Anatomy 5 Flashcards
What are the boundaries of the posterior triangle in the neck?
1) Posterior border of the sternocleidomastoid muscle
2) Anterior border of the trapezius muscle
3) The middle 1/3 of the clavicle
The trunks of what descend posteroinferiorly through the posterior triangle of the neck?
The trunks of the brachial plexus
Why would a stab wound to the posterior triangle of the neck possibly lead to breathlessness and paralysis of the upper limb?
1) Could stab the apex of the lung leading to pneumothorax
2) May damage the upper trunk of the brachial plexus - branches of this innervate most muscles of the arm so can lead to paralysis of arm
The accessory nerve courses posteroinferiorly through the posterior triangle of the neck, which 2 muscles are supplied by this nerve?
Sternocleidomastoid and trapezius muscles
What are the boundaries of the anterior triangle of the neck?
Anterior border of the sternocleidomastoid
Inferior border of the mandible
Midline of the neck
What is the laryngeal prominence?
Prominence in the midline of the thyroid cartilage
Is the hyoid bone inferior or superior to the thyroid cartilage?
Superior
What 3 parts make up the thyroid gland?
Right lobe
Left lobe
isthmus (in middle)
Can the thyroid gland be palpated?
No, the lobes lie deep to muscle and the isthmus cannot be palpated either
The external jugular vein descends through the subcutaneous tissue of the neck on the surface of what muscle?
The sternocleidomastoid
What are the surface markings of the external jugular vein?
4cm along a line from middle of clavicle to angle of mandible is where the vein pierces deep fascia
Which muscles lie deep to the omohyoid and sternohyoid muscles?
The sternothyroid and thyrohyoid muscles
What is the general function of the sternohyoid muscle?
Depresses the hyoid bone after swallowing
What is the function of the omohyoid muscle?
Depresses and fixes the hyoid bone
What is the nerve supply to the sternohyoid and omohyoid muscles?
Anterior rami of C1 to C3 through the ansa cervicalis
Where does the sternohyoid muscle run between?
From the sternum to the hyoid bone
Where does the sternothyroid muscles run from?
The sternum to the thyroid cartilage
Where does the thyrohyoid muscle run between?
From the thyroid cartilage to the hyoid bone
What are the 4 infra hyoid muscles?
1) Sternohyoid
2) Sternothyroid
3) Thyrohyoid
4) Omohyoid
Where does the cricothyroid membrane run between?
Between the thyroid cartilage and the cricoid cartilage
Where does the cricoid cartilage lie?
Inferior to the thyroid cartilage
What are the 4 suprahyoid muscles?
1) Stylohyoid
2) Digastric
3) Mylohyoid
4) Geniohyoid
What are the attachments of the 2 bellies of the digastric muscle?
Anterior belly
Origin = Digastric fossa on the lower side of the mandible
Posterior belly
Origin = mastoid notch on the medial side of the mastoid process of the temporal bone
Insertion of both =Attachment of tendon of 2 bellies on hyoid bone
What is the function of the 2 bellies of the digastric muscle?
Anterior belly = opens mouth by lowering mandible and raises hyoid bone
Posterior belly = pulls hyoid bone superiorly and posteriorly
What is the carotid sheath?
Thick layer of fascia that binds together the common carotid artery, the internal jugular vein and the vagus nerve
In the upper part of the neck what does the carotid sheath contain?
The internal carotid artery
Internal jugular vein
last four cranial nerves
From which nerves do the roots of the ansa cervicalis take origin?
Superior roots = C1 & C2
Inferior roots = C2 & C3
At which vertebral level does the carotid bifurcation lie?
Between C3 and C4
What are the surface landmarks of the internal jugular vein?
Lateral and parallel to that of the common carotid
marked by a line from the sternal end of the clavicle to the upper border of the hyoid bone
Where would you palpate to locate the common carotid pulse?
Lateral to the upper border of the thyroid cartilage, medial to the anterior border of sternocleidomastoid
Why should you not palpate both sides of the neck to find the carotid pulse at once and why should you not rub the vessel?
Carotid sinus contains baroreceptors which detect blood pressure and slow or increase the heart rate accordingly, when you put pressure on them you risk slowing the heart rate, this is called carotid sinus massage
What are the 4 major anterior branches of the external carotid artery?
1) Maxillary a.
2) Facial a.
3) Lingual a.
4) Superior thyroid a.
What is the term for the process of the production of sound and where does it begin?
Phonation, it begins in the larynx
Other than phonation what is the other function of the larynx?
Prevents choking during eating and drinking as it caps the lower respiratory tract
How are sound waves produced by the larynx?
Sound is produced by vibration of the vocal cords in the larynx, at rest the folds are separated. During phonation the folds are adducted, obstructing the flow of air. Pressure builds up and the folds are forced apart, air escapes and the folds return to the adducted position. Rapid repetition of these movements results in vibration of the folds giving rise to sound waves
How is pitch altered in phonation?
