This slide gives a complete description on Norma Lateralis( Lateral view of skull)

1. AREEB FATIM A
ST U DENT DOCT OR OF PHYSICA L T HERA PY
GOVERNM ENT COLLEGE U NIVERSIT Y
HUMAN ANATOMY
Head and Neck

2. Introduction and Osteology
(Part 2)

3. EXTERIOR OF THE SKULL

4. Norma Lateralis
 Bones:
 Frontal
 Parietal
 Occipital
 Temporal
 Sphenoid
 Zygomatic
 Mandible
 Maxilla
 Nasal

5. Figure: Norma Lateralis
Norma
lateralis
(Lateral
aspect of
cranium)

6. Figure: Norma Lateralis
Norma
Lateralis
(Lateral
view of
skull)
Colour
coded

7. Norma Lateralis (Continued)
 Temporal lines:
 Begin at the zygomatic process of frontal bone, arch backwards
and upwards, and cross the frontal bone, the coronal suture and
the parietal bone.
 Over the parietal bone, there are two lines superior and inferior.
Traced anteriorly they fused to form a single line.
 Traced posteriorly, the superior line fades out over the posterior
part of parietal bone.
 The inferior temporal line, in its posterior part, turns downwards
and forwards and becomes continuous with the supramastoid
crest on the squamous temporal bone near its junction with the
mastoid temporal. This crest is continuous anteriorly with the
posterior root of the zygomatic arch.

8. Norma Lateralis (Continued)
Squamous part of
temporal bone
Superior temporal
line
Inferior temporal
line
Supramastoid
crest
Mastoid process of
temporal bone
Zygomatic crest

9. Norma Lateralis (Continued)
 Zygomatic arch or Zygoma:
 Horizontal bar on the side of head, in front of the ear, a little above the
tragus.
 Formed by:
 Anterior one third: Temporal process of zygomatic bone.
 Posterior two third: Zygomatic process of temporal bone.
 Zygomaticotemporal suture crosses the arch obliquely.
 Temporal fossa and muscle:
 Above zygomatic arch is temporal fossa, which is filled by temporalis muscle.
 Masseter muscle is attached to the lower margin of zygomatic arch.
 Contraction of temporalis and masseter muscle may be felt by clenching the
teeth.
 Separation of arch from skull:
 Arch is separated from the side of the skull by a gap which is deeper in front.

10. Norma Lateralis (Continued)
 Anterior surface is subcutaneous.
 Jugal point:
 Anterior end of the upper border.
 The posterior end of zygomatic arch is attached to the
squamous temporal bone by anterior and posterior roots.
 The anterior root passes medially in front of the articular fossa.
 The posterior root passes backwards along the lateral margin of
the mandibular or articular fossa, then above the external acoustic
meatus to become continuous with the supramatoid crest.
 Projections visible in relation to these roots:
 Articular tubercle: At its lower border.
 Postglenoid tubercle: Behind the mendibular fossa.

11. Norma Lateralis (Continued)
Zygomatico temporal suture
Zygomatic bone
Temporal process of
zygomatic bone
Temporal bone
Zygomatic arch of
temporal bone
Posterior root
Articular tubercle

12. Norma Lateralis (Continued)
 External acoustic meatus:
 Opens just below the posterior part of posterior root of zygoma.
 Margins:
 Anterior, inferior margin and lowest part of inferior margin: Tympanic
plate.
 Posterosuperior margin: Squamous temporal bone.
 Margins are roughened for attachment of auricular cartilage.
 Suprameatal triangle or triangle of Macewen:
 Small depression posteriosuperior to the meatus.
 Boundaries:
 Above: Supramastoid crest.
 Front: Posterosuperior margin of the external meatus.
 Behind: Vertical tangent to the posterior margin of the meatus.

13. Norma Lateralis (Continued)
 At birth thickness is 1mm and the thickness increases 1mm per
year and reaches up to 12-15mm.
 The triangle forms the lateral wall of tympanic or mastoid
antrum.
 Suprameatal spine:
 Present on the interoinferior margin of the triangle.

