Majed Sharayha
Posts : 130
Reputation : 5
Join date : 2011-08-23
Age : 31
 |  Subject: Dr.Shreen, Sheet #2 - 722012 "Not Corrected yet"  Thu Feb 09, 2012 2:35 am | |
| Download Link ---------> Click here-------------------------------------------------------------- Anatomy Sheet #2
The Face:
Layers of the face:
Skin
Superficial fascia: This contains the cutaneous innervations and cutaneous blood vessels.
Deep fascia: There’s NO DEEP FACSIA in the face, because its presence will affect the pulling of the muscles to the facial skin resulting in weak facial expressions.
It is ONLY PRESENT over the parotid gland (parotid fascia) and over the Buccinator muscle and a part of the pharynx (Buccopharyngeal fascia)
Contents of the face:
Muscles
Blood vessels
Innervations
Muscles of the face:
There are around 28 muscles in the face but we will be only addressing the main ones in this lecture.
Orbicularis Oculi ( muscle surrounding the eye/orbit)
It’s divided into 3 parts:
Orbital Part: It makes a complete circle around the orbit.
Origin: Medial palpebral ligament (this ligament is situated in the medial angle of the eye and is holding the eye lid [anything related to the eye lid is called palpebral])
Insertion: Same as origin, since it makes a complete circle
Action: It closes the eyes tightly in case of fear, bright light hitting the eyes
Palpebral part of Orbicularis Oculi
Origin: Medial palpebral ligament
Insertion: Lateral palpebral ligament
Action: It closes the upper eye lid gently in case of blinking and sleeping.
Lacrimal part of Orbicularis Oculi
In order to understand this part, some info will be given on the lacrimal gland.
It’s situated on the lateral roof of the orbit.
It secretes tears. Tears will move through canaliculi and drain into a canal. This canal will connect the eye with the nose [that’s why when you cry, you will have a runny nose as well], this canal is called Nasolacrimal duct.
The nasolacrimal duct is situated in the nasolacrimal groove.
Origin: Margins of the nasolacrimal groove and the d fascia of the nasolacrimal duct.
Insertion: one part will be inserted on the upper eye
lid and the other will be inserted on the lower eye lid.
Action: pulls the fascia of the nasolacrimal duct creating negative pressure inside the duct, causing a flow of tears from duct to the nose.
Nerve supply: Facial Nerve (Cranial nerve # 7)
Buccinator (main bulk of the cheek)
Origin:
1) From above: Maxilla (opposite the last 3 molars)
2) From below: Mandible (opposite the last 3 molars)
3) In between: Pterygomandibular ligament
[Looks like a tilted U]
Insertion:
Upper fibres: upper lip
Lower fibres: lower lip
Middle fibres: Decussation (crossing) of the fibres,
In which the upper fibres will be inserted on the lower lip and the lower fibres will be inserted on the upper lip and the meeting point is called a modiolus (غمازات!!!)
Action: Compression between the cheeks and the teeth from the inside to prevent the accumulation of food inside the vestibule of the mouth.
In case of paralysis, a person cannot compress the cheeks and the food will keep on accumulating in the vestibule until the food starts to drip from the angles of the mouth.
Nerve supply: Facial nerve
Orbicularis Oris: (muscle surrounding the labial aperture)
It’s divided into two parts:
Superficial part ( Extrinsic fibres) :
Originated from outside the lips.
The buccinator muscle is considered a part of the extrinsic fibres.
Deep part ( Intrinsic fibres) :
Originated and inserted from inside the lips.
Action: closes the labial aperture [closes the lips]
Helps in whistling.
Nerve supply: Facial Nerve
Circum- Orbital Muscles: muscles controlling the orbital aperture [ opening and closing of the eye lids]
2 parts:
Sphincters (closing the eye lids)
Orbicularis Oris ( only 2 parts of it which
are the orbital part and the palpebral part)
Corrugator supercilii muscle
Origin: Medial end of the superciliary arch
Insertion: Skin of the middle of the eyebrows
Action: Drags the eyebrows inferomedially causing the longitudinal wrinkles on the forehead.
