Skeletal System Divisions

Divisions of the Skeletal System

• The human body contains approximately 206 bones along with associated cartilage.
• The skeleton system includes groups of bones that work together
• Components of the skeleton include the axial and appendicular skeletons.

Axial Skeleton

• The axial skeleton lies along the body's longitudinal axis.
• Its primary function is protection; it encases body cavities and protects organs.
• It consists of the skull (22 bones: 8 cranial, 14 facial), vertebral column (33 bones), and thoracic cage.
• The 24 individual vertebrae protect the spinal cord.
• The thoracic cage encompasses and protects the lungs, heart, and other delicate contents of the thoracic cavity.

Appendicular Skeleton

• The appendicular skeleton is primarily responsible for movement, support and, muscle attachment
• It compromises the pectoral girdle, upper limbs, pelvic girdle, and lower limbs.
• The pectoral girdle includes the clavicle and scapula, which anchors the upper limb to the trunk.
• The upper limb consists of the arm (humerus), forearm (radius and ulna), wrist, and hand (carpals, metacarpals, phalanges).
• The pelvic girdle which includes the two pelvic bones and sacrum, anchors the lower limb to the trunk.
• The lower limb consists of the thigh (femur), leg (tibia and fibula), ankle, and foot (tarsals, metatarsals, phalanges).

Bone Markings

• Bones possess surface features known as bone markings.
  • Depressions allow passage for pathways for blood vessels and nerves, or sites for articulations or joints between bones.
  • Openings enclose delicate structures and allow them to travel through bones.
  • Projections are sites where bones articulate or where ligaments and tendons attach.

Skull Bone Groups

• The skull consists of 22 bones divided into cranial (8 bones) and facial (14 bones) groups.
• Cranial bones consist of single frontal, occipital, ethmoid, and sphenoid bones.
• The cranial bones consist of paired temporal and parietal bones.
• The facial bones includes the maxillary, zygomatic, nasal, lacrimal, palatine and inferior nasal conchal bones.
• The facial bones also includes the mandible and vomer.

Overview of the Skull

• Most skull bones, except the mandible, are fused via immovable joints (sutures).
• Many skull bones contain sinuses, which are air-filled membrane lined spaces.
• Four bones surrounding the nasal cavity contain large paranasal sinuses.

Cranial Cavity

• The cranial vault is the superior portion of the cranial cavity.
• The cranial base forms the inferior portion, and divides superior portion into anterior, middle, and posterior cranial fossae, where the brain sits.

Smaller Cavities of the Skull

• Orbits contain the eyeballs.
• The nasal cavity houses sensory receptors for smell.
• The oral cavity encompasses the teeth, tongue(taste receptors).
• Other small cavities contain organs for hearing and balance.

Anterior View of the Skull

• Facial bones visible
• Frontal bones and portions of the sphenoid and ethmoid bones visible
• Facial bones Virgil Is Now Making My Pet Zebra Laugh (Vomer, Inferior nasal conchae, Mandible, Maxillae, Palatine, Zygomatic, Lacrimal)

Lateral View of the Skull

• All of the cranial bones and many of the facial bones are visible
• This is the best spot to view bones that contribute to the zygomatic arch and how the the temporal bone and mandible articulate
• Bones that form a "weak spot" due to their vulnerability to fracture, at the temple: Parietal, Ethmoid, Sphenoid, Temporal, Occipital, Frontal (PEST OF 6)

Posterior, Inferior, and Superior Views of the Skull

• Can see the occipital, parietal, and temporal bones along with posterior sides of maxillae and mandible
• Useful for viewing surface markings of occipital bone and the sagittal, squamous, an lambdoidal sutures
• The hard palate structure can be seen, as well as the maxillae uniting at the intermaxillary structure
• Can also see the sphenoid bone as well as the pteryoid processes and greater wings

Medial Midsaggital View of the Skull

• This view shows the nasal septum structure
• Includes ethmoid and vomer bones
• Also shows several paranasal sinuses (frontal sinus and sphenoid sinus)

Internal View of the Skull

• Best way to show how the cranial fossae cradle the brain
• Specifically it allows for viewing of cribiform plates on the ethmoid bone
• Also shows the lesser and greater wings and sella turica of the sphenoid bone, and the petrous part of the temporal bone

Cranial Bones - Frontal Bone Description

• The frontal bone forms the frontal squama, also known as the forehead.
• Frontal sinuses (part of the paranasal sinuses) are located inside the frontal bone.
• Supraorbital margins are sharp ridges, which form the superior and superomedial boundaries of the orbits.
• A tiny supraorbital foramen, for passage of blood vessels and nerves, is found along the middle of the supraorbital margin.
• Glabella (the smooth region between the two supraorbital margins).

