Bio 221 - Lab 3
Skeletal System Introduction & Axial Skeleton
I. Skeletal System: The skeletal system provides an internal
framework to support our body. The primary organs of this
system are our bones. The skeleton is divided into two divisions:
the axial skeleton and the appendicular skeleton. This lab focuses
on introductory aspects of this organ system and on the bones of
the axial division.
A. Classification of Bones (based on shape)
 Long bones
 Short bones
o Sesamoid bones
 Flat bones
 Irregular bones
B. Anatomy of a long bone
 Types of osseous tissue: compact bone and spongy bone
 Diaphysis
 Epiphysis (location of red bone marrow)
 Medullary cavity (location of yellow bone marrow)
 Epiphyseal line (between diaphysis & epiphysis)
C. Microscopic Anatomy of Compact Bone
 Osteon/Haversian system
 Central/Haversian canal
 Perforating/Volkmann’s canal
 Lacuna
 Osteocyte
 Lamella(e)
 Canaliculi/Canaliculus
D. Divisions of the Skeletal System
 Axial
 Appendicular
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II. Axial Skeleton: This skeletal division includes the bones of the
skull, the bones of the vertebral column, the bones of the bony
thorax, and the hyoid bone. For each of the assigned bones, you
should know to which skeletal division they belong, their
classification (based on shape), their name, and their assigned
markings.
A. Skull bones & sutures
 Sutures
 Coronal suture
 Sagittal suture
 Squamous suture
 Lambdoid(al) suture
 Frontal bone
 Supraorbital foramen or supraorbital notch (holes or
notches above each orbit)
 Parietal bones
 Temporal bones
 Zygomatic process (part of the zygomatic arch)
 External acoustic meatus
 Mastoid process
 Styloid process
 Mandibular fossa (see figures 5.10 & 5.11)
 Occipital bone
 Occipital condyle
 Foramen magnum
 External occipital protuberance
 Sphenoid bone
 Sella turcica
 Greater wing (lower, broader, flared projections, fig. 5.10
& 5.11)
 Ethmoid bone
 Crista galli
 Cribriform plates (with olfactory foramina)
 Perpendicular plate (forms upper ¾ of nasal septum; see
red portion of nasal septum, fig 5.12)
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 Maxillary bones/Maxilla(e)
 Infraorbital foramen (holes below the orbit, fig. 5.12)
 Alveolar process(es)
 Palatine process (anterior part of hard palate)
 Palatine bones (posterior part of hard palate)
 Zygomatic bones
 Temporal process (part of zygomatic arch, attaches to
zygomatic process of temporal bone)
 Lacrimal bones (often shattered & missing in real skulls)
 Nasal bones
 Vomer bone (lower part of nasal septum)
 Inferior Nasal Concha(e) bones
 Mandible
 Mandibular condyle (articulates with mandibular fossa
of temporal bone, fig. 5.9)
 Coronoid process (projection anterior to mandibular
condyle, fig 5.9)
 Mental foramen (holes in body of mandible, fig. 5.12)
B. Fetal Skull
 Anterior fontanel
 Posterior fontanel
 Frontal bone(s)
 Parietal bone(s)
 Temporal bone(s)
 Occipital bone
C. Vertebral Column
Be able to give the name and number of any cervical, thoracic,
or lumbar vertebra within a fully articulated vertebral column.
 Primary curvatures
 Thoracic curvature
 Sacral curvature
 Secondary curvatures
 Cervical curvature
 Lumbar curvature
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 Abnormal spinal curvatures (fig. 5.18)
 Scoliosis
 Kyphosis
 Lordosis
 Cervical vertebra(e)
 Body/centrum
 Vertebral foramen
 Transverse process(es)
 Spinous process(es)
 Superior articular process
 Inferior articular process
 Transverse foramen (hole in transverse processes of C1C6)
 Atlas (C-1)
 Anterior arch
 Posterior arch
 Axis (C-2)
 Dens/odontoid process
 Thoracic vertebra(e)
 Body/centrum
 Vertebral arch
 Vertebral foramen
 Spinous process
 Transverse process
 Superior articular process
 Lumbar vertebra(e)
 Body/centrum
 Vertebral arch
 Vertebral foramen
 Spinous process
 Transverse process
 Superior articular process
 Inferior articular process
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 Sacrum
 Body
 Sacral canal
 Median sacral crest
 Anterior/ventral & Posterior/dorsal sacral foramina
 Ala
 Coccyx
D. Bony Thorax/Thoracic Cage
 Sternum
 Manubrium
 Body/gladiolus
 Xiphoid process
 Jugular notch
 Sternal angle
 Ribs
 True ribs
 False ribs
 Floating ribs
 Costal cartilage
E. Hyoid bone
 body
 greater horn
 lesser horn
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