Dilators ( opening the eye lids)
Frontal belly of occipitofrontalis muscle: it pulls the eyebrow upwards causing the eyelids to open.
Levator palpebrae superioris muscle
NOTE:
Orbital part of Orbicularis Oculi [closes tightly] is the OPPONENT of the frontal belly of occipitofrontalis muscle.
Palpebral part of Orbicularis Oculi [closes gently] is the OPPONENT of the levator palpebrae superioris muscle
Innervations of the face:
Sensory innervations:
Parts in front of the auricle are innervated by trigeminal nerve (cranial nerve # 5)
Parts behind the auricle are innervated by cervical nerve
Lateral Part: from the ventral Rami
Back: from the posterior Rami
The trigeminal nerve has 3 branches:
Ophthalmic nerve: surrounds the eye/orbit
Maxillary nerve: lies on the maxilla and its surroundings
Mandibular nerve: lies on the mandible and its surroundings
Motor innervations:
Facial nerve:
It exits the skull through stylomastoid foramen.
Gives a branch that goes behind the ear called posterior auricular nerve that supplies occipital belly of the occipitofrontalis muscle.
It will deviate anteriorly in front of the ear and will enter the parotid gland. It’s the most superficial structure in the gland.
Inside the gland, the facial nerve will give 5 branches and these branches will exit the gland from the upper border and the anterior border of the parotid gland.
The 5 branches of the facial nerve:
Temporal branch: innervates the frontal belly of occipitofrontalis and UPPER half of orbicularis oculi
Zygomatic branch: innervates the LOWER half of orbicularis oculi
Buccal branch [on the buccinator muscle]: innervates the buccinator muscle
Marginal mandibular branch [on the lower margins of the mandible]: innervates the orbicularis oris
Cervical mandibular branch[on the neck]
Blood supply of the face:
The main arterial supply is the Facial artery
Facial Artery:
Origin: External Carotid Artery
Course:
It pierces the deep fascia of the neck
Enters the face through the anteroinferior angle of Masseter muscle
It will deviate towards the angle of the mouth.
It’s tortuous to prevent its rupture due to heavy movements of the face and skull.
It keeps on deviating towards the lateral angle of the mouth until it reaches medial angle of the eye.
Branches:
Lower labial: supplies lower lip
Upper labial: supplies upper lip
Lateral nasal: supplies the lateral side of the nose. This branch will reach the angle of the eye and it’s then called Angular artery.
The angular artery is the terminal arch of the facial artery. It’s united with an artery coming from the orbit called the dorsal nasal artery.
Venous drainage of the face:
2 veins surround Sternomastoid muscle, one is above it which is called external jugular vein and the other is below and it is called internal jugular vein.
Anteriorly: supratrochlear vein and supraorbital vein unite to give the Anterior facial vein
Superficial temporal vein unites with maxillary vein to give the retromandibular vein [behind the mandible]. The retromandibular vein is located inside the parotid gland and at the end of the gland it divides into two divisions: anterior and posterior divisions.
The anterior division unites with anterior facial to give the common facial vein and then drains into internal jugular vein [main venous drainage of the neck].
The posterior division unites with the posterior auricular vein to give a vein superficial to the Sternomastoid muscle which is the external jugular vein and then drains into subclavian vein.
Lymphatic drainage of the face:
Lymph nodes:
Submental lymph nodes: under the chin on the midline
Submandibular lymph nodes: under the mandible
Preauricular lymph nodes: in front of the ears
Occipital Lymph nodes: on the occipital bone
The scalp:
Anterior part drains into submandibular lymph nodes
Middle part drains into preauricular lymph nodes
Posterior part drains into occipital Lymph nodes
All the face drains into submandibular lymph nodes except:
Lateral part of the eye lids drains into preauricular lymph nodes
Central part of the lower lid drains into submental lymph nodes
Best wishes,
Done by: Al-Batoul Faisal A.
| |
|
