Norma Basalis OBJECTIVES At the end of this lecture, students will ...

Posterior Part
• Foramen magnum
– Posterior to basilar portion of occipital bone
– Transmit
- Medulla oblongata & its membranes
- Accessory nerves
- Vertebral arteries
- Anterior & posterior spinal arteries
- Ligaments connecting occipital bone with axis
Occipital condyles
– By which foramen magnum is bounded laterally
– On medial surfaces of which attach alar ligaments
– Articulate with superior articular surfaces overlying lateral
masses of atlas
• Jugular process
– Lateral to each occipital condyle
– Attachment for rectus capitis lateralis muscle & lateral atlantooccipital
ligament
• Hypoglossal canal
– Courses forward & laterally from inner aspect of occipital bone
within cranium just above foramen magnum to opening that
perforates occipital bone externally at lateral part of base of
occipital condyle
– Transmits hypoglossal nerve & a branch of posterior meningeal
artery
• Condyloid fossa
– Posterior to each occipital condyle
– Perforated on one or both sides by condyloid canal, for
transmission of a vein from sigmoid sinus to vertebral veins in
upper cervical region
• External occipital crest
• External occipital protuberance
• Superior & inferior nuchal lines
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