OVERVIEWS-II. & III. COMMITTEES
II. COMMITTEE
Introduction to anatomy
Definition of anatomy
Anatomy is the setting (structure) in which the events (functions) of life occur.
a branch of morphology that deals with the structure of organisms http://www.merriamwebster.com/medical/anatomy
Etymology: “Cutting through” in Ancient Greek and Latin. Anatomy deals with parts of the human body
and investigates the body by the naked eye.
Types of anatomy
1. Regional (topographical) anatomy 2. Systematic anatomy 3. Clinical (applied) anatomy
In systematic anatomy, various structures may be separately considered. On the other hand, in topographical
or regional anatomy, the organs and tissues may be studied in relation to one another. Surface anatomy is an
essential part of the study of regional anatomy. Clinical (applied) anatomy emphasizes aspects of bodily
structure and function important in the practice of medicine, dentistry, and the allied health sciences. It
incorporates the regional and systemic approaches to studying anatomy and stresses clinical application.
The importance of learning anatomy as a futue medical doctor:
-To understandbodily function and how both structure and function are modified by disease.
-To interpret the images that are produced by the sophisticated imaging techniques, such as CT, MRI, DTI.
-To understand the pathway for targeting therapy to a specific site
-To examine the patient properly
-To communicate with the colleagues properly
The ways of learning anatomy
Cadaver
Dissection
Prosection
Other materials of learning human anatomy: anatomy models, anatomy atlases, videos, textbooks, charts,
medical dictionaries, etc.
The field of Human Anatomy has a prestigious history, and is considered to be the most prominent of the
biological sciences of the 19th and early 20th centuries. The final major anatomist of ancient times was
Galen (of Bergama), active in the 2nd century. His collection of drawings, based mostly on dog anatomy,
became the anatomy textbook for 1500 years. Andreas Vesalius is the first modern anatomist who wrote the
first anatomy textbook of the modern times; De humani corporis fabrica (On the Fabric of the Human Body.
Anatomical position: All anatomical descriptions are expressed in relation to one consistent position,
ensuring that descriptions are not ambiguous.
head, gaze (eyes), and toes directed anteriorly (forward), arms adjacent to the sides with the palms facing
anteriorly, and lower limbs close together with the feet parallel.
Variations: Occasionally a particular structure demonstrates so much variation within the normal range that
the most common pattern is found less than half the time!
Terminology in anatomy
It is important for medical personnel to have a sound knowledge and understanding of the basic anatomic
terms. With the aid of a medical dictionary, you will find that understanding anatomic terminology greatly
assists you in the learning process.
Anatomical planes: All descriptions of the human body are based on the assumption that the person is
standing erect, with the upper limbs by the sides and the face and palms of the hands directed forward. This
is the so-called anatomic position. The various parts of the body are then described in relation to certain
imaginary planes. Median, sagittal, frontal-coronal, and transverse-axial) that intersect the body in the
anatomical position. The sagittal plane, like an arrow, divides the body into right and left, coronal anterior to
posterior, and axial superior to inferior parts.
With reference to the anatomical planes: Superior inferior anterior posterior medial lateral
Relating primarily to the body's surface: Superficial, intermediate, and deep (Lat. profundus, profunda)
external internal proximal distal
Terms of laterality: Unilateral and bilateral, ipsilateral and contralateral
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Terms of movemement: Flexion extension abduction adduction circumduction (medial and lateral) rotation
Pronation, supination, eversion, inversion, opposition, reposition, elevation, depression
Positions of the body: The supine position of the body is lying on the back. The prone position is lying face
downward
Introduction to systematic anatomy
Trillions of the cells in the human body form tissues, and tissues make up the 78 organs in the body. The
organs serving for the same function are organized under 12 systems (some say 13, counting the vestibular
system; which contributes to our balance and our sense of spatial orientation not under the nervous system,
but separately).
1. Integumentary system
2. Skeletal System
3. Articular system
4. Muscular System
5. Cardiovascular (Circulatory) System
6. Lymphatic system
8. Digestive (Alimentary) System
9. Urinary (Excretory) System
10. Reproductive (Genital) System
11. Endocrine System
12. Nervous system
None of the systems functions in isolation. The passive skeletal and articular systems and the active
muscular system collectively constitute a supersystem, the locomotor system, because they must work
together to produce locomotion of the body. Although the structures directly responsible for locomotion are
the muscles, bones, joints, and ligaments of the limbs, other systems are indirectly involved as well.
Bones are organs, and along with the cartilages form the skeletal system.
The articular system consists of joints and their associated ligaments, connecting the bony parts of the
skeletal system and providing the sites at which movements occur.
The three types of muscle can be characterized by whether they are controlled voluntarily or involuntarily,
whether they appear striated (striped) or smooth, and whether they are associated with the body wall
(somatic), or with organs and blood vessels (visceral).
