1.1 Organisation Flashcards
(23 cards)
What is the cranium split into?
Neurocranium
Viscerocranium
How are the muscles of the face and scalp divided?
Muscles of facial expression
- dilators or sphincters
- cranial nerve VII / facial nerve
Muscles of mastication
- open/close the jaw
- act on the temporomandibular joint
- cranial nerve V / trigeminal nerve
Facial (cranial nerve VII) branches
Temporal Zygomatic Buccal Marginal Mandibular Cervical
To Zanzibar By Motor Car
Trigeminal (cranial nerve V)
Va - opthalmic division –> sensory
Vb - maxillary division –> sensory
Vc - mandibular division –> motor and sensory
Platysma
- Very thin muscle
- Superficial - in subcutaneous layer
- Facial (cranial VII nerve) - cervical branch
- Depresses angles of mouth and tenses neck
Sternocleidomastoid
- 2 heads - superior clavicle and sternum
- Obliquely up the neck
- Spinal accessory nerve
- Rotates neck contralaterally
Anterior triangle of neck
- Superior border - inferior border of mandible
- Lateral border - anterior edge of sternocleidomastoid
Medial border - midline of neck
Contains:
- IJV
- suprahyoid muscles
- hyoid bone
- carotid triangle
Posterior triangle of neck
- Anterior border - posterior edge of SCM
Posterior border - anterior margin of trapezius - Inferior border - Clavicle
- Floor - scalene muscles
Contains:
- subclavian artery and vein
- brachial plexus trunks
- omohyoid muscle
- EJV
Carotid triangle
- Medial border - omohyoid
- Lateral border - anterior edge of SCM
- Superior border - posterior edge of digastric
Important in surgery - easy access to carotid artery.
Suprahyoid muscles
- Above hyoid bone
- Attach to base of jaw OR base of skull
- Elevate the hyoid bone
- Depress the mandible
Infrahyoid muscles
- ‘Strap muscles’
- Overlie the larynx and thyroid gland
- Depress and stabilise hyoid bone
Importance of neck compartments
- Ease movement between structures e.g. when swallowing
- Can restrict but also allow spread of infection
Compartments / layers of the neck
- Superficial fascia
- Investing layer
- Pre-tracheal layer
- Pre-vertebral layer
- Buccopharyngeal layer (posterior aspect of oesophagus)
Retropharyngeal space
- Between buccopharyngeal and pre-vertebral layer
- Posterior to pharynx and oesophagus
- Communicates with mediastinum inferiorly
- Infection can spread to there to cause mediastinitus
Pterygoid muscles
- Deep to mandible
- Both protrude the jaw
- Trigeminal (cranial V nerve) - Vc mandibular division
Lateral Pterygoid - depresses mandible
Medial pterygoid - elevation of mandible
Occipitofrontalis
- Elevates eyebrows
- Located in the temples/forehead
- Facial (cranial VII nerve) - temporal branch
Orbicularis oris
- Purses lips
- Located around the mouth
- Facial (cranial VII nerve) - buccal branch
Orbicularis oculi
- Closes eyes /blink
- Located around eyes
- Facial (cranial VII nerve) - temporal branch
Buccinator
- Compresses cheeks against teeth when chewing
- Located across cheek to angle of mouth
- Facial (cranial VII nerve) - zygomatic branch
Zygomaticus
- Draws angle of mouth laterally/superiorly (smile)
- Facial (cranial VII nerve) - zygomatic branch
- Major and minor muscle
Risorius
- Pulls corner of mouth laterally (smile)
- Facial (cranial VII nerve) - zygomatic branch
Masseter
- Main elevator of mandible - closes jaw
- Palpable when contracted
- Trigeminal (cranial V nerve) - Vc mandibular division
- Upper jaw/below ear
Temporalis
- Elevates mandible (closes jaw)
- Posterior fibres retract jaw
- Trigeminal (cranial V nerve)
