Term
| What are the suprahyoid muscles? |
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Definition
•Mylohyoid •Geniohyoid •Stylohyoid •Digastric |
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Term
| What are the origin, insertion, innervation and action of the mylohyoid muscle? |
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Definition
•Origin: mylohyoid line of the mandible •Insertion: Raphe and body of hyoid bone •Innervation: Mylohyoid nerve <– branch of inferior alveolar nerve <– branch of mandibular nerve <– branch of trigeminal nerve •Action: Elevates hyoid bone, floor of mouth and tongue during swallowing and speaking |
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Term
•What are the structures lying superficial to the mylohyoid muscle? |
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Definition
•Anterior belly of digastric •Submental artery and accompanying vein •Nerve to mylohyoid •mylohyoid vessels •superficial part of the submandibular gland |
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Term
| What structures lie deep to the mylohyoid muscle? |
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Definition
The hyoglossus muscle and the structures that lie superficial to it: Styloglossus Hypoglossal nerve Veins accompanying hypoglossal nerve Submandibular ganglion Lingual nerve Deep part of the submandibular gland Submandibular duct |
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Term
| What are the origin, insertion, action and innervation of the geniohyoid muscle? |
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Definition
•Origin: inferior mental spine of mandible •Insertion: Body of hyoid bone •Innervation: C1 via the hypoglossal nerve •Action: Pulls hyoid bone anterosuperiorly, shortens floor of mouth and widens pharynx |
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Term
| What are the origin, insertion, innervation and action of the stylohyoid bone? |
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Definition
Origin: Styloid process of temporal bone Insertion: Body of hyoid bone Innervation: Facial nerve Action: Elevates and retracts hyoid bone thereby elongating floor of mouth |
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Term
| What are the origin, insertion, innervation and action of the anterior belly of the digastric muscle? |
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Definition
Origin: Digastric fossa of mandible Insertion: Intermediate tendon of body and greater horn of hyoid bone Innervation: Nerve to mylohyoid - branch of inferior alveolar nerve - branch of the mandibular nerve- branch of trigeminal nerve Action: Depresses mandible, along w/ posterior belly raises hyoid bone and steadies it during speech and swallowing |
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Term
| What are the origin, insertion, innervation and action of the posterior belly of the digastric muscle? |
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Definition
Origin: Mastoid notch of temporal bone Insertion: Intermediate tendon and greater horn of hyoid bone Innervation: Facial nerve Action: Depresses mandible, along w/ anterior belly raises hyoid bone and steadies it during speech and swallowing |
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Term
| What are the infrahyoid muscles? |
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Definition
Sternohyoid Omohyoid Sternothyroid Thyrohyoid |
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Term
| What are the origin, insertion, action and innervation of the sternohyoid muscle? |
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Definition
Origin: Manubrium of the sternum and medial end of the clavicle Insertion: Body of the hyoid Action: Depresses hyoid after it has been elevated during swallowing Innervation: C1-C3 through branches of the ansa cervicalis branches |
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Term
| What are the origin, insertion, innervation and action of the omohyoid? |
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Definition
•Origin: Superior border of scapula near suprascapular notch •Insertion: inferior border of hyoid bone •Innervation: C1-C3 by a branch of ansa cervicalis •Action: Depresses, retracts, and steadies hyoid bone |
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Term
•What is the sternothyroid muscle? |
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Definition
•Origin: Posterior surface of manubrium of sternum •Insertion: Oblique line of thyroid cartilage •Innervation: C2 and C3 by a branch of ansa cervicalis •Action: Depresses hyoid bone and larynx |
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Term
•What is the thyrohyoid muscle? |
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Definition
•Origin: Oblique line of thyroid cartilage •Insertion: Inferior border of body and greater horn of hyoid bone •Innervation: C1 via hypoglossal nerve •Action: Depresses hyoid bone and elevates larynx |
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Term
•What are the scalene muscles? |
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Definition
•Anterior, medius, and posterior scalenes |
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Term
•What is the anterior scalene muscle? |
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Definition
• Origin: transverse processes of C3-C6 •Insertion: Scalene tubercle of 1st rib (ant to subclavian a and post to subclavian v) •Innervation: Cervical plexus: Ventral rami of cervical spinal nerves C4-C6 •Action: raises 1st rib |
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Term
| What are the origin, insertion, action and innervation of the medial scalene muscle? |
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Definition
•Origin: costotransverse lamellae of transverse process of C2-C6 •Insertion: 1st rib posterior to subclavian artery •Innervation: Cervical plexus: Ventral rami of cervical spinal nerves C4-C6 •Action: raises 1st rib |
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Term
| What are the origin, insertion, innervation and action of the posterior scalene muscle? |
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Definition