The Circulatory (Cardiovascular) System transports fluids throughout the body. The heart and blood
vessels make up the blood transportation network, the cardiovascular system. The heart pumps blood
throughout the body, and the blood vessels, which are a closed network of tubes that transport the blood.
There are three types of blood vessels: arteries, veins, capillaries.
The respiratory system consists of air passages & lungs. The respiratory system supplies oxygen to
the blood and eliminates carbon dioxide from it. The thorax is an irregularly shaped cylinder with a narrow
opening (superior thoracic aperture) superiorly and a relatively large opening (inferior thoracic aperture)
inferiorly. The superior thoracic aperture is open, allowing continuity with the neck; the inferior thoracic
aperture is closed by the diaphragm. The diaphragm forms a section between thorax and abdomen.
The digestion starts in the mouth. Most of the digestive organs are localized in the abdomen. The abdominal
wall covers a large area. It is bounded superiorly by the xiphoid process (the third-most inferior part- of the
sternum) and costal margins, posteriorly by the vertebral column, and inferiorly by the upper parts of the
pelvic bones.
The urinary (excretory) system consists of the kidneys, ureters, urinary bladder, and urethra, which filter
blood and subsequently produce, transport, store, and intermittently excrete urine (liquid waste). The two
bean-shaped kidneys are located in the posterior abdominal region. The ureters are muscular tubes that
transport urine from the kidneys to the bladder.The ureters descend down to the pelvis exiting from the
kidneys on each side. They enter the pelvic cavity, and continue their journey to the bladder.
The reproductive tracts are located in the pelvic cavity. The pelvic cavity, between the pelvic inlet
superiorly and the pelvic diaphragm inferiorly, contains the terminal parts of the urinary and digestive
systems, the internal genital organs, the associated vascular structures, and the nerves supplying both the
pelvis and lower limbs.
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The endocrine system consists of specialized structures that secrete hormones, including discrete ductless
endocrine glands (such as the thyroid gland), isolated and clustered cells of the gut and blood vessel walls,
and specialized nerve endings.
The central nervous system (CNS) has two parts: the brain and the spinal cord.The peripheral nervous
system (PNS) is the remainder of the nervous system outside of the CNS. The peripheral nervous system
(PNS) consists of nerve fibers and cell bodies outside the CNS that conduct impulses to or away from the
CNS. The PNS is organized into nerves that connect the CNS with peripheral structures.
Introduction to regional anatomy
Regional anatomy (topographical anatomy) considers the organization of the human body as major parts or
segments: a main body, consisting of the head, neck, and trunk (subdivided into thorax, abdomen, back, and
pelvis/perineum), and paired upper limbs and lower limbs. All the major parts may be further subdivided
into areas and regions.
Cavities in the body
Dorsal Body Cavities Cranial cavity & vertebral cavity
Ventral Body Cavities Thoracic cavity & abdominopelvic cavity
Diaphragm: divides body cavity into thoracic and abdominopelvic cavities.
Regions in the body
Anatomists have divided the body into several regions. These regions help localize disease names, surgeries,
and have other medical implications.
The head (cranial region; made by the cranium) is the superior part of the body that is attached to the trunk
by the neck. The head is composed of a series of compartments, which are formed by bone and soft tissues.
They are:
the cranial cavity;
two ears;
two orbits;
two nasal cavities; and
an oral cavity
The cranial cavity is the largest compartment and contains the brain and associated membranes (meninges).
The neck (cervical region; skeleton of the neck is made up by the 7 cervical vertebrae) is the
transitional area between the head and the trunk. The neck extends from the head above to the shoulders and
thorax below.
•
Upper limb – includes the hand, wrist, forearm, elbow, arm, and shoulder.
Shoulder: proximal segment of the limb that overlaps parts of the trunk (thorax and back) and lower lateral
neck.
The axilla is the gateway to the upper limb, providing an area of transition between the neck and the arm.
Arm (L. brachium): first segment of the free upper limb (more mobile part of the upper limb independent of
the trunk) and the longest segment of the limb. It extends between and connects the shoulder and the elbow.
It includes one bone.
Forearm (L. antebrachium): second longest segment of the limb. It extends between and connects the elbow
and the wrist (L. carpus). There are two bones in the forearm.
Hand (L. manus): part of the upper limb distal to the forearm. It is composed of the wrist, palm, dorsum of
hand, and digits (fingers, including an opposable thumb).
•
Thorax – the region of the chest from the thoracic inlet to the thoracic diaphragm.
•
Abdomen- the part of the trunk between the thorax and the pelvis. It is a flexible, dynamic container,
housing most of the organs of the alimentary system and part of the urogenital system. Containment of the
abdominal organs and their contents is provided by musculoaponeurotic walls anterolaterally, the diaphragm
superiorly, and the muscles of the pelvis inferiorly.
