Anterior Triangle

Question 1

Digastric (anterior belly)

Answer 1

Origin: digastric fossa of mandible

Insertion: intermediate tendon

Action: elevates hyoid bone, depresses mandible

Nerve: Mylohyoid n.

Artery: Submental a.

Question 2

Digastric (posterior belly)

Answer 2

Origin: Mastoid notch of temporal bone

Insertion: intermediate tendon

Action: elevates hyoid, depresses mandible

Nerve: Facial n. (CN VII)

Artery: occipital a.

Question 3

Sternohyoid

Answer 3

Origin: posterior surface o fthe manubrium, sternal end of clavicle

Insertion: lower border of hyoid bone, medial to omohyoid insertion

Action: depression and stabilization of hyoid bone, larynx

Nerve: superior root of ansa cervicalis

Artery: superior thyroid a.

Question 4

Sternothyroid

Answer 4

Origin: posterior surface of manubrium, below origin of sternohyoid

Insertion: oblique line of thyroid cartilage

Action: depression, stabilization of hyoid bone

Nerve: superior root of ansa cervicalis

Artery: superior thyroid a.

Question 5

Omohyoid (superior belly)

Answer 5

Origin: intermediate tendon

Insertion: lower border of hyoid bone, lateral to sternohyoid

Action: depression, stabilization of hyoid and larynx

Nerve: superior root of ansa cervicalis

Artery: superior thyroid a., transverse cervical a.

Question 6

Thyrohyoid

Answer 6

Origin: oblique line of thyroid cartilage

Insertion: lower border of the hyoid bone

Action: depression, stabilization of hyoid and elevation of larynx

Nerve: hypoglossal n. (CN XII), superior root of ansa cervicalis

Artery: superior thyroid artery

Question 7

Cricothyroid

Answer 7

Origin: anterior surface of cricoid cartilage laterally

Insertion: lower margin of thyroid lamina

Action: laterally rotates thyroid cartilage

Nerve: external branch of superior laryngeal n.

Artery: cricothyroid a.