Bones of the Neck, Cervical Fascia, Triangles of the Neck, Prevertebral Muscles and Arteries & Veins of the Neck Flashcards
- Typical cervical vertebrae (C3-C6) have: (3)
o Small vertebral body
- Concave superiorly and convex inferiorly
o Large and triangular vertebral foramen
o Transverse foramina in the transverse processes
- Where vertebral arteries run towards the head
- Typical cervical vertebrae (C3-C6) have:
o Superior facets of articular processes directed
_________
o Inferior facets of articular processes directed
_________
o Short _______ processes
superoposteriorly
inferoposteriorly
spinous
- Atlas (C1): (4)
o Ring-like and kidney-shaped
o Lacks a spinous process and body
o Consists of 2 lateral masses connected by anterior and posterior arches
o Concave superior articular facets receive the occipital condyles
- Axis (C2):
o A peg-like dens projects superiorly from its body (odontoid process)
- Vertebra prominens (C7): (2)
o Has a long spinous process that is not bifid
o Has large transverse processes but small transverse foramina
What is the hyphoid? (4)
- Lies anteriorly at the level of C3 between mandible and thyroid cartilage
- Has no articulations with any other bone
- Suspended from the styloid process of temporal bones by the stylohyoid ligaments
- Firmly bound to the thyroid cartilage
What is the Superficial Cervical Fascia? (2)
- Layer of fatty connective tissue lying between the dermis of the skin and the investing layer of the deep cervical fascia
- Thinner than superficial fascia in other regions of the body, especially anteriorly
Superficial Cervical Fascia:
Contents: (4)
o Cutaneous nerves, blood and lymphatic vessels
o Superficial lymph nodes
o Variable amounts of fat
o Platysma
Cutaneous and superficial muscles of the neck:
Platysma
Origin:
Insertion:
Innervation:
Main action:
- Inferior border of mandible.
Skin and subcutaneous tissue. - Deep fascia covering superior parts of deltoid and pectoralis major
- Cervical branch of facial nerve
- Draws corners of mouth inferiorly
Tenses skin of the neck
Cutaneous and superficial muscles of the neck:
SCM
Origin:
Insertion:
Innervation:
Main action:
Cutaneous and superficial muscles of the neck:
Trapezius
Origin:
Insertion:
Innervation:
Main action:
Layers of deep fascia: (4)
- Investing
- Pretracheal
- Prevertebral
- Carotid
What is the Investing layer of the Deep Cervical Fascia? (3)
- Most superficial layer of deep fascia
- Surrounds the entire neck deep to the skin and subcutaneous tissue
- At the 4 corners of the neck, it splits into superficial and deep layers to enclose the trapezius and sternocleidomastoid muscles
o These muscles are both innervated by accessory nerve (CN XII)
Relevance of the deep cervical fasciae: (3)
- Natural cleavage planes allowing tissues to be
separated during surgery - Limit the spread of abscesses resulting from infection
- Allows structures in the neck to move freely over one another without difficulty
Deep cervical fasciae
* Superior attachments: (6)
o Superior nuchal lines of occipital bone
o Mastoid processes of temporal bones
o Zygomatic arches
o Inferior border of mandible
o Hyoid bone
o Spinous processes of cervical vertebrae
Deep cervical fasciae
* Inferior attachments: (3)
o Manubrium of sternum
o Clavicles
o Acromions and spines of scapulae
Deep cervical fasciae
* Contents: (4)
o Sternocleidomastoid
o Trapezius
o Submandibular gland
o Parotid gland (forms its fibrous capsule)
What is the deep cervical fascia continuous with? (4)
- Continuous with the periosteum of C7 spinous process and with the nuchal ligament
- Splits into 2 above the manubrium to enclose sternocleidomastoid
o One layer attaches to the anterior and the other to the posterior surface of the manubrium
o Suprasternal space- lies between these layers and encloses
What does the Suprasternal space enclose? (4)
- Anterior jugular veins
- Jugular venous arch
- Fat
- Deep lymph nodes
What is the 1. Pretracheal layer?
