anatomy #1 intro. - axial skeleton

8/13/2019 Anatomy #1 Intro. - Axial Skeleton

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Anatomy of TheMusculoskeletal

System

Dr. Nabil khouri MD, MSc, Ph.D


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What we will study!

The Muscular and Skeletal system

Skeletal system: is made of Bones that is a

hard supporting tissue

Bones are used to make up the skeleton

Found in many forms including:

small, large, long, short and flat

Bones are held together byJoints

whichallow and/or restrict movements.

Movements are performed by Muscle upon

their contractions

Muscle is made of muscular tissue


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Excitability

Contractility

Extensibility

Elasticity

- Tissue can receive & respond to stimulation

- Tissue can shorten & thicken

- Tissue can lengthen

- After contracting or lengthening, tissue

always wants to return to its resting state

There are four characteristics

associated with muscle tissue:


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Movementboth voluntary & involuntary.

Maintaining posture.

Supporting soft tissues within body cavities

Guarding entrances & exits of the body

Maintaining body temperature

The characteristics of muscle tissue enableit to perform some important functions,

including:


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Types of Ordinary Body Movements

Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Flexiondecreases angle of joint and bringstwo bones closer together

Extension- opposite of flexion

Rotation- movement of a bone in longitudinalaxis, shaking head no

Abduction/Adduction

Circumduction


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Body MovementsCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings


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Left: Abduction

moving the

leg away fromthe midline

Above

Adduction-

moving toward

the midline

Right:

Circumduction: cone-shaped movement,

proximal end doesnt

move, while distal end

moves in a circle.


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Types of Muscles

Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Prime movermuscle with the majorresponsibility for a certain movement

Antagonistmuscle that opposes orreverses a prime mover

Synergistmuscle that aids a primemover in a movement and helps preventrotation


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Objectives

Divisions of the Skeleton

Classification of Bones

Major bony landmarks
http://upload.wikimedia.org/wikipedia/commons/8/85/Human_skeleton_front.svg


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Bones: Forms In the skeleton and are arrangedinto Axial and appendicular groups

Vertebral Column 26

Axial skeleton

Skull 22 Hyoid bone 1

Ribs and sternum 25

-------

Appendiclular skeleton

Upper Extremities 64

Lower Extremities 62

--------

Auditory bones 6

--------

The total number of bones 206


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Divisions of the Skeleton

The Axial skeleton The skull The sternum The ribs The vertebral column

The appendicular skeleton Upper extremities Lower extremities The shoulder girdle

The pelvic girdle


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Long Bones Long bonesare characterized by

having one shaft (the Diaphysis)that is much greater in length than

width and two extremities(epiphysis).

They are comprised mostly ofcompact boneand lesser amountsof marrow, which is located withinthe medullary cavity, and spongybone.

Most bones of the limbs, includingthose of the fingersand toes, are

long bones.
http://www.peti.pl/wiki/Long_boneshttp://www.peti.pl/wiki/Diaphysishttp://www.peti.pl/wiki/Cortical_bonehttp://www.peti.pl/wiki/Bone_marrowhttp://www.peti.pl/wiki/Medullary_cavityhttp://www.peti.pl/wiki/Cancellous_bonehttp://www.peti.pl/wiki/Cancellous_bonehttp://www.peti.pl/wiki/Metacarpushttp://www.peti.pl/wiki/Metatarsushttp://www.peti.pl/wiki/Metatarsushttp://www.peti.pl/wiki/Metacarpushttp://www.peti.pl/wiki/Cancellous_bonehttp://www.peti.pl/wiki/Cancellous_bonehttp://www.peti.pl/wiki/Medullary_cavityhttp://www.peti.pl/wiki/Bone_marrowhttp://www.peti.pl/wiki/Cortical_bonehttp://www.peti.pl/wiki/Diaphysishttp://www.peti.pl/wiki/Long_bones


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Short bones

Cube-shaped

bones of thewrist and ankle

Bones thatform within

tendons (e.g.,patella)


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Flat bones

Thin, flattened,and a bit curved(e.g., sternum,and most skullbones)


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Flat bones

Flat bonesare thin and generallycurved, with two parallel layers of

compact bones sandwiching a layer ofspongy bone.

Most of the bones of the skullare flat

bones, as is the sternum.

I l
http://www.peti.pl/wiki/Flat_bonehttp://www.peti.pl/wiki/Skullhttp://www.peti.pl/wiki/Sternumhttp://www.peti.pl/wiki/Sternumhttp://www.peti.pl/wiki/Skullhttp://www.peti.pl/wiki/Flat_bone


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Irregularbones

bones with

complicatedshapes

(e.g., vertebraeand hip bones)


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Irregular bones

Irregular bonesdo not fit into the abovecategories.

They consist of thin layers of compact bonesurrounding a spongy interior.