•
Back – consists of the posterior aspect of the body and provides the musculoskeletal axis of support
for the trunk. Bony elements consist mainly of the vertebrae. The back contains the spinal cord and proximal
parts of the spinal nerves, which send and receive information to and from most of the body.
•
Pelvis and Perineum – the pelvis consists of everything from the pelvic inlet to the pelvic diaphragm.
The perineum is the region between the sex organs and the anus.
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•
Lower limb – everything below the inguinal ligament, including the hip, the thigh, the knee, the leg,
the ankle, and the foot.
The gluteal region (G. gloutos, buttocks) is the transitional region between the trunk and free lower limbs.
The femoral region (thigh) is the region of the free lower limb that lies between the gluteal, abdominal, and
perineal regions proximally and the knee region distally. It includes one bone.
The knee region is the transitional area between the thigh and the leg. The posterior region of the knee (L.
poples) is called the popliteal fossa.
The leg region is the part that lies between the knee and the narrow, distal part of the leg. The leg (L., crus)
connects the knee and foot. Often laypersons refer incorrectly to the entire lower limb as “the leg.” There are
two bones in the leg. The ankle region (L. tarsus) or talocrural region (L. regio talocruralis) is the region
where the foot and the leg met. The foot (L. pes) or foot region (L. regio pedis) is the distal part of the lower
limb.
Introduction to Osteology
Osteology (Gk, osteon, bone, logos, science) is the branch of medicine concerned with the development and
diseases of bone tissue. The human skeleton is composed of 270 bones in the newborn, 222 bones in
children and 206 bones in adults.
• The axial skeleton consists of the bones of the head (cranium or skull), neck (hyoid bone and cervical
vertebrae), and trunk (ribs, sternum, vertebrae, and sacrum).
• The appendicular skeleton consists of the bones of the limbs, including those forming the pectoral
(shoulder) and pelvic girdles.
Bone is a living tissue capable of changing its structure as the result of the stresses to which it is subjected.
Like other connective tissues, bone consists of cells, fibers, and matrix. It 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).
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. Cartilage is an avascular form of connective tissue consisting of
extracellular fibers embedded in a matrix that contains cells localized in small cavities.
Bone is a calcified, living, connective tissue that forms the majority of the skeleton. It consists of an
intercellular calcified matrix, which also contains collagen fibers, and several types of cells within the
matrix.
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.
A fibrous connective tissue covering which is called periosteum surrounds each skeletal element like a
sleeve, except where articular cartilage occurs; whereas that around cartilage is perichondrium. The
periosteum and perichondrium nourish the external aspects of the skeletal tissue. They are capable of laying
down more cartilage or bone (particularly during fracture healing) and provide the interface for attachment
of tendons and ligaments.
Long bones develop by replacement of hyaline cartilage plate (endochondral ossification). They have a shaft
(diaphysis) and two ends (epiphyses). The metaphysis is a part of the diaphysis adjacent to the epiphyses.
The diaphysis encloses the marrow cavity.
There are two types of bones according to histological features:
• compact bone
• spongy (trabecular) bone
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.
Bones are classified according to their shape (gross anatomy):
1) Long bones are tubular (e.g., the humerus in the arm).
2) Short bones are cuboidal and are found only in the tarsus (ankle) and carpus (wrist).
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3) Flat bones usually serve protective functions (e.g., the flat bones of the cranium protect the brain).
4) Irregular bones have various shapes other than long, short, or flat (e.g., bones of the face).
5) 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.
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. 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.
Bones are richly supplied with blood vessels. Most apparent are the nutrient arteries (one or more per bone)
that arise as independent branches of adjacent arteries outside the periosteum and pass obliquely through the
compact bone of the shaft of a long bone via nutrient foramina. Veins accompany arteries through the
nutrient foramina. Nerves accompany blood vessels supplying bones. The periosteum is richly supplied with
sensory nerves—periosteal nerves—that carry pain fibers.
Introduction to Skull & Neurocranium
The skeleton of the head is the skull. We rather use the ancient Greek term “cranium”, e.g. the cranial
nerves. The skull has 22 bones, excluding the ossicles of the ear. Except for the mandible, which forms the
lower jaw, the bones of the skull are attached to each other by sutures, are immobile, and form the cranium.
The part that is covering the cranial cavity and the brain in it is called neurocranium. The skeleton of the
face is called viscerocranium or facial skeleton. It is the lower part of the cranium.
