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Kaan Yücel M.D., Ph.D. 26. February.2013 Tuesday

OSTEOLOGYBONES

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Osteology (Gk, osteon, bone, logos, science) branch of medicine concerned with the development

and diseases of bone tissueThe human skeleton

206 bones in adults

1.INTRODUCTION TO OSTEOLOGY

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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 matrixsome elasticity

results from the organic mattergreat 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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HISTOLOGY OF THE BONE

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 weightvery 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. Osteogenic cells2. Osteoblasts3. Osteocytes4. Osteoclasts

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Periosteummembrane surrounding the bone tissue

provides a route for the vasculature and nerve supply. participates in bone growth and repair.

Endosteumlines the marrow cavity

active during bone growth, repair, and remodelingcovers 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.

CARTILAGES AND BONES

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 avascularDiffusion

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 forcesMore collagen fibers, less flexible cartilage.

CARTILAGES AND BONES

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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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1. Hyalinemost common, matrix w/ moderate amount of collagen fibers articular surfaces of bones2. Elasticlarge number of elastic fibers external ear3. Fibrocartilagelimited number of cells & ground substance amidst substantial amount of collagen fibers intervertebral discs

Types of cartilage

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Bones function as supportive structures for the bodyprotectors of vital organsreservoirs of calcium and phosphoruslevers on which muscles act to produce movementcontainers for blood-producing cells

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TYPES OF BONESaccording to their shape gross anatomy1) Long bones tubular humerus in the arm

3) Flat bones protective functionsflat bones of the cranium protect the brain

2) Short bonescuboidal tarsus (ankle) carpus (wrist)

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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 capprotect 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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Skullis 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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Occipital boneat the back and lower part of the craniumtrapezoid 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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Parietal Bonesform, by their union, the sides and roof of the craniumeach bone irregularly quadrilateral in formexternal surface convex, smooth

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Frontal Bone@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.

Temporal Bones

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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.

Sphenoid Bone

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exceedingly light and spongycubical in shapeat the anterior part of the base of the cranium

between the two orbits, at the roof of the nosecontributes to each of these cavities.

Ethmoid bone

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Anterior cranial fossaoccupied by the inferior and anterior parts of the frontal lobes of the brain shallowest cranial fossa

Middle cranial fossabutterfly-shaped central part composed of the sella turcica on the body of the sphenoid large, depressed lateral parts on each side

Posterior cranial fossalargest and deepest cranial fossaformed mostly by the occipital bone

Cranial Fossae

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Facial BonesNasal Boneso 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 mandibleo form the whole of the

upper jaw.Form the boundaries of 3 cavitieso roof of the moutho floor and lateral wall of the nose o floor of the orbit

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Lacrimal Bonesmallest & most fragile bone of the faceat the front part of the medial wall of the orbit

Zygomatic Bone (Malar Bone)small and quadrangularat the upper and lateral part of the face

forms prominence of the cheekpart of the lateral wall & floor of the orbit.

Facial Bones

Zygomatic arch zygomatic process of the temporal bone temporal process of the zygomatic bone

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Palatine Bone@ back part of the nasal cavity. contributes to the walls of three cavities 1) floor and lateral wall of the nasal cavity2) roof of the mouth3) floor of the orbit.

Inferior Nasal Concha extends horizontally along the lateral wall of the nasal cavity.

Facial Bones

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Vomerin the median planethin, somewhat quadrilateral in shapeforms hinder & lower part of the nasal septum.

Mandible (Lower Jaw)largest and strongest bone of the faceserves for the reception of the lower teeth.

 

Facial Bones

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Facial BonesHyoid 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:Headone facet for articulation with the numerically corresponding vertebra one facet for the vertebra superior to it NeckTubercle 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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S T E R N U M

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G. sternon, chestHas 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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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.

HUMERUS

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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.

HUMERUS

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BONES OF THE FOREARMThe 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.

ULNA

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.

RADIUS

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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 BoneThe 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 tail-like 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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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.

TIBIA (SHİNE BONE)

on the anteromedial side of the leg, nearly parallel to the fibula

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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.

TIBIA (SHİNE BONE)

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slendertibiofibular syndesmosisno function in weight-bearingserves mainly for muscle attachment.distal end enlarges prolonged as lateral malleolusproximal end an enlarged head superior to a small neck.

FIBULAposterolateral to the tibia

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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 FOOTTarsus (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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