Chapter 7 Part 1) Axiel Skeleton

Question 1

Axiel Skeleton

Answer 1

• 80 Bones divided into three sections (Skull, Vertebreal column, thoracic cage).
• Three Functions
  
  • Form Longitudial Axis of body
  • Support head neck and trunk
  • Protect brain, spinal chord, and thoraic organs

Question 2

The Skull

Answer 2

• Formed by Facial Bones and Cranial Bones
• Joints in Cranial skull are called sutures.

Question 3

Cranial Base

Answer 3

• Formed by the Anterior, Middle, and Posterior Fossae (depression)

Question 4

Cranial Cavities

Answer 4

• Middle Ear Cavity
• Internal Ear cavity
• Nasal Cavity
• Orbital Cavity (eyeballs)

Question 5

Parietial Bone and Major Sutures

Answer 5

• We have two Large Parietial Bones on the most superior aspect of the cranial vault.
• Four major sutures of the Parietal Bone
  
  • Coronal Suture) Between Parietal and Frontal Bone
  • Sagital Suture) Between Left and Right Parietal Bones
  • Lambdoid Suture) Between Parietial and Occipitial Bone
  • Squamous Sutures) Between Paritetal and Temproral bones.

Question 6

Occipital Bone

Answer 6

• Most of the Posterior Wall and Posterior Cranial Fossa of the Skull.
• Major Structures
  
  • Foramen Magnum) Large Base Hole
  • Occipital Condyles) Articulate with first vertebre. Allows “yes” head motion
  • Hypoglossal canal) Cranial nerve XII
  • External Occipital Protuberance) Large bump on back of head
  • External Occipital Crest) Secures ligamentum nechea
  • Superior and Inferior Nuchal Lines

Question 7

Temporal Bone

Answer 7

• 2 Found on the Sides of the head
• Made of 4 parts) Squamous, Tymphanic, Mastoid, Peatrous.
• Major Structures
  
  • Zygomatic Process) Meats zygmotic bone anteriorly
  • External Acoustic Meatus) Passage in eardrum
  • Petrous Part) Holds middle and internal ear cavitites
  • Jugular Foramen) Jugular, Nerves IX, X, XI
  • Cartoid Canal) Cartoid Artery
  • Foramen Lacerum) Cartlidge in living person
  • Internal Acutsic Meatus) Cranial Nerves VII and VIII
  • Mastoid Process) anchoring for some muscles.
  • Styloid Process) Attachment for tounge and neck muscles, and ligament that holds hyloid bone to the skull.
  • Stylomastoid Formen) Between styloid and mastoid process, allows nerve VII to leave skull.

Question 8

Sphenoid Bone

Answer 8

• Keystone Bone of Cranial Bones. This is because it articulates with all other cranial bones.
• Three Processes
  
  • Greater Wings
  • Lesser Wings
  • Pterygoid Processes) Anchor ptergoid Muscles (chewing muscles) `
• Major Parts
  
  • Sella Turcia) Turks Saddle, Hypophysis fossa which forms an enclosure for the petuitarty gland.
  • Optic Canals) allow optic nerve (II) to pass through.
  • Superior Orbital Fissure) Allows Cranial nerves that control eye movment to (III, IV, VI)
  • Forman Rotundum) Passage of cranial nerve V
  • Forman Ovale) Passage of cranial nerve V
  • Forman Spinosum) Tranmsits meninginal artery, serves internal face of cranial bone.

Question 9

Ethmoid Bone

Answer 9

• Deepest Skull Bone
• Helps build the Roof of the Nasal Cavity.
• Imprortnant parts
  
  • Cribriform Plates) Form roof of nasal cavity. Contain Cribriform/Olfactory Formina that allows passage of olfactary nerve (I).
  • Crista Galli (Rooster Comb) Outermost covering of brain attaches to the crista galli and secures brian to cranial cavity.
  • Perpendicular Plate) Forms superior part of Nasal Septum.
  • Lateral Mass) contains ethmoid air cells which are thin walled celular cavities.
  • Middle Nasal Conchae) Increases air flow
  • Superior Nasal Conche) Increases Air flow.

Question 10

Sutural Bones

Answer 10

• Tiny bones in the Sutures of the Skull, Not everyone has these

Question 11

Frontal Bone

Answer 11

• Forms the Anterior Portion of the Cranial bones
• Major Structures
  
  • Anterio Cranial Fossa) Holds Brain.
  • Frontnasal Suture)
  • Frontal Sinisus) Lateral to the glabella
  • Squamous Part) Forhead
  • Supraorbital Foramen) Allows passage of supraorbital artery and nerve
  • Suprorbital Margin) Forms part of the Orbit.

