Practical 1: Larynx

muscle?

-sternocephalicus

• sternomastoid (dorsal portion)

• sternooccipitalis (ventral portion)

-sternocephalicus

not in view:

• origin: manubrium sterni

• insertion: mastoid part of temporal bone; dorsal nuchal line of occipital bone

dark blue?

(ventral)

-sternocephalicus mastoideus

light blue

(ventral)

-sternocephalicus pars occipitalis

-sternocephalicus

• origin: manubrium sterni

• insertion: mastoid part of temporal bone; dorsal nuchal line of occipital bone

• innervation: CN XI (accessory)

dark blue?

-sternocephalicus mastoideus

light blue?

-sternocephalicus pars occipitalis

(ventral)

-sternocephalicus

note: distinct V shape

(cranial)

--sternocephalicus

note: distinct V shape

equine:

what is another name for the sternocephalicus?

-sternomandibularis

what is another name for the:

-sternocephalicus m pars mastoideus

-sternocephalicus m pars occipitalis

-sternomastoid

-sterno-occipitalis

of the two parts of the sternocephalicus m, which is:

most dorsal?

ventral?

dorsal: sterno-occipitalis

ventral: sternomastoid

which (2) extrinsic laryngeal mm are caudal to basihyoid

(also, caudal extrinsic laryngeal mm)

-sternohyoid

-sternothyroid

which (3) extrinsic mm are cranial to the basihyoid?

(also, cranial extrinsic mm)

-thyrohyoid

-hyoepiglottic

-geniohyoid

anatomy side:

where is the basihyoid?

-ventral

fx:

sternocephalic m

-flex neck

which mm lie over the ventral surface of trachea?

-sternohyoideus

-sternothyroid

• (predominant in horses)

fx:

sternohyoideus

-pull tongue and basihyoid caudally

sternohyoideus

• origin: deep part of manubrium, cranial edge of first costal cartilage

• insertion: basihyoid bone

• innervation: ansa cervicalis (loop formed by the anterior rami of spinal nerves C1-C3 within the cervical plexus); sometimes CNXII

sternohyoideus

• origin: deep part of manubrium, cranial edge of first costal cartilage

• insertion: basihyoid bone

• innervation: ansa cervicalis (loop formed by the anterior rami of spinal nerves C1-C3 within the cervical plexus); sometimes CNXII

sternohyoideus

• origin: deep part of manubrium, cranial edge of first costal cartilage

• insertion: basihyoid bone

• innervation: ansa cervicalis (loop formed by the anterior rami of spinal nerves C1-C3 within the cervical plexus); sometimes CNXII

sternohyoideus

• origin: deep part of manubrium, cranial edge of first costal cartilage

• insertion: basihyoid bone

• innervation: ansa cervicalis (loop formed by the anterior rami of spinal nerves C1-C3 within the cervical plexus); sometimes CNXII

(2)

sternohyoideus

• origin: deep part of manubrium, cranial edge of first costal cartilage

• insertion: basihyoid bone

• innervation: ansa cervicalis (loop formed by the anterior rami of spinal nerves C1-C3 within the cervical plexus); sometimes CNXII

(3)

sternothyroideus

• origin: first costal cartilage

• insert: lateral surface of thyroid lamina (thyroid cartilage)

• nerve: ansa cervicalis, a nerve loop formed by the anterior rami of the first three cervical spinal nerves (C1-C3)

sternothyroideus

• origin: first costal cartilage

• insert: lateral surface of thyroid lamina (thyroid cartilage)

• nerve: ansa cervicalis, a nerve loop formed by the anterior rami of the first three cervical spinal nerves (C1-C3)

sternothyroideus

• origin: first costal cartilage

• insert: lateral surface of thyroid lamina (thyroid cartilage)

• nerve: ansa cervicalis, a nerve loop formed by the anterior rami of the first three cervical spinal nerves (C1-C3)

what m covers the sternothyroid m?

-sternocephalicus

where does the sternothyroideus m lie in relation to the sternohyoideus m?

-dorsal

fx:

sternothyroideus m

-draw hyoid apparatus, larynx and tongue caudally

-sternohyoideus m

-sternothyroideus m

-sternothyroideus m

fx:

thyrohyoideus m

-move hyoid caudally and dorsally

thyrohyoideus m

• origin: lamina of thyroid cartilage

• insert: caudal border of thyrohyoid bone

• innervation: CN XII

thyrohyoideus m

• origin: lamina of thyroid cartilage

• insert: caudal border of thyrohyoid bone

• innervation: CN XII

in relation to the sternothyroideus m, where does the thyrohyoideus m sit?

