Skull

The bony framework of the head. Comparisons must distinguish deformation after death from biological differences.

The anterior cranial fossa is the anterior depression of the internal skull base supporting the frontal brain regions. Its bony floor also relates to the orbit and nasal region. Thin partitions here connect intracranial anatomy to nearby sensory passages.

A skull-base projection that contacts the palatal apparatus. Its size and articulation contribute to constraints on cranial kinesis.

Movement between parts of the skull beyond ordinary lower-jaw rotation. joint surfaces, soft tissues, muscles and constraints elsewhere in the skull jointly determine realized movement.

The roof of the mouth and its supporting anatomy. In avian comparisons, contacts among the vomer, palatine bone, pterygoid bone and braincase are important for cranial kinesis.

An avian palatal arrangement with more mobile pterygoid–palatine articulation and reduced bracing compared with the palaeognathous palate. Mobility varies among species and cannot be read from the group name alone.

An avian palatal arrangement with extensive bracing among the vomer, pterygoid bone, palatine bone and skull base. It is associated with Palaeognathae; the name does not establish evolutionary primitiveness.

The eye socket, distinct from a temporal fenestra behind it.

A fibrous attachment at the apex of the orbit (anatomy) from which the four rectus extraocular muscles arise. Its relations distinguish structures passing through the optic canal and different parts of the superior orbital fissure.

The periosteum lining the orbit (anatomy). In an orbital dissection, it separates the surrounding bones from the contents until opened.

The inferior orbital fissure is a gap in the posterior-inferior orbital wall connecting the orbit with neighboring deep facial spaces. It transmits nerves and vessels, including routes associated with the maxillary division of the trigeminal nerve. It is distinct from the superior fissure.

The superior orbital fissure is an opening at the posterior orbit transmitting several ocular motor nerves and other structures. Relations to the common tendinous ring determine which pathways pass through or outside the ring. The nearby optic canal is a separate route.

The optic canal is the bony passage carrying the optic nerve and ophthalmic artery into the orbit. Its location differs from the superior orbital fissure used by several ocular motor nerves. This separation helps relate a local lesion to different patterns of visual and motor impairment.

The braincase is the part of the skull enclosing and protecting the brain. Openings transmit nerves and vessels while the surrounding skeletal walls provide support. Comparative reconstructions distinguish this neural enclosure from the jaws and more external skull-roof components.