Question 12

Mandible

Answer 12

• Forms the Lower Jaw. Largest, Strongest Facial bone
• Important Parts
  
  • Temporomandinular Joint) Only freely movable joint in skull.
  • Mandibular Formina) allows lower jaw teeth to have nerve sensation. (Dentists inject ludocaine to numb area in this formina)
  • Mental Formina) Allows blood vessels and nerves to pass to skin of chin.
  • Condylar Process) articualtes with mandibular fossa making the tempomandular joint.
  • Aveolar Process)
  • Corniod Process) Insertion for jaw muscle that elevates mandible.
  • Mandubular Angle
  • Mandibular Notch
  • Mandibular Sumpahysis) Medial fusion point for mandibles

Question 13

Maxillary Bone

Answer 13

• KEYSTONE BONE) articulates with all other facial bones except the mandible. Holds Maxillary Sinisus.
• Major Structures
  
  • Incissive Fossa) Leads to incisicve canal. For passage of nerves and blood vessels.
  • Infoerior Orbital Fissure) Zygomatic Nerve, Maxillary Nerve and bloodvessels to pass to face.
  • Infraorbital Formen) Allows infraorbital nerve to reach the face.
  • Anterior Nasal Spine) Outer part of nose
  • Frontal Process) Front face
  • Hard Palate) forms roof of mouth. Contains Palitine Process
  • Maxillary Sinuses)
  • Zygomatic Process) of maxilla.

Question 14

Zygomatic Bones

Answer 14

• Inferolateral margins of orbits
• Three processes
  
  • Temporal processes
  • Frontal Processes
  • Maxillia processes

Question 15

Nasal Bones

Answer 15

• Form the bridge of the nose
• Cartlidge attaches inferiorly to the nasal bone to form the nose.

Question 16

Lacermial Bones

Answer 16

• In medial walls of the orbits
  
  • Lacrimal fossa) depression for tearduct.

Question 17

Palentine Bones

Answer 17

• Posterior 1/3 of hard palate and Posterolateral walls of the nasal cavity.
  
  • Horizonatal Plate) Roof of mouth.
  • Perpendicular Palate) Forms the part of the poterolateral walls of the nasal cavity.

Question 18

Vormer

Answer 18

• Forms inferior part of the nasal septum.

Question 19

Inferior Nasal Conche

Answer 19

• Form part of the lateral walls of the nasal cavity.

Question 20

Hyoid Bone

Answer 20

• Not in skull. Anchored by the stylohyoid ligaments to the styloid process
• Acts as movable base for tongue and attachment for speach and sswallowing muscles.

Question 21

Orbits

Answer 21

• Encase eyes and lacrimal glands.
• Sites of attachemt for eye muscles
• Formed by
  
  • Frontal Bone) orbital plate and the zygomatic process
  • Sephnoid Bone) Lesser wing forms roof of the orbit and the greater wing forms part of the lateral wall of the orbit.
  • Zygomatic Bone) forms lateral wall and floor of orbit
  • Palentine bone) little dot
  • Lacrimal bone) medial wall. has lacrimal gland.

Question 22

Nasal Cavity

Answer 22

• Formed by the parts of several bones
  
  • Roof) formed by caribiform plates of the ethmoid bone.
  • Lateral Walls) Superior and middle conchoid of the ethmoid. Perpendicular plates of palatine. Inferior Nasal Conche.
  • Floor) Processes of palatine and maxillary bones
• Nasal Septum
  
  • Posterior) Vormir and perpendicualr plate of the ethmoid
  • Anterior) nasal cartlidge.

Question 24

Nasal Sinuses

Answer 24

• Frontal Sinus) in frontal bone
• Spehoid Sinus) in spehoid bone
• Ethmoid Sinus) in ethmoid bone
• Paired Maxillary Sinsus) formed by paired maxillary bones.

Question 25

Vertebraeal Column

Answer 25

• Spine or Spinal Collum. Trasnmits weight of the trunk, protects the spinal chord, provides attachment for ribs and muscles
• Five regions
  
  • Cervical Vertebrae) 7 In the neck. Concave Posteriorly.
  • Thoracic vertabrae) 12 in middle (thoracic) back. Convex Posteriorly
  • Lumbar Vertabrae) 5 In lower back. Concave Posteriorly
  • Sacrum) Bone inferior to lumbar vertebrae. Covex Posteriorly
  • Coxyx) bottom of vertebrecal collum.

Question 26

Abnormal Spine Curvatures

Answer 26

• Scoliosis) abnormal lateral curbe
• Kyphosis) Dorsally exadurated thoracic curvature
• Lordosis) Excentuated lumbar curvature.

Question 27

Intervertebral discs

Answer 27

• Cushion like pads made of fibrocartlidge in between vertabrae.

