Anatomy Lab: Skull bones and Facial Muscles

Osteon

cylindrical structures, composed of concentric rings of lamellae

central canal

the innermost region of an osteon that contains blood vessels and nerves.

Lamellae

thin layers of bone matrix that form the structural framework of an osteon. os

canaliculi

small channels that connect osteocytes within the lamellae to the central canal, facilitating nutrient and waste exchange.

Spongy bone

a type of bone tissue that is characterized by a porous structure, providing strength and lightweight support, commonly found at the ends of long bones and in the interior of others.

Trabeculae

the small, rod-like structures that make up the framework of spongy bone, providing support and housing bone marrow.

marrow cavity

the central hollow space within a bone that contains bone marrow, responsible for the production of blood cells.

Long bones

longer than they are wide

Short bones

equal length and width

flat bones

flat, thin bone with curved surfaces (maybe)

irregular bones

bones with complex shapes that do not fit into the other categories, such as the vertebrae and certain skull bones.

diaphysis

shaft of long bone

epiphyses

knobby region on each end of long bone

epiphyseal line

remnants of epiphyseal plate in adults, divides diaphysis and epihyses

periosteum

layer of CT that lines the external surface of bone shaft

Hyaline cartilage location

epiphyseal plate & articular ends of long bones

Fibrocartilage location

intervertebral discs (weight bearing)

Elastic cartilage location

external ear, epiglottis

lacunae in cartilage

houses chondrocytes

chondrocyte

make cartilage cells that produce and maintain cartilage by making sure no blood vessels form in matrix

perichondrum

a layer of dense connective tissue that surrounds cartilage, providing support and nourishment.

osteoblast

synthesize and secrete osteoid, make new bone tissue

osteocyte

a mature bone cell that maintains the bone matrix and communicates with other bone cells to regulate mineral content.

8 Cranial bones

Occipital, Parietal (2), frontal, temporal (2), ethmoid, sphenoid

14 facial bones

Nasal (2), Vomer, Lacrimal (2), Zygomatic( 2), Palatine (2), Maxilla (2), Mandible, Inferior nasal concha (2)

Bone that is not really part of skull

Hyoid bone

Cranial bone structures: temporal bones

Styloid process, mastoid process, external acousitc meatus, mandibular fossa

Cranial bone structures: ethmoid bone

Cribriform plate, Crista galli

Cranial bone structures: Sphenoid bone

Sella turcica, optic foramen

Muscles for mastication

Masseter, temporalis

muscles for facial expression

Frontalis, orbicularis oculi, orbicularis oris, zygomaticus major

Muscles for cervical movement

Sternocleidomastoid, scalenes, erector spine

Name for C1 bone

atlas

Name for C2 bone

axis

feature on C2/axis bone

Odontoid process or dens

Fibrous joints

joints connected by dense connective tissue, immobile/slightly mobile, hold together bones

Three classifications of fibrous bones

Gomphoses, suture, syndesmosis

Gomphoses joints ex

hold teeth in place

suture joints ex

Holds skull together

Syndesmosis joints

Bones joined along length via dense regular CT

Cartilagenous joints

Cartilage between bones, no joint cavity, immobile/slightly mobile

Two classifications of cartilaginous joints

Synchondrosis & symphysis

Synchondrosis joints

Joined by hyaline cartilage

symphysis joints

have pod of fibrocartilage (vertebrae)

Synovial joints

freely mobile w/ joint cavity

classifications of synovial joints

Planar, hinge, pivot, condylar, saddle, ball-and-socket

Planar joints

allow gliding or sliding movements between flat surfaces

ex. inter carpal joints

Hinge joints

permit flexion and extension around a single axis, similar to a door hinge.
ex. elbow joint

Pivot joints

allow rotational movement around a single axis,

ex. atlantoaxial joint between first and second cervical vertebrae.

condyloid joint

allow movement in two planes, enabling flexion, extension, adduction, and abduction.
ex. wrist joint

saddle joint

allow movement in multiple directions, including flexion, extension, adduction, abduction, and opposition.
ex. thumb joint

Ball & socket joint

allow movement in multiple axes, including flexion, extension, adduction, abduction, and rotation.
ex. hip and shoulder joints

functional classifications of joints

synarthrosis, amphiarthroses, diarthroses

Degree of movement allowed by functional classifications of joints

synarthrosis- immobile

amphiarthroses- slightly mobile

diarthroses- freely mobile

Components of synovial joint structure

Articular capsule, synovial joint capsule, articular cartilage, extrinsic ligaments

Articular capsule components

synovial membrane, fibrous layer

What does the synovial joint cavity contain?

synovial fluid