Bones of the Axial Skeleton

Your goal is to be able to identify, using the mounted skeleton and individual bones, all of the following bones, landmarks, and, for ribs and paired skull bones, whether a bone is left or right.

Skull
The bones of the skull can be divided into two groups, those enclosing the brain (cranial bones) and those forming the face (facial bones)
Cranial Bones
- Frontal (unpaired)
  1. surfaces & parts
    - glabella
    - frontal eminence
    - superciliary arch
    - orbital plate
  2. projections
    - zygomatic process
  3. sutures
    - coronal (parietofrontal)
    - frontal bone also articulates with each of the following bones:
      zygomatic, ethmoid, nasal, sphenoid, maxilla, lacrimal, palatine
  4. other features
    - supraorbital notch or foramen
    - temporal line
- Parietal (paired)
  1. surfaces & parts
    - parietal eminence
  2. sutures
    - coronal (parietofrontal)
    - sagittal (interparietal)
    - squamosal (parietotemporal)
    - lambdoid (parietooccipital)
  3. other features
    - temporal fossa
    - superior & inferior temporal lines
- Temporal (paired)
  1. surfaces & parts
    - squamous part
    - tympanic part
    - petrous (petromastoid) part
  2. projections
    - zygomatic process (meets temporal process of zygomatic to form zygomatic arch)
    - mastoid process
    - styloid process
  3. sutures & articulations
    - squamosal (parietotemporal)
    - temporal bone also articulates with each of the following bones:
      zygomatic, sphenoid, occipital, mandible (temporamandibular joint [TMJ])
  4. other features
    - external auditory (acoustic) meatus
    - internal auditory (acoustic) meatus
    - mandibular fossa
- Occipital (unpaired)
  1. surfaces & parts
    - basilar part
    - lateral (condylar) parts
    - squamous part
    - external occipital protuberance
    - internal occipital protuberance
    - internal occipital crest
  2. sutures & articulations
    - lambdoid (parietooccipital)
    - occipital bone also articulates with each of the following bones:
      temporal, sphenoid, vertebra C1 (atlantooccipital joint)
  3. other features
    - foramen magnum
    - occipital condyle
- Sphenoid (unpaired)
  Helps to form the nasal and orbital cavities and midcranial fossa.
  1. surfaces & parts
    - body
      - dorsum sellae
      - sella turcica
      - tuberculum sellae
      - optic canals
      - anterior clinoid processes
    - lesser wing
    - greater wing
  2. projections
    - pterygoid process
  3. articulations
    - articulates with each of the following bones:
      zygomatic, ethmoid, sphenoid, maxilla, palatine, frontal
  4. other features
    - temporal fossa
    - pterygoid plates
- Ethmoid (unpaired)
  1. surfaces & parts
    - horizontal plate
      cribriform plate is central, with crista galli dividing it
    - perpendicular plate
    - ethmoidal labyrinths
    - superior nasal concha
    - middle nasal concha
  2. projections
    - crista galli
  3. articulations
    - articulates with each of the following bones:
      frontal, sphenoid, maxilla, vomer, inferior nasal concha, palatine
Facial Bones
- Maxilla (paired)
  1. surfaces & parts
    - alveolar ridge
  2. projections
    - frontal process
    - palatine process (forms anterior 4/5th of hard palate)
    - zygomatic process
  3. articulations
    - articulates with each of the following bones:
      zygomatic, ethmoid, nasal, frontal, sphenoid, lacrimal, palatine
  4. other features
    - incisive fossa
    - lacrimal canal
    - infraorbital foramen
- Nasal (paired)
  1. articulations
    - articulates with each of the following bones:
      frontal, maxilla
- Vomer (unpaired)
  1. articulations
    - articulates with each of the following bones:
      ethmoid, maxilla, sphenoid, palatine, occipital
- Inferior nasal concha (turbinate) (paired)
  1. articulations
    - articulates with ethmoid
- Lacrimal (paired)
  1. articulations
    - articulates with each of the following bones:
      frontal, maxilla, ethmoid
- Zygomatic (paired)
  1. surfaces & parts
    - body
  2. projections
    - frontal process
    - maxillary process
    - temporal process (meets zygomatic process of temporal to form zygomatic arch)
  3. articulations
    - articulates with each of the following bones:
      frontal, sphenoid, maxilla, temporal
- Palatine (paired)
  1. projections
    - horizontal process (forms posterior 1/5th of hard palate)
    - vertical process
    - orbital process
  2. articulations
    - articulates with each of the following bones:
      ethmoid, sphenoid, maxilla, vomer
- Mandible (unpaired)
  1. surfaces & parts
    - body
    - mandibular symphysis
    - alveolar ridge
    - angle
    - neck
    - condyle
  2. projections
    - ramus
    - coronoid process
    - condyloid process
  3. articulations
    - articulates with temporal bone at temporomandibular joint (TMJ)
  4. other features
    - oblique line
    - condyle
    - mandibular notch
    - mandibular foramen
    - mental foramen
Vertebral Column
Basic Design of Vertebra
1. body
  all thoracic vertebrae have at least one facet for head of rib; most have a superior & inferior demifacet
2. pedicle
  - lamina
    spinous process (generally bifid in cervical vertebrae; acuminate in middle thoracic)
  - superior articular process
    superior articular facet
  - inferior articular process
    inferior articular facet
  - transverse process
    cervical vertebrae have transverse foramina for vertebral a & v
    most thoracic vertebrae have costal facet
Vertebral Regions
- Cervical (C1–C7)
  1. C1 (atlas)
    - anterior arch
    - posterior arch
    - articular surface for dens
    - articular surfaces for occipital condyles
  2. C2 (axis)
    - dens (odontoid process)
- Thoracic (T1–T12)
- Lumbar (L1–L5)
- Sacrum (S1–S5)
  - composed of five fused sacral vertebrae
  - ala of sacrum
  - sacral promontory
  - body of sacral vertebrae
  - ventral sacral foramina
  - sacral canal
  - sacral hiatus
  - median sacral crest
  - lateral sacral crest
  - dorsal sacral foramina
- Coccyx (Co1–Co5)
  - composed of three–five fused coccygeal vertebrae
  - coccygeal cornua
Thoracic Cage
- Ribs
  1. ends
    - vertebral: head
    - sternal: tipped with costal cartilages
  2. projections
    - tubercle
  3. articular surfaces
    - head: superior & inferior facets
      articulate with demifacets on bodies of thoracic vertebrae
    - facet on tubercle
      articulates with costal facet on transverse process of thoracic vertebra
  4. other features
    - neck
    - angle
    - shaft
    - costal groove
  5. types of ribs
    - vertebrosternal (true) ribs (ribs 1–7)
    - false ribs (ribs 8–12)
      - vertebrochondral ribs (ribs 8–10)
      - vertebral (floating) ribs (ribs 11–12)
- Sternum
  1. components
    - manubrium
    - body
    - xiphoid process
  2. articulations
    - manubriosternal symphysis (sternal angle)
    - xiphisternal symphysis
    - costochondrosternal joints
    - sternoclavicular joints
  3. other features
    - suprasternal (jugular) notch

[ A&P1 Syllabus ]

Version 1.0c