L5: Scalp Flashcards
What is the extent of the scalp?
In front: Supraorbital margin (Eyebrows).
Behind: Highest nuchal lines.
Laterally: Temporal line and superior temporal line.
❖ The area from the superior temporal lines downwards to the zygomatic arch is called the temple.
What are the layers of the scalp?
S: SKIN C: CT A: APONEUROSIS (EPICRANIAL) L: LOOSE AREOLAR TISSUE P: PERIOCRANIUM
The skin of the calp
It is rich in hair follicles and sebaceous glands.
CT of the scalp
It is rich in fat and fibrous septa that connect the skin to the underlying aponeurosis.
Numerous arteries and veins, that freely anastomose, are found in this layer and thus scalp wound leads to marked bleeding.
EPICRANIAL aponeurosis of the scalp
It is a fibrous band attached:
anteriorly (through the frontal bellies of the occipitofrontalis muscle) to the skin over the superciliary arches.
posteriorly (through the occipital bellies of the
occipitofrontalis muscle) to the highest nuchal lines and a part of the aponeurosis extends between the occipital bellies to be attached to the external occipital protuberance.
on each side, the aponeurosis is attached to the superior temporal line.
Loose areolar tissue of the scalp
It is the 4th layer.
It lies between the aponeurosis and the pericranium.
Allows the forward and backward movements of the first three layers of the scalp over the skull.
Contains emissary’s veins.
It extends anteriorly to the eyelid beneath orbicularis oculi.
Bleeding in it may appear in upper eyelids causing (black eye)
Periosteum of the scalp
It is adherent to the skull bones.
At the suture lines, it becomes continuous with the endosteum.
What is the muscle of the scalp?
Occipito-frontalis
What are the bellies of the occipital-frontalis?
Frontal and occipital
What is the origin of the frontal bellies?
the skin of the forehead and the eyebrows
What is the insertion of the frontal bellies of the occipital frontalis?
the epicranial aponeurosis.
What Is the nerve that suppliers the frontal bellies of the occipital-frontals?
The temporal branch of the facial nerve
What is the function of the frontal bellies?
transversely corrugates the skin of the forehead (expression of surprise).
What is the origin of the occipital bellies og the occipital-frontal is?
from the highest nuchal lines
What is the insertion of the occipital bellies of the occipital-frontalis?
the epicranial aponeurosis.
What is the nerve that supplies the occipital bellies of the occipital-frontalis?
the posterior auricular branch of the facial nerve.
What is the function of the occipital bellies of the occipital-frontalis?
draw the scalp backward
What is the arterial supply of the scalp?
The scalp is supplied by 5 arteries on each side:
2 in front of the auricle
2 behind it.
1 in the middle part of the scalp
What are the arteries in front of the scalp?
❖ Supratrochlear artery and Supraorbital artery:
They are branches of the ophthalmic artery which is a branch from the internal carotid artery.
They accompany the corresponding nerves.
What are the arteries in the middle of the scalp?
❖ Superficial temporal artery:
One of the two terminal branches of the external carotid artery inside the parotid gland at the level of the neck of the mandible.
It emerges from the upper border of the parotid gland to enter the scalp where it divides into terminal anterior and posterior branches.
It gives the transverse facial artery which emerges from the anterior border of the parotid to share in the arterial supply of the face.
What are the arteries in the posterior of the scalp?
Posterior auricular artery
-Arises from the posterior aspect of the external carotid artery
-passes backward along the upper border of the posterior belly of digastric
-supply the skin of the scalp behind the auricle.
Occipital artery
-Arises from the posterior aspect of the external carotid artery
-passes backward along the lower border of the posterior belly of the digastric.
-supplies the back of the scalp.
What are the veins of the scalp?
Superficial veins: -
1-Supraorbital vein & Supratrochlear vein:
Both unite to form the facial vein.
2- Superficial temporal vein:
Unites with the maxillary vein to form the retromandibular vein.
The anterior facial vein unites with the anterior division of the retromandibular vein to form the common facial vein.
3-Posterior auricular vein:
Unites with the posterior division of the retromandibular
vein to form the external jugular vein.
4-Occipital vein:
Drains into the suboccipital venous plexus.
Deep veins: emissary veins.
What is the lymph drainage of the scalp?
