lecture 7 ; axial skeleton Flashcards
another name for joints
articulations
how many bones in the body
206
subdivision of bones
- axial (80 bones)
2. appendicular (126 bones)
- bodies most complex bony structure
- formed by cranial and facial bones
- -enclose and protect the brain
- provide attachment sites for some muscles of the head and neck
the skull
- formed framework of the face
- form cavities for sense organs of sight, taste and smell
- provide opening for passage of air and food
- hold teeth in place
- anchor muscles of the face
facial bones of the skull
cranium is divided into 2 parts
cranial vault and base
paired bones of the cranial bone includes
-temporal and parietal bones
unpaired bones the cranial bone includes
frontal, occipital,shpenoid, and ethmoid bones
4 sutures of the cranium
- coronal
- squamous
- sagittal
- lamboid
runs in the coronal plane
-located where parietal bones meet the frontal bone
coronal suture
occurs where each parietal bone meets a temporal bone inferiorly
squamous suture
occurs where right and left parietal bones meet superiorly
sagittal suture
occurs where the parietal bones meet the occipital bone posteriorly
lambdoid suture
smooth part of frontal bone between superciliary arches
glabella
- site for neck muscle attachment
- contains air sinuses
mastoid process
- projects medially, contributes to cranial base
- houses cavities of middle and internal ear
petrous part
- keystone of the cranium
- spans width of the cranial floor
- resembles a bat with its winds spread
- consists of body and 3 pairs of processes
sphenoid bone
- lies between nasal and sphenoid bones
- forms most of the medial bony region between nasal cavity and orbits
ethmoid bones
4 parts of ethmoid bone
- cribriform plate
- crista galli
- perpendicular plate
- ethmoidal labyrinth
unpaired bones of the facial bone
-mandible and vomer
paired bones of the facial bone
-maxillae, zygomatic, nasal, lacrimal, palatine, inferior nasal conchae
-largest and strongest facial bone
-only moveable bone of the skull
2 parts ; horizontal body and two upright rami
mandible
- keystone of the bones of the face
- articulates with all other facial bones besides mandible
- contains maxillary sinuses
maxillary bones
special parts of the skull
- nasal cavity
- paranasal sinuses
- orbits
- hyoid bone
air filled sinuses located within these parts of the facial/skull bones
- lined with mucous membrane
- lighten the skull
-frontal
-ethmoid
-sphenoid
-maxillary
bones
- lies inferior to the mandible
- only bone with no articulation with any other bone
- acts as a movable base for tongue
hyoid bone
- in adult, 26 bones formed
- transmit weight of trunk to the lower limbs
- surrounds and protects the spinal cord
- serves as attachments site for muscles of neck and back
- held in place by ligaments
the vertebral column
vertebral column has 5 major regions
- 7 cervical vertebrae
- 12 thoracic vertebrae
- 5 lumbar vertebrae
- scrum 5 fused bones
- coccyx
- cushion like pads between vertebrae
- composed of
- -nucleus pulposus
- -anulus fibrosus
intervertebral discs
- gelatinous inner sphere
- absorbs compressive stresses
nucleus pulposus
- outer rings formed of ligament
- inner rings formed of fibrocartilage
- contains the nucleus pulposus
annulus fibrosus
-types of movement that occur between vertebrae
- flexion and extension
- lateral flexion
- rotation in the long axis
-smallest and lightest vertebrae
cervical vertebrae
- c1 of the neck
- lacks a body and spinous process
- supports the skull
- allows flexion and extension of neck
atlas
- has a body and spinous process
- dens projects superiorly
- acts as a pivot for rotation of the atlas and skull
- participates in rotating the head from side to side
axis
- articulate with ribs
- heart shaped bodies from the superior view
- spinous process are long and point inferiorly
thoracic vertebrae
- bodies are thick and robust
- spinous process are thick and blunt point posteriorly
lumbar vertebrae
- shapes the posterior wall of pelvis
- formed from 5 fused vertebrae
- inferiorly articulates with coccyx
sacrum
develops from fused rib elements
ala
-where first sacral vertebrae bulges into pelvic cavity
sacral promontory
- tailbone
- formed from 3-5 fused vertebrae
- offers only slight support to pelvic organs
coccyx
- forms bony framework of the chest
- components ;
- thoracic vertebrae- posteriorly
- ribs- laterally
- sternum and costal cartilage- anteriorly
- protects thoracic organs
- supports shoulder girdle and upper limbs
- provides attachment sites for many muscles of the back
thoracic cage
formed in three sections;
- manubrium
- body
- xiphoid process
sternum
superior section of the sternum
-clavicular notches articulate with medial end of clavicles
manubrium
- bulk of sternum
- sides are notched at articulations for costal cartilage of ribs 2-7
body
- inferior end of sternum
- ossifies around age 40
xiphoid process
anatomical landmarks for the sternum
- jugular notch
- sternal angle
- xiphisternal joint
- superior seven pairs of ribs
- attach to sternum by costal cartilage
true ribs
-inferior 5 pairs of ribs
false ribs
ribs 11-12
floating ribs
- common congenital disorder
- right and left halves of palate fail to fuse medially
cleft palate
- narrowing of the vertebral canal
- can compress roots of spinal nerves
stenosis of the lumbar spine
-abnormal lateral curvature
scoliosis
an exaggerated thoracic curvature
kyphosis
accentuated lumbar curvature “swayback”
lordosis
unossified remnants of membranes
fontanelles
