Basic Structures Flashcards
Describe the platysma muscle. (2)
Depresses lower jaw and tenses skin of neck.
Cervical branch of facial.
Describe orbicularis oculi. (4)
Orbital portion: forceful closure of the eye - temporal branch of facial.
Palpebral portion: unconscious eye closure eg blink - zygomatic branch.
Examination: resist opening.
Describe levator palpebrae superioris. (3)
Elevates upper eyelid - occulomotor nerve.
Examination: check for ptosis.
Describe occipitofrontalis. (3)
Elevates eyebrows - temporal branch of facial.
Elevate eyebrows against resistance.
Describe the layers of the epicranial apineurosis. (5)
Skin Loose connective tissue Aponeurosis of occipitofrontalis. Dense connective tissue Pericranium. Spells SCALP.
List the 8 muscles of facial expression
Platysma Orbicularis oculi Levator palpebrae superioris Occipitofrontalis Epicranial aponeurosis Orbicularis oris Dilator muscles of the lips Buccinator
Describe orbicularis oris (2)
Closes mouth - buccal branch of facial.
Describe the dilator muscles of the lip. (3)
Separate the lips, buccal and mandibular branches.
Describe the buccinator. (3)
Flattens cheek to keep food from the space between check and gums - buccal branch of facial.
Blow out cheeks and resist ‘popping’.
List the 4 muscles of mastication.
Lateral pterygoid
Medial pterygoid
Masseter
Temporalis
Describe the lateral pterygoid. (3)
Protrudes mandible, opens jaw, moves jaw side to side. Mandibular.
Describe the medial pterygoid. (2)
Elevate jaw, side to side. Mandibular.
Describe the masseter. (3)
Elevates mandible. Mandibular branch. Palpate in clench just below zygomatic arch.
Describe temporalis. (3)
Elevates mandible. Mandibular branch. Palpate on clench in temple.
Describe the trapezius. (2)
Shrugs shoulders (test against resistance). Accessory nerve.
Describe the sternocleidomastoid. (2)
Laterally flexes the Head and rotates chin. Accessory nerve.
Describe suprahyoids. (3)
Hyoid bone to mandible, act to elevate hyoid or depress mandible. Eg digastric.
Describe infrahyoids (3)
Strap muscles that overly the thyroid and larynx. They depress the hyoid and stabilise. Eg omohyoid.
Describe the anterior triangle of the neck. (4)
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.
Describe the posterior triangle of the neck. (4)
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.
Describe the carotid triangle. (7)
Where the carotid sheath is accessible.
Boundaries are omohyoid, posterior digastric and SCM.
Contains the common carotid, the inferior jugular and the vagus nerve.
Describe the 4 fascial compartments (8)
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.
Describe deep neck spaces. (3)
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.
Describe the cervical plexus (8)
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.