Cranial Bones - Parietal Bones Description

• The two parietal bones form the superior and part of the lateral wall of the cranial vault.
• They articulate with cranial bones at several sutures, including the Sagittal suture
  • The parietal bones meet frontal bones at the coronal suture.
  • Each parietal bone meets a temporal bone at the squamous suture.
  • They meet the occipital bone at the lambdoid suture.

Cranial Bones - Occipital Bone Description

• It forms the posterior part of the cranial cavity and the posterior cranial fossa
  • spinal cord passes through the foramen magnum (big hole) to enter the vertebral cavity.
• Occipital condyles, which articulate with the first cervical vertebra are located on either side of the foramen magnum.
• The posterior surface features the superior and inferior nuchal lines, which are two parallel ridges.
• External occipital protuberance runs through the superior nuchal line then it continues interiorly as the external occipital crest.

Cranial Bones - Temporal Bones Description

• They form the lateral walls of the cranium.
• They consist of the squamous region including the zygomatic process zygomatic arch and the mandibular fossa (articulates with mandible.)
• Also made up of a tympanic region which contains the entry to the external acoustic meatus
  • includes the styloid process, a needle-like spur of bone.
• Consist of the mastoid region of the skull, near the projection at the mastoid process, which contains tiny sinuses called mastoid air cells.
• The medial or internal petrous region forms part of the middle cranial fossa.
  • consists of the internal acoustic meatus, a canal leading from the inner ear.
  • at the jugular foramen where the temporal bone meets the occipital bone, which is a posterior opening through which the internal jugular vein and nerve passes.
  • at the carotid canal, through which the internal carotid artery passes as it enters the cranial cavity.
  • at the foramen lacerum, which allows for passage for blood vessels and nerves.

Cranial Bones - Sphenoid bone Description

• It articulates with every other cranial bone and forms part of the anterior and middle cranial fossae.
• The central body contains air-filled sphenoidal sinuses.
• The Optic foramina, leads into the optic canals, passes vision nerves through the sphenoids body .
• The superior surface which houses the sella turcica.
• The greater wings extend out laterally to form part of the middle cranial fossae with the temporal bones.
  • They form part of the orbit’s posterior walls.
  • the greater wings contain foramen rotundum’s anteriorly, foramen ovale, and the posterior formen spinosum
• The Superior Orbital Fissure which lies next to the lesser sphenoid bone’s wings which is where the nerves are that regulate eye movement will pass.
• The pterygoid processes are the inferior projections of this bone, which form part of the postier wall of the oral and nasel cavities are the site for muscle attachment in that area.

Cranial Bones - Ethmoid bone Description

• It sits deep in the anterior cranium between the eyes and posterior to the nasal bones.
• The cribriform plate which form part of the roof of the nasal cavity on the superior surface.
• Olfactory and cranial nerves connect into the the cirbriform
• Cresta Galli attach to brain’s surrounding membranes.
• The perpendicular plate, which forms a nasal septum.
• and there are right and left ethmoidal sinuses.
• Has medial projections
• Including a pair at the ethmoid bone’s lateral masses, and also features the superior and middle nasal conchae.

Facial Bones - Description

• Nasal Bones-Form superior part of bridge of nose

  • Attach hyaline cartilage that form nose framework’s

• Lacrimal Bones-(Smallest and Delicate)-Found:

  • Medial wall of each orbit.
  • Has a lacrimal fossa to pass tears through.

• Zygomatic Bones-Zygomatic Arch

  • Joins processes from temporal bones and maxillae.
  • The Zygomatic arches laterally orbit and form the cheeks.

• Palatine Bones-(L shaped)-Forms two-plates

  • Horizontal: posterior part of bones that create hard plate
  • Perpendicular: part wall’s at lateral nasal section.

