ribs):
directly to the sternum.
 False (vertebrochondral) ribs
(8th, 9th, and usually 10th ribs):
indirect with the sternum
 Floating (vertebral, free) ribs
(11th, 12th, and sometimes 10th ribs):
No connection with the sternum
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Typical ribs (3rd-9th) have the following components:
Head
one facet for articulation with the numerically corresponding vertebra
one facet for the vertebra superior to it
Neck
Tubercle articulates with the corresponding transverse process of the vertebra.
Body (shaft)
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Costal cartilages prolong the ribs anteriorly and contribute to the
elasticity of the thoracic wall, providing a flexible attachment
for their anterior ends.
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 Intercostal spaces separate the ribs and their costal cartilages from
one another.
 The spaces are named according to the rib forming the superior
border of the space—for example, the 4th intercostal space lies
between ribs 4 and 5.
 There are 11 intercostal spaces and 11 intercostal nerves. Intercostal
spaces are occupied by intercostal muscles and membranes, and two
sets (main and collateral) of intercostal blood vessels and nerves,
identified by the same number assigned to the space.
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G. sternon, chest
Has three parts:
1. Manubrium
2. Body
3. Xiphoid process
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VERTEBRAL COLUMN
 In an adult typically consists of 33 vertebrae arranged in five regions:
7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal.
 The vertebrae gradually become larger as the vertebral column
descends to the sacrum and then become progressively smaller
toward the apex of the coccyx.
The change in size is related to
the fact that successive
vertebrae bear increasing
amounts of the body's weight
as the column descends.
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The vertebrae reach maximum size immediately superior to the
sacrum, which transfers the weight to the pelvic girdle at the
sacroiliac joints.
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The vertebral column is flexible because it consists of many relatively
small bones, called vertebrae (singular = vertebra), that are separated
by resilient intervertebral (IV) discs.
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 Vertebrae vary in size and other characteristics from one region of
the vertebral column to another, and to a lesser degree within each
region; however, their basic structure is the same.
 A typical vertebra consists of a vertebral body, a vertebral arch, and
seven processes.
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vertebral body
anterior part of the bone that gives strength to the vertebral column and supports body
weight.
vertebral arch
posterior to the vertebral body.
vertebral arch & posterior surface of the vertebral body form
walls of the vertebral foramen.
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7 cervical vertebrae
characterized mainly by their
small size and the presence of
a foramen in each transverse
process , bifid spinous process
12 thoracic vertebrae
characterized by their
articulated ribs , spinous
process projecting inferiorly
five lumbar vertebrae,
characterized by their large
size
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BONES OF THE UPPER LIMB
&
THE SHOULDER
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CLAVICLE (TR. KÖPRÜCÜK KEMİĞİ)
 The clavicle (collar bone) connects the upper limb to the trunk.
 The shaft of the clavicle has a double curve in a horizontal plane.
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CLAVICLE (TR. KÖPRÜCÜK KEMİĞİ)
 Its medial half articulates with the manubrium of the sternum.
 Its lateral half articulates with the scapula.
 These curvatures increase the resilience of the clavicle and give
it the appearance of an elongated capital S.
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The clavicle:
 increases the range of motion of the limb.
 affords protection to the neurovascular bundle supplying the upper
limb.
 transmits shocks (traumatic impacts) from the upper limb to the axial
skeleton.
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Scapula (Tr. Kürek kemiği)
The scapula (shoulder blade) is a triangular flat bone that lies on the
posterolateral aspect of the thorax.
The scapula has an articular surface; a glenoid cavity (G. socket) for
the articulation with the head of the humerus.
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HUMERUS
 largest bone in the upper limb
 articulates with the scapula at the
glenohumeral joint
 articulates with the radius and ulna at the
elbow joint.
 The proximal end of the humerus has a head,
surgical and anatomical necks, and greater
and lesser tubercles.
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HUMERUS
spherical head of the humerus
articulates with the glenoid
cavity of the scapula.
surgical neck of the humerus,
a common site of fracture, is
the narrow part distal to the
head and tubercles.
distal end of the humerus
makes up the condyle of the
humerus.
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BONES OF THE FOREARM
The two forearm bones serve together to form the second unit of an
articulated mobile strut (the first unit being the humerus), with a
mobile base formed by the shoulder, that positions the hand.
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stabilizing bone of the forearm
medial and longer of the two forearm bones.
Its more massive
proximal end is
specialized for
articulation with the
humerus proximally
and the head of the
radius laterally.
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lateral and shorter of the two forearm bones.
Its proximal end includes a short head, neck.
Proximally, the head of the radius is concave
for articulation with the humerus during
flexion and extension of the elbow joint.
The head also articulates with the ulna.
The shaft of the radius, in contrast to that of
the ulna, gradually enlarges as it passes
distally.
