Head Anatomy

• It's time to start something new and trust the magic of beginnings.
• The Faculty of Dentistry aspires to be a recognized educational institution regionally and internationally.
• This is achieved through advanced educational programs, innovative applied research, and sustainable development.
• The mission is to prepare knowledgeable and well-trained dentists committed to human values and professional ethics
• This is achieved by developing advanced educational programs that correspond to the actual needs of the dental workforce.

The Scalp

• Soft tissue overlying the skull vault

Extent of the Scalp

• Supraorbital margin (anterior)
• Superior temporal line (lateral)
• Highest nuchal line (posterior)

Layers of the Scalp

• There are five layers
• The first three layers are intimately bound together and move as a single unit.
  • S: Skin
  • C: Connective tissue
  • A: Aponeurosis
  • L: Loose areolar tissue
  • P: Pericranium

Skin

• The skin is thick and hairy.
• It also contains sebaceous glands.

Connective Tissue

• Strong fibrous septa divide the layer into partitions.
• Partitions contain lobules of fats, blood vessels, and nerves of the scalp.
• Infection tends to remain localized because it cannot spread outside the septa.
• A small wound causes profuse bleeding due to the adherence of the connective tissue septa to the artery walls, preventing contraction.

Aponeurosis

• Aponeurosis is from the occipitofrontalis muscle.
  • Frontal bellies(anterior)
  • Superior Temporal line(lateral)
  • Occipital bellies( posterior)

Loose Areolar Tissue

• Allows mobility of the first 3 layer on the underlying periosteum.
• Continuous anteriorly with the eyelids.
• Accumulation of blood or pus in this layer spreads below the aponeurosis anteriorly only.
• Occipital bellies of occipitofrontalis attach to the occipital bone
• Frontal bellies are not attached to bone; blood can reach the eyelids, resulting in "black eye".

Pericranium

• Loosely attached to the bones
• Firmly attached to the sutures
• Bleeding below this layer leads to blood collection (hematoma) taking the shape of the underlying skull bone.

Muscles of the Scalp

• Orbicularis oculi
• Zygomaticus
• Buccinator
• Orbicularis oris
• Platysma
• Epicranius frontalis
• Epicranius Occipitalis
• Temporalis
• Masseter
• Sternocleidomastoid
• Trapezius
• Splenius capitis

Occipitofrontalis Muscle

• Frontal Belly
  • Origin: from the anterior border of the epicranial aponeurosis
  • Insertion: into the skin of the forehead.
  • Nerve supply: temporal branch of the facial nerve
  • elevates eyebrows
• Occipital Belly
  • Origin: highest nuchal lines (1cm above superior nuchal line)
  • Insertion: the posterior border of the epicranial aponeurosis.
  • Nerve supply: auricular branch of the facial nerve
  • Action: tighten the aponeurosis

Arteries of the Scalp

• Rich supply of blood.
• The smallest cut bleeds profusely.
• 10 arteries (5 on each side) enter the scalp from its periphery to its center, forming an anastomosis.
• 5 arteries on each side (3 in front of the auricle and 2 behind it).

Supra-trochlear Artery (S.T)

• A branch from the ophthalmic artery
• Ophthalmic artery (branch from the internal carotid artery).
• It leaves the orbit medial to the supraorbital artery, supplying the forehead and scalp.

Supraorbital Artery (S.O)

• A branch from the ophthalmic artery.
• Leaves the orbit, and supplies forehead and scalp as far as the lambdoid suture.

Superficial Temporal Artery

• Arises within the parotid gland as one of two terminal branches of the external carotid artery.
• Ascends to the scalp in front of the auricle.
• Ends by dividing into frontal and parietal branches.

Posterior Auricular Artery

• It arises from the back of the external carotid artery.
• Supplies the scalp behind the auricle.

Occipital Artery

• Arises from the back of the external carotid artery.
• It supplies the back of the scalp.

Formative assessment questions!

• The innervation of the occipital part of the occipitofrontalis is the posterior auricular branch
• The insertion of the occipital part of the occipitofrontalis is the epicranial aponeurosis.