•Origin: posterior tubercle of transverse process of C4-C6 •Insertion: lateral surface of 2nd rib •Innervation: cervical and brachial plexus •Action: elevates 2nd rib |
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Term
•Where does the phrenic nerve lie? |
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Definition
•Phrenic nerve lies anterior to the scalenus anterior deep to the prevertebral fascia and crossed by the transverse cervical and suprascapular arteries. |
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Term
•What runs between the anterior and middle scalene muscles? |
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Definition
•Subclavian artery and Trunks of the brachial plexus run between the scalenus anterior and scalenus medius |
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Term
•What are some of the marks on the 1st rib? |
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Definition
•Scalenus anterior is inserted into the scalene tubercle on the upper surface of the 1st rib. Subclavian artery grooves the upper surface of the 1st rib behind the scalene tubercle. Subclavian vein grooves 1st rib in front of the scalene tubercle. |
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Term
•What is scalenus anterior syndrome? |
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Definition
•Scalenus anterior syndrome: Compression of the lower trunk of brachial plexus and subclavian artery against the 1st rib by a hypertonic scalenus anterior muscle. Also called scalenus anticus syndrome. |
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Term
•What are the styloid group of muscles? |
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Definition
•Styloglossus •Stylopharyngeus •Stylohyoid |
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Term
| What are the origin, insertion, innervation and action of the styloglossus muscle? |
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Definition
•Origin: lower end of styloid process •Insertion: side and undersurface of tongue •Innervation: hypoglossal nerve •Action: retracts tongue and pulls the tongue upwards |
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Term
| What are the origin, insertion, action and innervation of the stylopharyngeus muscle? |
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Definition
Origin: Root of the styloid process Insertion: Thyroid cartilage and wall of pharynx Innervation: Glossopharyngeal nerve Action: Elevates pharynx and larynx |
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Term
| What are the origin, insertion, action and innervation of the stylohyoid bone? |
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Definition
Origin: Styloid process Insertion: Hyoid bone on either side of the intermediate tendon of the digastric muscles Innervation: Facial nerve Action: Elevates hyoid |
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Term
•What is the hyoglossus muscle? |
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Definition
•Hyoglossus muscle •It is a quadrilateral muscle which arises from the hyoid bone and is inserted into the side of the tongue. •Its anterior part is overlapped by the mylohyoid muscle. The deep part of the submandibular gland lies in the interval between these two muscles. •Action: It depresses the side of the tongue •Nerve supply: hypoglossal nerve |
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Term
•What structures lie superficial to the hyoglossus muscle? |
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Definition
–Styloglossus muscle –Lingual nerve –Submandibular ganglion –Deep part of the submandibular gland –Submandibular duct –Hypoglossal nerve –Veins accompanying hypoglossal nerve |
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Term
•What structures lie deep to the hyoglossus muscle? |
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Definition
•Genioglossus •Glossopharyngeal nerve •Stylohyoid ligament •Lingual artery and accompanying veins |
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Term
•What is the nerve supply of the stylohyoid muscle? |
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Definition
•Stylohoid: arises from the styloid process and is inserted into the hyoid bone. It usually splits at its insertion. It runs parallel to the posterior belly of digastric. It is supplied by the facial nerve |
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Term
•What is the nerve supply of the posterior belly of the digastric muscle? |
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Definition
•Posterior belly of the digastric muscle: It arises from a groove (mastoid notch) on the medial side of the mastoid process. It is inserted by its intermediate tendon which is common to it and the anterior belly to the hyoid bone. Nerve supply of the posterior belly of digastric is: facial nerve. |
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Term
•Where does the facial nerve exit skull and what is its development? |
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Definition
•Remember that facial nerve passes through the stylomastoid foramen which lies between the styloid process and mastoid process and therefore the facial nerve supplies these two muscles which arise from the styloid process and mastoid notch respectively. Facial nerve is the nerve of the 2nd arch & the muscles supplied by it are derived from the 2nd arch. |
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Term
•What is the nerve supply of the anterior belly of digastric muscle? |
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Definition
•It is supplied by the nerve to mylohyoid which supplies the mylohyoid and anterior belly of digastric muscles. |
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Term
•What is the development of the mandibular nerve? |
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Definition
•Mandibular nerve is the nerve of the 1st arch and the muscles supplied by it are developed from 1st arch. |
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Term
•Are all muscles attached to the mandible innervated by the mandibular nerve? |
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Definition