- Limited to the anterior part of the neck
- Pretracheal layer:
* Extent:
o inferiorly from the hyoid to thorax where it
blends with the pericardium
- Pretracheal layer:
* Has 2 parts:
o Thin muscular part
- Encloses infrahyoid muscles
o Visceral part
- Encloses thyroid gland, trachea and oesophagus
What is the 1. Pretracheal layer continuous with? (2)
- continuous posteriorly and superiorly with the buccopharyngeal fascia of the pharynx
- blends laterally with the carotid sheaths
What is the 2. Prevertebral layer?
- Forms a tubular sheath for the vertebral column and the muscles associated with it
- Prevertebral layer:
o Anteriorly-
o Laterally-
o Posteriorly-
o Anteriorly- longus colli and longus capitis
o Laterally- scalenes
o Posteriorly- deep cervical muscles
- Prevertebral layer:
* Extent:
o Superiorly-
o Inferiorly-
o Laterally-
o Superiorly- attached to cranial base
o Inferiorly- blends with the endothoracic fascia peripherally and fuses with the anterior longitudinal ligament centrally at the T3 vertebra
o Laterally- continuous with the axillary sheath
- Carotid layer:
* Extent:
cranial base to root of the neck
o Communicates with mediastinum and cranial base- pathways for spread of infection and
extravasated blood
* Blends anteriorly with investing and pretracheal layers and posteriorly with the prevertebral layer
- Carotid layer:
* Contents: (6)
o Common and internal carotid arteries
o Internal jugular vein
o Vagus nerve
o Carotid sinus nerve
o Sympathetic nerve fibers (carotid periarterial plexuses)
o Deep cervical lymph nodes
What is the Retropharyngeal space?
- Potential space consisting of loose connective tissue
Retropharyngeal space:
* Extent: (2)
o Superiorly- between the prevertebral layer (deep) and buccopharyngeal fascia (superficial)
o Inferiorly- the buccopharyngeal fascia is continuous with the pretracheal layer
What is the Alar fascia? (2)
- Subdivides the retropharyngeal space (into anterior and posterior)
- Attached along the midline of the buccopharyngeal fascia from the cranium to C7 vertebral level
o Extends laterally and terminated in the carotid sheath
Alar fascia:
* Closed superiorly by the _____ ______ and on each side by the carotid layer
* Opens inferiorly into the ________
cranial base
mediastinum
What does the Alar fascia allow movement of?
- Allows movement of the pharynx, oesophagus, larynx and trachea
Spread of infections in the neck:
Anterior Triangles of the Neck:
Mylohyoid
Origin:
Insertion:
Innervation:
Main action:
Mylohyoid line of mandible
Mylohyoid raphe and body of hyoid
n. to mylohyoid from CN V3
Elevates hyoid, floor of mouth and tongue
Anterior Triangles of the Neck:
Geniohyoid
Origin:
Insertion:
Innervation:
Main action:
Inferior mental spine of mandible
Body of hyoid
C1 via CN XII
Pulls hyoid anterosuperiorly Shortens floor of mouth and widens pharynx
Anterior Triangles of the Neck:
Stylohyoid
Origin:
Insertion:
Innervation:
Main action:
Styloid process of temporal
Body of hyoid
Stylohyoid n. from CN VII
Elevates and retraces hyoid- elongates floor of mouth
Anterior Triangles of the Neck:
Digastric (Anterior)
Origin:
Insertion:
Innervation:
Main action:
Anterior belly: digastric fossa of mandible
Intermediate tendon to body and greater horn of hyoid
n. to mylohyoid from CN V3
Depresses mandible against resistance
Anterior Triangles of the Neck:
Digastric (Posterior)
Origin:
Insertion:
Innervation:
Main action:
Posterior belly: mastoid notch of temporal bone
Intermediate tendon to body and greater horn of hyoid
Digastric br. of CN VII
Elevates and steadies hyoid during swallowing/speaking
What are the Suprahyoid Muscles? (4)
What are the Infrahyoid Muscles? (4)
Anterior Triangles of the Neck:
Sternohyoid
Origin:
Insertion:
Innervation:
Main action:
Manubrium of sternum and medial end of clavicle
Body of hyoid
C1-C3 by a br. of ansa cervicalis
Depresses hyoid after elevation during swallowing
Anterior Triangles of the Neck:
Omohyoid
Origin:
Insertion:
Innervation:
Main action:
Superior border of scapula near suprascapular notch
Inferior border of hyoid
C1-C3 by a br. of ansa cervicalis
Depresses, retracts and steadies hyoid
Anterior Triangles of the Neck:
Sternothyroid
Origin:
Insertion:
Innervation:
Main action:
Posterior surface of manubrium
Oblique line of thyroid cartilage
C2 -C3 by a br. of ansa cervicalis
Depresses hyoid and larynx
Anterior Triangles of the Neck:
Thyrohyoid
Origin:
Insertion:
Innervation:
Main action:
Oblique line of thyroid cartilage
Inferior border of body and greater horn of hyoid
C1 via CN XII
Depresses hyoid and elevates larynx
Submental Triangle:
Boundaries:
- Lateral:
- Inferior:
- Apex:
- Floor:
- Lateral: Anterior bellies of digastric
muscle - Inferior: Hyoid bone
- Apex: Mandible
- Floor: Mylohyoid muscle
Submental Triangle:
Contents: (2)
- Anterior jugular veins
- Submental lymph nodes
Submandibular Triangle
Boundaries:
* Superior:
* Inferior anterior and posterior:
* Floor:
* Roof:
- Superior: Ramus of mandible
- Inferior anterior and posterior:
o Anterior belly of digastric muscle
o Posterior belly of digastric muscle - Floor
o Mylohyoid muscle
o Hyoglossus muscle
o Middle constrictor muscle of the
pharynx - Roof: Investing fascia
Submandibular Triangle
Contents: (5)
- Submandibular gland
- Submandibular lymph nodes
- Hypoglossal nerve (CN XII)
- Nerve to mylohyoid
- Parts of facial artery and vein
Muscular Triangle
Boundaries:
* Superior:
* Inferior:
* Medial:
* Floor:
- Superior: Superior belly of omohyoid
- Inferior: Anterior border of SCM
- Medial: Midline
- Floor: pretracheal fascia
Muscular Triangle
Contents: (3)
- Infrahyoid muscles
- Thyroid and parathyroid glands
- Recurrent laryngeal nerve
Carotid Triangle
Boundaries:
- Superior:
- Inferior:
- Lateral:
- Floor:
- Superior: posterior belly of digastric
muscle - Inferior: superior belly of omohyoid
- Lateral: anterior border of SCM
- Floor
o thyrohyoid muscle
o middle constrictor muscle of the
pharynx
o inferior constrictor muscle of the
pharynx
Carotid Triangle
Contents: (13)
- Common carotid artery
- Internal and external carotid artery
- Carotid sinus and carotid body
- Internal jugular vein
- Glossopharyngeal nerve
- Vagus nerve
- Spinal accessory nerve
- Hypoglossal nerve
- Superior root of ansa cervicalis
- Branches of cervical plexus
- Thyroid gland
- Larynx and pharynx
- Deep cervical lymph nodes
Boundaries of the posterior triangle of the neck:
- Anterior:
- Posterior:
- Inferior:
- Apex:
- Roof:
- Floor:
- Anterior: Posterior border of SCM
- Posterior: Anterior border of trapezius
- Inferior: Middle 1⁄3 of the clavicle
- Apex: At superior attachments of SCM and
trapezius - Roof: Investing fascia
- Floor: Prevertebral fascia and muscles
o Splenius capitis, levator scapulae and
middle, posterior and anterior scalene
Posterior Triangle of the Neck:
Divisions:
(divided by inferior belly of omohyoid)
* Occipital triangle
* Omoclavicular triangle
Occipital Triangle:
Superficial contents: (4)
- Cutaneous branches of cervical plexus (C1-4)
- External jugular vein
- Superficial branch of transverse cervical artery
- Superficial cervical lymph nodes
What are the cutaneous branches of cervical plexus (C1-4)? (4)
o Great auricular nerve
o Lesser occipital nerve
o Supraclavicular nerve
o Transverse cervical nerve
Occipital Triangle
Deep contents: (5)
- Spinal accessory nerve (CN XI)
- Phrenic nerve
- Trunks and roots of brachial plexus
- Occipital artery
- Thyrocervical truck (1st part of subclavian a.)