• Mandible = INFERIOR JAW JOINT(only moveable skull part)

• BODY: Forms the lower part of the face/ the jaw region including

  • Mental Foramen - (mental means "chin").
  • Alveolar Process to house lower teeth
  • also made up of a mandibular ramus, (ramus = a branch)

• On the Mandibular Ramus’s in the medial lateral portion lies a MANDIBULAR NOTCH!

• The CondylAR PROCESS and the MANDIBULAR CONDYLE create a place to joins with the temporal bone’s MANIDBULAR FOSSA to allow temporo-mandibular joint.

• Process on the MANDIBLE: coronoid, and condylar.

Facial Bones - Description of Maxilla

• MAXILLAE bone which fused together
• The Teeth roots are near - Alveolar Process AND Palatine bone: - Forms “Hard Palate” at the mouth’s roof" &
• Inferior nasal conchae - Is a thin/ curved bone that projects the lateral nasal cavity and are situated-INFERIOR to ethmoid’s bone’s-MIDDLE NASAL CONCHAE.
• Lastly the Vomer -(IS BOTTOM SIDE OF NOSE DEEP DOWN)-and shapes parts of the NASAL SEPTUM.”

The Orbit

• it requires 7 fused-TOGETHER” bones!

• They for many walls that ENCASE the eyeball” LACRIMAL GLANDS to HOLD blood flow, muscles also NERVES.

• The wall consists bones called FRONTAL = Superior & superior and behind /posteriosuperior orbit

MAXILLA The back side of the lateral/the back side of-bottom orbit walls and a small bit from Palatine bone

ZYGO bonesshapes/runs at lateralside THE SIDE RUNNING at ANTERIOR SIDE ETHMOID” +Lacrimal /Palatine shaped WALL THE MEDIAL the middle SHAPED bone to form and SHAPE spEHNOID” THE most lateral AND posterior - shaped as a wall

Nasal Cavity

• The bony opening is made of lots small bones.
• A mainpart/1st job is to give/pass flow for RESPIRATORY TRACT.
• Its split wall sections: from all parts of that bones. (section parts such as:)
• 1-Ethmoid / & 2-Perpendicular-shaped wall / 3- palatine form aLATERAL wall (Sphenoid Bones with its all wall called)POSTERIOR.wall. The floor form of "Palatine AND also PALATINE - maxillae section! " The TOP form wall. -Called :THE CRIBIFORM” wall. Anterior= connective of the nose and cartilages with all borders maxialle area!! form ANTERIOR. -THE “Nasal - Septum”,
  AND THE divide is form the nasal wall area. Has nasal Fossa that is made by Perpendicular plate which create ETHMOID BONE & the Vomer AND Anterior/ The bone is divide by HYALINE parts.

The Paranasal Sinuses

• Found inside ethmoid, sphenoid, also frontal area to all maxillary and also bone section to ALL.
• It joins together with ”adajcent bone sections to " pass air flow to sinus”
• The Sinuses all join, to form, give = a mucus to warm, and then to make air inspired!! " "

The Fetal Skull and Remembering the Skulls

• fontanelles-membraneous(a soft area form) that is
• between Fetal cranium!!!
• then develops and has
  • Kids development and make "18-24 MONTH" completion of cranial/bone progress!!!

Remembering the Skull

• *REMEMBER by studying "P.E.S.T.O. F" 6 bone for memory = (parietal, ethmoid, sphenoid, temporal, occipital, frontal )
• The bones from bat, with "ethmoid is in from iceberg-shaped look".""
• Fontanelles allow flex room, and space FOR enlargement of skull brain!

Hyliod

• Join and group from with cranial for locations ""Is not connected any with all" cranial parts!!" Is “superior area" AND shaped neck bone that is C. Connect to hold the cartilage to styloid from process by the "temporal region+ larynx area. which help for the tongue,

Forensic Skull Anatomy

• fore- head area- that is sloped in with males face VS in ladies part straight and have bone face parts.. that face
• males face is SUPAAORBITAL ridge looks so Prominent."
• Male; bone made < 90 area for angel vs women = >90* area.
• male is mastoid

Vertebral Column

• Is form with 33 section (with "vertebrae.
• They locate and shape (with "vertebrae") parts with -a location to the letters
• All letters form spinal root.

