CAS 3 Flashcards
What kind of joint is the atlanto occipital joint and Atlanto-axial joints ?
synovial joints
between what
between convex occipital condyles and concave facets on the lateral mass of the atlas
what does it allow
The Atlanto-occipital joints allow nodding and lateral flexion movements of the head
The curved surfaces are adapted for
head flexion and extension, and abduction (lateral flexion) of the skull on the atlas vertebra. In the erect position, the centre of gravity of the skull lies anterior to the joints and the head is held in position by the tone of the extensor muscles (postvertebral group of muscles) in the back of the neck.
Testing the movements at atlanto-occipital joints
Patient sits with their head held in erect position looking straight ahead. The examiner stands behind the patient and holds the neck just below the jaws with one hand, and instructs the patient to nod the head up and down, as if to say “yes”, while the examiner keeps check of the rest of the cervical spine does not bend.
The dense of axis is held in position by the what
the transverse limb of the cruciate ligament.
the atlanto-axial joints allow
rotation of the head.
The muscles responsible for rotation are
sterno-mastoids and sub-occipital muscles (splenius capitis, inferior oblique).
Testing the movements at atlanto-axial joints
Patient is seated with their head held in erect position looking straight ahead. The examiner stands behind the patient and holds the neck just below the jaws with one hand, and instructs the patient to rotate their head side to side, as if to say “no”, while the examiner keeps check of the rest of the cervical spine does not bend.
The submandibular ducts from the right and left submandibular glands open at the
sublingual caruncle on either side of the frenulum of the tongue
The duct of the parotid gland opens into the vestibule of the mouth opposite to
the upper 1st molar tooth.
where can opening of the auditory tube can be seen
on the lateral wall of the nasopharynx, on a level with the inferior concha of the nasal cavity
In human there are how many sets of dentition
here are two sets of dentition
what are they
the deciduous and the permanent§
deciduous
set has 20 teeth that erupt between 6 months to 2.5 years
permanent
The permanent set has 32 teeth. The 1st permanent tooth (1st permanent molars) erupts at 6 years and the rest of the permanent teeth continue until 18 years and very often beyond ( the 3rd molars can vary)
Between 6-12 years
mixed d
Glossopharyngeal Nerve (CN IX) Function
Motor: Innervates the stylopharyngeus muscle of the pharynx
Sensory: Innervates the oropharynx, posterior 1/3 of the tongue.
Special Sensory: Taste sensation to the posterior 1/3 of the tongue.
Parasympathetic: Parasympathetic innervation to the parotid glan
anatomical course
The glossopharyngeal nerve arises from the medulla oblongata of the brain and leaves the cranium via the jugular foramen.
Testing
To test the glossopharyngeal nerve (CN IX) elicit the gag reflex using a tongue depressor against the posterior of the tongue.
This allows us to test CN IX because CN IX provides sensory innervation to the oropharynx, acting as an afferent limb for the gag reflex.
Clinical Relevance
When a foreign object touches the back of the mouth, this stimulates CN IX, beginning the reflex. The efferent nerve in this process is the vagus nerve, CN X. An absent gag reflex can indicate damage to the glossopharyngeal nerve.
Vagus Nerve (CN X) function
Motor: Innervation to most of the muscles of the pharynx and larynx.
Sensory: Innervation to the skin of the external acoustic meatus and some of the surfaces of the laryngopharynx and superior larynx. Also provides visceral sensory information from the trachea, lungs, heart oesophagus and most of the abdominal organs.
Parasympathetic: innervating the lungs and most of the gastrointestinal tract as well as helping to control heart rate
Anatomical Course
The vagus nerve arises from the medulla oblongata of the brainstem and exits the cranium via the jugular foramen.
In the neck
Pharyngeal branches – innervates most of the muscles of the pharynx and soft palate.
Superior laryngeal nerve – innervates the cricothyroid muscle of the larynx and sensation to the laryngopharynx and superior larynx.
Recurrent laryngeal nerve - On the right side only (hooks around the right subclavian artery and innervates most of the muscles of the larynx
Testing
To test the vagus nerve (CN X), ask the patient to open their mouth out wide and say “Ahh”. This allows us to test CN X because CN X provides motor innervation to levator veli palatini. If both vagus nerves are intact then the small palate, and thus uvula, will rise symmetrically when saying “ahh”.
Clinical Relevance
If the right vagus is damaged, then the right palate will not raise, but the left will still rise, so the uvula will deviate to the left (away from the side of the lesion).
Spinal Accessory Nerve (CN XI)
Accessory nerve (CN XI) has only somatic motor function innervating the sternocleidomastoid and trapezius muscles.