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OSTEOLOGY BONES Kaan Yücel M.D., Ph.D. 23. September 2011 Wednes

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OSTEOLOGY BONES. 23. September 2011 Wednesday. Kaan Yücel M.D., Ph.D . Osteology ( Gk , osteon, bone, logos, science) is the branch of medicine concerned with the development and diseases of bone tissue. The human skeleton 206 bones in adults . - PowerPoint PPT Presentation

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OSTEOLOGYBONES

 

Kaan Yücel M.D., Ph.D. 23. September 2011 Wednesday

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Osteology (Gk, osteon, bone, logos, science) is the 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 is one of the hardest structures of the animal body, because of the calcification of its extracellular matrix.

Living bones have some elasticity (results from the organic matter) and great rigidity (results from their lamellous structures and tubes of inorganic calcium phosphate).

Its color, in a fresh state, is pinkish-white externally, and deep red within.

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Cartilage and Bones

The skeleton is composed of cartilages and bones.

Cartilage is a resilient, semirigid form of connective tissue that forms parts of the skeleton where more flexibility is required—for example, where the costal cartilages attach the ribs to the sternum.

Also, the articulating surfaces (bearing surfaces) of bones participating in a synovial joint are capped with articular cartilage that provides smooth, low-friction, gliding surfaces for free movement.

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Blood vessels do not enter cartilage (i.e., it is avascular); consequently, its cells obtain oxygen and nutrients by diffusion.

The proportion of bone and cartilage in the skeleton changes as the body grows; the younger a person is, the more cartilage he or she has.

The bones of a newborn are soft and flexible because they are mostly composed of cartilage.

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Bone has a protective function; the skull and vertebral column, for example, protect the brain and spinal cord from injury; the sternum and ribs protect the thoracic and upper abdominal viscera.

It serves as a lever, as seen in the long bones of the limbs, and as an important storage area for calcium salts.

It houses and protects within its cavities the delicate blood-forming bone marrow.

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Classification of Bones Bones are classified according to their shape.1) Long bones 2) Short bones3) Flat bones 4) Irregular bones 5) Sesamoid bones

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Classification of Bones Long bones are tubular (e.g., the humerus in the arm).

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Classification of Bones Short bones are cuboidal and are found only in the tarsus (ankle) and carpus (wrist).

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Classification of Bones Flat bones usually serve protective functions (e.g., the flat bones of the cranium protect the brain).

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Classification of Bones Irregular bones have various shapes other than long, short, or flat (e.g., bones of the face).

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Classification of Bones Sesamoid bones (e.g., the patella or knee cap) develop in certain tendons and are found where tendons cross the ends of long bones in the limbs; they protect the tendons from excessive wear and often change the angle of the tendons as they pass to their attachments.

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There are two types of bones according to histological features: compact bone and spongy (trabecular) bone.

They are distinguished by the relative amount of solid matter and by the number and 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 latter is replaced by a medullary (marrow) cavity.

Spongy bone is found at the expanded heads of long bones and fills most irregular bones.

Compact bone forms the outer shell of all bones and also the 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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The 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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Ossa CraniiThe Occipital bone: situated at the back and lower part of the cranium, is trapezoid in shape and curved on itself.

It is pierced by a large oval aperture, the foramen magnum, through which the cranial cavity communicates with the vertebral canal.

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The curved, expanded plate behind the foramen magnum is named the squama; the thick, somewhat quadrilateral piece in front of the foramen is called the basilar part, whilst on either side of the foramen is the lateral portion.

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Some prominent features of the occipital bone:External occipital protuberance: between the summit of the bone and the foramen magnumNuchal lines: Lateral to the external occipital protuberanceCruciate eminence: Divides the interior surface of the occipital bone into four fossae.

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Some prominent features of the occipital bone:Internal occipital protuberance: At the point of intersection of the four divisions of the cruciate eminenceInternal occipital crest: The lower division of the cruciate eminence

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The Parietal Bones: form, by their union, the sides and roof of the cranium. Each bone is irregularly quadrilateral in form.

The external surface is convex, smooth, and marked near the center by an eminence, the parietal eminence (tuber parietale).

Crossing the middle of the bone in an arched direction are two curved lines, the superior and inferior temporal lines.