Vertebrae Sections:

7 - is cervical-that means "in neck" from all C- 1 /to/7/ 12- Is "thoracic " which connect rib side-1 THRU/ to /12/. 5 - Is “lumbar” =side with behind and back" bone part

• from l"through/ to5/ 5 - Is “sacral + coccygeal bone to connect sacrum/pelvic portion .",
• Breakfast to connect 7 / lunch is connect 12 /dinner it is a group with "vertebrae group from"7 cervical plus 12 with thoracic group and also plus 5 from lumbar with."bone.

the Thoracic Spinal Column with Curva

“NewBorn” child’s “ Vertebrae spinal column" all with shapes called “C.”" The children grow to form as: S -curved group"

The Primary and the Spinal Column

• 1st/ main shape and region is “sacral and thoracic”.
• and with fetal the bone/shaping - progress"

2”Secondary -Shape

• cervical / plus lumbar".
• these help then"
• THE CRITICAL to help walk better -Helpto adjust to shift and hold weight to bones to legs.""

curvature parts:

:scoliosis-

• a "lateral section Lordosis - curve behind allKyphlosis back" and also like "C"

Bone and vertebrae Structure-to help joint!

""Body or centrum “anterior region that touch and shapevertebra. INTERVERTEBRAl disc (to connect all vertebrae)

• all"vertebrae part:

-to ”help to take press/ shock/force when all "impact." happens

""Vertebrae Frame

• has/needs(2)PEDICLES
• to touch all frame and joints"
• all helps/to create border or connect then to FRAME -connect lamina which make posterier!""

Superior and inferior Process

transverse- to give section all the "join to spinous process AND for attach that area with muscle!"*

Spinal column

• the “smallest region, where they pass veins Arteries

""Smallest of ALL vertebrae is THE C7 ""It forms the transverse process, with help (to process with all Arteries to help

ALL/each from “/ to all spinal area with c5-6" bone.

• NOTABLY help all spinal portion".

Atlas1:

• (Lacks vertebrae'body)
• With 2 the posterior front Help lateral group that for many upper /bottom connect face-1 area

Axil (2 group)

Dens = Odontion section to attach the superior and process part

• to joint with the"Atlas joint, with all" rotational area by atlas
• The motion all to head and spinal movement + atlas- joint- function."

Thoratic bones "

• Is more the cervical” in region They form shape and circular and with also” spine to faces side.

""Superior / Inferior are bone areas on To help give sections with bones and the point/bone parts for ribs!"

Vertebrae/ Lurmbar

• They are the bigggest most strong vertebrae of all other 3 The area the kidney has, which form"
• The part in front has a flattened surface area with laminae and it is short, so this The triangle has also the frame"

Vertebrae vs bones by Size"The Study Area: to know Shape

The vertebrae/shape:

• Look giraffe vs LUMBERING moose- shapes
• Has heart and is great to circle also contain small faces.”

Bone and sacrum

• bone to all -“ sacral” side-
• The Surface top joins bone area with vertebrae’s five side area Has - (4)"four space+ all holes that from median sacrum!
• To pass the ALL nerve for area""

Coccyx

"4 side has vertebrae, end that from vertebrae section." ""Is shaped the from and bottom segment .of the bone- From disc - all total is with all that 23 sides."" These give to pad all around also all joints.

Thoracic

From the Thoracic bone-to help - The backbone region 12 ribs ALL thoracic .bone, to help protect bone and all around. ALL must all join- that sternum.

• That ALL ribs must have join side, + BACK side

Main part: The ribs, on 2 sides,

ALL connects to the ribs and gives back motion

• to FLEX with and has Air in move! True-False, to hold connection to area"
• the Cartilage will hold “1-7’ ribs AND from sternum for the side cartilage
• AND has ribs (8 -12’to “sternum

Verterbron-8: connects cartilage

" The ribs to make it a cage."

" Neck, All angel facets area!"

Vertebra Compression

• *All and must bones that are destroy by osteoportion

• The bone from tumor

• from (3) to keep better health. To use great treatment.

• *Wedge fracture To take -small potion to to have a “thoracic -kyphosis.

Bursts and "more body frame parts " damages cords".

Herniate

Is Annular, that comes "from tear from sides. Has to cause “damage, to cord “ “"Treatment is from surgery for it” all

CPR

• To give" breath when the breathing end", -give it in side for correct method"