I.                Chapter 6.  Bones of the Axial Skeleton

A.               Axial vs. Appendicular Skeleton (Fig 6.1)

B.               The Skull (Fig 6.2)

1.                Skull Geography

a)                Sutures

(1)             Coronal suture: parietal and frontal (Fig 6.3b, Fig 6.3c)

(2)             Squamous suture: parietal and temporal (Fig 6.3c)

(3)             Sagittal suture: midline between parietals (Fig 6.3b)

(4)             Lambdoid suture: parietals and occipital (Fig 6.3a)

2.                Cranium

a)                Occipital Bone (Fig 6.6a, Fig 6.6b)

(1)             Foramen magnum: central foramen, transmits spinal cord

(2)             Occipital condyles: art w/ first vertebra

(3)             Hypoglossal canal: on lip of foramen magnum, transmits CN XII (hypoglossal)

(4)             External occipital protuberance: secures ligamentum nuchae w/ ext. occipital crest

b)               Parietal Bones (Fig 6.3c)

c)                Frontal Bone (Fig 6.7a, 6.7b, 6.7c)

(1)             Superciliary arches: protrusions superior to orbits

(2)             Glabella: flat area between superciliary arches

(3)             Supraorbital foramina (notches)

d)               Temporal Bones (Fig 6.8, 6.8c)

(1)             Regions:

(a)              Squamous region: flat area on superior portion

(b)             Tympanic region: surrounds external auditory meatus

(c)              Mastoid region: contains mastoid process, posterolateral protrusion

(d)             Petrous portion: thick medial contributor to cranial floor, houses inner ear

(2)             Styloid process

(3)             Jugular foramen: between petrous portion and occipital bone

(4)             Carotid canal: anterior to jugular foramen

(5)             Foramen lacerum: formed w/ petrous portion and sphenoid

(6)             Mandibular fossa: art w/ mandible

(7)             Internal acoustic meatus: transmits CN VII & VIII

e)                Sphenoid Bone (Fig 6.9a, 6.9b)

(1)             Body, lateral greater/lesser wings, inferolateral pterygoid processes

(2)             Sella turcica: houses pituitary gland

(3)             Optic foramina: in medial portion of lesser wing; transmit CN II

(4)             Superior orbital fissure: between greater & lesser wings; transmits CN III (oculomotor), IV (trochlear), V (ophthalmic div of trigeminal), VI (abducens)

(5)             Foramen rotundum & ovale: transmit branches of CN V (trigeminal, maxillary & mandibular divs)

(6)             Foramen spinosum: posterolateral, transmits middle meningeal artery

f)                Ethmoid Bone (Fig 6.10, 6.10b)

(1)             Crista galli, lateral masses & perpendicular plate (sup part of nasal septum)

(2)             Cribriform plate: smooth areas lateral to crista galli that contain olfactory foramina

(3)             Superior & middle nasal conchae: scroll-shaped bones that protrude into nasal cavity

g)                Cranial Fossae (Fig 6.11)

(1)             Anterior, middle, posterior

3.                Facial Bones

a)                Maxillae (Fig 6.12)

(1)             Orbital surface, alveoli & alveolar margin, palatine process, zygomatic process

(2)             Infraorbital foramen, infraorbital fissure

b)               Palatine Bones (Fig 6.13)

(1)             Horizontal plates, vertical plates, orbital surfaces

c)                Nasal Bones (Fig 6.15a, 6.15b)

d)               Inferior Nasal Conchae (Fig 6.16ab, 6.16d)

e)                Zygomatic Bones (Fig 6.3c)

(1)             Temporal process, [frontal process]

f)                Lacrimal Bones (Fig 6.15a, 6.15b)

g)                Vomer (Fig 6.5)

h)               Mandible (Fig 6.14)

(1)             Ramus, angle, body, coronoid process, mandibular condyle, mandibular notch

(2)             Mental foramen, mandibular foramen

4.                Orbits (Fig 6.15a, 6.15b)

a)                Made up of orbital plate of frontal, sphenoid (greater/lesser wings), orbital surf of zygomatic, ethmoid, maxilla, lacrimal, palatine

5.                Nasal Cavity (Fig 6.16ab, 6.16d)

6.                Hyoid Bone (Fig 6.17)

a)                Greater/lesser cornu (horn), body

C.               The Vertebral Column

1.                Divisions and Curvature (Fig 6.19)

a)                Abnormal Curvatures: Kyphosis, Lordosis, Scoliosis (Fig 6.20)

C₇ – T₁₂ – L₅ – S₅(fused) – Coccyx(4 fused)

Cervical, thoracic, lumbar curvatures

2.                General Vertebral Anatomy (Fig 6.21)

a)                Intervertebral discs

Annulus fibrosus, nucleus pulposus

3.                General Structure of Vertebrae (Fig 6.21)

a)                Body

b)               Vertebral arch

(1)             Pedicles

(2)             Laminae

c)                Transverse processes

d)               Spinous process

e)                Superior/inferior articular processes

f)                Foramina: vertebral foramen, transverse foramen (only in cervical – transmits vertebral a.)

4.                Regional Vertebral Characteristics (Table 6.3)

a)                Cervical (Fig 6.22)

(1)             Atlas & Axis (C1 & C2; Fig 6.23ab, Fig 6.23cd, Fig 6.23ef)

(2)               Short, bifid spinous process; transverse foramen; large vertebral foramen

(3)               Atlas (C₁): sup articular facets on lateral masses

(4)               Axis (C₂): Dens (odontoid process), kind of a body

b)               Thoracic (Fig 6.24)

(1)                Demifacets on body for rib artic, circular vertebral foramen, long spinous process pointing inferiorly

c)                Lumbar (Fig 6.25)

(1)               Thick, kidney-shaped body, small pedicles, triang vert foramen, stubby spinous process

d)               Sacrum (Fig 6.26)

(1)             Anterior

(a)              Ala, sacral promontory, sacral foramina

(2)             Posterior

(a)              Ala, sacral canal, sup articular process, median sacral crest, hiatus, dorsal sacral foramina

e)                Coccyx (Fig 6.26)

D.              The Bony Thorax (Fig 6.27)

1.                Sternum (Fig 6.27a)

a)                Manubrium, body, xiphoid process

b)               Sternal angle, jugular notch, clavicular notch

2.                Ribs (Fig 6.27a)

a)                Head, neck, angle, shaft (Fig 6.27bd)

b)               Articular tubercle, costal groove, articular facets

c)                Seven true ribs, five false ribs (not directly connected to sternum via costal cartilage), two floating ribs per side