Axial Skeleton Flashcards
How many cranial and facial bones are in the skull?
8 cranial, used to protect brain and attachments for head and neck muscles
14 facial bones for openings for food and supports teeth
How many auditory ossicles are there and what are their names?
6, malleus, incus and stapes
What are connective tissues made of?
Cells and Extra-cellular matrix
What does the matrix contain?
Fibres and ground substance
Three types of cartilage connective tissues are?
➢ Hyaline cartilage
➢ Fibrocartilage
➢ Elastic cartilage
Cells of cartilage and where are they found?
Chondrocytes and lacunae
Matrix of a cartilage contains?
Ground substance composed of proteoglycans which
create flexible & resilient structures
➢ Many collagenous fibres (for tensile strength)
Cells of the bone tissue?
➢ Osteoblast – cell that builds bone
➢ Osteocyte - mature cell that maintains bone
➢ Osteoclast – cell that breaks down bone
Matrix of the bone tissue
Approximately 1/3 of bone matrix is collagenous fibres
➢ Provides strength & some flexibility
Approximately 2/3 of bone matrix is inorganic matter
➢ 85% calcium phosphate salt (Hydroxyapatite)
➢ 10% calcium carbonate
What are the two types of bone tissues and key characteristics?
- Compact (Cortical / Dense) bone
➢ Makes up the dense outer layer of bones
➢ Main structural unit is the osteon - Spongy (Cancellous / Trabecular) Bone
➢ Consists of interconnecting plates of bone called trabeculae
➢ Contains spaces filled with bone marrow
Name of hollow cylinders that surround haversian canal?
Lamellae
How do blood vessels and nerves gain access from in the bones?
Haversian and Volkmann’s canals
What is the canaliculi?
Links osteocytes to blood supply
What is the spongy bone made of?
Trabeculae
What is the axial skeleton made of?
Skull, bony thorax and vertebral column
Describe the epiphyses
Expanded ends of long bones
➢ Exterior is compact bone, interior is spongy bone
➢ Joint surface lined with articular (hyaline) cartilage
➢ In immature bones, the epiphyseal plate separates the
diaphysis from the epiphyses
Endochondral ossification
Produces most bones of the skeleton below the skull
➢ Uses hyaline cartilage “bones” as template material
➢ Epiphyseal plate facilitates lengthwise growth of long
bones until puberty
What are the 3 cranial fossas?
Anterior fossa: supports frontal lobe of brain
➢ Middle fossa: supports temporal lobes of brain
➢ Posterior fossa: supports cerebellum
What is the nasal cavity composed of?
➢ Constructed of bone & cartilage
➢ Dived into right & left parts by nasal septum
➢ Helps warm, moisten & purify air
What are the sutures of the skull?
Sagittal suture
Links the left & right parietal bones
Coronal / Frontal suture
Links the frontal bone to both the parietal bones
Lambdoidal suture
Links the occipital bone to the parietal bones
What does the paranasal sinuses do?
➢ Lighten skull / humidify air
➢ Lined by pseudostratified ciliated columnar (respiratory)
epithelium.
What are the paranasal sinuses?
➢ frontal (2 or more)
➢ maxillary (2)
➢ ethmoidal (many)
➢ sphenoidal (2)
What are the bones of the orbits?
Frontal bone Sphenoid bone Ethmoid bone Lacrimal bone Palatine bone Zygomatic bone Maxilla
Features of the parietal bones
Squamosal suture
Temporal lines- thickened regions of bones arcing across parietal and frontal bones
Points of attachment for temporalis muscle
Features of temporal bones
- Mastoid process
Conical process that acts as attachment point for sternocleidomastoid muscle. - Styloid process
slender process anterior & medial to mastoid process
Attachment point for muscles & ligaments. - External acoustic meatus
Canal which terminates at tympanic membrane (eardrum) adjacent
to middle ear.
Features of the occipital bone
Foramen magnum surrounds spinal cord ➢ Skull rests on atlas at occipital condyles ➢ Jugular foramen: allows passage for cranial nerves & blood vessels (e.g. internal jugular vein).
Features of the sphenoid bone
A butterfly-shaped bone that spans the width of the
middle cranial fossa
➢ Articulates with all other cranial bones
➢ Contains sella turcica which houses pituitary gland
➢ Characterised by greater & lesser wings
➢ Contains air sinuses & numerous foramina
Features of the ethmoid bone
➢ Located medial to orbits ➢ Forms lateral walls & roof of nasal cavity ➢ Contain air sinuses ➢ Perpendicular plate forms part of nasal septum ➢ Contain superior & middle conchae
Features of the Maxillae
➢ 2 medially fused bones that form the superior jaw
➢ All facial bones except mandible articulate with it
➢ Holds upper teeth & contains air sinuses
➢ Palatine process contributes to hard palate (roof of mouth)
Features of the mandible
➢ Only moveable bone of skull ➢ Holds the lower teeth ➢ Coronoid process: attachment points for muscles of mastication ➢ Mandibular condyles: form articulations with mandibular fossa of temporal bone
Nasal bones
2 medially fused bones
that form the bridge of
the nose
Lacrimal Bones
2 bones that contribute to
medial walls of orbits
Palatine Bones
2 bones that form portions of the hard palate, orbits & lateral
walls of nasal cavities
Vomer
A plough-shaped bone that forms part of
nasal septum
Inferior Nasal Conchae
2 curved bones that form part of the lateral
walls of the nasal cavity
Bones of the vertebral Column
7 cervical vertebrae
12 thoracic vertebrae
5 lumbar vertebrae
Sacrum and coccyx
3 main physical features of the Vertebrae
1. Body ➢ Disk- shaped anterior portion ➢ Weight bearing structure of vertebra 2. Vertebral arch ➢ Extends posteriorly from body ➢ Surrounds vertebral foramen (spinal cord) 3. Processes ➢ Normally seven processes arise from arch ➢ Points of attachment for muscles ➢ Articulate with other vertebrae
Thoracic vertebrae features
➢ Heart shaped body ➢ Long spinous processes angled inferiorly ➢ Costal facets for articulation with ribs
Lumbar features
➢ Large kidney shaped bodies
➢ Relatively short processes
Sacrum features
➢ Formed by 5 fused
vertebrae
➢ Articulates with
coxal bones of pelvis
Coccyx features
Formed by 4 fused
vertebrae
3 elements of the adult sternum are
- Manubrium Sterni
- Body/Corpus
- Xiphisternum (Xiphoid
process)
Hyoid bone
Lies inferior to mandible. Provides attachment for neck muscles involved with raising larynx during speech & swallowing Only bone in body that does not articulate with another bone.
