Neck anatomy Flashcards
Superior boundary of the neck
Pericraniocervical line Inferior mandible and base of the skull
Inferior boundary of the neck
Manubrium, clavicle and acromion to C7 spinous process
Suprahyoid muscles
Mylohyoid
Digastric
Stylohyoid
All elevate the hyoid bone
Infrahyoid muscles
Omohyoid
Sternohyoid
Scalene muscles (anterior, middle, posterior)
Thyrohyoid
Sternothyroid
Depress the hyoid bone, supplied by ansa cervicalis (C1-C3)
Label the muscles of the anterior neck
Posterior muscles of the neck
Levator scapulae - elevates shoulders (dorsal scapula nerve, C3 and C4)
Splenius capitis, semispinalis capitis - flex and extend the neck and head (posterior rami of spinal nerves)
Suboccipital muscles: extend the head on C1, rotate the head on C2 (C1 posterior ramus)
Ligamentum nuchae - strong median ligament of the neck.
Compartments of the neck
Four comparments enclosed by an outer musculofascial collar (investing fascia)
- Vertebral compartment (cervical vertebrae and postural muscles). Covered by prevertebral fasia
- Visceral compartment (glands - thyroid, parathyroid, thymus). Covered by pretracheal fascia
- Vascular compartment x 2(carotid vessels and vagus nerve). Covered by carotid sheaths
Borders of the anterior triangle of the neck
Medial: midline
Lateral: sternocleidomastoid
Superior: inferior margin of mandible
Borders of the posterior triangle
Medial: sternocleidomastoid
Lateral: trapezius
Base: clavicle
Apex: mastoid process
Subdivisions of the anterior triangle
Contents of the carotid triangle
Carotid, thyroid, facial & lingual arteries
Internal jugular & facial veins
CN X, XI, XII, VII
Superior laryngeal nerve
Thyroid gland
Which landmarks would you use to locate the common carotid pulse?
Common carotid artery lies in a groove between the trachea and infrahyoid muscles.
Palpated deep to anterior border of sternocleidomastoid at the level of the thyoid cartilage
Contents of the submandibular triangle
Submandibular lymph nodes
Submandibular salivary gland
Hypoglossal nerve
Lingual artery
Facial artery & vein
Marginal mandibular branch of CN VII
Contents of submental triangle
Submental lymph nodes
Anterior jugular vein tributaries
Subdivisions of the posterior triangle
Divided by omohyoid muscles into occipital triangle and supraclavicular triangle
Fascia of the neck
Superficial fascia of the neck contains a thin sheet of muscle (platysma) which begins in the thorax and runs upwards to the mandible
Deep fascia is organised into layers.
Investing layer - completely surrounds the neck
Prevertebral layer - surrounds vertebral column and muscles (prevertebral, scalene muscles, depe muscles of the back)
Pretracheal layer - surround the trachea, oesophagus and thyroid. hyoid bone to upper thoracic cavity
Carotid sheath - surround common carotid, internal carotid, internal jugular vein, vagus nerve. Sympathetic chain lies posterior to sheath
Fascial spaces in the neck
Prevertebral space - between investing layer of the cervical fascia and pretracheal fascia. Passes between the neck and anterior part of the superior mediastinum
Retropharyngeal space - between the buccopharyngeal fascia (part of pretracheal) and prevertebral fascia. Extends from the base of the skill to upper part of the posterior mediastinum.
Retropharyngeal space
Between buccopharyngeal fascia (pretracheal) and prevertebral fascia. Extends from the base of the skull to posterior mediastinum.
Alar fascia crosses the retropharyngeal space.
Consists of loose connective tissue. Permits movement of the pharynx oesophagus and larynx during swallowing.
Major pathway for the spread of infection
Spread of infection in the neck
Investing layer of deep cervical fascia helps prevent the spread of absesses.
If an infection occurs between the investing layer and pretracheal fascia the infection does not spread beyond the manubrium.
If infection occurs between the investing fascia and the visceral part of the pretracheal fascia it can spread into the thoracic cavity anterior to the pericardium.
Buccopharyngeal fascia
Posterior part of the pretracheal fascia. Separates the pharynx and the oesophagus from the prevertebral layer.
Begins at the base of the skull and ends in the thoracic cavity.
Axillary sheath
Prevertebral fascia of the neck that extends from the anterior and middle scalene muscles to surrounds the brachial plexus and subclavian artery as they pass into the axilla.
~ In axilla, axillary sheath contains 1st part of axillary artery, axillary vein and cords of the brachial plexus.