Out of the 22 bones in the skull, 8 of them are in the neurocranium. They are:
•
1 Frontal bone; the bone in the front of the head
•
1 Occipital bone; the bone at the back of the head
•
2 Parietal bones; “paries” means wall, and these though bones are on the lateral sides of the skull.
•
2 Temporal bones; “temple” has two meanings “time” and “temple”. Time can make more sense for
the temporal bones, as where they are the hair becomes grey first.
•
1 Sphenoid bone in the middle (Greek sphēnoeidēs wedge-shaped)
•
1 Ethmoid bone again in the middle (In Moore’s textbook it is part of the facial skeleton,though)
The skeleton of your face is made up by the remaining 14 bones of the cranium.
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. The butterfly-shaped middle cranial
fossa has a central part composed of the sella turcicae on the body of the sphenoid and large, depressed
lateral parts on each side. The bones forming the lateral parts of the fossa are the greater wings of the
sphenoid and squamous parts of the temporal bones laterally and the petrous parts of the temporal bones
posteriorly. The posterior cranial fossa, the largest and deepest of the three cranial fossae is formed mostly
by the occipital bone, but the dorsum sellae of the sphenoid marks its anterior boundary centrally and the
petrous and mastoid parts of the temporal bones contribute its anterolateral “walls.”
Sutura is that form of articulation where the contiguous margins of the bones are united by a thin layer of
fibrous tissue; it is met with only in the skull. The major suturae in the skull are; coronal, lambdoid, and
sagittal suturues.
The bones of the calvaria of a newborn infant are separated by membranous intervals. They include the
anterior and posterior fontanelles and the paired sphenoidal and mastoid fontanelles.
Skull (Splanchocranium)
The skeleton of your face is made up by the remaining 14 bones of the cranium.
They are:
•
Two Nasal bones
•
Two Maxillæ
•
Mandible
•
Two Lacrimal bones
•
Two Zygomatic bones
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•
Two Palatines
•
Two Inferior Nasal Conchæ
•
Vomer
The viscerocranium forms the anterior part of the cranium and consists of the bones surrounding the mouth
(upper and lower jaws), nose/nasal cavity, and most of the orbits (eye sockets or orbital cavities). The
viscerocranium consists of 14 irregular bones: 2 singular bones centered on or lying in the midline
(mandible and vomer) and 6 bones occurring as bilateral pairs (maxillae; inferior nasal conchae; and
zygomatic, palatine, nasal, and lacrimal bones).
Vertebral Column, Ribs and Sternum
VERTEBRAL COLUMN
The vertebrae and intervertebtal (IV) discs collectively make up the vertebral column (spine), the skeleton of
the neck and back that is the main part of the axial skeleton (i.e., articulated bones of the cranium, vertebral
column, ribs, and sternum). The vertebral column extends from the cranium (skull) to the apex of the
coccyx.
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. The 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. 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.
Regional variations in the size and shape of the vertebral canal accommodate the varying thickness of the
spinal cord.
Cervical vertebrae form the skeleton of the neck. The smallest of the 24 movable vertebrae, the cervical
vertebrae are located between the cranium and the thoracic vertebrae. Their smaller size reflects the fact that
they bear less weight than do the larger inferior vertebrae. The most distinctive feature of each cervical
vertebra is the oval foramen transversarium (transverse foramen) in the transverse process.
The thoracic vertebrae are in the upper back and provide attachment for the ribs. Thus the primary
characteristic features of thoracic vertebrae are the costal facets for articulation with ribs. The middle four
thoracic vertebrae (T5-T8) demonstrate all the features typical of thoracic vertebrae.
Lumbar vertebrae are in the lower back between the thorax and sacrum. Because the weight they support
increases toward the inferior end of the vertebral column, lumbar vertebrae have massive bodies, accounting
for much of the thickness of the lower trunk in the median plane.
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 coccyx (tail bone) is a small triangular bone that is usually formed by fusion of the four rudimentary
coccygeal vertebrae, although in some people, there may be one less or one more. Coccygeal vertebra 1
(Co1) may remain separate from the fused group.
RIBS
Ribs (L. costae) are curved, flat bones that form most of the thoracic cage. They are remarkably light in
weight yet highly resilient. Each rib has a spongy interior containing bone marrow (hematopoietic tissue),
which forms blood cells. There are three types of ribs that can be classified as typical or atypical:
•
True (vertebrocostal) ribs (1st-7th ribs): They attach directly to the sternum through their own costal
cartilages.
•
False (vertebrochondral) ribs (8th, 9th, and usually 10th ribs): Their cartilages are connected to the
cartilage of the rib above them; thus their connection with the sternum is indirect.
•
Floating (vertebral, free) ribs (11th, 12th, and sometimes 10th ribs): The rudimentary cartilages of
these ribs do not connect even indirectly with the sternum; instead they end in the posterior abdominal
musculature.
Typical ribs (3rd-9th) have the following components:
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Head: wedge-shaped and has two facets.