14. Norma Lateralis (Continued)
 Mastoid part of temporal bone:
 Lies just behind the external acoustic meatus.
 Continuous anterosuperiorly with the squamous temporal
bone.
 Squamomastoid suture:
 Visible in front.
 Parallel to roughened area for muscular insertion.
 Articulations:
 Posterosuperiorly: Posteroinferior part of parietal bone at the
horizontal parietomastoid suture.
 Posteriorly: Squamous occipital bone at the occipitomastoid
suture.
 These two sutures meet at lateral end of lambdoid suture.

15. Norma Lateralis (Continued)
 Asterion:
 Parietomastoid, occipitomastoid, and lambdoid sutures meet.
 In infants, site of posterolateral or mastoid fontanelle, which
closes by 12 month.
Parietomastoid suture
Lambdoid suture
Asterion
Temporomastoid suture

16. Norma Lateralis (Continued)
 Styloid process:
 Needle like thin long projection
from the temporal bone.
 Situated anteromedial to the
mastoid process.
 Directed downwards, forwards,
and slightly medially.
 Base partly ensheathed by
tympanic plate.
 Apex or tip usually hidden
from view by the posterior
border of the ramus of the
mandible.

17. Norma Lateralis (Continued)
 Temporal fossa:
 Boundaries:
 Above: superior temporal line.
 Below:
 Laterally: upper border of zygomatic arch.
 Medially: Infratemporal crest of the greater wing of the sphenoid bone.
 Anterior wall: Zygomatic bone, frontal and sphenoid bone. This wall separates the fossa from
the orbit.

18. Norma Lateralis (Continued)
 Floor
 Pterion:
 Anterior part of the floor is crossed
by an H-shaped suture.
 Frontal, parietal, greater wing of
sphenoid and temporal bone form
pterion.
 Lies 4 cm above the midpoint of
zygomatic arch and 2.5 cm behind
the frontozygomatic suture.
 Deep to pterion lie:
• Middle meningeal vein.
• The anterior division of the middle
meningeal artery
• Stem of lateral sulcus of brain
(Sylvian point).
 Zygomaticotemporal foramen:
 On temporal surface of the zygomatic
bone forming the anterior wall of
fossa.
Pterion

19. Norma Lateralis (Continued)
 Infratemporal fossa:
 Irregular space below
zygomatic arch.
 Boundaries:
 Anterior: posterior surface
of body of maxilla.
 Roof: Infratemporal surface
of greater wing of sphenoid.
 Medial: Lateral pterygoid
plate and pyramidal process
of palatine bone.
 Lateral: Ramus of
mandible.

20. Norma Lateralis (Continued)
 Infratemporal fossa:

21. Norma Lateralis (Continued)
 Pterygopalatine fossa:
 A bilateral, cone-shaped depression extending deep from
the infratemporal fossa all the way to the nasal cavity via the
sphenopalatine foramen.
 Boundaries:
 Anterior: Posterior wall of the maxillary sinus.
 Posterior: Pterygoid process of the sphenoid bone.
 Inferior: Palatine bone and palatine canals.
 Superior: Inferior orbital fissure of the eye.
 Medial: Perpendicular plate of the palatine bone
 Lateral: Pterygomaxillary fissure

22. Norma Lateralis (Continued)

23. Norma Lateralis (Continued)
 Attachments:
Structures attached Parts
Temporal fascia Superior temporal lines and the
area between two temporal lines.
Inferiorly, to the outer and inner
lips of the upper border of the
zygomatic arch.
Temporalis muscle Temporal fossa, except the part
formed by zygomatic bone.
Masseter muscle Medial surface and lower border of
zygomatic arch
Lateral ligament of the
temporomandibular joint
Tubercle of the root of zygoma

24. Norma Lateralis (Continued)
 Attachments:
Structures attached Parts
Sternocleidomastoid, splenius captis,
and longissimus captis
Inserted from before backwards on
the posterior part of the lateral
surface of the mastoid process.
Posterior belly of digastric Arises from mastoid notch
Tendon of the temporalis muscle
Deep temporal vessels
Deep temporal nerves
Gap between zygomatic arch and side
of skull

25. Norma Lateralis (Continued)
 Structures passing through foramina:
Foramina Structure passing
Tympanomastoid fissure Auricular branch of vagus
nerve
Mastoid foramen Emissary vein connecting
the sigmoid sinus with the
post auricular vein
Zygomatico temporal
foramen
Nerve of same name and
minute artery.