N.B. Infection in the vertebral compartment can spread to the upper limb via the axillary sheath
Plexus block via injection is done via the axillary sheath.
Central lines
Lesser supraclavicular fossa used to access internal jugular vein - space between the origin of the two heads of sternocleidomastoid
Contents of the supraclavicular/omoclavicular triangle
Subclavian artery and vein
Supraclavicular nodes
Suprascapular nerve
Points where brachial plexus can be anaesthatised
Supraclavicular triangle
Axillary sheath
Interscalene (anterior and middle)
Floor of posterior triangle
Formed by prevertebral facia overlying muscles of the neck
Splenius capitus
Levator scapulae
Scalenes
Inferior belly of omohyoid
Nerves in the posterior triangle
Phrenic nerve
Brachial plexus
Acessory nerve
Doral scapular nerve
Long thoracic nerve
Superficial drainage of the neck
External jugular veins and anterior jugular veins
Exernal jugular vein is formed by post auricular and retromandibular vein. Runs from the angle of the mandible diagonally across sternocleidomastoid to the lateral point where it meets the clavicle. It then pierves the investing and enters the subclavian vein.
Anterior jugular veins are paired venous channels that drain the anterior aspect of the neck. They begin as small veins descend on either side of the midline. Each anterior vein pierces the investing facia to enter the subclavian vein. Connected by a jugular venous arch at the suprasternal notch.
Lymph nodes in the head and neck
Submental - lower lip, tip of tongue
Submandibular - lip, lateral body of tongue, nose, face
Parotid (preauricular): temporal scalp and eye
Mastoid: external acoustic meatus and pinna
Occipital: occipital scalp to vertex
Superficial cervical: runs with external jugular vein
Jugulo-digastric: tonsil, pharynx, posterior tongue
Deep cervical chain: superficial node groups
Jugulo-omohyoid: superficial node groups, central tongue
Supraclavicular: surround thoracic duct,
Describe the origin and course of the carotid arteries
Common carotid: Right common carotid - originates from the brachicephalic trunk. Left common carotid - direct branch of the arch of the aorta that pases into the neck. Both pass superiorly into the neck at the sternoclavicular joint and ascend lateral to the trachea and oesophagus within the carotid sheath. Divide into the external and internal carotid arteries at the thyroid cartilage (C3/C4 vert.)
Internal carotid arteries: ascend towards the base of the skill and enters the cranial cavity through the carotid canal. Supplies cerebral hemispheres, eyes and forehead
External carotid arteries give off branches immediately after the bifurcation to supply the neck and face.
Describe the distribution of the branches of external carotid arteries
External carotid arteries give off branches immediately after the bifurcation of the common carotid arteries
- superior thyroid - supplies thyroid gland, larynx, muscles (TH, SCM)
- ascending pharyngeal artery - pharyngeal constrictors, palate, tonsil, pharyngotypmanic tube
- lingual artery - musles of the tongue, palatine tonsil, soft palate, floor of the mouth, sublingual gland
- facial artery - structures of the face
- occiputal artery - SCM, deep muscles of the back, scalp
- posterior auricular artery - parotid and surrounding muscles, exernal and inner ear
- superficial temporal artery - parotid, masseteer, temoporalis, external ear
- maxillary artery - EAM, middle ear, mandible and maxilla (skin, gums, teeth), nasal cavity
Mylohyoid
Support and elevation of the flood of the mouth
Elevation of hyoid
CN V3
Digastric
Lowers mandible to open mouth, raises hyoid bone and pulls is back
Anterior belly: CN V3
Posterior belly: CN VII
Omohyoid
Depresses and flexes hyoid bone
Ansa cervicalis (Anterior rami C1-)
Stylohyoid
Pulls hyoid bone posterosuperiorly
CN VII
Sternohyoid
Depresses hyoid bone after swallowing
Ansa cervicalis (C1-C3)
Sternothyroid
Draws larynx/thyroid cartilage downwards
Ansa cervicalis
Scalene muscles
Anterior, middle elevate rib 1
posterior elevates rib 2
Anterior rami C3-C7
Thyrohyoid
Depresses hyoid bone, raises larynx when hyoid is fixed
C1
What key structures present at the bifurcation of the common carotid?
Carotid sinus contained in the dilation of the common carotid at point of bifurcation. Contains receptors that monitor changes in bp. Innervated by glossopharyngeal nerve (CNIX)
Carotid body detect changes in pO2 and pCO2. Innervated by branches of CNIX and CNX