Neck: connects the head of the rib with the body at the level of the tubercle.
Tubercle: located at the junction of the neck and body.
Body (shaft): thin, flat, and curved, most markedly at the costal angle.
STERNUM
The sternum (G. sternon, chest) is the flat, elongated bone that forms the middle of the anterior part of the
thoracic cage. It directly overlies and affords protection for mediastinal viscera in general and much of the
heart in particular. The sternum consists of three parts: manubrium, body, and xiphoid process.
III. COMMITTEE
Bones of the Upper Limb
The upper limb is characterized by its mobility and ability to conduct fine motor skills
(manipulation). These characteristics are especially marked in the hand. One of the major functions of the
hand is to grip and manipulate objects. Based on the position of its major joints and component bones, the
upper limb is divided into shoulder, arm, forearm, and hand for precise description.
The superior appendicular skeleton articulates with the axial skeleton only at the sternoclavicular
joint, allowing great mobility. The clavicles and scapulae of the pectoral girdle are supported, stabilized, and
moved by axioappendicular muscles that attach to the relatively fixed ribs, sternum, and vertebrae of the
axial skeleton.
The clavicle is the only bony attachment between the trunk and the upper limb. The medial end is called
“sternal end". The lateral end is called “acromial” end”.
The scapula lies on the posterolateral aspect of the thorax. It has medial, lateral, and superior borders and
superior, lateral, and inferior angles. The posterior surface of the scapula is unevenly divided by spine of the
scapula, into a small supraspinous fossa and a much larger infraspinous fossa. 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. The concave costal surface of most of the scapula forms a large subscapular
fossa.
The skeletal support for the arm is the humerus. The humerus (arm bone) 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. The distal end of the humerus has a condyle,
two epicondyles, and three fossae.
Ulna is the medial and longer of the two forearm bones. It is the stabilizing bone of the forearm. Radius is
the lateral and shorter of the two forearm bones.
The hand is the region of the upper limb distal to the wrist joint. It is subdivided into three parts: wrist,
(carpus); metacarpus; digits (five fingers including the thumb).
Introduction to arthrology
Arthrology (Greek a rqron joint –logy) is the science concerned with the anatomy, function, dysfunction and
treatment of joints. Joints (articulations) are unions or junctions between two or more bones or rigid parts of
the skeleton. Joints exhibit a variety of forms and functions.Joints are classified according to the tissues that
lie between the bones: fibrous joints, cartilaginous joints, and synovial joints.
Fibrous joints: The bones are united by fibrous tissue.
Cartilaginous joints: The bones are united by hyaline cartilage or fibrocartilage. In primary cartilaginous
joints, or synchondroses, the bones are united by hyaline cartilage, which permits slight bending during early
life. Secondary cartilaginous joints, or symphyses, are strong, slightly movable joints united by
fibrocartilage. The fibrocartilaginous intervertebral discs between the vertebrae consist of binding
connective tissue that joins the vertebrae together.
Synovial joints: The bones are united by a joint (articular) capsule (composed of an outer fibrous layer lined
by a serous synovial membrane) spanning and enclosing an articular cavity. Synovial joints are the most
common type of joints and provide free movement between the bones they join; they are joints of
locomotion, typical of nearly all limb joints. A synovial joint has three common features: 1) Joint cavity, 2)
Articular cartilage, 3) Articular capsule.
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OVERVIEWS-II. & III. COMMITTEES
The six major types of synovial joints are classified according to the shape of the articulating surfaces and/or
the type of movement they permit:
1. Plane joints (gliding joints) permit gliding or sliding movements in the plane of the articular surfaces.
Most plane joints move in only one axis, hence they are called uniaxial joints.
2. Hinge joints (ginglymus, trochlear joints) also uniaxial and permits flexion and extension only, around the
transverse axis.
3. Saddle joints permit abduction and adduction as well as flexion and extension, movements occurring
around two axes at right angles to each other; biaxial joints.
4. Condyloid (ellipsoid type) joints permit flexion and extension as well as abduction and adduction; thus
condyloid joints are also biaxial.
5. Ball and socket joints (enarthrosis, spheroidal joint) allow movement in multiple axes and planes: flexion
and extension, abduction and adduction, medial and lateral rotation, and circumduction; thus ball and socket
joints are multi-axial joints.
6. Pivot joints permit rotation around a central axis; thus they are uniaxial. The rounded part of a bone
rotates in a sleeve or ring like osteofibrous structure.
Joints of the Upper Limb
Movement of the pectoral girdle involves the sternoclavicular, acromioclavicular, and glenohumeral joints,
usually all moving simultaneously. Functional defects in any of the joints impair movements of the pectoral
girdle. Mobility of the scapula is essential for free movement of the upper limb. The clavicle forms a strut
that holds the scapula, and hence the glenohumeral joint, away from the thorax so it can move freely.
