!!A&P Lab: Axial Skeleton-Review last

Cranial Bones

Surrounds and encloses the brain

Cranial bones form the cranium

8 cranial bones

Paired Cranial bones

Parietal and Temporal

Unpaired cranial bones

Ethmoid, frontal, occipital, and sphenoid

Frontal Bone

Forehead

The superior and anterior parts of the skull

Unpaired

Glabella

Superior to nasal bone

Supraorbital foramen

Hole above orbits where nerves pass through

Supraorbital Margin

Forms superior border of orbit

Parietal Bone

• Paired

• Pariet = wall

• Flat skull bones that form lateral and superior walls of the skull

Superior and inferior temporal line

Arch structure that is the attachment site for temporals muscle

Temporal Bone

• Paired

• Makes up the inferior and lateral walls of the skull

Zygomatic Process

Articulates with zygomatic bone. Forms zygomatic arch.

Mandibular Fossa

A shallow depression that articulates the condyle of the mandible

External acoustic meatus

External ear opening, the passageway to middle ear

Mastoid process

Projection that is the attachment site for neck muscles. Shaped like a breast.

Styloid process

Projection that is the attachment site for hyoid bone ligament muscle of the tongue neck. Styl= stake

Internal acoustic meatus

opening into the skull for Facial (VII) and Vestibulocochlear

(VIII) Nerve

Petrous part/apex of temporal bone

Petrous=rock. Contains inner and middle ear

Occipital Bone

Forms posterior and inferior portions of the skull

Foramen magnum

Passageway for spinal cord

Occipital condyles

Articulate with 1st vertebra

External Occipital Protuberance

Attachment site for neck, ligaments, and muscles

Ethmoid Bone

• Makes up the anterior portion of the cranial fossa, forms part of the nasal septum, and is the roof of the nasal cavity.

• ______ = sieve-like (strainer)

Cribiform Plate

Horizontal plate that contains cribriform foramina

cribriform foramina

Contains foramina (passageway for olfactory neurons)

Crista Galli

Cranial dura septa (the partition between 2 cerebral hemispheres) attaches here to help stabilize the brain

Ethmoidal sinuses (Ethmoid air cells)

Lighten skull, affect voice resonance

Nasal Conchae

Shell-shaped bone that increases turbulence of inhaled air

Perpendicular plate

Makes up superior portion of nasal septum

Sphenoid Bone

• Forms the base of the skull and the posterior part of the orbit

• Bat-shaped bone

greater wing

Makes up middle portion of cranial fossa and lateral aspect of skull and orbits

Sella turcica

Enclosure around hypophyseal toss.Turkish saddle

Optic canal

Optic nerve from the eyes pass through here where they will extend to the brain

Hypophyseal Fossa

Depression in sphenoid bone that contains sella turcica

Paired facial bones

zygomatic, lacrimal, nasal, inferior, nasal conchae, palatine, and maxilla

Unpaired facial bones

Vomer and Mandible

Nasal bone

Forms bridge of nose

Two small, oblong bones

Lacrimal Bone

• Forms the medial wall of the orbit of the eye

• Lacrim = teardrops

• Lacrimal fossa - houses lacrimal sac (tear drainage

area)

Zygomatic Bone

• Paired

• Forms cheeks and part of the orbit (lateral)

