Question

What is a skull? How many views of the skull are present? Describe in detail the views of the skull?

Answer 1

• The skull as a whole may be looked at from above (norma verticalis), from front (norma frontalis), from back (norma occipitalis), from below (norma basalis), and from the side (norma lateralis).
• These different aspects are to be described systematically one by one in time of describing a skull as a whole.

Norma Verticalis:

• The following features may be noted:
• The contour which is more or less oval or sometimes nearly circular.
• The sutures, namely,
  • (a) coronal-in between the frontal and the two parietal bones.
  • (b) the sagittal-lies between the two parietal bones.
  • (c) the lamboidal between the parietal bones and the occipital bone.
• The bones, namely,
  • (a) the frontal with its two frontal eminences.
  • (b) the two parietals-with parietal tuberosities, one on each bone .
  • (c) the occipital-squama of the occipital.
• The important landmarks are
  • (a) the bregma-the meeting place of the coronal and sagittal sutures.
  • (b) the lambda-the junction of the sagittal and lamboidal sutures.
  • (c) the obelion-in between the two parietal foramina.
  • (d) the vertex-the highest point in the median plane.

Norma Frontalis:

• The following are some of the important features to be noted on the frontal aspect of the skull.
• The more or less oval outline, wider above than below. The forehead formed by the frontal bone.
• The super ciliary arch above the orbit.
• The orbits - Each orbit has medial and lateral walls, a roof, a floor, a base or orbital opening and an apex. The orbital cavity is pyramidal in shape.
• The nasal aperture - bounded by the maxillae and the nasal bones.
• The maxilla - The zygomatic process of the maxilla.
• The supra-orbital foramen and infra-orbital foramen.
• The sutures, e.g. (a) fronto-nasal (b) fronto-maxillary (c) fronto-zugal (d) intra-nasal (e) naso-maxillary (f) intermaxillary (h) zygomatico-maxillary, etc.
• The landmarks, e.g. (a) glabelia (b) nasion (c) rhinion (d) nasospinale (e) prosthion, etc.

Norma Occipitalis:

• The outline is roughly pentagonal, being convex above and on each side, and flattened below.
• The external occipital protuberance is the most important feature on this aspect.
• The nuchal lines-the inferior. the superior and the supra or the highest, are also to be noted.
• Of the anatomical points the inion is very important. The sutures are: (a) occipitomastoid. (b) parietomastoid and (c) lamboid.

Norma Basalis:

• For descriptive purposes it can be divided into an interior part, a middle part and a posterior part.
• The anterior part is formed by the palatine process of the maxillae and the horizontal plates of the palatine bones.
• The following are the important features in this part: (a) intermaxillary suture, (b) interpalatine suture, (d) palato-maxiIlary suture, (d) incisive fossa. (e) lateral incisive foramina, n median incisive foramina, (g) greater palatine foramina, (h) lesser incisive foramina, (0 tubercle of the palatine bone, palatine crest, (k) posterior nasal spine,(0) alveolar process.
• The middle part lies posterior to the anterior part of the norma basalis extending up to an arbitrary line drawn transversely through the anterior margin of the foramen magnum:
• The important features to be noted are (a) pharyngeal tubercle, (b) pterygoid process along with pterygoid fossa, medial and lateral pterygoid lamina and pterygoid hamulus, (d) foramen ovale, (d) foramen spinosum, (e) foramen lacirum ( carotid canal, (g) tympanic part of the temporal bone.
• The posterior part is formed by the rest of the norma basalis.
• The important features are (a) foramen magnum, (b) occipital condyle. (c) condyler fossa, (d) jugular foramen, (e) styloid process. ( mastoid process, etc.

Norma Lateralis:

• The noteworthy features are: (a) Temporal line, (b) temporal fossa, (d) zygomatic arch, (d) pterion. (e) external auditory meatus. squama of the temporal. (g) mastoid portion of the temporal bone, (h) mastoid process, (i) styloid process, (j) infratemporal fossa, (k) pterygopalatine fossa, etc.
  
  

The skull is a bone structure that forms the head in vertebrates. It supports the structures of the face and provides a protective cavity for the brain.