Danger triangle of the face
Encyclopedia
The dangerous triangle of the face or maxillofacial death pyramid (MDP) consists of the area from the corners of the mouth
to the bridge of the nose
, including the nose and maxilla
. Due to the special nature of the blood
supply to the human
nose
and surrounding area, it is possible (although very rare) for retrograde infection
s from the nasal area to spread to the brain
.
This is possible because of venous communication (via the ophthalmic veins) between the facial vein and the cavernous sinus
. The cavernous sinus lies within the cranial cavity
, between layers of the meninges
and is a major conduit of venous drainage from the brain.
It is a common misconception that the vein
s of the head do not contain one-way valves like other veins of the circulatory system. In fact, it is not the absence of venous valves but the existence of communications between the facial vein and cavernous sinus and the direction of blood flow that is important in the spread of infection from the face. Most, but not all, people have valves in the veins of the face.
An example of disease that may be caused by this process is meningitis
, an inflammation of the meninges, the coverings of the brain. Such bacterial infections can be caused by pus entering the brain's blood supply if pimples in the danger triangle are picked.
gets inflamed it will constrict the structures that are going through it or surround it. Inside cavernous sinus we can find constriction of the following nerves: CN3Oculomotor nerve
, CN4 Trochlear nerve
, CN6Abducens nerve, CN5trigeminal nerve
, specifically V1Ophthalmic nerve
and V2maxillary nerve branches. Failure of each of the nerves listed above will manifest in loss of function of the specific muscle, gland or a parasympathetic innervations (from CN3). In addition following structures will be compressed: Optic Chiasm
(resulting in vision problems), Pituitary gland
.
Failure of the CN3 Oculomotor nerve
will result in loss of function of the following muscles: Medial Rectus (look medially, towards nose), Superior Rectus (look up when eye is looking laterally, outside), Inferior Rectus (look down when eye is looking laterally, outside), Inferior Rectus. As well as muscles that are responsible for raising an eyelid: Levator palpebrae superioris muscle
(voluntary muscles, keeps eye open for short period of time) and Superior tarsal muscle
(Muller’s muscle).(involuntary under sympathetic innervation, is the one to keep eye open for a long time). (The first muscle(LPS) raises an eyelid but it does not have much stamina, quickly becoming tired and in absence of sympathetic innervation to Superior tarsal muscle
(Muller’s muscle), the eyelid is slowly drooping down. Eye is half closed and the patient need to stimulate Levator palpebrae superioris again to open eyelid). The Superior tarsal (Muller’s) muscle is the one that keeps the eye open throughout the day.
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....
to the bridge of the nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
, including the nose and maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
. Due to the special nature of the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
supply to the human
Human
Humans are the only living species in the Homo genus...
nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
and surrounding area, it is possible (although very rare) for retrograde infection
Retrograde infection
Retrograde is defined as "In reverse action", therefore a retrograde infection is an infection that enters or spreads through the body through a means that is usually considered backwards. An example is spreading into the salivary glands through the saliva ducts....
s from the nasal area to spread to the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
.
This is possible because of venous communication (via the ophthalmic veins) between the facial vein and the cavernous sinus
Cavernous sinus
The cavernous sinus , within the human head, is a large collection of thin-walled veins creating a cavity bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica.-Contents:...
. The cavernous sinus lies within the cranial cavity
Cranial cavity
The cranial cavity, or intracranial space, is the space formed inside the skull. The brain occupies the cranial cavity, which is lined by the meninges and which contains cerebrospinal fluid to cushion blows....
, between layers of the meninges
Meninges
The meninges is the system of membranes which envelopes the central nervous system. The meninges consist of three layers: the dura mater, the arachnoid mater, and the pia mater. The primary function of the meninges and of the cerebrospinal fluid is to protect the central nervous system.-Dura...
and is a major conduit of venous drainage from the brain.