•Remember that all muscles which are attached to the mandible are supplied by the mandibular nerve branches except the geniohyoid, platysma, buccinator and small origin of superior constrictor of pharynx |
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Term
•Which muscle attached to the mandible are innervated by the mandibular nerve? |
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Definition
•Lateral pterygoid •Medial pterygoid •Temporalis •Masseter •Mylohyoid •Anterior belly of digastric |
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Term
•What is the submandibular gland and its parts? |
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Definition
• Submandibular Salivary Gland •It is the chief content of the digastric triangle •Parts: The submandibular gland has two parts: the superficial and deep. •The superficial part •It is situated in the submandibular triangle between the anterior belly of digastric and stylomandibular ligament. The investing layer of deep cervical fascia splits to enclose the submandibular space & the gland. •It lies superficial to mylohyoid and hyoglossus muscles •It presents three surfaces: •The inferior surface •the medial surface •the lateral surface • |
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Term
•What is related to the inferior surface of the superficial part of the submandibular gland? |
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Definition
–Skin –Superficial fascia with platysma –Cervical branch of facial nerve –Marginal mandibular branch of facial nerve –Investing layer of cervical fascia –Facial vein –Submandibular lymph nodes |
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Term
•What are the relations of the medial surface of the superficial part of the submandibular gland? |
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Definition
•Mylohyoid •Nerve to mylohyoid •Submental vessels •Styloglossus •Hyoglossus |
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Term
•What are the lateral relations of the superficial part of the submandibular gland? |
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Definition
–Submandibular fossa of the mandible –Medial pterygoid –Facial artery |
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Term
•What are the lateral relations of the superficial part of the submandibular gland? |
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Definition
•The lateral surface is related to the following: –Submandibular fossa of the mandible –Medial pterygoid –Facial artery |
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Term
•What is the path of the facial artery? |
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Definition
•Facial artery grooves the posterior border of the submandibular gland and then traverses the space between the gland and the medial surface of the mandible before it winds round the lower border of the mandible at the anteroinferior part of the masseter muscle. |
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Term
•What is the relation of the facial vein to the submandibular gland? |
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Definition
•Facial vein crosses superficial to the gland |
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Term
•What is the location of the deep part of the submandibular gland? |
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Definition
•The small deep part lies between the mylohyoid and hyoglossus muscles. •It lies on the hyoglossus muscle and is related to the structures lying on the superficial surface of hyoglossus. (See notes given above on superficial relations of hyoglossus) |
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Term
•What is the course of the submandibular duct? |
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Definition
•Submandibular duct: •It is 5 cm long •It passes between the mylohyoid and hyoglossus •It is hooked around by the lingual nerve. Lingual nerve hooks around the submandibular duct from lateral to medial side. •It passes between the genioglossus muscle and sublingual gland •It opens on the summit of the sublingual papilla at the side of the frenulum of the tongue •In submandibular sialogram, radio-opaque material is injected into the opening of the duct. |
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Term
•What is the blood supply/drainage and the lymphatic drainage of the submandibular gland? |
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Definition
• •Submental artery which is a branch of the facial artery •Submental vein •Lymphatic drainage: to the deep cervical, particularly to the jugulo-omohyoid node. |
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Term
•What is the nerve supply of the submandibular gland? |
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Definition
•Nerve supply of the submandibular gland: •Sympathetic: postganglionic fibers from the superior cervical ganglion superior salivatory nucleus -> facial nerve -> chorda tympani nerve -> lingual nerve -> submandibular ganglion (pre-ganglionic fibers end and post-ganglionic fibers begin) -> supply the submandibular and sublingual gland |
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Term
•What nerves are in danger of injury when operating on the submandibular gland? |
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Definition
•During excision of the gland, skin incision is made 2.5 cm below the angle of the mandible to avoid injury to the marginal mandibular branch of the facial nerve. •When incising the duct, care should be taken to avoid injury to the lingual nerve. |
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Term
•What is Ludwig’s angina? |
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Definition
•Infections of the teeth may spread over to the submandibular space surrounding the gland and this is called Ludwig’s angina. |
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Term
•What is the sublingual gland and what are its relations? |
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Definition
• A small almond shaped gland •It lies below the mucous membrane of the floor of the mouth •It raises a sublingual fold •Laterally it is related to the sublingual fossa of the mandible •Medially it is related to the genioglossus muscle with the lingual nerve and submandibular duct in between. |
