KAAP309 Lecture Notes - Lecture 7: Anterior Cranial Fossa, Sphenoidal Sinus, Coronal Suture
18 May 2018
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Chapter 7A
I. The Axial Skeleton
A. 80 bones segregated into 3 regions
1. Skull
2. Vertebral column
3. Bony thorax
II. Skull
A. Bod’s ost ople o struture
B. Formed by the cranium and facial bones
1. Cranium – protects brain; site of attachment for head and neck muscles
2. Facial bones
a) Framework for the face, sense organs, and teeth
b) Provide openings for passage of air and food
c) Anchor facial muscles of expression
III. Anatomy of the Cranium
A. Eight cranial bones: two parietal, two temporal, frontal, occipital, sphenoid, and
ethmoid
B. Cranial bones thin and strong for their weight
C. Frontal bone
1. Anterior portion of the cranium
2. Articulates posteriorly with the parietal bones via the coronal suture
3. Major markings include: supraorbital margins, anterior cranial fossa,
frontal sinuses (internal and lateral to the glabella)
D. Parietal bones and associated structures
1. Form most of the superior and lateral aspects of the skull
2. Coronal, sagittal, lambdoid, squamous sutures
E. Occipital bones
1. Fors ost of skull’s posterior wall and base
F. Temporal bones
1. Form the inferolateral aspects of the skull and parts of the cranial floor
2. Divided into four major regions – squamous, tympanic, mastoid, and
petrous
3. Major markings include: zygomatic, styloid, and mastoid processes,
middle cranial fossa
4. Major openings include: external auditory meatus, internal auditory
meatus, stylomastoid and jugular foramina, carotid canal
G. Sphenoid bone
1. Butterfly-shaped bone that spans the width of the middle cranial fossa
2. Forms the central wedge that articulates with all other cranial bones
3. Central body, greater wings, lesser wings, and pterygoid processes
4. Major markings: sella turcica, hypophyseal fossa, pterygoid processes,
sphenoid sinuses, middle cranial fossa
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5. Major openings include: optic canals, superior orbital fissure
H. Ethmoid bone
1. Deepest skull bone; lies between the sphenoid and nasal bones
2. Forms most of the bony area between the nasal cavity and the orbits
3. Major markings include: cribriform plate, crista galli, perpendicular
plate, superior & middle nasal conchae, ethmoid sinuses
IV. Facial Bones
A. Fourteen bones
B. Only mandible and vomer are unpaired
C. Paired bones: maxillae, zygomatics, nasals, lacrimals, palatines, inferior conchae
D. Mandible
1. Lower jawbone; largest, strongest bone of face
2. Major markings include: coronoid process, mandibular condyle,
alveolar margin, mandibular angle, mandibular and mental foramina
E. Maxillary Bones
1. Medially fused bones make up upper jaw and central portion of the
facial skeleton
2. Facial keystone bones that articulate with all other facial bones except
mandible
3. Major markings include: palatine, frontal, and zygomatic processes
(artic. w/ respective bones), alveolar margins, maxillary sinuses
F. Zygomatic Bones - irregularly shaped bones (cheekbones), form prominences of
cheeks and inferolateral margins of orbits
G. Nasal bones – thin medially fused bones, form bridge of nose
H. Lacrimal bones – contribute to medial walls of orbits; contain lacrimal fossae
which house lacrimal sacs
I. Palatine bones – two bone plates, form portions of hard palate, posterolateral
walls of nasal cavity, and small parts of orbits
J. Vomer – plow-shaped bone, forms part of nasal septum
K. Inferior nasal conchae – paired, curved bones in nasal cavity, form part of lateral
walls of nasal cavity
Chapter 7B: Vertebral Column
I. Vertebral Column
A. 26 irregular bones (vertebrae) connected to form a flexible curved structure
1. Cervical vertebrae – 7 bones of neck
2. Thoracic vertebrae – 12 bones of torso
3. Lumbar vertebrae – 5 bones of lower back
4. Sacrum – bone inferior to the lumbar vertebrae that articulates with
the hip bones (fusion of 5, starts ~> puberty, done mid-20s)
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B. Curvatures
1. Kyphosis: posteriorly convex
curvature. Thoracic and
sacral normally kyphotic
(but not too much).
2. Lordosis: posteriorly
concave curvature. Cervical
and lumbar normally
lordotic (but not too much).
3. Abnormal spinal curvatures
a) Scoliosis (lateral curve)
b) Excessive kyphosis
(hunchback)
c) Excessive lordosis
(swayback)
d) What happens in pregnancy?
e)
C. Ligaments
1. Anterior and posterior longitudinal ligaments – continuous bands down
the front and back of the spine from the neck to the sacrum
2. Short ligaments connect adjoining vertebrae together
D. Intervertebral Discs
1. Cushion-like pad composed
of two parts
a) Nucleus pulposus –
inner gelatinous
nucleus that gives the
disc its elasticity and
compressibility
b) Annulus fibrosus –
surrounds the nucleus
pulposus with a collar
composed of collagen
and fibrocartilage
E. General Structure of Vertebrae
1. Body or centrum – disc-shaped, weight-bearing region
2. Vertebral arch – composed of pedicles and laminae that, along with the
centrum, enclose the vertebral foramen
3. Vertebral foramina – make up the vertebral canal through which the
spinal cord passes
4. Spinous processes project posteriorly, and transverse processes project
laterally
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Document Summary
The axial skeleton: 80 bones segregated into 3 regions, skull, vertebral column, bony thorax. Thoracic and sacral normally kyphotic (but not too much): lordosis: posteriorly concave curvature. Cervical vertebrae: seven vertebrae (c1-c7): smallest, lightest vertebrae, c3-c7: distinguished by oval bodies, short spinous processes, large, triangular vertebral foramina. Articular facets (sup & inf) form joints with vetrebrae above. T11, t12: long spinous process, location, orientation of articular facets prevents sagittal plane flexion and extension, but allows rotation and limited lateral flexion, of thoracic spine. Coccyx: tailbone, the coccyx is made up of four (in some cases three to five) fused vertebrae that articulate superiorly with the sacrum. Sternum: breastbone, dagger-shaped, flat bone lying in the anterior midline of thorax, results from fusion of three bones manubrium, body, xiphoid process, anatomical landmarks include: jugular (suprasternal) notch, sternal angle, xiphisternal joint. Appendicular skeleton: limb bones and their girdles, pectoral girdles attach upper limbs to trunk, pelvic girdle secures lower limbs.
