The document summarizes the bones of the head and neck, including the skull and cervical vertebrae. It describes how the skull can be divided into the calvaria/brain box with 14 paired and unpaired bones, and the facial skeleton with another 14 bones. Key bones like the frontal, parietal, temporal, sphenoid, ethmoid, and maxilla are discussed in more detail. The three cranial fossae - anterior, middle, and posterior - are also summarized briefly, including their boundaries and key structures.
7. Forms the forehead,most of
the roof of orbit & most of
the floor of anterior cranial
fossa.
3 parts:-
1)Squamous part
2)Orbital part
3)Nasal part
8. The importance of the frontal bone in facial
trauma is its relationship to the anterior
midfacial skeleton & the paranasal sinuses.
The frontal sinus is drained by the
frontonasal duct into the anterior middle
meatus of the nose.
9. Forms a large part of
the roof & sides of vault
of skull.
Quadrilateral in shape
11. Occupies posterior &
inferior part of the skull.
Divided into 3 parts-
1) Squamous part
2) Basilar part
3) Condylar/lateral part
12.
13. Situated at the sides &
base of the skull.
Comprises of-
1) Squamous part
2) Petromastoid part
3) Tympanic part
4) Styloid process
14.
15. Resembles a bat with outstretched wings.
Comprises-
Body in the centre
Two lesser wings from the anterior part of body
Two greater wings from the lateral part of body
Two pterygoid (wing like)processes,directed downwards
from the junction of body & greater wings.
16. Sphenoid sinuses-drain out onto the roof of
nasal cavity. The pituitary gland can be
surgically accessed via passing through the
nasal roof,into the sphenoid sinus & through
the sphenoid bone.
17. 2nd largest bone of
the face.
A paired bone of the
upper jaw fused to form
one bone & is the central
focus of the middle 3rd of
the face.
18. Each hemimaxilla contains a large pyramid
shaped body,the maxillary sinus (antrum of
Highmore) & 4 prominent processes-the
frontal,alveolar,zygomatic & palatine process.
The sinus opens superiorly & medially into
the nasal cavity at the semilunar hiatus in the
middle meatus.
19. Largest & strongest bone
of the face.
Develops from 1st pharyngeal
arch.
It has a horse shoe shaped
body & a pair
of rami.
The rami provides attachment
to the muscles of mastication.
20. Body:-
Outer surface-
Symphysis menti
Mental protuberance
Mental foramen
Oblique line
Incisive fossa
Inner surface-
Mylohyoid line
Submandibular fossa
sublingual fossa
Superior & inferior
genial tubercles
Ramus:-
Processes-Coronoid
Condyloid
21. Skull can be studied externally in following
views:-
Superior-Norma verticalis
Posterior-Norma Occipitalis
Anterior-Norma Frontalis
Lateral-Norma Lateralis
Inferior-Norma Basalis
Skull can be studied internally as:-
Internal surface of the cranial vault
Internal surface of the cranial base showing
Anterior; Middle and Posterior cranial fossa
22.
23.
24.
25. Features:
Bregma=Anterior fontanelle. Closes at 18-24
months of age.It allows growth of brain.
Lambda=Posterior fontanelle. Closes at birth-
2 or 3 months of age.
Bones override at the fontanelle helping to
decrease size of head during vaginal delivery.
26. Caput succedaneum-Soft tissue swelling on
any part of skull due to rupture of capillaries
during delivery.Skull becomes normal within
few days in post natal life.
27.
28.
29.
30.
31. Features:-
Superciliary arch-overlies the frontal sinus
Glabella-median elevation connecting two
superciliary arches
Nasion-junction of internasal suture &
frontonasal suture
Frontal tuber/eminence-low rounded
elevation above superciliary arch
Supraorbital notch/foramen-at the junction
of lateral 2/3rd & medial 1/3rd of supraorbital
margin
Nasal bone is one of the most commonly
fractured bones of the face.Mandible &
parietal bones are the next to be fractured
32.
33.
