Basic Structures

Question 1

Describe the platysma muscle. (2)

Answer 1

Depresses lower jaw and tenses skin of neck.

Cervical branch of facial.

Question 2

Describe orbicularis oculi. (4)

Answer 2

Orbital portion: forceful closure of the eye - temporal branch of facial.
Palpebral portion: unconscious eye closure eg blink - zygomatic branch.
Examination: resist opening.

Question 3

Describe levator palpebrae superioris. (3)

Answer 3

Elevates upper eyelid - occulomotor nerve.

Examination: check for ptosis.

Question 4

Describe occipitofrontalis. (3)

Answer 4

Elevates eyebrows - temporal branch of facial.

Elevate eyebrows against resistance.

Question 5

Describe the layers of the epicranial apineurosis. (5)

Answer 5

Skin
Loose connective tissue 
Aponeurosis of occipitofrontalis. 
Dense connective tissue
Pericranium. 
Spells SCALP.

Question 6

List the 8 muscles of facial expression

Answer 6

Platysma
Orbicularis oculi 
Levator palpebrae superioris
Occipitofrontalis 
Epicranial aponeurosis 
Orbicularis oris 
Dilator muscles of the lips
Buccinator

Question 7

Describe orbicularis oris (2)

Answer 7

Closes mouth - buccal branch of facial.

Question 8

Describe the dilator muscles of the lip. (3)

Answer 8

Separate the lips, buccal and mandibular branches.

Question 9

Describe the buccinator. (3)

Answer 9

Flattens cheek to keep food from the space between check and gums - buccal branch of facial.
Blow out cheeks and resist ‘popping’.

Question 10

List the 4 muscles of mastication.

Answer 10

Lateral pterygoid
Medial pterygoid
Masseter
Temporalis

Question 11

Describe the lateral pterygoid. (3)

Answer 11

Protrudes mandible, opens jaw, moves jaw side to side. Mandibular.

Question 12

Describe the medial pterygoid. (2)

Answer 12

Elevate jaw, side to side. Mandibular.

Question 13

Describe the masseter. (3)

Answer 13

Elevates mandible. Mandibular branch. Palpate in clench just below zygomatic arch.

Question 14

Describe temporalis. (3)

Answer 14

Elevates mandible. Mandibular branch. Palpate on clench in temple.

Question 15

Describe the trapezius. (2)

Answer 15

Shrugs shoulders (test against resistance). Accessory nerve.

Question 16

Describe the sternocleidomastoid. (2)

Answer 16

Laterally flexes the Head and rotates chin. Accessory nerve.

Question 17

Describe suprahyoids. (3)

Answer 17

Hyoid bone to mandible, act to elevate hyoid or depress mandible. Eg digastric.

Question 18

Describe infrahyoids (3)

Answer 18

Strap muscles that overly the thyroid and larynx. They depress the hyoid and stabilise. Eg omohyoid.

Question 19

Describe the anterior triangle of the neck. (4)

Answer 19

A pathway for structures moving between the Head and the thorax.
Boundaries are midline of neck, anterior border of SCM and the inferior border of the mandible.

Question 20

Describe the posterior triangle of the neck. (4)

Answer 20

A pathway for structures travelling between the thorax/neck and the upper limb eg the brachial plexus.
Boundaries are posterior SCM, anterior trapezius and the clavicle.

Question 21

Describe the carotid triangle. (7)

Answer 21

Where the carotid sheath is accessible.
Boundaries are omohyoid, posterior digastric and SCM.
Contains the common carotid, the inferior jugular and the vagus nerve.

Question 22

Describe the 4 fascial compartments (8)

Answer 22

Investing - outer but under platysma. Surrounds SCM and trapezius.
Prevertebral - surrounds the vertebrae and blends with the thorax.
Pretracheal - splits around infrahyoids, thyroid, oesophagus and pharynx.
Buccopharyngeal - extension of pretracheal that runs between the two lobes of the thyroid (making a triangular space) to protect the oesophagus.

Question 23

Describe deep neck spaces. (3)

Answer 23

Allows infections of the head and neck to spread inferiorly to the mediastinum.
Paratracheal space is between the pretracheal fascia (between the infrahyoids and the thyroid gland).
Retropharyngeal space is posterior to puccopharyngeal fascia, anterior to prevertebral fascia.

Question 24

Describe the cervical plexus (8)

Answer 24

Made up of the anterior rami of the first four spinal nerves which lie on the surface of scalene and levator scapulae, deep to SCM. It’s sensory branches emerge cutaneously to the posterior border of SCM at Erb’s point (used for cervical nerve block) and move to supply dermatomes C2-C5. Its motor branches form a loop called ansa cervicalis which supplies the infrahyoids.

Question 25

Explain the most important nerve of the cervical plexus. (2)

Answer 25

The phrenic nerve - carried roots from C3 C4 and C5 to innervate the diaphragm.