Norma Occipitalis Anatomy PDF

NORMA OCCIPITALIS NORMA OCCIPITALIS  Posterior or back view of the skull  Simplest view among all the views  Upper part is convex and lower part is flat Principal bones 1. Unpaired occipital bone (squamous part) 2. Paired parietal bones (posterior part) 3. Paired mast...

NORMA OCCIPITALIS NORMA OCCIPITALIS  Posterior or back view of the skull  Simplest view among all the views  Upper part is convex and lower part is flat Principal bones 1. Unpaired occipital bone (squamous part) 2. Paired parietal bones (posterior part) 3. Paired mastoid process and squamous part of temporal bones (minimal contributions on lateral and inferior aspect of skull) Principle sutures 1. Posterior third of sagittal suture, present between the two parietal bones 2. Lambdoidal suture – present between the occipital and two parietal bones 3. Occipitomastoid suture – present between the occipital bone and the mastoid part of the temporal bone 4. Parietomastoid suture – present between the parietal bone and the mastoid part of the temporal bone Prominent landmarks & reference points 1. Lambda 2. External occipital protuberance 3. Inion 4. Superior nuchal line 5. Inferior nuchal line 6. Highest nuchal line 7. Mastoid processes of temporal bone Prominent landmarks & reference points 1. Lambda – point of intersection of the sagittal and lambdoidal sutures 2. External occipital protuberance – is a raised roughened areas on the midline 8-10cm below the lambda 3. Inion – most prominent point of the external occipital protuberance ??? Prominent landmarks & reference points 1. External occipital crest – midline crest present between the external occipital protuberance and posterior border of foramen magnum; also called as median nuchal line 2. Mastoid processes of temporal bone – present at the inferolateral angles of the skull in norma occipitalis; situated immediately behind the auricle or external acoustic meatus Prominent landmarks & reference points 1. Superior nuchal line – prominent horizontal ridge running laterally from the external occipital protuberance to the mastoid process of temporal bone 2. Highest nuchal line – faint ridge present above and parallel to superior nuchal line 3. Inferior nuchal line – running on lateral side of middle of external occipital crest Prominent landmarks & reference points 1. Superior nuchal line – prominent horizontal ridge running laterally from the external occipital protuberance to the mastoid process of temporal bone 2. Highest nuchal line – faint ridge present above and parallel to superior nuchal line 3. Inferior nuchal line – running on lateral side of middle of external occipital crest 4. External occipital crest – U 5. Mastoid processes of temporal bone – present at the  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaa Attachments Red – muscle origin Blue – muscle insertion Green – ligaments ??? Neurovascular exit portals  Parieto-mastoid foramina  Parietal foramina Other features  Sutural bones or Wormian bones  Interparietal bones