❖ The forehead and the anterior part of the face: drain into the submandibular lymph nodes.
❖ The lateral part of the scalp drains into the pre-auricular lymph nodes.
❖ The posterior part of the scalp drains into the mastoid (occipital) lymph nodes.
What is the cause of the gaping of scalp cut wounds?
The contraction tone of the frontal belly and the 2 occipital bellies of the occipital-frontalis
What is the cause of profuse hemorrhage in scalp cut wounds?
The extensive anastomosis between the arteries
can infection spread from scalp through the emissary veins to inside the cranial cavity?
Yes
How are scalp wounds sutured? And why?
Cut wounds of the scalp are sutured by thick silk thread due to the presence of the aponeurosis and the thickness of the scalp
What are the nerves that supply the scalp?
A) In front of the auricle: 4 sensory branches from the trigeminal nerve & 1 motor branch from the facial nerve
- supratrochlear
- supraorbital
- zygomaticotemporal
- auriculotemporal
- temporal
B) Behind the auricle: 4 sensory branches from the cervical nerves & 1 motor branch from the facial nerve
- great auricular
- lesser occipital
- great occipital
- third occipital
- posterior auricular
What is the origin of the supratrochlear nerve?
One of the two terminal branches of the frontal nerve which is a branch from the ophthalmic division of the trigeminal nerve
What is the course of the supratrochlear nerve?
Comes out of the orbit one finger breadth from the midline.
What is the supply of the supratrochlear nerve?
the medial 1/3 of the upper eyelid and the skin of the forehead above the root of the nose.
What is the origin of the supraorbital nerve?
The other terminal branch of the frontal nerve.
What is the course of the supraorbital nerve?
Comes out of the orbit through the supraorbital foramen two fingers breadth from the midline
What is the supply of the supraorbital nerve?
the middle 1/3 of the upper eyelid and the skin of the scalp as far back as the lambdoid suture.
What is the origin of the zygomaticotemporal nerve?
One of the two terminal branches of the zygomatic nerve which is a branch from the maxillary division of the trigeminal nerve.
What is the course of the zygomaticotemporal nerve?
Comes out of the orbit from the zygomaticotemporal foramen.
What is the supply of the zygomaticotemporal nerve?
the skin of the temporal region and a small area of the scalp above the temporal region.
What is the origin of the auriculotemporal nerve?
A branch from the posterior division of the mandibular branch of the trigeminal nerve.
What is the course of the auriculotemporal nerve?
Appears in the scalp just in front of the auricle.
What is the supply of the auriculotemporal nerve?
the skin of the scalp above the auricle & the upper 2/3 of the outer surface of the auricle and a part of the external auditory tube and ear drum.
What is the origin of the temporal nerve?
Facial nerve
What is the supply of the temporal nerve?
the frontal belly of the occipito frontalis.
What is the origin of the great auricular nerve?
Arises from the ventral rami of C2&3
What is the course of the great auricular nerve?
Appears at the middle of the posterior border of the sternomastoid then passes upwards and forwards superficial to the muscle. It divides into two branches that pass in front and behind the auricle
What is the supply of the great auricular nerve?
the skin over the angle of the mandible, a small area of the scalp behind the auricle, lower 1/3 of the outer and the lower 2/3 of the inner surfaces of the auricle as well as the capsule of the parotid gland
What is the origin of the lesser occipital nerve?
Arises from the ventral ramus of C2
What is the course of the lesser occipital nerve?
Appears at the middle of the posterior border of the sternomastoid then passes upwards and backwards.
What is the supply of the lesser occipital nerve?
the skin of the scalp behind the auricle and the upper 1/3 of the inner surface of the auricle.
What is the origin of the great occipital nerve?
Arises from the dorsal ramus of C2.
What is the course of the great occipital nerve?
Appears near the external occipital protuberance
What is the supply of the great occipital nerve?
a large area of the skin of the back of the scalp.
What is the origin of the third occipital nerve?
Arises from the dorsal ramus of C3.
What is the course of the third occipital nerve?
Appears in the back of the scalp below the greater occipital nerve.
What is the supply of the third occipital nerve?
an area of the skin of the back of the scalp as well as the back of the neck.
What is the origin of the Posterior auricular nerve?
Facial nerve
What is the supply of the posterior auricular nerve?
the occipital belly of the occipito frontalis.