Lecture 9: Neck Flashcards
Suprahyoid muscles- nerve Innervation
Stylohyoid- facial
Digastric- anterior belly:mylohyoid nerve of mandibular
Posterior belly: facial nerve
Mylohyoid:- mylohyoid nerve of mandibular
Geniohyoid- c1 of cervical nerves
Suprahyoid muscles
Stylohyoid
Digastric
Mylohyoid
Geniohyoid
Digastric Attachments
Superior:
anterior belly- digastric fossa of mandible
Posterior belly- mastoid notch
Inferior:
Hyoid bone
Mylohyoid attachment
Superior:
Mylohyoid line of the mandible
Inferior attachment:
Hyoid bone
Larynx
modifies exit of air for vocalisation Innervation Sensory- internal laryngeal nerve Motor- recurrent laryngeal nerve Except cricothryoid muscle which is Innervation by external laryngeal nerve
The hyoid bone is at what level?
C3
The larynx is at what level?
C4-C6
The thyroid gland is at what level?
C5-T1
What makes up the anterior triangle of the neck?
Anterior border of SCM, Inferior border of mandible, Midline of neck
What makes up the posterior triangle of the neck?
Posterior border of SCM
Anterior border of trapezius
Middle 1/3 of clavicle
SCM and trapezius innervated by?
spinal accessory nerve CN XI
Submental triangle of the neck
apex: mandibular Symphysis , base: hyoid bone
Submandibular triangle of the neck
between mandible & digastric muscle, filled by submandibular
gland
Carotid triangle of the neck
anterior border SCM, posterior belly digastric
What is the purpose of the fascia of the neck?
Support viscera and provide “slipperiness” that allows structures to move and pass over one another without difficulty, as when you turn your head.
What are the three cervical fascia of the neck?
• Cervical subcutaneous tissue and platysma • Deep cervical fascia => investing layer => pre-tracheal layer =>pre-vertebral layer • Retropharyngeal space
Investing layer of deep cervical fascia does what?
“invests” SCM and trapezius
Pre-tracheal layer of deep cervical fascia does what?
only anterior neck. Encloses infra-hyoid muscles, thyroid gland, trachea and oesophagus. From hyoid to fibrous pericardium.
What is inside the common carotid sheath?
encloses common & internal carotid arteries, IJV, CN X, deep cervical lymph nodes, carotid sinus nerve, sympathetic nerve fibres. Extends from cranial base to thorax.
Retropharyngeal space permits what movement?
movement of pharynx, oesophagus, larynx & trachea relative to
vertebral column during swallowing
What is the platysma innervated by?
Innervated by cervical branch of facial nerve CN VII
Sternocleidomastoid muscle origin insertion action Innervation?
- Superior attachment: mastoid process
- Inferior attachment: sternum and clavicle
- innervation: XI Spinal accessory nerve, Branches of the anterior rami of C2-3
What are the four infrahyoid muscles and their Innervation?
- Thyrohyoid (C1)
- Sternohyoid (C1-C3 through ansa cervicalis)
- Omohyoid (C1-C3 through ansa cervicalis)
- Sternothyroid (C1-C3 through ansa cervicalis)
Sternothyroid superior and inferior attachment and action ?
- Superior attachment: lamina of thyroid cartilage
- Inferior attachment: manubrium of sternum
- Actions: Depresses thyroid cartilage (larynx)
Sternohyoid superior and inferior attachment and action?
- Superior attachment: manubrium
- Inferior attachment: hyoid bone
- Actions: Depresses hyoid bone at the end of swallowing
Thyrohyoid superior attachment, Inferior attachment and actions?
- Superior attachment: thyroid cartilage
- Inferior attachment: hyoid bone
- Actions: Depresses hyoid bone or raises larynx if hyoid bone is fixed
Trapezius superior attachment, inferior attachment, action and Innervation?
Superior attachment: superior nuchal line, external occipital protuberance, nuchal ligament, spinous processes of C7 to T12
Inferior attachment: lateral 1/3 of clavicle, acromion, spine of the scapula
Actions:
Upper trapezius: elevate the scapula
Middle trapezius: adduction of the scapula
Lower trapezius: depresses the scapula
Rotates the scapula in abduction of humerus above >90 degrees
Innervation: Spinal accessory nerve and
Branches of the anterior rami of C2-3
Ansa cervicalis supplies
- STERNOTHYROID
- STERNOHYOID
- OMOHYOID
Hypoglossal nerve supplies
Intrinsic muscles of tongue •GENIOGLOSSUS •HYOGLOSSUS •GENIOHYOID •THYROHYOID •STYOLGLOSSUS
Structures passing between thorax & head?
- Sympathetic trunk & cervical ganglia (x3)
- Vagus (CN X) + recurrent laryngeal nerve
- Phrenic (C3, C4, C5)
Brachial plexus emerges between?
anterior and middle scalene muscles
Cervical plexus
- Anterior rami C1-C4
- Deep to SCM
- Anteromedial to levator scapulae and middle scalene.
- Superficial branches = cutaneous sensory
- Deep branches = motor (phrenic nerve, ansa cervicalis)
Cervical plexus nerves
- Lesser occipital (C2)
- Great auricular (C2 and C3)
- Transverse cervical (C2 and C3)
- Supraclavicular (C3 and C4)
What is ansa cervicalis?
Loop of nerve fibres from C1-C3 that provides motor
innervation to infra-hyoid muscles (sternohyoid, omohyoid,
sternothyroid)
What is the course of the right recurrent laryngeal nerve?
nerve hooks around right subclavian and heads superiorly to
innervate laryngeal muscles.
What is the course of the left recurrent laryngeal nerve?
nerve hooks around 6th aortic arch which becomes ductus arteriosus or ligamentum arteriosum and heads superiorly to innervate laryngeal muscles.
Cervical ganglia of sympathetic trunk levels?
- Superior: level C1/C2; large; sends post-synaptic sympathetic fibres into cranial cavity & C1-C4 spinal nerves.
- Middle: level TP of C6; small; post-synaptic sympathetic fibres to C5-C6 spinal nerves.
- Inferior: level of TP of C7; star-shaped (“stellate”) when fused with first thoracic ganglion; post-synaptic sympathetic fibres to C7-C8 spinal nerves.
Name two endocrine organs?
=> thyroid and
=> parathyroid glands
Positioning if the thyroid gland?
Deep to sternothyroid & sternohyoid muscles
Extends C5-T1
Blood supply to the thyroid glands?
inferior thyroid artery
Parathyroid gland secretes what?
• Secrete parathyroid hormone, most important hormone for Ca2+ balance
Sympathetic Innervation of parathyroid gland?
Cervical ganglia
What is the purpose of the larynx?
communicates with oropharynx and trachea, modifies exit of air for vocalisation
Purpose of the trachea?
provides a patent airway, conducts air to lungs