What are the sub-divisions of the Thyrocervical truck (1st part of subclavian a.)? (5)
o Suprascapular artery
o Transverse cervical trunk
o Dorsal scapular artery
o Ascending cervical artery
o Inferior thyroid artery
Omoclavicular Triangle
Superficial contents: (2)
- Inferior part of external jugular vein
- Superficial cervical lymph nodes
Omoclavicular Triangle
Deep contents: (5)
- 3rd part of subclavian artery and vein
- Suprascapular artery, vein and nerve
- Phrenic nerve
- Supraclavicular lymph nodes
- Trunks of brachial plexus
What are the Anterior vertebral muscles? (4)
What are the Lateral vertebral muscles? (5)
Prevertebral Muscles:
Longus colli
Innervation:
Main action:
Anterior rami of C2-C6
Flexes neck with rotation contralaterally if unilateral contraction
Prevertebral Muscles:
Longus capitis
Innervation:
Main action:
Anterior rami of C1-C3
Flex head
Prevertebral Muscles:
Rectus capitis anterior
Innervation:
Main action:
C1-C2
Flex head
Prevertebral Muscles:
Anterior scalene
Innervation:
Main action:
C4-C6
Flex head
Prevertebral Muscles:
Rectus capitis lateralis
Innervation:
Main action:
C1-C2
Flexes and stabilises head
Prevertebral Muscles:
Splenius capitis
Innervation:
Main action:
Posterior rami of middle cervical spinal nn.
- Lateral flexion and rotation of head on the same side
- Extends head and neck
Prevertebral Muscles:
Levator scapulae
Innervation:
Main action:
Dorsal scapular n. (C5) & C3-C4
Downward rotation of scapula
Prevertebral Muscles:
Middle scalene
Innervation:
Main action:
Anterior rami of cervical spinal nn.
Flexes neck laterally
Prevertebral Muscles:
Posterior scalene
Innervation:
Main action:
Anterior rami of C7-C8
Flexes neck laterally
Boundaries of the root of the neck:
- Inferior-
- Lateral-
- Anterior-
- Posterior-
- Inferior- superior thoracic aperture
- Lateral- 1st pair of ribs and their costal
cartilages - Anterior- manubrium of the sternum
- Posterior- T1 vertebra
Suboccipital Triangle:
Boundaries:
- Superomedial-
- Superolateral-
- Inferior-
- Floor-
- Roof-
- Superomedial- rectus capitis posterior major
- Superolateral- obliquus capitis superior
- Inferior- obliquus capitis inferior
- Floor- posterior atlantooccipital membrane and posterior arch of C1 vertebra
- Roof- semispinalis capitis
Suboccipital Triangle
Contents: (2)
- Vertebral artery
- Suboccipital nerve
What is the Carotid arterial system?
- At the level of the superior border of the thyroid cartilage, the common carotid divides into the internal and external carotid arteries.
What is the carotid sinus? (3)
o A dilation of the proximal part of the internal carotid artery
o Innervated mostly by the glossopharyngeal n. via the carotid sinus n., but also the vagus n.
o Baroreceptor that reacts to changes in arterial blood pressure
What is the Carotid body? (3)
o Small reddish-brown ovoid mass lying in a septum on the medial side of the bifurcation
o Innervated mainly by the carotid sinus n. and vagus n.
o Chemoreceptor that monitors the levels of oxygen in the blood
- Initiates a reflex that increases the rate and depth of respiration, cardiac rate and blood pressure
What is the Internal carotid artery? (2)
- Direct continuation of the common carotid a. superior to the origin of the external carotid a.
- Enters the cranium through carotid canal in the petrous part of the temporal bone
What are the branches of the External carotid artery?
