Human Anatomy: Neck PDF

PART I NECK OLSZTYN 2019 1 This guide of Head & Neck is created for the students to understand the basic fundamentals concerning the morphology of the bones, muscles, nerves & vessels of the head & neck. I would like to express great appreciation to my colleagues for their insight and dedication tow...

PART I NECK OLSZTYN 2019 1 This guide of Head & Neck is created for the students to understand the basic fundamentals concerning the morphology of the bones, muscles, nerves & vessels of the head & neck. I would like to express great appreciation to my colleagues for their insight and dedication towards the completion of this manual. I am indebt to the students, members of the Anatomical Research Group for their advice. Jerzy Gielecki M.D., Ph.D J. St. Gielecki & NECK 2 Lab. session 1 I. Regions of the neck II. Fascia of the neck 2.1. The superficial cervical fascia 2.2. The deep cervical fascia III. Muscles of the neck 3.1. The anterior group 3.2. The middle group 3.3. The posterior group IV. Fasciae and the tissue spaces of the neck 4.1. Anterior tissue space 4.2. Middle tissue space 43. Posterior tissue space V. The triangles of the neck 5.1. Anterior triangle of the neck 5.2. Posterior triangle of the neck 5.3. Fissures of the scalene muscles I. Regions of the neck J. St. Gielecki & NECK 3 1. Anterior cervical region or anterior cervical triangle (regio cervicalis anterior) Submandibular triangle (trigonum submandibulare) Carotid triangle (trigonum caroticum) Muscular triangle or omotracheal triangle (trigonum musculare) Submental triangle (trigonum submentale) 2. Trigonum submentale (regio sternocleidomastoidea) Lesser supraclavicular fossa (lateral cervical region) 3. Lateral cervical region; Posterior cervical triangle (regio cervicalis lateralis) Omoclavicular triangle (trigonum omoclaviculare) Greater supraclavicular fossa (fossa supraclavicularis maior) 4. Nuchal region or posterior cervical region (nucha) Fig. 1-1. Regions of the head & neck lateral view. J. St. Gielecki & NECK 4 II. Fascia of the neck The neck has two types of fascia: superficial and deep. These terms are used to distinguish the different types that can be incised and sutured. 1. The superficial cervical fascia The superficial cervical fascia (fascia colli superficialis) includes: Variable amounts of adipose tissue The platysma - voluntary muscle of facial expression. 2. The deep cervical fascia The deep cervical fascia (fascia colli profunda) gives off septa which can be subdivided into five parts: 1. The investing layer of deep cervical fascia. It splits to enclose: - sternocleidomastoid muscle - trapezius muscle - submandibular gland - parotid gland. 2. The pretracheal fascia forms a sheath around the thyroid gland. -It merges laterally with the investing layer of the deep cervical fascia and with the connective tissues comprising the carotid sheath. -Attachments of the pretracheal fascia are: - superiorly - body of the hyoid bone - laterally - omohyoid muscle - inferiorly - it extends into superior mediastinum of the thorax along the great vessels to merge with the fibrous pericardium. 3. The prevertebral fascia lies in front of 4 structures: 1. vertebral column 2. the prevertebral muscles 3. the cervical plexus 4. brachial plexuses. It extends from the base of the skull to the longitudinal ligament of the third vertebra. 4. The carotid sheath is a condensation of fascia of the neck. It encloses 1. The internal jugular vein laterally 2. The common and internal carotid artery medially 3. The vagus nerve posteriorly 5. Retropharyngeal Speace: Potential space that exists between the pretracheal fascia and the prevertebral fascia J. St. Gielecki & NECK 5 III. Muscles of the neck The sixteen muscles of the neck are divided into anterior, middle, and posterior group. 1. The Anterior Group The anterior group consists of two muscles: 1. Platysma muscle (musculus platysma) ORIGIN: origin:: inferior border of the mandible, fascia, and skin of the face INSERTION: insertion:: fascia and skin over the great pectoral and deltoid muscles FUNCTION: tenses the skin of the neck, assists during the depression of the mandible INNERVATION : nerve supplying:: CN VII 2. Sternocleiodomastoid muscle (musculus sternocleiodomastoideus) Fig. 1-3. ORIGIN: mastoid process of the temporal bone (lateral surface) and nuchal line of the occipital bone INSERTION: manubrium of the sternum (anterior surface) FUNCTION: acting alone (one side) it turns the face superiorly towards the opposite side; acting together, turns the face superiorly upwards, flexing the neck. INNERVATION: cervical plexus and cervical part of CN XI Fig. 1-6. Muscles of the neck J. St. Gielecki & NECK 6 1. The middle group The middle group consists of eight muscles subdivided into 2 groups: a. suprahyoid muscles (musculi suprahyoidei) contains four muscles: 1 Mylohyoid muscle (musculus mylohyoideus) ORIGIN: mylohyoid line on the internal aspect of the mandible INSERTION: the posterior fibres attach to the body of the hyoid bone, the anterior and middle fibres unite into a median fibrous raphe to form the muscular floor of the oral cavity FUNCTION: elevates the floor of the oral cavity, hyoid bone, and tongue INNERVATION: CN V3. 