Sternoclavicular joint: the only articulation between the upper limb and the axial skeleton. The sternal end of
the clavicle articulates with the manubrium and a small part of the 1st costal cartilage. Saddle type, but
functions as a ball-and-socket joint.
Acromioclavicular joint: The acromial end of the clavicle articulates with the acromion of the scapula. Plane
type.
Glenohumeral (Shoulder) joint: More freedom of movement than any other joint in the body. Humeral head
articulates with the relatively shallow glenoid cavity of the scapula, which is deepened slightly but
effectively by the glenoid labrum (L., lip). Ball-and-socket type of synovial joint.
Elbow joint: The spool-shaped trochlea and spheroidal capitulum of the humerus articulate with the
trochlear notch of the ulna and the slightly concave superior aspect of the head of the radius, respectively;
therefore, there are humeroulnar and humeroradial articulations. Hinge type
Proximal (Superior) radio-ulnar joint: The head of the radius articulates with the radial notch of the ulna.
Pivot type.
Distal (Inferior) radio-ulnar joint: The head of the ulna articulates with the ulnar notch on the medial side of
the distal end of the radius.Pivot type.
Wrist (Radiocarpal) joint: The wrist (carpus), the proximal segment of the hand, is a complex of eight carpal
bones, articulating proximally with the forearm via the wrist joint and distally with the five metacarpals. The
ulna does not participate in the wrist joint. The distal end of the radius and the articular disc of the distal
radio-ulnar joint articulate with the proximal row of carpal bones, except for the pisiform. Condyloid
(ellipsoid) type.
Intercarpal joints: Carpal bones (the intercarpal joints interconnect the carpal bones). Plante type.
Carpometacarpal joints: The distal surfaces of the carpals of the distal row articulate with the carpal surfaces
of the bases of the metacarpals. The important carpometacarpal joint of the thumb is between the trapezium
and the base of the 1st metacarpal; it has a separate articular cavity. Like the carpals, adjacent metacarpals
articulate with each other. The carpometacarpal and intermetacarpal joints are the plane type of synovial
joint, except for the carpometacarpal joint of the thumb, which is a saddle joint. The metacarpophalangeal
joints are the condyloid type of synovial joint that permit movement in two planes: flexion-extension and
adduction-abduction. The interphalangeal joints are the hinge type of synovial joint that permit flexionextension only. The heads of the metacarpals articulate with the bases of the proximal phalanges, and the
heads of the phalanges articulate with the bases of more distally located phalanges.
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Skeleton of the Pelvis
In common usage, the pelvis (L. basin) is the part of the trunk inferoposterior to the abdomen and is the area
of transition between the trunk and the lower limbs. The bones of the pelvis consist of the right and left
pelvic (hip) bones, the sacrum, and the coccyx.
The pelvic girdle is a basin-shaped ring of bones that connects the vertebral column to the two femora. The
pelvic girdle is strong and rigid, especially compared to the pectoral (shoulder) girdle.
The pelvic bone is irregular in shape and has two major parts separated by an oblique line on the medial
surface of the bone:
pelvic bone above this line represents the lateral wall of the false pelvis, which is part of the abdominal
cavity; pelvic bone below this line represents the lateral wall of the true pelvis, which contains the pelvic
cavity.
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.
The ilium is the superior, fan-shaped part of the hip bone. The ala iliaca, wing of the ilium represents the
spread of the fan, and the body of the ilium, the handle of the fan.
On its external aspect, the body participates in formation of the acetabulum. The entire superior margin of
the ilium is thickened to form a prominent crest (iliac crest), which is the site of attachment for muscles and
fascia of the abdomen, back, and lower limb and terminates anteriorly as the anterior superior iliac spine and
posteriorly as the posterior superior iliac spine.
The ischium has a body and ramus. The body of the ischium helps form the acetabulum and the ramus of the
ischium forms part of the obturator foramen. 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.
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.
The pelvis is divided into greater (false) and lesser (true) pelves by the oblique plane of the pelvic inlet
(superior pelvic aperture). The bony edge (rim) surrounding and defining the pelvic inlet is the pelvic brim.
The pelvic inlet is the circular opening between the abdominal cavity and the pelvic cavity. Through the
pelvic inlet structures traverse between the abdomen and pelvic cavity. It is completely surrounded by bones
and joints. The pelvic outlet is diamond shaped, with the anterior part of the diamond defined predominantly
by bone and the posterior part mainly by ligaments.
The pelvic cavity is a body cavity that is bounded by the bones of the pelvis. Its oblique roof is the pelvic
inlet (the superior opening of the pelvis). Its lower boundary is the pelvic floor. The pelvic cavity primarily
contains reproductive organs, the urinary bladder, the pelvic colon, and the rectum.