• Bone features / markings

• Frontal process

• Temporal process

• Maxillary Process

Inferior Nasal Conchae

• Paired scroll-like (shell) shaped bone

• Located in the nasal cavity

• Increases airflow (turbulence) in the nasal

cavity

palatine bone

• Paired bones

• Form the posterior portion of the palate

• Forms a small part of the nasal cavity and orbit wall

• Bone Features and markings

• Horizontal plate

• Perpendicular plate

horizontal plate

Forms posterior part of hard palate. Connects to maxilla palatine process

Perpendicular plate

Forms part of nasal cavity and orbit

Maxilla Bone

• Paired bones fused in the midline

• Forms upper jaws

• Forms the lateral wall of the nasal cavity,

• Forms part of the floor of the orbit and the roof of the oral cavity

Infraorbital Margin

Forms the inferolateral border of the orbit

Infraorbital foramen

Passageway for infraorbital artery and vein

Alveolar process

Houses the teeth

Zygomatic Process

Articulates with zygomatic bone

Palatine Process

Forms most of bony palate

Vomer bone

• Unpaired bone

• Forms the inferior por-on of the nasal septum

Mandible

• Forms lower jaw

• Only articulatng bone in the head region

Mental Foramen

Passageway for vessels and nerves

Mental protuberance

Chin

Body

Horizontal portion of mandible

Ramus

Vertical portion of mandible

Coronoid process

Anterior projection off ramus

Condylar process of mandible

Posterior projection off ramus, contains head of mandible

Hard Palate

Formed by the palatine process of maxillae and palatine bones

Zygomatic Arch

Fused portion of temporal process of the zygomatic bone and zygomatic process of the temporal bone

Calvaria

• Dome-like roof/skull cap

• Top of cranium- Frontal bone, parietal bone & occipital bone

Cranial Fossa

• Cranial bones form around the developing brain

• ‘Stepping down stairs’

• Anterior, middle, & posterior cranial fossae

Coronal

Between frontal and left and right parietal bones

Sagittal

Between left and right parietal bones

Lambdoidal

Between occipital bone and left and right parietal bones

Squamosal

Between parietal bones and squamous portion of temporal bones

Hyoid Bone

found in the anterior neck region, below the mandible. Has a broad “U” shape that resembles an archer’s bow lying on its side. The bone consists of a central body and two pairs of projections called lesser and greater horns.

Malleus

Attached to tympanic membrane, most lateral

Incus

Middle

Stapes

Most medial, shaped like stirrup

Cervical Vertebrae

• Form the bones of the neck

• C1 - C 7

• Small and light vertebrae

• The distinguishing characteristic of cervical vertebrae is the transverse

foramina (houses vertebral artery/vein) and a bifid spinous process

Atlas (C1)

• Lacks a spinous process and vertebral body

• Articulates with occipital condyles

• Part of the atlanto-occipital joint

• Allows you to shake your head to indicate “yes.”

Axis (C2)

• Dens (tooth) projects from the vertebral body

• Articulates with C1

• Part of the atlantoaxial joint - allows for rotation of the head to shake your head to indicate "No." (Pivot joint)

• Axis (C2) superior view

Vertebra Prominens (C7)

• Prominent spinous process

• Can be felt at the base of the neck

Thoracic Vertebrae

• Each thoracic vertebra acidulates two pairs of ribs (laterally from vertebrae)

• T1-T12

• The transverse process is longer

• Less mobile than cervical or lumbar vertebrae

Lumbar Vertebrae

• Forms small of the back

• L1-L5

• Largest of the vertebrae with a thicker body

• Bears most of the weight of the vertebral column

Sacrum

• Formed by 5 sacral vertebrae that fuse in the late 20s

• S1-S5

• Articulates with hip bones

Coccyx

• 4 vertebrae unite during puberty

• Co1 - Co4

Manubrium

• The superior portion of the sternum

Contains:

• Clavicular notches - to ar-culate

sternum with clavicles

• Suprasternal notch

Body of Sternum

• The longest part of the sternum

• Costal notches articulated with ribs 2-7 via costal cartilages

Xiphoid Process

• Tip of sternum

• Avoid pushing here during CPR due to risk of it breaking off and puncturing deep tissues

True Ribs

• Ribs 1-7

• Connect individually to the sternum through costal cartilage (hyaline cartilage)

False Ribs

• Ribs 8-12

• Ribs share costal cartilage; does not directly attach to the sternum

Floating Ribs

• Ribs 11-12

• No connection to sternum