As implied by the name, their shapes are

irregular and complicated. The bones of the spine and hips are

irregular bones.
http://www.peti.pl/wiki/Irregular_boneshttp://www.peti.pl/wiki/Irregular_boneshttp://www.peti.pl/wiki/Irregular_boneshttp://www.peti.pl/wiki/Irregular_bones


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Surface Features of theBone

1). Projections that form joints a). Head: The proximal articular end of the bone

b). Facet:A small, flattened articular surface

c). Condyle: A large, rounded articular process

d). Ramus:An arm-like branch off the body of abone


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Surface Features of the Bone

2). Sites of muscle &ligament attachment.

a). Tuberosity: A projection or bump with a roughened surface

b). Crest:A prominent elevation or ridge

c). Trochanter: A specific tuberosities located on specific bones Femur

d). Line

e). Tubercle: A projection or bump with a roughened surface,

generally smaller than a tuberosityf). Epicondyle: A projection near to a condyle but not part of thejoint.

g). Spine: A relatively long, thin projection or bump

h). Process: A relatively large projection or prominent bump.(gen.)


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3). Openings that allow blood vessels and nerves to

pass a). Meatus: A short canal

b). Fissure

c). Foramen: An opening through a bone.

d). Sinus: Pocket (cavity) like structure within the

cranial bone

e).Canal: A long, tunnel-like foramen, usuallya passage for notable nerves or bloodvessels


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4). Depressions

a). Fossa: A broad, shallow depressed area

b). Grove

c). Notch: A small depression


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The Axial Skeleton

Eighty bones segregated into three

regions Skull

Vertebral column

Bony thorax


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The Skull

The skull, the bodys most complex bonystructure, is formed by the cranium and facial

bones

Cranium

protects the brain and is the site ofattachment for head and neck muscles

Facial bones

Supply the framework of the face, the sense

organs, and the teeth Provide openings for the passage of air and

food

Anchor the facial muscles of expression


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Developmental Aspects of the Skeleton:


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Developmental Aspects of the Skeleton:Fetal Skull


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Frontal Bone

Forms the anterior portion of the cranium

Articulates posteriorly with the parietalbones via the coronal suture

Major markings include the supraorbital

margins, the anterior cranial fossa, and thefrontal sinuses (internal and lateral to theglabella)

k ll i i


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SkullAnterior View

Parietal Bones: lateral aspects of the skull


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Parietal Bones: lateral aspects of the skull


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Occipital Bone: Posterior view of the skull

Forms most ofskulls posterior

wall and base Major markings

include theposterior cranialfossa, foramen

magnum,occipitalcondyles, and thehypoglossal canal

O i it l B d It M j M ki


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Occipital Bone and Its Major Markings

T l B L t l A t f th Sk ll


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Temporal Bone: Lateral Aspects of the Skull

Temporal Bones


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Temporal Bones

Form the inferolateral aspects of the skull andparts of the cranial floor

Divided into four major regionssquamous,tympanic, mastoid, and petrous

M d l t l A t f th Sk ll


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Med-lateral Aspects of the Skull

Inferior Aspect of the Skull base


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Inferior Aspect of the Skull base

Superior view of the skull base


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Superior view of the skull base


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Sphenoid

Bone


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Maxillary Bones

Medially fused bones that make up the upper jawand the central portion of the facial skeleton

Facial keystone bones that articulate with allother facial bones, except the mandible

Their major markings include palatine, frontal,

and zygomatic processes, the alveolar margins,inferior orbital fissure, and the maxillary sinuses

Maxillary Bones


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Maxillary Bones


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Mandible Bone


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Mandible Bone

The mandible (lowerjawbone) is the largest,

strongest bone of theface

Its major markingsinclude the coronoidprocess, mandibular

condyle, the alveolarmargin, and themandibular and mentalforamina


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Other Facial Bones

Vomerplow-shaped bone that forms part ofthe nasal septum

Inferior nasal conchaepaired, curved bonesin the nasal cavity that form part of the lateralwalls of the nasal cavity

The Orbit


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The Orbit

Bony cavities in whichthe eyes are firmlyencased and

cushioned by fattytissue Formed by parts of

seven bonesfrontal,sphenoid, zygomatic,maxilla, palatine,lacrimal, and ethmoid

The Orbit


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The Orbit

Figure 7.9b


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Ethmoid Bone

Most deep of the skull bones; lies between thesphenoid and nasal bones

Forms most of the bony area between thenasal cavity and the orbits

Major markings include the cribriform plate,crista galli, perpendicular plate, nasalconchae, and the ethmoid sinuses

E h id B


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Ethmoid Bone


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Nasal Cavity

Constructed of bone and hyaline cartilage

Roofformed by the cribriform plate of the

ethmoid Lateral wallsformed by the superior and

middle conchae of the ethmoid, theperpendicular plate of the palatine, and the

inferior nasal conchae Floorformed by palatine process of the

maxillae and palatine bone

Nasal Ca it


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Nasal Cavity


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Paranasal Sinuses

Mucosa-lined, air-filled sacs found in five skullbonesthe frontal, sphenoid, ethmoid, and

paired maxillary bones Air enters the paranasal sinuses from the nasal

cavity and mucus drains into the nasal cavityfrom the sinuses

Lighten the skull and enhance the resonance ofthe voice


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Hyoid Bone

Not actually part of the skull,but lies just inferior to themandible in the anterior neck

Only bone of thebody that does notarticulate directlywith another bone

Attachment point

for neck musclesthat raise andlower the larynxduring swallowingand speech

anatomy #1 intro. - axial skeleton

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