Osteology

Question 1

skull

Answer 1

1)
A) Foramen cribriform - olfactory nerve (site for cranial spead of covid)
B) Optic canal - optic nerve and opthalmic Artery
C) Ant and posterior ethmoidal foramen - corresponding vessels and nerve
D) superior orbital fissure - CN 3,4,6 and superior opthalmic vein, lacrimal nasociliary frontal branch of 5th CN
E) Foramen rotundum - maxillary nerve
F) Foramen oval - mandibular nerve, accesory middle meningial artery, lesser petrosal nerve, emissory veins
G) Foramen spinosum - middle meningial artery and vein, emissary vein, nervi spinosum ( meningial branch of mandibular nerve)

JUGULAR FORAMEN IS B/W TEMPORAL AND OCCIPITAL BONE.
ROTUNDUM, SPINOSUM, OVAL - IN GREATER WING OF SPHENOID.

H) Foramen lacerum - misnomer - cartilage close lower part

• ICA enters the cranial cavity from carotid canal and traverses Lacerum
• sympathetic plexus of deep petrosal nerve joint with greater petrosal nerve (which enters lacerum) and form vidian nerve that pass thorough pterygoid canal and ends in pterygoid ganglion (pterygopalatine fossa)

I) Internal auditory canal - in petrous part of temporal bone

• falciform crest divide IAC in two part - superior and inferior
• Bill’s bar divide IAC in Anterior and Posterior
• 7th - superior Anterior
• chochlear - Inferior Anterior
• superficial vestibular - superior Posterior
• Inferior vestibular - Inferior Posterior
• singular nerve - Inferior Posterior, branch of IVN. Sensory fibers from Posterior semicircular canal.

J) Jugular foramen

• Anterior - Inferior petrosal sinus, meningial branch of ascending pharyngeal Artery
• middle - 9,10,11
• Posterior - sigmoid sinus - continue as IJV, meningial branch of occipital artery

K) Foramen magnum

• Anterior - apical lig of dens, upper border of cruciate ligament, tectorial membrane (continuation of Posterior longitudinal ligament)
• Posterior - lower part of medulla, ant and Posterior spinal artery, 4th part vertebral artery, spinal accesory nerve. Also cerebellar tonsils

L) Incisive foramen - nasopalatine nerve , greater palatine vessels

M) stylo mastoid - 7th CN

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Question 2

1) Ethmoid bone
2) Mandible
3) Fontanelles of skull

Answer 2

1)
- Lamina papyracea - seperate Ethmoid bone from orbit
- perpendicular plate - medial wall of nasal septum
- cribriform plate - roof of nose
- middle and superior turbinate.
- uncinate process

2)
Head of mandible - lateral pterygoid muscle
Coronoid process - temporalis muscle
Outer ramus - masseter
Inner ramus - medial pterygoid (postero - inferior)
Mandibular foramen - Inferior alveolar nerve, vessels
Mylohyoid grove - nerve to mylohyoid (branch of inf. Alveolar)
Mylohyoid line - mylohyoid muscle - divide mandible in sublingual and submandibular fossa.

3) skull form from membrane
- Anterior and Posterior - unpaired
- mastoid and sphenoid - paired
Close at
Anterior - 18 - 24 months
Posterior - 2-3 months
Mastoid - 1 yrs
Sphenoid - 2-3 months

> Anterior Fontanelles

• length - 4, breadth - 2.5 cm, deep - 3-5 mm
• superior sagittal sinus present
• puncture = scalp —⟩ membrane —⟩ Dura (endosteal and meningial layer) —⟩ DVS —⟩ Arachnoid —⟩ CSF.

Question 3

1) syndrome

Answer 3

1) cavernous sinus thrombosis - 3,4,6,5 (opthalmic)
2) superior orbital fissure syndrome - 3,4,6,5 (opthalmic)
3) petrous apex syndrome - 5,6
4) vernet syndrome - 9,10,11
5) collect sicard syndrome - 9,10,11,12
6) villaret syndrome - 9,10,11,12, sympathetic chain