Anatomy II Head & Neck BY: DR.Yahya Alfarra CANADIAN BOARD IN DENTISTRY
Superficial Anatomy of the Neck The neck lies between • The lower margin of the mandible. • The suprasternal notch and upper border of the clavicle.
Fascia of the neck • Superfiscial fascia : A thin layer immediately beneath the skin and encloses: • The platysma muscle • Cutaneous nerves • Superficial veins : External Jugular Vien. • Superficial lympatics • Deep fascia : • Investing layer • Pretracheal layer • Prevertebral layer • Carotid sheath
Cutaneous Nerves of the Neck Anteriolateral region : • Lesser occipital nerve (C2) • Greater auricular nerve (C2, C3) • Transverse cutaneous nerve(C2, C3) • Supraclavicular nerves(C3, C4) (medial, intermediate, lateral).
Cutaneous Nerves of the Neck Ant. Lateral area: Posterior region: over the trapezius m. and the posterior scalp . • Greater occipital nerve (post ramus of C2) • Posterior rami of C3, C4 and C5.
Platysma • Origin: deep fascia that covers the upper parts of the pectoralis major and deltoid muscles • Insertion: lower margin of the mandible and the angle of the mouth • Innervation: cervical branch of the facial nerve (CN VII) • Action: depresses the mandible and the lower lip and the angle of the mouth.
Cutaneous Nerves of the Neck • Trigeminal N and it’s branches: • Ophthalmic N. • Maxillary N. • Mandibular N.
Superficial veins of the neck The external jugular vein • It begins by the union of of two veins: 1. Posterior auricular vein 2. A branch of the retromandibular (posterior facial) vein.
Anterior jugular vein • Starts below the chin by the union of small veins • Unite in the suprasternal notch forming the jugular arch
Triangles of the neck • Anterior triangle(by hyiod Bone divide into 4 triangles By 2 Ms ( Digastric Ms+omohyoid Ms) • Submental • Digastric • Carotid • Muscular • Posterior triangle • Occipital • Supraclavicular (Subclavian triangle)
Anterior triangle of the Neck • Boundaries: • Midline • Anterior border of SCM • Lower margin of the mandible subdivided into • 4 triangles by 2Ms • Digastric Ms. • Omohyoid Ms. • (topography)
Posterior triangle of the Neck • Posterior triangle • Occipital • Supraclavicular (Subclavian triangle) Borders: *SCM *Trapezius Ms *Middle third of clavicle
Nerves of post. triangle 1- spinal accessory N.?? 2- Cervical plexus 3- Brachial plexus
Sternoclidomastoid Muscle • Origin: - sternal head: manibrium sterni - clavicular head: medial upper third of clavicle • Insertion: The two heads unite and insert into the mastoid tip and superior nuchal line
Nerve supply: Spinal root of accessory nerve • Action: Extention of head & Flextion of neck Note: N. crossing SCM. ??
Omohyoid muscle • Inferior belly: originates from the upper margin of the scapula, passes deep to the SCM and ends in the intermediate tendon. • Intermediate tendon: held by the deep fascia of the clavicle and first rip. • Superior belly: inserts into the lower border of the hyoid bone body. • Nerve supply: Ansa cervicalis (C1, 2, 3) • Action: depresses the hyoid bone
Strap muscles(Infrahyoid muscles) 1-Thyrohyoid -- deepest 2-Sternothyroid _ deepest 3-Sternohyoid 4-Omohyoid • Together with the suprahyoid muscles stabilize the hyoid bone to provide movements of the tongue and the larynx during swallowing.