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The Frontal Bone: resembles a cockle-shell in form, and consists of two portions:1) A vertical portion, the squama, corresponding with the region of the

forehead2) An orbital or horizontal portion, which enters into the formation of

the roofs of the orbital and nasal cavities.

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Some prominent features of the frontal bone:Nasal process: The downward projection of the nasal part of the frontal bone which terminates as the nasal spine.Frontal crest: The internal surface of the squama frontalis of the frontal bone is concave and presents in the upper part of the middle line a vertical groove, the sagittal sulcus, the edges of which unite below to form a ridge, the frontal crest. Zygomatic process: is the part of the zygomatic process consisting of the frontal bone.

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Some prominent features of the frontal bone:Foramen cecum: The frontal crest of the frontal bone ends below in a small notch which is converted into a foramen, the foramen cecum (or foramen caecum), by articulation with the ethmoid.

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The Temporal Bones: are situated at the sides and base of the skull. Each consists of five parts, viz., the squama, the petrous, mastoid, and tympanic parts, and the styloid process.Some prominent features of the temporal bone:Zygomatic process: projects from the lower part of the squama as a long, arched process.

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The Sphenoid Bone: is situated at the base of the skull in front of the temporals and basilar part of the occipital.

It somewhat resembles a bat with its wings extended, and is divided into a 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.

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Tuberculum sellæ: behind the chiasmatic groove is an elevation, the tuberculum sellae; and still more posteriorly, a deep depression, the sella turcica, the deepest part of which lodges the hypophysis cerebri and is known as the fossa hypophyseos (or fossa hypophysialis).

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Clivus: (Latin for "slope") is a part of the cranium, a shallow depression behind the dorsum sellæ that slopes obliquely backward.

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The Ethmoid bone: is exceedingly light and spongy, and cubical in shape. It is situated at the anterior part of the base of the cranium,

between the two orbits, at the roof of the nose, and contributes to each of these cavities.

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The ethmoid bone consists of 4 parts: A horizontal or cribriform plate, forming part of the base of the

cranium; A perpendicular plate, constituting part of the nasal septum; 2 lateral masses or labyrinths

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Cranial Fossas

The inferior and anterior parts of the frontal lobes of the brain occupy the anterior cranial fossa, the shallowest of the three cranial fossae.

The fossa is formed by the frontal bone anteriorly, the ethmoid bone in the middle, and the body and lesser wings of the sphenoid posteriorly.

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The butterfly-shaped middle cranial fossa has a central part composed of the sella turcica on the body of the sphenoid and large, depressed lateral parts on each side.

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The posterior cranial fossa, the largest and deepest of the three cranial fossae, lodges the cerebellum, pons, and medulla oblongata.

The posterior cranial fossa is formed mostly by the occipital bone.

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The Facial Bones 1. Nasal Bones2. Maxillæ (Upper Jaw)3. Lacrimal Bone4. Zygomatic Bone (Malar Bone) 5. Palatine Bone6. Inferior Nasal Concha (Concha Nasalis Inferior; Inferior Turbinated Bone) 7. Vomer8. Mandible (Lower Jaw) 9. Hyoid Bone

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VERTEBRAL COLUMN, RIBS AND THE STERNUM

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Ribs (L. costae) are curved, flat bones that form most of the thoracic cage. There are 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 Neck Tubercle 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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52

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S T E R N U M

53

G. sternon, chestHas three parts:

1. Manubrium

2. Body 

3. Xiphoid process 

Jugular notch @ sup. margin of the manubriumLevel of T2 vertebra

Clavicular notch

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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.

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The change in size is related to the fact that successive vertebrae bear increasing amounts of the body's weight as the column descends.

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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The vertebral body is the more massive, roughly cylindrical, anterior part of the bone that gives strength to the vertebral column and supports body weight.

The size of the vertebral bodies increases as the column descends, as each bears progressively greater body weight.

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The vertebral arch is posterior to the vertebral body and consists of two (right and left) pedicles and laminae.

The pedicles are short, stout cylindrical processes that project posteriorly from the vertebral body.

The vertebral arch and the posterior surface of the vertebral body form the walls of the vertebral foramen.