Pitch is varied by altering the length and tension of the vocal folds (which alters the frequency of their vibration), these features are adjusted by the intrinsic muscles of the larynx
Define the term intrinsic muscles of the larynx?
Muscles of the larynx involved in phonation and control of air flow during breathing
Which cranial nerve supplies the intrinsic muscles of the larynx, how does the nerve supply of the cricothyroid differ from the others?
Vagus nerve CNX
Cricothyroid supplied by the external branch of the superior laryngeal nerve from the vagus nerve
All other are supplied by the recurrent laryngeal branch of the vagus nerve
What is the loudness of sound produced by the larynx related to?
The pressure of expired air
What does the quality or timbre of the voice depend on?
Depends on resonating chambers above the vocal cords
Through which spaces do sound waves pass to reach the outside world?
Pharynx
Oral cavity
Nasal cavity
What is articulation and what parts of the body are responsible for it?
Articulation is the process of breaking sound up into recognisable vowels and consonants and is achieved through the action of the tongue and lips
Which cranial nerves supply muscles responsible for the movements of the lips?
Facial nerve CN VII
Which cranial nerves supply muscles responsible for the movements of the tongue?
Hypoglossal nerve CN XII
Which nerve supplies sensory fibres to the larynx?
The vagus nerve CN X
Which 2 branches does the vagus give off to the larynx and where do they run to?
1) Superior laryngeal nerve - runs to the upper boundary of the larynx
2) Recurrent laryngeal nerve - runs to the lower boundary of the larynx
The superior laryngeal nerve and its external laryngeal branch lie close to which artery, a branch of which artery?
Lie close to the superior thyroid artery which is one of the 4 major anterior branches of the external carotid artery
Where does the external laryngeal nerve enter the larynx?
Descends along the lateral wall of the pharynx to supply and penetrate the inferior constrictor of the pharynx and ends by supplying the cricothyroid muscle
What does the internal laryngeal nerve supply?
Sensory to the laryngeal cavity down to the level of the vocal folds
Where does the left laryngeal nerve arise?
In the thorax, at the level of the arch of the aorta
The recurrent laryngeal nerve is closely related to which artery?
The inferior thyroid artery
Why does hoarseness sometimes result from the thyroid surgery?
Due to damage to the recurrent laryngeal nerve
Which other cranial nerves pass out of the skull alongside the vagus nerve?
1) CN IX - glossopharyngeal
2) CN XI - Accessory
All pass out of the foramen jugular foramen
Which 4 branches come off anterior from the vagus nerve in the neck region?
From superior to inferior
1) The pharyngeal branch
2) Carotid body branch of vagus
3) Superior laryngeal nerve (which branches into an internal and external branch
4) Cardiac branch
What are the 3 subdivisions of the pharynx and the structures which separate them?
Nasopharynx Oropharynx Laryngopharynx Soft palate Epiglottis
The first stage of swallowing is voluntary and involves passage of a bolus of food from the oral cavity into the oral part of the pharynx, how is this achieved?
Soft palate controls the bolus of food
Epiglottis is still open so can breathe and chew
Which group of muscles is involved in the first stage of swallowing?
The suprahyoid
What is the nerve supply of the suprahyoid muscles?
Stylohyoid - facial nerve CN VII Mylohyoid - Trigeminal nerve CN V Digastric anterior belly - CN V Digastric posterior belly - CN VII Geniohyoid - C1 roots with hypoglossal CN XII
After the first stage of swallowing the remaining stages are involuntary controlled by a series of reflexes involving which cranial nerves?
CN IX, X and XI
Which cranial nerve supplies sensory fibres to the posterior 1/3 of the tongue ad the oropharynx?
Glossopharyngeal CN XII
When a bolus of food comes into contact with the posterior 1/3 of the tongue and the oropharynx the soft palate is tensed and elevated, why?
To allow passage of food into oropharynx
When a bolus of food comes into contact with the posterior 1/3 of the tongue and the oropharynx the hyoid bone is pulled upwards and forwards, and with it the larynx and the root of the tongue, what are the effects of these movements?
To open the laryngopharynx and tilt the epiglottis down over the laryngeal inlet
Other than the epiglottis, which other structures help to close the laryngeal inlet during swallowing?
Contraction of laryngeal muscles cause the 2 aryepiglottic folds to move towards the midline
In swallowing, contraction of what muscles moves the bolus of food down over the closed inlet of the larynx and on into the oesophagus?
Contraction of the circular constrictor muscles of the pharynx
Virtually all the muscles of the pharynx and the soft palate receive their nerve supply via what, sensory fibres from the pharyngeal wall also pass via this?
The pharyngeal plexus
What is the pharyngeal plexus, what is it formed from?
Complex network of nerves in the pharyngeal wall
Formed from:
1) The pharyngeal branch of the glossopharyngeal nerve
2) The pharyngeal branch of the vagus nerve - which carries some fibres which have originated in the cranial part of the accessory nerve
3) Autonomic fibres
The pharyngeal fibres of cranial nerves IX (glossopharyngeal) and X (vagus) arise very close to what?
The base of the skull