Branches of external carotid artery: Some Anatomists Like Freaking Out Poor Medical Students
External carotid artery
Superior thyroid branch
Direction:
Distribution:
Anterior
Thyroid gland, infrahyoid muscles and SCM and larynx
External carotid artery
Ascending pharyngeal branch
Direction:
Distribution:
Medial
Pharynx, prevertebral muscles, middle ear and cranial meninges
External carotid artery
Lingual branch
Direction:
Distribution:
Anterior
Tongue
External carotid artery
Facial branch
Direction:
Distribution:
Anterior
Palatine tonsils, soft palate, pterygoid, mylohyoid, and digastric muscles, the submandibular gland, and all of the face
External carotid artery
Occipital branch
Direction:
Distribution:
Posterior
Posterior scalp
External carotid artery
Occipital branch
Direction:
Distribution:
Posterior
Posterior scalp
External carotid artery
Posterior auricular branch
Direction:
Distribution:
Posterior
Adjacent muscles, parotid gland, facial nerve, structures in the temporal bone, auricle and scalp
Maxillary =
Superficial temporal =
Maxillary = (Terminal branch)
Superficial temporal = (Terminal branch)
Subclavian Artery:
* Course: (2)
o Arch superolaterally, reaching an apex as they pass posterior to anterior scalene muscles
o As the descend, they lie posterior to the middle of the clavicles
- The parts of the subclavian artery are described relative to the anterior scalene:
o 1st part-
o 2nd part-
o 3rd part-
o 1st part- medial to anterior scalene
o 2nd part- posterior to anterior scalene
o 3rd part- lateral to anterior scalene
What are the branches of the Subclavian Artery? (5)
Subclavian Artery:
Vertebral artery
Distribution:
Medulla, spinal cord, cerebellum, deep muscles of the neck, dura mater of PCF
Subclavian Artery:
Internal thoracic
Distribution:
First 6 intercostal spaces
Subclavian Artery:
Thyrocervical trunk - Suprascapular
Distribution:
May arise independently. Supplies muscles on the posterior aspect of scapula.
Subclavian Artery:
Thyrocervical trunk - Ascending cervical
Distribution:
Lateral muscles of the upper neck and spinal branches into the intervertebral foramina
Subclavian Artery:
Thyrocervical trunk - Ascending cervical
Distribution:
Lateral muscles of the upper neck and spinal branches into the intervertebral foramina
Subclavian Artery:
Thyrocervical trunk - Inferior thyroid
Distribution:
Larynx, trachea, oesophagus, thyroid and parathyroid glands and adjacent muscles
Subclavian Artery:
Thyrocervical trunk - Transverse cervical
Distribution:
Bifurcates into superficial cervical and dorsal scapular*. Supplies rhomboids, levator scapulae, trapezius and trunks of the brachial plexus
Subclavian Artery:
Costocervical trunk - Superior intercostal
Distribution:
First two intercostal spaces
Subclavian Artery:
Costocervical trunk - Deep cervical
Distribution:
Posterior deep cervical muscles
Subclavian Artery:
Costocervical trunk - Deep cervical
Distribution:
Posterior deep cervical muscles
Subclavian Artery:
Dorsal scapular* -
Distribution:
May arise from thyrocervical trunk. Participates in scapular arterial anastomosis
What are the parts of the vertebral artery? (4)
- Cervical part
- Vertebral part
- Suboccipital part
- Cranial part
Vertebral artery
* Cervical part:
o Ascends into the pyramidal space between the scalene and longus colli & capitis muscles
Vertebral artery
* Vertebral part:
o At the apex of the pyramidal space the artery passes deep to course through the foramina transversaria of vertebrae C1-C6
Vertebral artery
* Suboccipital part:
o Courses in a groove on the posterior arch of the atlas and through the suboccipital triangle before entering the cranium through foramen magnum
Vertebral artery:
* Cranial part:
o At the inferior border of pons, the right and left arteries join to form the basilar artery
What is the Internal jugular vein?
- Commences at the jugular foramen in the posterior cranial fossa as the direct continuation of the sigmoid sinus
Internal jugular vein:
* Superior bulb-
* Inferior bulb-
- Superior bulb- dilation at its origin
- Inferior bulb- dilation at the inferior end that has a bicuspid valve to prevent backflow into the vein
Internal jugular vein:
Branches: (7)
o Occipital vein
o Facial vein
o Lingual vein
o Superior laryngeal vein
o Superior thyroid vein
o Middle thyroid vein
o Pharyngeal vein
What is the external jugular vein? (5)
- Begins near the angle of the mandible
- Posterior division of the retromandibular vein unites with posterior auricular vein
- Crosses the SCM obliquely and pierces investing fascia at the posterior border
- Receives the cervicodorsal, suprascapular and anterior jugular veins
- Terminates in the subclavian vein
What is the Subclavian vein? (2)
- Passes anterior to the anterior scalene muscle and phrenic nerve
- Unites at the medial border of anterior scalene with internal jugular vein to form the brachiocephalic vein
What is the Anterior Jugular vein? (2)
- Arises near the hyoid from confluence of the superficial submandibular veins
- Superior to the manubrium they unite across the midline to form the jugular venous arch in the suprasternal space
