Posterior And Ventral Aspect Of Mammal Skull (Bones And Structures)

Front 1

occipital bone

Back 1

constitutes the posterior wall of the braincase and is formed by the fusion of four bones (#7 on pic)

Front 2

occipital crest (lamboidal crest)??

Back 2

ridge of bone across the postero-dorsal margin of the cranium; usually part of the supraoccipital bone; neck muscle attachment

Front 3

foramen magnum

Back 3

this is the large opening in the occipital bone; conduit for the spinal cord and vertebral arteries

Front 4

occipital condyles

Back 4

smooth raised surfaces on the exoccipital bones; these serve as articulation points for the skull, setting into depressions in the first vertebra (atlas)

Front 5

paroccipital process (exoccipital process)

Back 5

ventrally projecting projections of th eoccipital bone; close to and just posterior to the auditory bulla; serves for insetion of certain chewing muscles

Front 6

auditory bullae

Back 6

thin walled, swollen structures on either side of basioccipital and ventral to squamosal; the bullae protect the middle ear

Front 7

basisphenoid bone

Back 7

anterior to the basioccipital and located in the ventral midline of the skull

Front 8

presphenoid bone

Back 8

also in the ventral midline, between the paired pterygoids, posterior to the vomer and anterior to the basisphenoid

Front 9

pterygoid bones

Back 9

posterior to the internal opening of the nasal passages; often with an elongate process extending posterior from the ventral surface of each pterygoid

Front 10

palatine bones

Back 10

paired bones forming the posterior portion of the palate, between the cheekteeth and posterior to the maxillae

Front 11

Vomer bone

Back 11

a single bone in the ventral midline of the skull, anterior to the alisphenoid and forming the postero-ventral portion of the wall separating the two sides of nasal passages

Front 12

mandibular fossa

Back 12

on the ventral side of the base of each zygomatic process of the squamosal; point of articulation for jaw

Front 13

incisive foramen

Back 13

opening to vomer nasal organ on roof of mouth; when present located on premaxilla maxilla junction (between canines)

Front 14

internal nares??

Back 14

single large opening posterior and dorsal to the palatine bones; forms the proximal of the nasal passages

Front 15

infraorbital foramen

Back 15

large foramen in each maxilla terminating the orbit; serves for passage of blood vessels and nerves

Front 16

external auditory meatus

Back 16

ear canal; foramen in the side of each bullae across which the tympanic membrane (eardrum) is stretched