Anatomy of the Scalp PDF

Anatomy of the Scalp By Dr. Rania Elsyade Assistant professor of anatomy and embryology  Objectives By the end of this lecture, students will be able to: - Describe the anatomy of the scalp (Definition, Extent, and Layers)....

Anatomy of the Scalp By Dr. Rania Elsyade Assistant professor of anatomy and embryology  Objectives By the end of this lecture, students will be able to: - Describe the anatomy of the scalp (Definition, Extent, and Layers). - Describe the anatomy of the occipitofrontalis muscle. - Identify the arterial supply, venous drainage, nerve supply, and lymphatic drainage of the scalp.  Describe the anatomy of the scalp Definition: It is the soft tissue covering the vault of the skull. Extent: Anteriorly: the eyebrows. Posteriorly: the superior nuchal line and the external occipital protuberance. Laterally: the superior temporal lines.  Describe the anatomy of the scalp Layers: 1- Skin: Has hairs and numerous sebaceous glands. 2- Superficial fascia (dense connective tissue): It binds the skin tightly to the aponeurosis. It contains the blood vessels and the nerves of the scalp. The scalp is richly supplied with blood vessels and nerves. 3- Epicranial aponeurosis 4- Subaponeurotic space (loose areolar tissue). 5- The pericranium (Periosteum).  Describe the anatomy of the scalp 4- Subaponeurotic space It contains loose areolar tissue. It loosely connects the epicranial aponeurosis with the pericranium. It allows the movement of the first 3 layers of the scalp over the skull. It contains a few small arteries and emissary veins. Extent ✓ Anteriorly → extends beneath the orbicularis oculi into the eyelids. ✓ Posteriorly → superior nuchal line. ✓ Laterally → temporal fascia. Clinical importance: Bleeding anywhere beneath the aponeurosis (sub aponeurotic space) may appear in the upper eyelids causing a black eye. Describe the anatomy of the occipitofrontalis muscle It is the only muscle of the scalp. It consists of 2 frontal bellies in front and 2 occipital bellies behind. The frontal bellies are connected at the median plane. The occipital bellies are widely separated from each other by a gap of epicranial aponeurosis. Origin: Frontal bellies → the skin of the forehead and the eyebrows. Occipital bellies → each belly arises from the lateral 2/3 of the highest nuchal line. Describe the anatomy of the occipitofrontal muscle. Insertion: The frontal and occipital bellies are inserted to the epicranial aponeurosis. The Epicranial aponeurosis It lies over the top of the skull. Attachment Anteriorly → splits to enclose the frontal bellies. Posteriorly → passes between the two occipital bellies to the external occipital protuberance and the superior nuchal line Laterally → Attached to the superior temporal line. Describe the anatomy of the occipitofrontal muscle. Nerve supply: the facial nerve. Frontal bellies by the temporal branch. Occipital bellies by the posterior auricular branch. Action: Both frontal and occipital bellies move the scalp forward and backward. ✓ Frontal bellies draw the scalp forwards. ✓ Occipital bellies draw the scalp backward. Frontal bellies elevate the eyebrows as in surprise and are responsible for transverse wrinkles of the forehead. Identify the arterial supply of the scalp In front of the auricle: 1- Supratrochlear artery. 2- Supraorbital artery. ✓ They arise from the ophthalmic artery (a branch of the internal carotid). ✓ They supply the anterior part of the scalp.  Identify the arterial supply of the scalp In front of the auricle: 3- Superficial temporal artery It is one of the 2 terminal branches of the external carotid artery. It leaves the upper border of the gland, and then crosses the zygomatic arch in front of the auricle to enter the temporal fossa. It ends by dividing into anterior and posterior terminal branches, 2 inches above the zygomatic arch. They supply the side of the scalp  Identify the arterial supply of the scalp Behind the auricle: 1- Posterior auricular artery. It arises from the external carotid artery. It supplies the scalp just behind the ear. 2- Occipital artery. It arises from the external carotid artery. Is supplies the back of the scalp.  Arterial supply of the scalp In front of the Behind the auricle: auricle: 1- Supratrochlear. Superficial Posterior auricular and temporal Occipital 2- Supraorbital. from external from the external carotid from the ophthalmic carotid artery.  Identify the venous drainage of the scalp A) Superficial veins 1- Supraorbital vein and Supratrochlear veins: They unite together at the medial angle of the orbit to form the facial vein. 3- Superficial temporal vein: It unites with the maxillary vein to form the retromandibular vein. 4-Posterior auricular vein: It units with the posterior division of the retromandibular vein to form the external jugular vein. 5- Occipital vein: It drains into the suboccipital venous plexus which drains into the vertebral vein. The occipital vein may drain directly into the internal jugular vein. B) Deep veins (emissary veins) They present in the sub aponeurotic space. They communicate the superficial veins of the scalp with the dural venous sinuses.  Venous drainage of the scalp Superficial veins Deep veins 1- 4-Posterior Supratrochlear. auricular vein 5- Occipital Superficial temporal -3 vein: 2- Supraorbital. unites with the maxillary It units with the vein to form the posterior drains into the form the facial vein. suboccipital retromandibular vein. division of the retromandibula venous plexus r vein to form drain directly the external into the jugular vein internal jugular vein.  Identify the nerve supply of the scalp Sensory nerve supply A) In front of the auricle: 1- Supratrochlear and supraorbital nerves: They are branches from the ophthalmic division of the trigeminal nerve. 3- Zygomaticotemporal nerve: It is a branch from the maxillary division of the trigeminal nerve. 4- Auriculotemporal nerve: It is a branch from the mandibular division of the trigeminal nerve.  Identify the nerve supply of the scalp Sensory nerve supply A) Behind of the auricle: They are branches from the cervical plexus. 1- Great auricular nerve (c2, 3) 2- Lesser occipital nerve (c2) 3- Great occipital nerve (c2) 4- Third occipital nerve (c3)  Sensory nerve supply of the scalp In front of the auricle: Behind the auricle: Branches of the trigeminal branches from the cervical plexus 3- Zygomaticotemporal 1- Great auricular nerve (c2, 3) 1- Supratrochlear. tfrom he maxillary division 2- Lesser occipital nerve (c2) 2- Supraorbital. -4Auriculotemporal nerve 3- Great occipital nerve (c2) from the ophthalmic division from the mandibular division 4- Third occipital nerve (c3).  Identify the nerve supply of the scalp Motor nerve supply From branches of the facial nerve A) In front of the auricle: The temporal branch of the facial nerve supplies the frontal belly of the occipitofrontalis. B) Behind the auricle: The posterior auricular branch of the facial nerve supplies the occipital belly of the occipitorontalis.  Identify the Lymphatic drainage of the scalp A) In front of the auricle: The anterior part (forehead) and lateral part of the scalp drain into superficial parotid (preauricular) lymph nodes. B) Behind the auricle: The posterior part of the scalp drains into mastoid and occipital lymph nodes. Test yourself Identify the following????????????