The Axial SkeletonSalt Lake City Community CollegeHuman Anatomy Laboratory

http://homepage.smc.edu/wissmann_paul/bones/EBbonestutorial.html

Axial skeleton - forms long axis of bodySkullVertebral columnThoracic cage

Appendicular skeleton (next week) – appendages and what they attach toUpper limbs (arms)Pectoral girdle (shoulder)Lower limbs (legs)Pelvic girdle

Axial skeletonSkullVertebral columnThoracic cage

Axial skeleton is shown in green

The Skull = cranial bones and facial bones

Cranial bones

parietal parietalfrontal

temporal

parietal

occipital

_______sphenoid_____ethmoid

occipital

Temporal bones

this is the right temporal bone looking at it from the right side

Sphenoid

Ethmoid Small cranial bones…

Sutures

Largest 4 skull sutures: where bones articulate with parietal bones Coronal Sagittal Squamous Lambdoid (FIND THEM)

Find: coronal, squamous and lamboid sutures

Find: sagittal and lambdoid sutures

MandibleVomerMaxillae (paired)Zygomatics (paired)Nasal (paired)Lacrimal (paired)Palatines (paired)Inferior nasal conchae (paired)

Facial bones:

Mandible (lower jaw)

Maxilla (there are 2 that fuse, forming the upper jaw)

Paranasal sinuses Air-filled sacs in the bones “Paranasal” because they cluster around

and connect to the nasal cavity

Hyoid bone

Only bone which does not articulate with any other bone

Moveable base for the tongue

Points of attachment for neck muscles that raise and lower the larynx during swallowing

Remember that the Axial skeleton includes:

SkullVertebral columnThoracic cage

Axial skeleton is shown in green

The Vertebral Column

Adult: 24 vertebrae Cervical – 7 Thoracic - 12 Lumbar - 5 Sacrum (5 fused) Coccyx (4 fused)

Structure of a typical vertebra

The SacrumShapes posterior wall of pelvis

Composite bone of 5 fused vertebrae

Sacral foramina allow passage of vessels & nerves

Coccyx(the tailbone)

Remember that the Axial skeleton includes:

SkullVertebral columnThoracic cage

Axial skeleton is shown in green

The Thoracic Cage

Sternum Ribs

Manubrium

Body

Xiphoid process

True ribs 1-7

False ribs 8-12

Floating ribs 11,12

Fontanels

Unossified remnants of membranes

Present at birth Anterior fontanel largest Called “soft spots” Ossify by 1 ½ - 2 years

Continue to ossify into adulthood; the sutures can become fused in old age