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7 processes arise from the vertebral arch of a typical vertebra: 1 median spinous process projects posteriorly from the vertebral

arch at the junction of the laminae. 2 transverse processes project posterolaterally from the junctions of

the pedicles and laminae. 4 articular processes—two superior and two inferior—also arise from

the junctions of the pedicles and laminae, each bearing an articular surface (facet).

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BONES OF THE UPPER LIMB & 

THE SHOULDER

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Clavicle (Tr. Köprücük kemiği)

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 kemiği)

Its medial half is convex anteriorly, and its sternal end is enlarged and triangular where it articulates with the manubrium of the sternum at the sternoclavicular (SC) joint.

Its lateral half is concave anteriorly, and its acromial end is flat where it articulates with the acromion of the scapula at the acromioclavicular (AC) joint.

These curvatures increase the resilience of the clavicle and give it the appearance of an elongated capital S.

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Some prominent features of the superior and inferior surfaces of the clavicle:Sternal endAcromial end

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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 convex posterior surface of the scapula is unevenly divided by a thick projecting ridge of bone, the spine of the scapula, into a small supraspinous fossa and a much larger infraspinous fossa.

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Scapula (Tr. Kürek kemiği)

The concave costal surface of most of the scapula forms a large subscapular fossa.

The broad bony surfaces of the three fossae provide attachments for fleshy muscles.

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Scapula (Tr. Kürek kemiği)

The spine continues laterally as the flat expanded acromion which forms the subcutaneous point of the shoulder and articulates with the acromial end of the clavicle.

Superolaterally, the lateral surface of the scapula has a glenoid cavity which receives and articulates with the head of the humerus at the glenohumeral joint.

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Scapula (Tr. Kürek kemiği) The glenoid cavity is a shallow, concave, oval fossa, directed

anterolaterally and slightly superiorly—that is considerably smaller than the ball (head of the humerus) for which it serves as a socket.

The beak-like coracoid process (G. korakōdés, like a crow's beak) is superior to the glenoid cavity.

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Scapula (Tr. Kürek kemiği) The scapula has medial, lateral, and superior borders and superior,

lateral, and inferior angles.

The glenoid cavity is the primary feature of the head.

The shallow constriction between the head and the body defines the neck of the scapula.

The superior border of the scapula is marked by the suprascapular notch, which is located where the superior border joins the base of the coracoid process.

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Humerus The humerus (arm bone), the largest bone in the upper limb,

articulates with the scapula at the glenohumeral joint and 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 The spherical head of the humerus articulates with the glenoid cavity of the scapula.

The surgical neck of the humerus, a common site of fracture, is the narrow part distal to the head and tubercles.

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Humerus The shaft of the humerus has two prominent features: the deltoid tuberosity laterally, and the oblique radial groove posteriorly.

The inferior end of the humeral shaft widens as the sharp medial and lateral supraepicondylar (supracondylar) ridges form and then end distally in the especially prominent medial epicondyle and the lateral epicondyle, providing for muscle attachment.

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HumerusThe distal end of the humerus—including the trochlea; the capitulum; and the olecranon, coronoid, and radial fossae—makes up the condyle of the humerus.

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Bones of 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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The ulna is the stabilizing bone of the forearm and is the 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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For articulation with the humerus, the ulna has two prominent projections: 1. Olecranon projects proximally from its posterior aspect (forming the point of the elbow) and serves as a short lever for extension of the elbow2. Coronoid processprojects anteriorly.

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The radius is the lateral and shorter of the two forearm bones. Its proximal end includes a short head, neck, and medially directed tuberosity.

Proximally, the smooth superior aspect of the discoid head of the radius is concave for articulation with the capitulum of the humerus during flexion and extension of the elbow joint.

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The head also articulates peripherally with the radial notch of the ulna; thus the head is covered with articular cartilage.

The neck of the radius is a constriction distal to the head.

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 is essentially four sided when sectioned transversely.

Its medial aspect forms a concavity, the ulnar notch which 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: the pelvic girdle and the bones of the free lower limb.

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The pelvic girdle is 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.

Sacrum: formed by the fusion of five, originally separate, sacral vertebrae.

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Male and female pelves are distinct. The characteristic features of the normal (gynecoid) female pelvis reflect the fact that the fetus must traverse the pelvic canal during childbirth.

