Cervical Vertebrae & Neck.pdf

1|ANALEC Merida, MVC 1PTA THE NECK REGION o spinous processes are short and bifid Region of the body between the lower margin of ▪ At the back mandible above and suprasternal notch and upper...

1|ANALEC Merida, MVC 1PTA THE NECK REGION o spinous processes are short and bifid Region of the body between the lower margin of ▪ At the back mandible above and suprasternal notch and upper ▪ Bifid: with notch border of clavicle below; manubrium and clavicle o superior facet is directed superioposteriorly and Contains: inferior facet are directed inferoanterior o Extensor muscles (posterior to the vertebrae) ▪ Articulating facet - because vertebra on top o Flexor muscles connects to the one below it o Parts of respiratory system (larynx, trachea) and ▪ The superior facet faces superior backwards; alimentary tract (pharynx and esophagus) pass ▪ The inferior facet faces inferior forward through this region o Endocrine organs like the thyroid gland Cervical Vertebrae o Bones of the neck (cervical v, hyoid, cartilages) seven cervical vertebrae Cervical part of the vertebral column is convex forward Supports the skull (main function) Attach to where the skull lies Houses the spinal nerves which exits the foramen Atypical cervical vertebrae o C1 (atlas) ▪ Ring-like, lacking a spinous process and body; with 2 lateral masses connected by anterior and posterior arches Where occipital condyle of the skull articulates ▪ Carries the skull on top of it ▪ Its body became the odontoid which became the body of the axis Typical cervical vertebrae (C3, C4, C5, C6) o small and transversely broad (oval) body ▪ Lumbar - biggest and kidney shaped o o vertebral foramen is triangular and large ▪ Where the spinal column is located ▪ Largest foramen together with lumbar region ▪ Where nerves which goes to the o C2 (axis) arms(cervical) and to the legs(lumbar) exit ▪ has peg-like structure - dens (odontoid o transverse processes contains transverse process) which projects superiorly from its foramen for passage of vertebral vein and artery body ▪ The only one with a transverse foramen, ▪ Its odontoid process is believed to be the since for the other vertebrae, they only body of C1 contain transverse processes ▪ Articulates with the ring of atlas ▪ Vertebral artery and vein enters here o o 2|ANALEC Merida, MVC 1PTA o C7 (vertebra prominence) o Ligaments: anterior and posterior atlanto- ▪ so named because of its long spinous process occipital membrane which is non bifid; o C1 to the occiput ▪ foramen transversarium does not contain o Action: flexion, extension and lateral flexion vertebral artery ▪ looks like this because it’s the vertebra before T1 o o Atlanto-axial joint o Between the odontoid and anterior arch of atlas o C1 to C2 o Between the lateral mases of the bones o Pivot joint o Ligaments: o Comparison of typical cervical vertebrae and C7 ▪ Apical – apex of odontoid to anterior margin of foramen magnum ▪ Alar – odontoid to medial of occipital condyle; look like flare/wing ▪ Cruciate – transverse (attaching odontoid to anterior arch of atlas) and vertical parts (body to anterior margin of magnum); cross o ▪ Membrane tectoria – continuation of posterior longitudinal ligament up to occipital bone in foramen magnum; on top of everything; protect structures and joints ▪ an absence of ligaments can cause instability or it could be dislodged ▪ spinal cord could be pinched if dislodged o Action: rotation o o - 8 – Intervertebral canal/foramen wherein it will fuse to the one below it; spinal nerve root enters here Joints Atlanto-occipital joint o Between the occipital condyles and facets on superior surfaces of lateral masses of atlas o Condyloid joint (biaxial; flex and extend head and can laterally bend the neck); YES Joint 3|ANALEC Merida, MVC 1PTA Joints of vertebral column below axis Cricoid cartilage o Between the articular processes of two adjacent o Made up of Hyaline cartilage vertebrae o Opposite C6 vertebra o Plane joint; action is gliding o Shaped like a signet ring with broad plate behind Joints between two vertebral body and shallow arch in front o Between the two adjacent bodies and disc o Articulates with the inferior cornu of thyroid (fibrocartilage) o Posteriorly it articulates with arytenoid cartilage o False joint; Cartilaginous joint o Junction of larynx and trachea o Junction of pharynx and esophagus o Level of middle cervical sympathetic ganglion Hyoid Bone o Where inferior thyroid artery enters thyroid gland Single, U shape mobile