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 The distal end of the radius accommodates the head of the ulna.
 Its lateral aspect becomes increasingly ridge-like, terminating distally
in the radial styloid process.
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Bones of the hand
 The wrist, or carpus, is composed of eight carpal bones (carpals)
arranged in proximal and distal rows of four.
 The proximal surfaces of the distal row of carpals articulate with the
proximal row of carpals, and their distal surfaces articulate with the
metacarpals.
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 The metacarpus forms the skeleton of the palm of the hand
between the carpus and the phalanges.
 It is composed of five metacarpal bones (metacarpals).
 The proximal bases of the metacarpals articulate with the carpal
bones, and the distal heads of the metacarpals articulate with the
proximal phalanges and form the knuckles.
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 Each digit has three phalanges except for the first (the thumb),
which has only two.
 Each phalanx has a base proximally, a shaft (body) and a head
distally.
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BONES OF THE LOWER LIMB
&
THE PELVIC GRIDLE
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The skeleton of the lower limb (inferior appendicular skeleton)
may be divided into two functional components:
1. pelvic girdle
2. bones of the free lower limb.
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Pelvic girdle
a ring of bones that connects the vertebral column to the two femurs.
 The primary functions of the pelvic girdle are bearing and transfer of
weight
 secondary functions include protection and support of
abdominopelvic viscera and housing and attachment for structures of
the genital and urinary systems.
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In the mature individual, the pelvic girdle is formed by three bones:
Right and left hip bones (coxal bones; pelvic bones): large, irregularly
shaped bones, each of which develops from the fusion of three bones,
the ilium, ischium, and pubis.
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Hip Bone
The mature hip bone (L. os coxae) is the large, flat pelvic bone formed
by the fusion of three primary bones—ilium, ischium, and pubis.
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 The acetabulum (L., shallow vinegar cup) is the large cupshaped
cavity or socket on the lateral aspect of the hip bone that articulates
with the head of the femur to form the hip joint.
 All three primary bones forming the hip bone contribute to the
formation of the acetabulum.
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SACRUM
 The wedged-shaped sacrum (L. sacred) is usually composed of five
fused sacral vertebrae in adults.
 It is located between the hip bones and forms the roof and
posterosuperior wall of the posterior half of the pelvic cavity.
 The sacral canal is the continuation of the vertebral canal in the
sacrum.
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Coccyx (tail bone)
 Small triangular bone usually formed by fusion of the 4 rudimentary
coccygeal vertebrae. Remnant of the skeleton of the embryonic taillike caudal eminence.
 Does not participate with the other vertebrae in support of the body
weight when standing; however, when sitting it may flex anteriorly
somewhat, indicating that it is receiving some weight.
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FEMUR
 Longest and heaviest bone in the body
 Transmits body weight from the hip bone to the tibia when a person
is standing.
 Consists of a shaft (body) and two ends, superior or proximal and
inferior or distal.
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BONES OF THE LEG
 The tibia and fibula are the bones of the leg.
 The tibia articulates with the condyles of the femur superiorly and
the talus inferiorly and in so doing transmits the body's weight.
 The fibula mainly functions as an attachment for muscles, but it is
also important for the stability of the ankle joint.
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TIBIA (SHINE BONE)
on the anteromedial side of the leg, nearly parallel to the fibula
second largest bone
anterior border of the tibia
-most prominent border.
tibia & adjacent medial
surface subcutaneous
throughout their lengths
commonly known as the
“shin”
periosteal covering and
overlying skin vulnerable to
bruising.
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TIBIA (SHINE BONE)
Inferior surface of the shaft & lateral surface of medial malleolus
articulate with the talus.
Interosseous membrane unites the two leg bones.
Inferiorly, the tibia articulates with the distal end of the fibula.
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FIBULA
posterolateral to the tibia
slender
tibiofibular syndesmosis
no function in weight-bearing
serves mainly for muscle attachment.
distal end enlarges prolonged as lateral malleolus
proximal end an enlarged head superior to a small neck.
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PATELLA (KNEE CAP)
largest sesamoid bone in the body
embedded in the quadriceps femoris tendon.
joint between the patella and femur share the same articular cavity
w/ the joint between femur & tibia
patellar ligament connects the patella to the tibia.
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BONES OF THE FOOT
Tarsus (7 bones)
Metatarsus (5 bones)
Phalanges (14 phalanges)
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 Calcaneus (L., heel bone) is the largest and strongest bone in the foot.
 When standing, the calcaneus transmits the majority of the body's
weight from the talus to the ground.
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Bones of the foot
 The metatarsus (anterior or distal foot, forefoot—) consists of five
metatarsals that are numbered from the medial side of the foot.
 The 14 phalanges are as follows: the 1st digit (great toe) has 2
phalanges (proximal and distal); the other four digits have 3
phalanges each: proximal, middle, and distal.
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