2 Stylohyoid muscle (musculus stylohyoideus) ORIGIN: styloid process of the temporal bone. It descends medially and parallel to the posterior belly of the digastric muscle and divides into two muscular slips in its lower portion. Both slips pass on both sides of the digastric tendon INSERTION: via two muscular slips into the body of the hyoid FUNCTION: with the posterior belly of the digastric muscle, draws the hyoid bone in a posterosuperior direction INNERVATION: CN VII 3 Digastric muscle (musculus digastricus) ORIGIN: anterior belly - digastric fossa of the mandible posterior belly - mastoid notch of the temporal bone INSERTION: both bellies via intermediate tendon into body of hyoid bone FUNCTION: both muscles elevate the hyoid bone; the anterior belly draws the hyoid forward, while the posterior belly draws it backward INNERAVATION: anterior belly - V3, posterior belly - CN VII 4 Geniohyoid muscle (musculus geniohyoideus) is located superior to the mylohyoid muscle ORIGIN: mental spine of the mandible INSERTION: body of the hyoid bone FUNCTION: draws the hyoid bone and the tongue anteriorly INNERVATION: cervical ansa b. infrahyoid muscles (musculi infrahyoidei) contains four muscles: 5 Omohyoid muscle (musculus omohyoideus) ORIGIN: inferior border of the hyoid bone - superior belly is united with the inferior belly by the intermediate tendon INSERTION: superior border of the scapula - inferior belly FUNCTION: depresses hyoid bone 6 Sternohyoid muscle (musculus sternohyoideus) ORIGIN: body of the hyoid bone INSERTION: manubrium of the sternum, medial end of the clavicle FUNCTION: depresses hyoid bone 7 Sternothyroid muscle (musculus sternothyroideus) ORIGIN: oblique line of the thyroid cartilage J. St. Gielecki & NECK 7 INSERTION: posterior surface of the manubrium of sternum FUNCTION: depresses hyoid bone and larynx 8 thyrohyoid muscle (musculus thyrohyoideus) ORIGIN: body and great horn of the hyoid bone INSERTION: oblique line of the thyroid cartilage FUNCTION: depresses hyoid bone and elevates larynx INNERVATION: branches of the cervicalis ansa supply all infrahyoid muscles 2. The Posterior group The posterior group is subdivided into two groups: a. medial or prevertebral group: 1. longus colli muscle (musculus longus colli) 2. longus capitis (musculus longus capitis) 3. rectus capitis anterior (musculus rectus capitis anterior) b. lateral group: 1. Scalenus anterior (musculus scalenus anterior) ORIGIN: transverse processes of the C3 and C6 vertebrae INSERTION: tubercle on the superior surface of the first rib FUNCTION: elevates the first rib, flexes the neck laterally, and plays a role in breathing. 2. Scalenus medius (musculus scalenus medius) ORIGIN: transverse processes of the C2 and C7 vertebrae INSERTION: superior surface of the first rib, posterior to the groove for the subclavian artery FUNCTION: elevates the first rib, flexes neck laterally 3. Scalenus posterior (musculus scalenus posterior) ORIGIN: transverse processes of the C2 and C7 vertebrae INSERTION: external surface of the second rib FUNCTION: elevates the second rib, flexes neck laterally INNERVATION: for both groups - ventral rami of the cervical nerves J. St. Gielecki & NECK 8 IV. Fasciae and the tissue spaces of the neck Fasciae and the tissue spaces of the neck (Fig. 1-4) are divided into three compartments: 1. Anterior tissue space Anterior tissue space (spatium colli anterius) of the neck lies between the investing layer of the deep cervical fascia and the pretracheal fascia. a. suprasternal space contains the anterior jugular vein and venous jugular arch b. supraclavicular spaces may contain lymphoid tissue as well as nodes. 