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Term
•What do the sublingual ducts open into? |
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Definition
•They are 8 to 20 and open on the sublingual fold and some of them may open into the terminal part of the submandibular duct. |
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Term
•What is the nerve supply of the sublingual gland? |
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Definition
•Nerve supply: Submandibular ganglion |
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Term
•What are the relations of the hypoglossal nerve? |
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Definition
•It passes forwards between the internal jugular vein and the internal carotid artery and crosses horizontally across the internal carotid and external carotid arteries below the level of the posterior belly of digastric muscle. It crosses superficial to the hyoglossus muscle and later supplies all the extrinsic and intrinsic muscles of the tongue except palatoglossus muscle. •It carries C1 fibers and these fibers leave the hypoglossal nerve as the superior root of ansa cervicalis and nerves to thyrohyoid and geniohyoid. •Hypoglossal nerve in the neck crosses superficial to 4 arteries: •Origin of the occipital artery •Internal carotid artery •External carotid artery •Loop of the lingual artery |
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Term
•How is the ansa cervicalis formed and what muscles does it supply? |
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Definition
•This is a loop of nerve formed by ventral rami of C1, C2 and C3 fibers •C1 fibers reach the ansa as its superior root from the hypoglossal nerve •C2 and C3 fibers reach separately as the inferior root of the ansa cervicalis. These fibers come from the cervical plexus. Therefore they are branches of ventral rami. •The ansa cervicalis lies anterior to carotid sheath. It supplies three muscles: –Omohyoid –Sternohyoid –Sternothyroid • It supplies all the infrahyoid muscles except the thyrohyoid |
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Term
•What innervates the thyrohyoid and the geniohyoid? |
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Definition
•The thyrohyoid is supplied by C1 fibers through the hypoglossal nerve •The geniohyoid muscle also is supplied by C1 fibers through the hypoglossal nerve but remember that geniohyoid is a suprahyoid muscle (above the level of hyoid bone) |
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Term
•How is the cervical plexus formed? |
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Definition
–It is formed by the ventral rami of C1, C2, C3 and C4 roots. Part of the C4 may contribute to the brachial plexus –It lies deep to the IJV and SCM and anterior to scalenus medius –C2, C3 and C4 divide into upper and lower branches to form loops. –C1 does not divide into upper and lower branch –C1 fibers join the hypoglossal nerve and supply muscles |
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Term
•What are the branches from the loop between C3 and C4? |
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Definition
•The loop between the C3 and C4 gives the supraclavicular nerves |
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Term
•What other muscles are supplied by the cervical plexus? |
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Definition
Longus capitis Longus coli Rectus capitis anterior Rectus capitis lateralis |
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Term
| What plexus does the Phrenic nerve emerge from? |
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Definition
| Cervical plexus (root value: C3-C5) |
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Term
•How is the phrenic nerve formed and what are its relations? |
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Definition
•Phrenic nerve: formed at the lateral border of scalenus anterior and descend anterior to scalenus anterior deep to IJV. It is crossed by the transverse cervical and suprascapular arteries. It runs down to thorax between the subclavian artery and vein to supply with sensory and motor fibers to diaphragm. It also supplies the mediastinal pleura and the pericardium. It also receives sympathetic fibers from the cervical sympathetic ganglia. The left phrenic crosses anterior to the 1st part of subclavian artery. The right phrenic it is separated from the 2nd part of the subclavian artery by the scalenus anterior. |
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Term
•What is the accessory phrenic nerve? |
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Definition
•Accessory Phrenic nerve: The contribution from C5 to the phrenic nerve may arise separately as a branch from the nerve to subclavius. If present, it lies lateral to the main nerve and descends posterior or anterior to the subclavian vein and join the main nerve in the root of the neck or in the thorax. |
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Term
•What happens if the phrenic nerve is severed? |
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Definition
•Severance of the Phrenic nerve cause paralysis of corresponding half of the diaphragm. |
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Term
•How is phrenic nerve block performed? |
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Definition
•Phrenic nerve block: The anesthetic (e.g., for a lung operation) is injected around the nerve where it lies on the anterior surface of the middle third of the scalenus anterior. •For longer period of paralysis (e.g., during repair of diaphragmatic hernia), the Phrenic nerve crush (with forceps) is performed. If an accessory Phrenic nerve is present, it must also be crushed. |
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Term
•How is cervical plexus block performed? |
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Definition
•Cervical plexus block: Anesthetic agents can be injected at the nerve point along the posterior border of the sternocleidomastoid muscle. |
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