The linea terminalis consists of the the arcuate line, the pecten pubis or pectineal line, and the pubic crest. It
is part of the pelvic brim, which is the edge of the pelvic inlet.
The primary joints of the pelvic girdle are the sacroiliac joints and the pubic symphysis. The sacroiliac joints
link the axial skeleton (skeleton of the trunk, composed of the vertebral column at this level) and the inferior
appendicular skeleton (skeleton of the lower limb). The lumbosacral and sacrococcygeal joints, although
joints of the axial skeleton, are directly related to the pelvic girdle. Strong ligaments support and strengthen
these joints.
The sacroiliac joints are strong, weight-bearing compound joints, consisting of an anterior synovial joint
(between the earshaped auricular surfaces of the sacrum and ilium, covered with articular cartilage) and a
posterior syndesmosis (between the tuberosities of the same bones). Weight is transferred from the axial
skeleton to the ilia via the sacroiliac ligaments, and then to the femurs during standing, and to the ischial
tuberosities during sitting. The sacrum is actually suspended between the iliac bones and is firmly attached
to them by posterior and interosseous sacroiliac ligaments.
The pubic symphysis is a secondary cartilaginous joint which consists of a fibrocartilaginous interpubic disc
and surrounding ligaments uniting the bodies of the pubic bones in the median plane. The ligaments joining
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the bones are thickened at the superior and inferior margins of the symphysis, forming superior and inferior
pubic ligaments.
L5 and S1 vertebrae articulate at the anterior intervertebral (IV) joint formed by the L5/S1 IV disc between
their bodies and at two posterior zygapophysial joints (facet joints) between the articular processes of these
vertebrae as lumbosacral joints.
The sacrococcygeal joint is a secondary cartilaginous joint with an intervertebral disc.
Joints of the Vertebral Column
The two major types of joints between vertebrae are.symphyses between vertebral bodies (n=2 one above,
and one below) and synovial joints between articular processes (n=4, two above and two below).
A typical vertebra has a total of six joints with adjacent vertebrae. Each symphysis includes an intervertebral
disc.
In addition to the joints between adjacent vertebrae, the vertebral column has the following joints below:
1) Craniovertebral (atlanto-axial and atlanto-occipital) joints
2) Costovertebral joints
3) Sacroiliac joints (will be discussed in the Pelvis)
The joints of the vertebral bodies are symphyses (secondary cartilaginous joints) designed for weightbearing and strength. The symphysis between adjacent vertebral bodies is formed by a layer of hyaline
cartilage on each vertebral body and an intervertebral disc, which lies between the layers. The articulating
surfaces are not only connected by intervertebral discs, but by ligaments as well.
The intervertebral disc consists of an outer anulus fibrosus, which surrounds a central nucleus pulposus.
The semifluid nature of the nucleus pulposus allows it to change shape and permits one vertebra to rock
forward or backward on another, as in flexion and extension of the vertebral column.
The synovial joints between superior and inferior articular processes on adjacent vertebrae are the
zygapophysial (facet) joints. The joints of the vertebral arches; the zygapophysial joints are often called
facet joints. These articulations are plane synovial joints between the superior and inferior articular
processes (G. zygapophyses) of adjacent vertebrae.
The lateral margins of the upper surfaces of typical cervical vertebrae are elevated into crests or lips termed
uncinate processes. These may articulate with the body of the vertebra above to form small "uncovertebral"
synovial joints (Luschka’s joints).
Joints between vertebrae are reinforced and supported by numerous ligaments, which pass between vertebral
bodies and interconnect components of the vertebral arches.
The anterior and posterior longitudinal ligaments are on the anterior and posterior surfaces of the vertebral
bodies and extend along most of the vertebral column. The ligamenta flava, on each side, pass between the
laminae of adjacent vertebrae. These thin, broad ligaments consist predominantly of elastic tissue and form
part of the posterior surface of the vertebral canal. The supraspinous ligament connects and passes along the
tips of the vertebral spinous processes from vertebra C7 to the sacrum. From vertebra C7 to the skull, the
ligament becomes structurally distinct from more caudal parts of the ligament and is called the ligamentum
nuchae. Interspinous ligaments pass between adjacent vertebral spinous processes.
There are two sets of craniovertebral joints, the atlanto-occipital joints, formed between the atlas (C1
vertebra), and the occipital bone of the cranium, and the atlanto-axial joints, formed between the atlas and
axis (C2 vertebra). The craniovertebral joints are synovial joints that have no intervertebral discs. Their
design gives a wider range of movement than in the rest of the vertebral column. The articulations involve
the occipital condyles, atlas, and axis.
A typical rib articulates with the bodies of adjacent vertebrae, forming a joint with the head of the rib; and
the transverse process of its related vertebra, forming a costotransverse joint.