It is a common misconception that the vein
Vein
In the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...
s of the head do not contain one-way valves like other veins of the circulatory system. In fact, it is not the absence of venous valves but the existence of communications between the facial vein and cavernous sinus and the direction of blood flow that is important in the spread of infection from the face. Most, but not all, people have valves in the veins of the face.
An example of disease that may be caused by this process is meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...
, an inflammation of the meninges, the coverings of the brain. Such bacterial infections can be caused by pus entering the brain's blood supply if pimples in the danger triangle are picked.
Inflammation of cavernous sinus
Furthermore if the cavernous sinusCavernous sinus
The cavernous sinus , within the human head, is a large collection of thin-walled veins creating a cavity bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica.-Contents:...
gets inflamed it will constrict the structures that are going through it or surround it. Inside cavernous sinus we can find constriction of the following nerves: CN3Oculomotor nerve
Oculomotor nerve
The oculomotor nerve is the 3rd of 12 paired cranial nerves. It enters the orbit via the superior orbital fissure and controls most of the eye's movements, including constriction of the pupil and maintaining an open eyelid by innervating the Levator palpebrae superiors muscle. The optic nerve is...
, CN4 Trochlear nerve
Trochlear nerve
The trochlear nerve is a motor nerve that innervates a single muscle: the superior oblique muscle of the eye....
, CN6Abducens nerve, CN5trigeminal nerve
Trigeminal nerve
The trigeminal nerve contains both sensory and motor fibres. It is responsible for sensation in the face and certain motor functions such as biting, chewing, and swallowing. Sensory information from the face and body is processed by parallel pathways in the central nervous system...
, specifically V1Ophthalmic nerve
Ophthalmic nerve
The ophthalmic nerve is one of the three branches of the trigeminal nerve, the fifth cranial nerve. The ophthalmic nerve carries only sensory fibers.-Branches:*Nasociliary nerve**sensory root of ciliary ganglion**posterior ethmoidal nerve...
and V2maxillary nerve branches. Failure of each of the nerves listed above will manifest in loss of function of the specific muscle, gland or a parasympathetic innervations (from CN3). In addition following structures will be compressed: Optic Chiasm
Optic chiasm
The optic chiasm or optic chiasma is the part of the brain where the optic nerves partially cross...
(resulting in vision problems), Pituitary gland
Pituitary gland
In vertebrate anatomy the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 g , in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity covered by a dural fold...
.
Failure of the CN3 Oculomotor nerve
Oculomotor nerve
The oculomotor nerve is the 3rd of 12 paired cranial nerves. It enters the orbit via the superior orbital fissure and controls most of the eye's movements, including constriction of the pupil and maintaining an open eyelid by innervating the Levator palpebrae superiors muscle. The optic nerve is...
will result in loss of function of the following muscles: Medial Rectus (look medially, towards nose), Superior Rectus (look up when eye is looking laterally, outside), Inferior Rectus (look down when eye is looking laterally, outside), Inferior Rectus. As well as muscles that are responsible for raising an eyelid: Levator palpebrae superioris muscle
Levator palpebrae superioris muscle
The levator palpebrae superioris is the muscle in the orbit that elevates the superior eyelid.-Structure:...
(voluntary muscles, keeps eye open for short period of time) and Superior tarsal muscle
Superior tarsal muscle
The superior tarsal muscle is a smooth muscle adjoining the levator palpebrae superioris muscle that helps to raise the upper eyelid.-Structure:...
(Muller’s muscle).(involuntary under sympathetic innervation, is the one to keep eye open for a long time). (The first muscle(LPS) raises an eyelid but it does not have much stamina, quickly becoming tired and in absence of sympathetic innervation to Superior tarsal muscle
Superior tarsal muscle
The superior tarsal muscle is a smooth muscle adjoining the levator palpebrae superioris muscle that helps to raise the upper eyelid.-Structure:...
(Muller’s muscle), the eyelid is slowly drooping down. Eye is half closed and the patient need to stimulate Levator palpebrae superioris again to open eyelid). The Superior tarsal (Muller’s) muscle is the one that keeps the eye open throughout the day.