206 SSNS - Anatomy Flashcards
Borders of Pterygopalatine Fossa
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
Which part of the auricle is LEAST likely to be affected by an auricular hematoma?
Lobule
- The lobule is a non-cartilaginous structure, and therefore is unlikely to be affected by an auricular hematoma.
Which structure marks the end of the external auditory meatus?
Tympanic membrane
The tympanic membrane is connected to the surrounding bone by a fibrocartilaginous ring. Which bone is it connected to?
Temporal
- The tympanic membrane is connected to the surrounding temporal bone by a fibrocartilaginous ring
Which structure forms the roof of the middle ear?
Petrous part of temporal bone
- The roof is formed by a thin bone from the petrous part of the temporal bone. It separates the middle ear from the middle cranial fossa
Which nerve innervates the tensor tympani muscle?
Mandibular nerve
- The tensor tympani originates from the auditory tube and attaches to the handle of malleus, pulling it medially when contracting. It is innervated by the tensor tympani nerve, a branch of the mandibular nerve
Where are the mastoid air cells in relation to the epitympanic recess?
Posterior
In which part of the temporal bone is the inner ear located?
Petrous
- The inner ear is located within the petrous part of the temporal bone. It lies between the middle ear and the internal acoustic meatus, which lie laterally and medially respectively
What lies directly inferior to the cochlear duct?
Scala tympani
Which structure forms the lateral wall of the cochlear duct of the inner ear?
Spiral ligament
- The lateral wall is formed by thickened periosteum, known as the spiral ligament.
Which cranial nerve is most associated with the auditory pathway?
CN VIII
- CN VIII is the vestibulocochlear nerve, which carries auditory and balance information from the inner ear to the brainstem.
In the primary auditory pathway, the first order neurons receive information from which structure?
Organ of Corti
- The first order neurons receive information from hair cells in the Organ of Corti
What is the most internal layer of the scalp?
Periosteum
- The periosteum is the outer layer of the skull bones. It becomes continuous with the endosteum at the suture lines.
In a scalp laceration, the resting tone of which muscle inhibits closure of the bleeding vessel and surrounding skin?
Occipitofrontalis
Which nerve provides innervation to the area of scalp behind the pinna?
Lesser occipital
- The lesser occipital nerve is derived from the anterior rami (division) of C2 and supplies the skin behind the pinna. The auriculotemporal nerve innervates the skin anterosuperior to the pinna.
Which cranial nerve innervates the orbicularis oculi muscle?
Facial nerve
- The orbicularis oculi is a muscle of facial expression - and so it is innervated by branches of the facial nerve.
The corrugator supercilii is a muscle of facial expression. What is its main action?
Drawing the eyebrows together
- The corrugator supercilii acts to draw the eyebrows together, creating vertical wrinkles on the bridge of the nose.
Which embryological structure do the muscles of mastication develop from?
First pharyngeal arch
Which nerve provides motor innervation to the muscles of mastication?
Mandibular nerve
What is the main action of the masseter muscle?
Elevation of the mandible
- closing mouth
What is the innervation of the extraocular muscle which chiefly acts to adduct the eyeball?
Oculomotor nerve
- The main action of the medial rectus is the adduct the eyeball. It is innervated by the oculomotor nerve
Which nerve provides somatic motor innervation to the levator palpebrae superioris?
Oculomotor
Where is the lacrimal gland located within the bony orbit?
Superior and lateral
- The lacrimal gland is located anteriorly in the superolateral aspect of the orbit, within the lacrimal fossa – a depression in the orbital plate of the frontal bone.
Which nerve provides sensory innervation to the lacrimal gland?
Lacrimal nerve
- The sensory innervation to the lacrimal gland is via the lacrimal nerve. This is a branch of the ophthalmic nerve (in turn derived from the trigeminal nerve).