Because atypical female pelves may not be conducive to a vaginal birth, determination of the pelvic diameters is of clinical importance.

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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 ilium is the superior, fan-shaped part of the hip bone.

The ala, or wing, of the ilium represents the spread of the fan, and the body of the ilium, the handle of the fan.

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Hip Bone• The iliac crest, the rim of the fan, has a curve that follows the contour

of the ala between the anterior and the posterior superior iliac spines.

• The anteromedial concave surface of the ala forms the iliac fossa.

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Hip Bone The ischium has a body and ramus (L. branch).

The large posteroinferior protuberance of the ischium is the ischial tuberosity.

The small pointed posteromedial projection near the junction of the ramus and body is the ischial spine.

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The pubis is an angulated bone with a superior ramus, which helps form the acetabulum, and an inferior ramus, which helps form the obturator foramen.

A thickening on the anterior part of the body of the pubis is the pubic crest, which ends laterally as a prominent swelling, the pubic tubercle.

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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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Sacrum On the pelvic and posterior surfaces of the sacrum between its

vertebral components are typically four pairs of sacral foramina for the exit of the posterior and anterior rami of the spinal nerves.

Its superior articular processes articulate with the inferior articular processes of the L5 vertebra.

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Sacrum The anterior its tapering inferior end, projecting edge of the body of

the S1 vertebra is the sacral promontory (L. mountain ridge).

The apex of the sacrum has an oval facet for articulation with the coccyx.

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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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Femur

The superior (proximal) end of the femur consists of a head, neck, and two trochanters (greater and lesser).

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Femur

The neck of the femur is trapezoidal, with its narrow end supporting the head and its broader base being continuous with the shaft.

The greater trochanter is a large, laterally placed bony mass that projects superiorly and posteriorly where the neck joins the femoral shaft. The medial and lateral femoral condyles make up nearly the entire inferior (distal) end of the femur.

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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

Located on the anteromedial side of the leg, nearly parallel to the fibula, the tibia (shin bone) is the second largest bone in the body.

It flares outward at both ends to provide an increased area for articulation and weight transfer.

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Tibia

The superior (proximal) end widens to form medial and lateral condyles that overhang the shaft medially, laterally, and posteriorly, forming a relatively flat superior articular surface, or tibial plateau.

This plateau consists of two smooth articular surfaces that articulate with the large condyles of the femur. The tubercles fit into the intercondylar fossa between the femoral condyles.

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Tibia

The anterior border of the tibia is the most prominent border.

It and the adjacent medial surface are subcutaneous throughout their lengths and are commonly known as the “shin”; their periosteal covering and overlying skin are vulnerable to bruising.

At the superior end of the anterior border, a broad tibial tuberosity provides distal attachment for the patellar ligament, which stretches between the inferior margin of the patella and the tibial tuberosity.

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Tibia

The inferior surface of the shaft and the lateral surface of the medial malleolus articulate with the talus.

The interosseous border of the tibia is sharp where it gives attachment to the interosseous membrane that unites the two leg bones.

Inferiorly, the sharp border is replaced by a groove, the fibular notch that accommodates and provides fibrous attachment to the distal end of the fibula.

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Fibula The slender fibula lies posterolateral to the tibia and is firmly

attached to it by the tibiofibular syndesmosis, which includes the interosseous membrane.

The fibula has no function in weight-bearing. It serves mainly for muscle attachment.

The fibers of the tibiofibular syndesmosis are arranged to resist the resulting net downward pull on the fibula.

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Fibula

The distal end enlarges and is prolonged laterally and inferiorly as the lateral malleolus.

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Fibula

The proximal end of the fibula consists of an enlarged head superior to a small neck. The head has a pointed apex.

The head of the fibula articulates with the fibular facet on the lateral tibial condyle.

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Bones of the footTarsus (7 bones) Metatarsus (5 bones) Phalanges (14 phalanges)

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Bones of the foot The 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 navicular (L., little ship) is a flattened, boat-shaped bone located

between the head of the talus posteriorly and the three cuneiforms anteriorly.

The cuboid, approximately cubical in shape, is the most lateral bone in the distal row of the tarsus.

The three cuneiform bones are the medial (1st), intermediate (2nd), and lateral (3rd).

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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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