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🍀 Complete Trigeminal Nerve (CN V) Lesion - Loss of sensation over the affected side of the face. - Absent corneal reflex (afferent limb). - Weakness and wasting of the muscles of mastication. - Jaw deviates toward the affected side. - Difficulty chewing. - Reduced bite strength. #Head_and_neck #CLINICAL_ANATOM

Olfactory Nerve

Olfactory Nerve (CN I) ● Origin : - Arises from the olfactory receptor neurons located in the olfactory epithelium of the roof of the nasal cavity. - The nerve fibers pass through the cribriform plate of the ethmoid bone to reach the olfactory bulb, then continue through the olfactory tract to the primary olfactory cortex. ● Type: - Special Sensory (SSA – Special Somatic Afferent) ● Function : - Responsible for the sense of smell (Olfaction). - Plays an important role in: - Taste perception (flavor recognition). - Detection of smoke, gas, and spoiled food. - Emotional and memory responses related to odors. Injury ● Common causes: - Head trauma (especially fractures of the cribriform plate). - Upper respiratory viral infections. - Nasal tumors. - Neurodegenerative diseases (e.g., Parkinson's disease and Alzheimer's disease). ● Clinical Features : - Anosmia → Complete loss of smell. - Hyposmia → Decreased sense of smell. - Reduced ability to appreciate food flavors. - In cribriform plate fractures, CSF rhinorrhea may accompany anosmia. 📌 Clinical Test : - Test each nostril separately using non-irritating familiar odors (e.g., coffee or vanilla). - Avoid substances such as ammonia, as they stimulate the trigeminal nerve (CN V) rather than the olfactory nerve. 🍀 High-Yield Points : - CN I = Special Sensory (Smell). - Passes through the cribriform plate. - Lesion → Anosmia. - Commonly injured in head trauma due to cribriform plate fracture. #Head_and_neck #CLINICAL_ANATOM

مساحتكم الخاصة للإستفسار عن اي معلومة ، ولطرح ارائكم 🍀 VAGUS #VAGUS_CHANNEL

🔸 Why is Subgaleal Hematoma the Most Dangerous? 1● It occurs in a very large potential space. The subgaleal space (between the galea aponeurotica and periosteum) is extensive and can It spreads freely and is not confined by sutures so it spreads from: • the Superciliary Arches (front) • to the nuchal region (back) • and laterally to the temporal lines 📍Because of this huge space, a massive volume of blood can accumulate. 2● It can hold a life-threatening amount of blood Newborns have a small total blood volume. The subgaleal space can hold up to 40–50% of the infant’s blood volume. 📍This can rapidly lead to hypovolemic shock. 3● It results from tearing of emissary veins ● Emissary veins connect scalp veins to intracranial venous sinuses. These veins are: ○thin-walled ○easily torn, especially during vacuum extraction 📍 Bleeding is continuous and brisk, not self-limited. #Head_and_neck #Case_of_the_Day #CLINICAL_ANATOMY

🍀Question: Why is Subgaleal Hematoma the Most Dangerous? #VAGUS_CHANNEL

🍀 Scalp Hematomas: ○ Caput Succedaneum ○ Cephalohematoma ○ Subgaleal Hemorrhage #Head_and_neck #Case_of_the_Day #CLINICAL_ANATOMY

🍀Subgaleal Hemorrhage: ● Definition: A hemorrhage occurring in the subaponeurotic (subgaleal) space, due to tearing of emissary veins during delivery. ● Location: Between the epicranial aponeurosis (galea aponeurotica) and the periosteum of the skull. ■ Clinical Notes: ○ Potentially life-threatening. ○ Can hold a large volume of blood → hypovolemic shock. ○ More common with vacuum extraction. #Head_and_neck #Case_of_the_Day #CLINICAL_ANATOMY

🍀Cephalohematoma : ● Definition: A subperiosteal hemorrhage resulting from rupture of vessels between the skull and its periosteum. ● Location: Occurs beneath the periosteum, confined to the surface of a single skull bone. ■ Clinical Notes: ○ Appears hours after birth, not immediately. ○ Firm, localized swelling. ○ May cause jaundice due to breakdown of accumulated blood. ○ Resolves over weeks. #Head_and_neck #Case_of_the_Day #CLINICAL_ANATOMY

🍀 Caput Succedaneum: ● Definition: A diffuse, soft swelling of the scalp caused by pressure of the presenting part of the fetal head against the cervix during labor. ● Location: Occurs in the subcutaneous tissue of the scalp (above the epicranial aponeurosis). ■ Clinical Notes: ○Present at birth. ○ Pitting, soft edema. ○ Resolves spontaneously within a few days. #Head_and_neck #VAGUS_CHANNEL #CLINICAL_ANATOMY

🍀Posterior Cranial Fossa Fracture: ● Clinical Features: - Blood collects deep to the postvertebral muscles in the nape of the neck. - After a few days, blood tracks between the muscles and appears in the posterior triangle near the mastoid process. - Bleeding into the nasopharynx. If the fracture involves the jugular foramen, the following cranial nerves may be injured: •CN IX •CN X •CN XI •CN XII is usually spared because , " Protected nerve CN XII (Hypoglossal) Protected by strong hypoglossal canal" ~ Key point: Posterior cranial fossa = Lower cranial nerve injury (IX, X, XI) #Case_of_the_Day #CLINICAL_ANATOMY

🍀Middle Cranial Fossa Fracture: - Most common basal skull fracture • Reason: - Weakest part of skull base - Contains many foramina and canals • Structures affected: - Middle ear - Sphenoid sinus - Petrous temporal bone - Cavernous sinus ● Clinical Features: -،Blood from external auditory meatus -،CSF otorrhea - Blood/CSF may pass to nose - Facial nerve (CN VII) injury - Vestibulocochlear nerve (CN VIII) injury - Oculomotor (CN III), Trochlear (CN IV), Abducens (CN VI) injury ~ Key point : Middle cranial fossa fracture → Ear bleeding + CN VII & VIII injury #Case_of_the_Day #CLINICAL_ANATOMY

Types of Skull Fractures According to Location: 🍀. Anterior Cranial Fossa Fracture • Structures injured: 1• Cribriform plate of ethmoid 2• Orbital plate of frontal bone 3• Frontal sinus • Clinical Features: - Epistaxis (nose bleeding) - CSF rhinorrhea - Subconjunctival hemorrhage - Orbital hemorrhage → Exophthalmos - Bleeding into frontal sinus ~ Key point: Cribriform plate injury = CSF rhinorrhea + Epistaxis #Case_of_the_Day #CLINICAL_ANATOMY

#Case_of_the_Day #CLINICAL_ANATOMY

🍀Question: Why are skull fractures different in children and adults?

Skull Fractures

Definition : Skull fracture is a break in one or more bones of the skull caused by trauma. ● The pattern of fracture depends on: - Age of the patient - Severity of trauma - Site of impact #Case_of_the_Day #CLINICAL_ANATOMY