Head/Neck Muscles

Question 1

Trapezius Muscle

Answer 1

1. Origin: Ext. Occipital Protuberance; Superior Nuchal line; Ligamentum nuchae; Spinous processes of T1 - T12
2. Insertion: Spine of the scapula; Acromion; Lateral 1/3 of the Clavicle
3. Actions: Elevate the scapula; Retract the scapula; Depress the scapula
4. Nerve Supply: Spinal Accessory Nerve; Branches from C3 and C4 (thought to be proprioceptive)
5. Blood Supply: transverse cervical artery

Question 2

Sternocleidomastoid Muscle

Answer 2

1. Origin: Manubrium; Medial 1/3 of the Clavicle
2. Insertion: Mastoid process of the temporal bone; Superior nuchal line
3. Actions: Unilaterally - turns face to contralateral side; head tilts to ipsilateral side; Bilaterally - head flexion
4. Nerve Supply: Spinal Accessory nerve
5. Blood Supply (3 parts): Upper 1/3 = Occipital artery; Middle 1/3 = Sup Thyroid/Carotid art; Lower 1/3 = suprascapular artery

Question 3

Digastric Muscle (Suprahyoid muscle)

Answer 3

1. Origin: Mastoid Process
2. Insertion: Digastric fossa of the mandible
3. Actions: Elevates hyoid bone; helps depress and retract the mandible
4. Nerve Supply: Facial n. (post. belly); Trigeminal n. (ant. belly)
5. Blood Supply: Ant Belly = submental branch of facial art.; Post Belly = occipital artery

Question 4

Omohyoid Muscle (Infrahyoid Muscle)

Answer 4

1. Origin: Superior border of the scapula
2. Insertion: Body of the hyoid
3. Actions: Depresses the hyoid; helps depress the larynx
4. Nerve Supply: Ansa cervicalis
5. Blood Supply: Inferior thyroid art.

Question 5

Stylohyoid Muscle (Suprahyoid muscle)

Answer 5

1. Origin: Styloid process
2. Insertion: Body of the hyoid
3. Actions: Elevates hyoid; retracts hyoid
4. Nerve Supply: Facial nerve
5. Blood Supply: Sup. Thyroid art, Suprahyoid br. of lingual artery

Question 6

Mylohyoid Muscle (Suprahyoid muscle)

Answer 6

1. Origin: Mylohyoid line of the mandible
2. Insertion: Mylohyoid muscle of opposite side at raphe; body of the hyoid
3. Action: Elevates hyoid; elevates floor of the oral cavity
4. Nerve Supply: Trigeminal n. (mandibular division)
5. Blood Supply: Sublingual art.; submental art. (branch of facial art.); mylohyoid br. of the inf. alveolar art (br. of maxillary art.)

Question 7

Geniohyoid Muscle (Suprahyoid muscle)

Answer 7

1. Origin: Inf. genial tubercle
2. Insertion: Body of the hyoid
3. Action: Helps move the hyoid and tongue anteriorly
4. Nerve Supply: C1 (ventral ramus which follows the hypoglossal n.)
5. Blood Supply: Sublingual a., Submental a., mylohyoid br. of the inferior alveolar a.

Question 8

Omohyoid Muscle (Infrahyoid Muscle)

Answer 8

1. Origin: Sup. Border of the scapula
2. Insertion: Body of the hyoid
3. Action: Depresses the hyoid
4. Nerve Supply: Ansa Cervicalis
5. Blood Supply: Sup. thyroid a.; lingual a.; Sup cervical a. & inf. thyroid arteries (thyrocervical trunk)

Question 9

Sternohyoid Muscle (Infrahyoid Muscle)

Answer 9

1. Origin: Manubrium
2. Insertion: Body of the hyoid
3. Action: Depresses the hyoid
4. Nerve Supply: Ansa cervicalis
5. Blood Supply: Lingual a.; sup. thyroid a.

Question 10

Sternothyroid Muscle (Infrahyoid Muscle)

Answer 10

1. Origin: Manubrium
2. Insertion: Oblique line of the thyroid cartilage
3. Action: Depresses the larynx
4. Nerve Supply: Ansa cervicalis
5. Blood Supply: Inf. thyroid a.; some sup. thyroid a.

Question 11

Thyrohyoid Muscle (Infrahyoid Muscle)

Answer 11

1. Origin: Oblique line of the thyroid cartilage
2. Insertion: Greater cornu (horn) of the hyoid
3. Action: Depresses the hyoid
4. Nerve Supply: C1 (ventral ramus which follows the hypopglossal n.
5. Blood Supply: Inf. thyroid a.; some sup. thyroid a.