CHAPTER 7 Axial Skeleton Bones of the Adult Skeleton 206 named bones make up the adult skeleton Bones are divided between two divisions Axial skeleton 80 bones cranial cavity ribs sternum Appendicular skeleton 126 appendages free limbs Arms legs The Skull The skull contains two sets of bones Cranial bones 8 form the cranial cavity Facial bones 14 form the face Anatomy Overview Skull General Features of the Skull Bones of the skull have numerous surface markings which aid in their identification Holes through the bone foramina Bony projections e g a spine Frontal Bones Form Facial Icons Forehead frontal bone Forms superior part of your eye socket ceiling roof or floor Eye socket superior part Also forms much of the anterior floor of the cranial cavity Parietal Bones Form much of the sides and roof of the cranial cavity 2 bones Form the inferior lateral part of the cranial floor plus part of the lateral wall Temporal Bones near the ear Temporal bones have Zygomatic process Zygomatic bones have Temporal process Together they make up the Zygomatic Arch Zygomatic Arch Mastoid process promenade surface right behind and below your ear Petrous houses sensory organs for hearing and equilibrium Temporal bones articulate with mandibal and forms tempro mandibular joint TMJ Have a carotid foramen a hole that a carotid artery goes through Jugular foramen hole that jugular vein goes through Internal auditory meatis opening to ear canal Purple temporal Blue frontal Red parietal Occipital gold in back Know where frontal bone starts stops etc Occipital Bone of the cranial cavity Forms much of the posterior wall and the posterior floor Prominent surface features Ligamentum nuchae elastic ligament has muscles attached to it that meet the condiles to help support the head runs down to C7 Foramen Magnum houses spinal cord largest foramen in body Occipital condiles articulate with the cervical vertebrae External occipital protuberis buldge on back of head superior to foramen magnum Sphenoid Bone Articulates with all other cranial bones providing considerable stability to the skull Has a complex shape resembling a bat Greater wings and lesser wings Greater wings part of lateral wall of the cranium Plerygoid process Attach muscles to mandibal Optic foramen Sphenoid sinus paranasal sinus these fill with fluid and cause Sella tersica depression in the spheniod bone that contains sinus headaches the pituitary gland Also forms part of posterior part of the eye socket Sphenoid Bone Ethmoid Bone Ethmoid Bone cont d Crista galli projects superiorly from the ethmoid attachment site for falx ceperbi membrane that separates the hemispheres of the cerebrum Forms part of cranial floor In that floor there are lots of formens Forms medial wall of eye sockets Forms superior part of nasal septum Superior and middle nasal cocha Filter and warms the air we breathe contributes to sense of smell increases sufrace area Olefactory foramen Cribiforum plate Perpendicular Plate Ethmoid Bone Frontal bone Go back label Facial Bones Nasal Lacrimal These are paired bones that form the bridge of the nose These are paired bones that form the anterior portion of the medial wall of the eye socket Lacrimal Sac where tears are produced Maxilla leads to lacrimal groove which leads to lacrimal sac Lacrimal groove passes through nasal cavity so when you cry nose runs Orbit of the Eye Facial Bones Palatine These are paired bones that form the posterior edge of the hard palate roof of mouth as well as portions of the eye socket and nasal cavity wall and floor Inferior nasal conchae All conchae help to swirl and filter air before it passes into the lungs A bone buy itself Facial Bones Vomer unpaired bone that sits on floor of nasal cavity Extends superiorly to meet the ethmoid bone to form nasal septum Maxillae form at midline to form upper jar and most of hard palate Internally these are hallowed out and form very large sinuses Zygomatic Cheek bones Has temporal process on it to form zygomatic arch Mandible lower jaw bone Mandibular Noch Orbits Three cranial bones and four facial bones form each orbit Associated with each orbit are five openings Optic foramen canal Superior orbital fissure Inferior orbital fissure Supraorbital foramen Lacrimal fossa Cartilage is all in the nasal septum Broken nose is usually more damage to the cartilage than the bone Unique Features of the Skull The skull exhibits the following unique features Sutures holds bones together Paranasal sinuses cavities in frontal bone ethnoid and cenal plays part in resonance of voice how it carries skull mass Fontanels soft spot on baby s head Paranasal Sinuses These are cavities within frontal sphenoid and ethmoid The sinuses lighten the skull s mass and play a role in resonance Paranasal Sinuses Not on exam Paranasal Sinuses Not on exam Sutures An immovable joint in adults Coronal unites frontal and parietal bones Sagittal unites two parietal bones Lambdoid unites two parietal bones with occipital bone Squamous unites parietal temporal bones Could be text or identification Fontanels at Birth Unoccupied Intermembrane occification takes place for flat bones most bones in skull are flat bones hardening of bones can pass through birth canal Fontanels at Birth Fontanels at Birth Cranial Fossae The cranium has three distinct regions called cranial fossae that correspond to the major contours of the inferior surface of the brain Anterior forms portions of frontal bone Crista galli Steniod Frontal lobes of cerebral hemispheres Middle holds temporal lobes of brain Posterior cerebellum pons medulla oblongata Cranial Fossae Hyoid Bone Does not articulate with any other bone suspended from styloid process with ligaents muscles Attachment site for tongue pharynx and our neck Vertebral Column Also known as the spine or backbone Cervical vertebrae C7 7 Thoracic vertebrae T4 12 Lumbar vertebrae L4 5 Fused sacral 1 vertebrae that form the sacrum Fused coccygeal 1 vertebrae that form the 5 coccyx 4 Parts of a Typical Vertebra Vertebrae typically consist of Body Vertebral arch Processes Clinical Connection Abnormal Curves of the Vertebral Column Normal curves include the convex cervical lumbar curves and the concave thoracic sacral curves Abnormal curves of the vertebral column Scoliosis problem with lateral alignment of vertebral column Kyphosis hunchback abnormal curve of the upper thoracic vertebrae Lordosis abnormal curve of lumbar vertebrae sway back Structures Common to Most Vertebrae