Question 28

General Structure of Vertabrae

Answer 28

• Body) Centrum. the Anterior weight bering part of the vertabrae.
• Vertebral arch) made of two parts
  
  • Two pedicles) short pillers that form the sides of each arch\
  • Two laminae) Flattened plated that form the posterior arch.
• Vetrebral Forman) large hole in the center which spinal chord passes through. Formed by the body and th arch coming together.
• Veterbral Colum) colum formed by lines of vertabreal forman
• Intervertebral Formina)lateral openings between vertebrae for passage of spinal nerves.

Question 29

Seven Processes of Vertabrae.

Answer 29

• Spinous Process) projects posteriorly
• Transcerse process (2) Project laterally (rib attachent)
• Superior articular process (2) Project supiorly
• Inferior articualr processes (2) project infeiorly.
  *

Question 30

Atlas vertebrae

Answer 30

• C1 Vertabrae
• NO body or Spinous process
• Has Anterior and Posterior Arch plus Two Lateral Masses
  
  • The superior surface of these lateral masses articulate with occipital condyles of skull. They “carry” the skull
• Responsible for moving the head up and down.

Question 31

Axis Vertebrae

Answer 31

• C2
• Has a body and process with a knob like projection called the Dens. The Dens projects superiorly onto the anterior Arch of the Atlas.
  
  • Dens is “missing body” of the Atlas.
• This allows for a piviot motion or moving the head “no”

Question 32

Cervical Vertebrae

Answer 32

• C1-C7. C3-C7 share common characteristics
• Oval shaped body
• Spineous process are split at ends
• Vertebracial froamen is large and triangular.
• Transverse Froamen in each Transverse Process
  
  • Vertebracial arteries travel through these processes.
• C7 is called the Vertebrea Prominens. Can be felt through the skin and is used as a landmark/

Question 33

Thoracic Vertebrae

Answer 33

• T1-T12) Articulate with ribs. Looks like girrafe
• Body is Heart Shaped
  
  • Has two small demifacets (half facets) that artiuclate with ribs.
• Vertebracial Froamen is circular
• Long, sharp spineous process
• Transverse Process hvae transverse costal facets which articulate with ribs

Question 34

Lumbar Vertebrae

Answer 34

• L1-L5. Relives stress so bodies are massive. Look like a cow.
  
  • Short thick Pedicles and Laminae (vertebrecial arch)
  • Vertebracial Froamen is triangular
    *

Question 35

Sacrum

Answer 35

• 5 Fused Vertebrae (S1-S5).
• Forms the posteior wall of the pelvis
• Major Structures
  
  • Alae) Top crest of structure
  • Auricular Surfaces) Articulate with Hip Bones to form Saroiliac Joint.
  • Sacral Canal) where the spinal chord continues from vertebrae above
  • Sacral Formina) transmits sacral spinal nerves.
  • Sacral hiatus) when 4th and 5th sacral vertebrae fuse incorrectly and there is a large opening,
  • Sacral Promontory) high crest of bone above the sacral formina.
  • Facets of Superior Articular Processs) Articulate with L5 supeiorly.

Question 36

Coxyx

Answer 36

• Tailbone. 3-5 fused verebrae that articulate with the sacrum.

Question 37

Thoracic Cage

Answer 37

• Consists of
  
  • Thoracic Vertebrae Posteriorly
  • Sternum and Costal Cartlidges Anteriorly
• Funtions
  
  • Protect Thoracic organs
  • Support Shoulder Girlde/Upper Limbs
  • Attachment sites for the muscles of the neck, back, chest and shoulders.

Question 38

Sternum (Brestbone)

Answer 38

• made of three fused bones
  
  • Manubrium) Superior part that articulates with the clavicles via the Clavicular Notches. Below this it artiuculates with Ribs 1 and 2.
  • Body) Midportion that articulates with costal cartlidges of ribs 2 through 7.
  • Xiphloid Process) Inferior end that is for muscle attachment.
• Other Important Parts
  
  • Sternal angle) where the manubrium meeths the body
  • Jugular Notch) where the cartoid artery branches from the aorta.

Question 39

Ribs and their Attachments

Answer 39

• 12 pairs form the thoracic cage. All attatch posteriorly to thoracic vertebrae.
• True (Vetebrosternal) ribs) Pairs 1-7
  
  • all attach directly to the sternum by costal cartlidges
• False (Vertebrochondral) ribs) Pairs 8-10
  
  • Attach indirectly to sternum by joining costal cartlidge of rib above
• Vertebral (floating ribs) Pairs 11-12
  
  • Do not attach to the sternum

Question 40

Parts of a Rib

Answer 40

• Shaft) Flat bone that makes most of rib.
  
  • Has costal groove which houses nerves and blood vessels
• Head) Posterior End. Articualtes with the Demi Facets on the bodies of the adjacent vertebrae
• Neck) Constricted (slimmer) portion beyond head of the rib.
• Tubracle of Rib) Knoblike structure lateral to the neck.
  
  • Articulates with the transverse facet of the same numbered thoracic vertebrae.