2. Middle tissue space Middle tissue space (spatium colli medium) of the neck is a visceral compartment between the pretracheal and prevertebral fascia. It is subdivided into two compartments: previsceral space lies in front of the trachea and thyroid gland retrovisceral space is located behind the oesophagus. Middle tissue space contains: 1. thyroid gland 2. larynx 3. trachea 4. pharynx 5. oesophagus Fig. 1-7. Transverse cross-section of the neck. S.C.M. - sternocleidomastoid muscle, ICA internal carotid artery, IJV- internal jugular vein, CN X - vagal nerve. J. St. Gielecki & NECK 9 3. Posterior tissue space Posterior tissue space (spatium colli posterius) or prevertebral space lies between the anterior surface of the vertebral column and the prevertebral fascia. It contains: a. prevertebral muscles b. cervical and brachial plexus. J. St. Gielecki & NECK 10 The triangles of the neck The regions of the neck are subdivided into two main cervical triangles: 1. Anterior triangle of the neck Anterior triangle of the neck (trigonum colli anterius) consists of: left triangle (a+b+c on the Fig. 1-5) right triangle Fig. 1-8. Triangeles of the neck. mp - mastoid process, md - mandible, scm - sternoclediomastiod muscle, trm - trapizues muscle, acr - acromion, st - manubrium of the sternum, shm - sternohyoid muscle, 1- anterior belly of digastric muscle, 2- posterior belly of digastric muscle, 3- superior belly of omohyoid muscle, 4inferior belly of omohyoid muscle. a. Submandibular triangle (trigonum submandibulare) - Fig. 1-5-a. It is bounded by: 1. Laterally by the posterior belly of the digastric muscle 2. Medially by the anterior belly of the digastric 3. Inferiorly by the mandible The floor is formed by: mylohyoid muscle hyoglossus muscle. The submandibular triangle contains: 1. submandibular gland 2. lymph nodes 3. facial artery 4. submental artery 5. CN XII /the end/ 6. mylohyoid nerve /CN V3/ 7. glossopharyngeal nerve J. St. Gielecki & NECK 11 b. Carotid triangle (trigonum caroticum) - Fig. 1-5-b. It is bounded by: sternocleidomastoid muscle lateral border omohyoid muscle - superior belly - medial border digastric muscle - posterior belly superior border The carotid triangle contains: 1. common carotid artery and its bifurcation 2. internal jugular vein 3. vagal nerve 4. cervical ansa 5. superior laryngeal nerve c. Muscular or omotracheal triangle (trigonum musculare seu omotracheale) - Fig. 1-5-c. It is bounded by: sternocleidomastoid muscle omohyoid muscle / superior belly - lateral border sternohyoid muscle. The omotracheal triangle contains: thyroid gland 2. Posterior triangle of the neck Posterior triangle of the neck (triangles d + e) d. Occipital triangle (trigonum occipitale) - Fig. 1-5-d. It is bounded by: sternocleidomastoid muscle omohyoid muscle /inferior belly / trapezius muscle. The floor is formed by: scalene muscles splenius capitis muscle levator scapulae muscle. The occipital triangle contains : 1. CN XI /external branch/ 2. cutaneous branches from the cervical plexus i. the lesser occipital nerve 3. the great auricular nerve 4. the transverse cervical nerve 5. the supraclavicular nerve e. Supraclavicular or subclavian triangle (trigonum supraclaviculare) Fig. 1-5-e It is bounded by: sternocleidomastoid omohyoid /inferior belly/ clavicle. The floor is formed by: scalene muscles + anterior and posterior scalene fissure. J. St. Gielecki & NECK 12 The supraclavicular triangle contains: 1. subclavian vein 2. subclavian artery 3. brachial plexus Fissures of the scalene muscles There are two fissures (Fig. 1-6) that are confined by the scalene muscles: a. Anterior fissure of the scalene muscles It is bounded by: anteriorly - sternocleiodomastoid muscle posteriorly - anterior scalene muscle inferiorly - first rib. The anterior fissure of the scalene muscles contains: subclavian vein (on the first rib is located a groove for the subclavian vein, anterior to the scalene tubercle). Fig. 1-9. Localisation of the fissures of the scalene muscle b. Posterior fissure of the scalene muscles It is bounded by: anteriorly - anterior scalene muscle posteriorly - middle scalene muscle inferiorly - first rib The posterior fissure of the scalene muscles contains: J. St. Gielecki & NECK 13 below - subclavian artery (on the first rib is situated a groove for the subclavian artery posterior to the scalene tubercle - see Bones Joints and Ligaments page. 59 or www.anatomy3a.com) above - brachial plexus The subclavian artery and the brachial plexus are sometimes separate by the minor scalene muscle, which is not always present. J. St. Gielecki & NECK 14 Fig. 1-10. Cranial Nerves (CN) & their fibres 1. Oh Once One Tries Taking Anatomy Finding Very Good Vacations Appear History 2. Some Say Marry Money But My Brother Says Big Brains Matters More J. St. Gielecki & NECK