Hyoid Apparatus.

What muscles attach, or insert via tendon, to the superior border of the hyoid bone? List them from most superficial to deepest.

1. Anterior and posterior bellies of Digastric Muscle. 2. Stylohyoid. 3. Mylohyoid. 4. Geniohyoid.

Name the infrahyoid muscles from superficial to deep.

1. Sternohyoid. 2. Omohyoid. 3. Thyrohyoid.

What nerve structure of the cervical plexus provides innervation to the infrahyoid muscles, and which muscle is the exception?

Ansa Cervicalis provides innervation to all infrahyoid muscles, except thyrohyoid which receives C1 fibers from CN 12.

What suprahyoid muscles are innervated by the mandibular branch of cranial nerve 5?

Anterior belly of Digastric and Mylohyoid are innervated by the mandibular branch of Trigeminal Nerve.

What is unique about the structure of the Digastric and Omohyoid muscles?

Both Omohyoid and Digastric muscles have an intermediate tendon in the middle of the muscle that separates the muscle into inferior/superior and anterior/posterior bellies respectively.

What major nervous and vascular structures pass through the scalene interval?

Brachial plexus and subclavian artery.

The anterior, or superior, loop of the ansa cervicalis contains fibers from what segmental spinal nerve?

C1

The posterior, or inferior, loop of ansa cervicalis is composed of fibers from what segmental spinal levels?

C2 & C3

They hyoid bone is at what vertebral level?

C3

What is the function of the pharyngeal constrictor muscles and how many are there?

Constrictor muscles function to propel food down the pharynx and into the esophagus via peristaltic motion. There are three of these constrictor muscles, superior, middle, and inferior.

What are the suprahyoid muscles?

Digastric, Stylohyoid, Mylohyoid, and Geniohyoid. (not pictured)

True or False. Compression of the scalene interval may impair venous return via the subclavian vein.

False. The subclavian vein passes anteriorly to the scalene interval and does not pass through it.

What hyoid muscles are innervated by C1 fibers?

Geniohyoid, Thryohyoid, and Superior belly of Omohyoid.

What anatomical structures of hyoid serves as the attachment points for the thyrohyoid membrane as it secures the bone to the thyroid cartilage?

Greater Horns and inferior aspect of the hyoid body.

What is the scalene interval and which scalene muscles are involved in its formation?

It is the a gap created between the Anterior and the Middle Scalene muscles as they diverge from each other as they descend to their insertion points on the 1st rib.

What are the major cutaneous nerves of the cervical plexus and in which cervical triangle do the emerge from?

Lesser Occipital. Greater Auricular. Transverse Cervical. Supraclavicular. All cervical cutaneous nerves pass through the posterior cervical triangle.

What are the attachment points of the stylohyoid ligament?

Lesser horns of the Hyoid and the styloid process of the skull.

What muscles are primarily responsible for cervical flexion?

Longus Coli, Scalenes, and Sternocleidomastoid.

What is the innervation of Mylohyoid?

Mandibular branch of Trigeminal Nerve, CN 5.

Which constrictor muscle attaches to the superior surface of the hyoid bone?

Middle Constrictor Muscle.

Which cervical fascial layer anchors Omohyoid's intermediate tendon to the clavicle?

Muscular layer of pretracheal fascia....of the deep cervical fascia.

What are the three parts of the pharynx from superior to inferior?

Nasopharynx, Oropharynx, and Laryngopharynx.

What is the innervation of Geniohyoid?

Nerve to Geniohyoid from Hypoglossal Nerve, CN 12.

Fibers from what segmental spinal nerve innervate geniohyoid, and how do these fibers travel to this muscle?

Nerve to geniohyoid is composed of ventral rami C1 fibers that travel with Hypoglossal nerve, CN12.

What is the origin, insertion, and innervation of stylohyoid muscle and which ligament does it parallel?

Origin: Styloid process. Insertion: Lesser horn of hyoid. Innervation: Facial Nerve, CN 7. It parallels stylohyoid ligament.

What is the most superficial muscle in the anterior neck?

Platysma

What is the innervation of the digastric muscle?

Posterior Belly: Digastric branch of Facial Nerve, CN 7. Anterior Belly: Mandibular branch of Trigeminal Nerve, CN 5.

Where do the anterior and posterior bellies of the digastric muscle attach to the skull?

Posterior belly: Mastoid Process. Anterior Belly: Digastric Fossa on posterior menti.

What is the innervation to Sternocleidomastoid?

Spinal Accessory Nerve, CN 11.

What is the "Strap Muscle" of the hyoid bone and why is it usually included in the infrahyoid muscle group even though it doesn't attach to the hyoid bone??

Sternothyroid is usually included with infrahyoid muscles due to its connection to the laryngeal cartilage. Movement of this muscle causes secondary movement of the hyoid via thyrohyoid.

What ligament attaches the hyoid bone to the skull?

Stylohyoid Ligament.

Anatomically, what portions of the hyoid bone are most prone to breakage during compression trauma?

The intersection of the Greater Horns and the body of the Hyoid.

What structures connect the hyoid bone inferiorly to the thyroid cartilage?

Thyrohyoid Membrane, Thyrohyoid Ligament (posteriorly & bilaterally), and the Median Thyrohyoid Ligament (Anteriorly).

True or False. Longus coli and Scalene muscles are innervated by segmental ventral rami of the cervical region.

True.

True or False. The thyroid cartilage is one of the components of the larynx.

True. It is the largest of 9 cartilaginous components that make up the laryngeal skeleton.

Awesome youtube video on cervical plexus.

https://www.youtube.com/watch?v=aAlTGQRQ5YU