Axial Skeleton the Skull Axial Skeleton 80 of

Axial Skeleton: the Skull

Axial Skeleton 80 of: total bones Functions: 1. Skull and facial bones (29) Protects Vital Organs 2. Thoracic Cage: sternum and ribs (25) Provides areas for muscle 3. Vertebral Column (26) attachment Composed of: 1. Skull and facial bones (29) 2. Thoracic Cage: sternum and ribs (25) 3. Vertebral Column (26)

Skull �Cranium = houses brain �Facial bones = protect/support digestive and respiratory entrances �Foramen = holes for nerves and blood vessels �Two foramen you

Major Bones of the Skull � Frontal � Parietal � Occipital � Temporal � Sphenoid � Maxilla � Mandible – only moveable bone of the skull

Facial Bones of the Skull � Need to know: � Nasal, vomer, ethmoid, maxilla, mandible, zygomatic, lacrimal, orbit , sphenoid

Sphenoid Bone Difficult bone to see, greater wing of sphenoid makes up side of skull, front part of bone makes up the orbitals

Bone Markings of the Skull � In addition to skull bones, you will also be required to recognize some special markings of the skull bones � Foramen - holes for nerves and blood vessels (mental foramen and foramen magnum) � Process – a projection or outgrowth of tissue from the body (styloid process, mastoid process, zygomatic process/arch) � Meatus – a natural body opening or canal (external auditory meatus) � Condyle – The rounded projection on the articulated (where joints occur) end of a bone (occipital condyle) � Ramus – any part that branches from another part (ramus of the mandible) � Notch - an indentation on the edge of a bone (Mandibular notch)

Bone Markings of the Skull

Bone Markings of the Skull Palatine Bone Occipital condyles Foramen Magnum

Skull Sutures � Sutures are interconnections between bones � Lambdoidal = parietal + occipital � Sagittal = 2 parietal bones � Frontal = frontal + parietal � Squamous Parietal = Temporal +

Sutures Sagittal Lambdoidal Squamous Frontal

Fontanels � Fontanels are spaces between the bones of the skull in an infant or fetus, where ossification is not complete and the sutures not fully formed (“soft spots” of infant’s skull). Sutures will not completely fuse until about 30 years old.

Sinuses �The sinus is an moist, air-filled chamber. It produces mucus to filter air and make the bones lighter. It also plays a role in how our voices sound.