-rostral, dorsal

thyrohoideus m

• origin: lamina of thyroid cartilage

• insert: most caudal border of thyrohyoid bone

• innerv: CN XII

thyrohyoideus m

• origin: lamina of thyroid cartilage

• insert: caudal border of thyrohyoid bone

• innervation: CN XII

fx:

hyoepiglotticus m

-move epiglottis ventrally

-hyoepiglotticus m

• origin: medial surface of ceratohyoid bone

• insert: ventral surface epiglottis

• nerve: vagus n → cranial laryngeal n → inner laryngeal n

-hyoepiglotticus m

• origin: medial surface of ceratohyoid bone

• insert: ventral surface epiglottis

• nerve: vagus n → cranial laryngeal n → inner laryngeal n

-hyoepiglotticus m

• origin: medial surface of ceratohyoid bone

• insert: ventral surface epiglottis

• nerve: vagus n → cranial laryngeal n → inner laryngeal n

-hyoepiglotticus m

• origin: medial surface of ceratohyoid bone

• insert: ventral surface epiglottis

• nerve: vagus n → cranial laryngeal n → inner laryngeal n

fx:

geniohyoid m

-to elevate the hyoid bone and pull it forward

-helps widen the airway and assists in swallowing

geniohyoideus m

• origin: medial surface mandible

• insert: basihyoid bone

• nerve: anterior ramus of the first cervical spinal nerve (C1) via CNXII

geniohyoideus m

• origin: medial surface mandible

• insert: basihyoid bone

• nerve: anterior ramus of the first cervical spinal nerve (C1) via CNXII

geniohyoideus m

• origin: medial surface mandible

• insert: basihyoid bone

• nerve: anterior ramus of the first cervical spinal nerve (C1) via CNXII

fx:

larynx

-to protect the lower airways from aspiration (food or liquids entering the trachea)

-to enable vocalization (houses vocal cords)

-regulates airflow during breathing

what structure houses the vocal cords?

-larynx

-larynx

-larynx

-larynx

which is the most abundant cartilage of the larynx?

-thyroid cartilage

what is thyroid cartilage made of?

-hyaline cartilage

what membrane connects the hyoid and the thyroid cartilage?

-thyrohyoid membrane

Sx:

what is important to note about the external jugular v?

-very superficial, easily cut

-external jugular v

-external jugular v

L: external jugular v

R: internal jugular v

dark navy oval

-trachea

fx:

trachea

-main airway

• moves air between outside and lungs

what m lies on the dorsal side of the trachea?

-trachealis m & membrane

• completes trachea dorsally

• trachealis m lies on top of membrane

what are the two main parts of the trachea?

-cartilagenous rings

-annular ligaments between each cartilagenous ring

(trachea)

-cartilagenous ring

-adventitia & serosa

-mucosa

-trachealis m

-thyroid gland

-thyroid gland

fx:

thyroid gland

-produces hormones that regulate metabolism

what is the main hormone secreted by the thyroid?

-thyroxine (T4)

• regulates various bodily functions, including metabolism, heart and digestive function, and brain development

• is converted into T3

-R common carotid a

-L common carotid a

-cranial thyroid a

-cranial laryngeal a

-cranial thyroid a

-common carotid a

(1)

-common carotid a

(3)

-external carotid a

(2)

-internal carotid a

(13)

-cranial thyroid a

(8)

-cranial laryngeal a

-cranial thyroid a

-external carotid a

-common carotid a

-cranial laryngeal a

-common carotid a

-external carotid a

-internal carotid a

-external carotid a

which a supplies the thyroid glands?

-cranial thyroid a

what does the cranial laryngeal a supply?

-larynx

• specifically the cricothyroid muscle

• upper portion of the laryngeal mucosa

which aa primarily supply the head?

-common carotids

which part of the head do the internal carotid aa supply?

-brain

which part of the head do the external carotid aa supply?

-face and superficial structures of the head

fx:

recurrent laryngeal n (RLN)

-controlling the larynx (voice box)

• most of larynx’s instrinsic mm (except cricothyroid m)

-enabling speech, swallowing, and airway protection

-provides sensory information from below the vocal cords

what does dysfunction to RLN look like?

-vocal cord paralysis

-hoarseness

what n innervates the cricothyroid m?

-cranial laryngeal n

which n does the RLN arise from?

-vagus n

if you can’t ID well, what’s important to note about the RLNs?

(ventral)

-they sit right beside the trachea on either side