Together, the costovertebral joints and related ligaments allow the necks of the ribs either to rotate around
their longitudinal axes, which occurs mainly in the upper ribs, or to ascend and descend relative to the
vertebral column, which occurs mainly in the lower ribs. The combined movements of all of the ribs on the
vertebral column are essential for altering the volume of the thoracic cavity during breathing.
The range of movement of the vertebral column varies according to the region and the individual. The
mobility of the vertebral column results primarily from the compressibility and elasticity of the
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intervertebral discs. The normal range of movement possible in healthy young adults is typically reduced by
50% or more as they age.
Although the movement between any two vertebrae is limited, the summation of movement among all
vertebrae results in a large range of movement by the vertebral column.
Movements by the vertebral column include flexion, extension, lateral flexion, rotation, and circumduction.
Movements by vertebrae in a specific region (cervical, thoracic, and lumbar) are determined by the shape
and orientation of joint surfaces on the articular processes and on the vertebral bodies.
Bones of the Lower Limb
The skeleton of the lower limb (inferior appendicular skeleton) may be divided into two functional
components:
-pelvic girdle
-bones of the free lower limb.
Body weight is transferred from the vertebral column through the sacroiliac joints to the pelvic girdle and
from the pelvic girdle through the hip joints to the femurs (L. femora). To support the erect bipedal posture
better, the femurs (better “femora”) are oblique (directed inferomedially) within the thighs so that when
standing the knees are adjacent and placed directly inferior to the trunk, returning the center of gravity to the
vertical lines of the supporting legs and feet.
The femur is the longest and heaviest bone in the body. It transmits body weight from the hip bone to the
tibia when a person is standing. Its length is approximately a quarter of the person's height. The femur
consists of a shaft (body) and two ends, proximal (superior) and distal (inferior).
The patella is the largest sesamoid bone (a bone formed within the tendon of a muscle) in the body and is
formed within the tendon of the quadriceps femoris muscle as it crosses anterior to the knee joint to insert on
the tibia.
The tibia is located on the anteromedial side of the leg, nearly parallel to the fibula.
Medial and larger of the two bones in the leg. The only one that articulates with the femur at the knee joint.
Second largest bone in the body. Flares outward at both ends to provide an increased area for articulation
and weight transfer.
Fibula is slender. Lies posterolateral to the tibia. Firmly attached to it by the tibiofibular syndesmosis, which
includes the interosseous membrane. No function in weight-bearing. Serves mainly for muscle attachment,
providing distal attachment (insertion) for one muscle and proximal attachment (origin) for eight muscles.
The bones of the foot include the tarsus, metatarsus, and phalanges. There are 7 tarsal bones, 5 metatarsal
bones, and 14 phalanges.
The tarsus consists of seven bones:
Talus
Calcaneus
Cuboid
Navicular
Three cuneiforms.
Only one bone, the talus, articulates with the leg bones.
Joints of the Lower Limb
The joints of the lower limb include the articulations of the pelvic girdle—lumbosacral joints, sacroiliac
joints, and pubic symphysis. The remaining joints of the lower limb are the hip joints, knee joints,
tibiofibular joints, ankle joints, and foot joints.
The hip joint forms the connection between the lower limb and the pelvic girdle. It is a strong and stable
joint.
Synovial joint type Multiaxial ball and socket type of synovial joint
Articular surfaces: The head of the femur is the ball, and the acetabulum is the socket. The round head of the
femur articulates with the cup-like acetabulum of the hip bone.
Knee joint is the largest and most superficial joint. Synovial joint type hinge type; allowing flexion and
extension; however, the hinge movements are combined with gliding and rolling and with rotation about a
vertical axis. Articular surfaces The articular surfaces of the knee joint are characterized by their large size
and their complicated and incongruent shapes.
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The tibia and fibula are connected by two joints: the tibiofibular joint and the tibiofibular syndesmosis
(inferior tibiofibular) joint. In addition, an interosseous membrane joins the shafts of the two bones.
The ankle joint (talocrural articulation) is located between the distal ends of the tibia and the fibula and the
superior part of the talus. The trochlea (L., pulley) is the rounded superior articular surface of the talus. The
medial surface of the lateral malleolus articulates with the lateral surface of the talus. Hinge-type
The many joints of the foot involve the tarsals, metatarsals, and phalanges. The important intertarsal joints
are the subtalar (talocalcaneal) joint and the transverse tarsal joint (calcaneocuboid and talonavicular joints).
Inversion and eversion of the foot are the main movements involving these joints. The other intertarsal joints
(e.g., intercuneiform joints) and the tarsometatarsal and intermetatarsal joints are relatively small and are so
tightly joined by ligaments that only slight movement occurs between them.
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