bone in midline of neck Floating in the neck Opposite C3 vertebra No articulation with other bones but is attached to the skull via stylohyoid ligament and to thyroid cartilage by thyrohyoid membrane Forms base of tongue o Arytenoid Cartilage Larynx o 2 arytenoid cartilages Organ that provides protective sphincter at the inlet of o Small and pyramid shape at back of larynx air passage o articulate with cricoid cartilage Responsible for voice production o At the back of cricoid (signet) Found below tongue and hyoid o Parts: apex, base, vocal process, muscular process Opens above into laryngeal part and below continues with trachea Formed by cartilages that are held by ligament Opposite C4-5 vertebrae Thyroid cartilage o Largest cartilage of larynx o Adam’s apple - Consists of two laminae that meet in midline (laryngeal prominence) o o Posterior: extends up into a superior cornu and down into inferior cornu 4|ANALEC Merida, MVC 1PTA o Fascia of the Neck Superficial Fascia o Thin layer of subcutaneous connective tissue that lies between the dermis of the skin and investing layer of deep cervical fascia o Contents: sensory/cutaneous nerves, blood and lymphatic vessels, superficial lymph nodes and o Investing (superficial) layer platysma muscle (in front) ▪ surrounds entire neck deep to the skin and superficial cervical fascia (anterior to posterior) ▪ Enclose the trapezius (at the back) and SCM (at the front) ▪ Encloses the submandibular gland, and o parotid gland o o Platysma ▪ wide thin subcutaneous sheet of striated muscle; embedded within superficial fascia ▪ action: tenses skin of the neck; draws corners of mouth inferiorly and assists in depressing mandible ▪ Pouting/sad face ▪ Facial nerve Deep Fascia Layer o Deep cervical fascia ▪ Divided into: Investing layer (light blue; in front and back), pretracheal layer (purple), prevertebral layer (red) o ▪ Supports the viscera, muscles, vessels and lymph nodes ▪ Fascial layers form natural cleavage planes through which tissues may be separated during surgery and limit spread of infections 5|ANALEC Merida, MVC 1PTA Muscle in the Investing Layer Sternocleidomastoid muscle o key landmark in the neck dividing neck into anterior and posterior triangles; left and right o Origin: Sternum and clavicle o Insertion: Mastoid o o Nerve: spinal accessory CN11 o action: unilateral ▪ Tilt head to its own side and rotates is so it is turned superiorly toward opposite side ▪ Tilt head on its right side and turn the chin toward the left o bilateral: flexes neck forward Deep Fascia of Neck o cranial nerve XI Pretracheal layer o attached above the thyroid and cricoid cartilage o Surrounding area of trachea o Also known as visceral layer o Extends into the thorax and blends with the fibrous pericardium o Blends with the carotid sheath and investing layer and surrounds the thyroid gland, gland to larynx, o parathyroid gland, esophagus and infrahyoid muscles o o Clinical notes ▪ Torticollis (wry neck) – lesion in the sternocleidomastoid muscle causing the head to turn to the side and face away from the affected side (turn right and chin points to the left) ▪ Affectation of muscle or nerve ▪ Not all stiff neck are torticollis ▪ Causes: congenital or acquired (pulled too hard during delivery) o o Trapezius o large flat triangular muscle o action: superior fibers elevate scapula, middle fibers retract it and inferior fibers depress it o Tension muscle o Spinal accessory nerve CN11 6|ANALEC Merida, MVC 1PTA Prevertebral layer o covers the longus capitis and longus cervicis o Passes around the neck to be attached to ligamentum nuchae o Surround muscles (longus cervicis, __ capitis) o Triangle forms a fascial floor and covers the sclenus anterior, medius and levator scapulae, splenius capitis and semispinalis capitis o o Enters thorax and blends with the anterior longitudinal ligament o Retrolaryngeal space – between pharynx and prevertebral fascia o o o Suprahyoid muscles Carotid sheath o Tubular, fascial investment that extends from Mylohyoid base of skull to root of neck o Origin: Body of mandible (mylohyoid line) o Blends with the investing, pretracheal and o Insertion: Body of hyoid prevertebral layer (contributes to carotid sheath) o Trigeminal nerve branch: Inferior alveolar nerve o Contains: o Elevates floor of mouth and hyoid bone; ▪ Common and internal carotid arteries depresses mandible External and interal ▪ Internal jugular vein ▪ Vagus nerve ▪ Deep cervical lymph nodes ▪ Carotid sinus nerve o ▪ Sympathetic nerve fibers