34. Clinical anatomy:-
Pterion/anterolateral fontanelle is thin part of
the skull.In roadside accidents,anterior
division of middle meningeal artery may be
ruptured leading to clot formation between
skull bone & duramater or extradural
haemorrhage.The clot compresses the motor
area of brain leading to paralysis of opposite
side. The clot must be sucked out at the
earliest by trephining
35.
36.
37. Foramen ovale-mandibular nerve,
accessory meningeal artery,
lesser petrosal nerve,
emissary vein
Carotid canal-internal carotid artery & venous
and sympathetic plexus around the artery
Foramen lacerum-meningeal branch of
ascending pharyngeal artery & emissary vein
from the lower part;
internal carotid artery with venous & sympathetic
plexus from the upper part;
nerve of the pterygoid canal(vidian’s nerve) from
the anterior part
38. Foramen magnum-
Narrow anterior part-
apical ligament of dens;
vertical band of cruciate ligament;
membrana tectoria
Wider posterior part-
lowest part of medulla oblongata;
three meninges
Through subarachnoid space-
spinal accessory nerves;
vertebral arteries & sympathetic
plexus around it;
posterior & anterior spinal artery
41. Cranium is lined internally by endocranium.
Cranial bones consist of an outer table,an
inner table and diploe which consists of
spongy bone filled with red marrow in
between the two tables.
Many bones like vomer, pterygoid plates do
not have any diploe.
42. Presents markings produced by meningeal
vessels,
venous sinuses,
arachnoid granulations
& to some extent by
cerebral gyri.
43.
44. Anterior cranial fossa
Boundaries:-
Anteriorly & on the
sides-frontal bone
Posteriorly-free
posterior border of
the lesser wing
of sphenoid,
anterior clinoid process
& anterior margin of
sulcus chiasmaticus
45.
46. Features:-
Cribriform plate of ethmoid bone-separates
anterior cranial fossa from the nasal cavity.
Anteriorly,cribriform plate has a midline
projection called crista galli.On each
side,there are foramina through which
anterior ethmoidal nerve & vessels pass to
the nasal cavity.
Jugum sphenoidal-separates anterior cranial
fossa from sphenoidal sinuses
Orbital plate of frontal bone-separates
anterior cranial fossa from the orbit.
47. Fracture of anterior cranial fossa may cause
bleeding & discharge of CSF through the
nose.It may also cause a condition called
black eye produced by seepage of blood into
the eyelid as frontalis muscle has no bony
origin.
48. Middle cranial fossa
Butterfly shaped
Boundaries:-
Anterior-posterior
border of lesser wing
of sphenoid,
anterior clinoid process,
anterior margin of sulcus
chiasmaticus
Posterior-superior
border of petrous
temporal bone,
dorsum sellae of sphenoid
Lateral-greater wing of
sphenoid,anteroinferior
angle of parietal bone,
squamous temporal
bone
49.
50. Superior orbital fissure-
Lateral part-
lacrimal nerve,
frontal nerve,
trochlear nerve,
superior ophthalamic vein
Middle part-
upper & lower division of
occulomotor nerve,
nasociliary nerve in between two
divisions of occulomotor,
abducent nerve inferolateral to
the foregoing nerves
Medial part-
inferior ophthalamic vein,
sympathetic nerves from the plexus
around the internal carotid artery
51. Fracture of middle cranial fossa produces-
Bleeding & discharge of CSF through the ear.
Bleeding through the nose or mouth may
occur due to involvement of sphenoid bone
VII & VIIIth cranial nerves may be damaged,if
the fracture also passes through the internal
acoustic meatus.If a semicircular canal is
damaged,vertigo may occur.
52. Posterior cranial fossa
Contains the hindbrain which
consists of cerebellum
Behind & pons and medulla
in front.
Boundaries:-
Anterior-superior border of
petrous temporal bone &
dorsum sellae of sphenoid
bone
Posterior-squamous part of
occipital bone
On each side-mastoid part of
temporal bone &
mastoid angle
of parietal bone.
53.
54. Fracture of the posterior cranial fossa causes
bruising over the mastoid region extending
down over the sternocleidomastoid muscle.
