Bones of the neck
- 1. BONES OF THE NECK ANATOMY
- 3. BONES OF THE NECK CERVICAL SPINE ▸ The cervical spine is the most superior portion of the vertebral column, lying between the cranium and the thoracic vertebrae ▸ It consists of seven distinct vertebrae, two of which are given unique names: ▸ The first cervical vertebrae (C1) is known as the atlas ▸ The second cervical vertebrae (C2) is known as the axis
- 5. BONES OF THE NECK CERVICAL SPINE: CHARACTERISTIC FEATURES ▸ The cervical vertebrae have three main features which distinguish them from other vertebrae: ▸ Triangular vertebral foramen ▸ Bifid spinous process ▸ where the spinous process splits into two distally ▸ Transverse foramina ▸ holes in the transverse processes ▸ give passage to the vertebral artery, vein and sympathetic nerves
- 7. BONES OF THE NECK CERVICAL SPINE: ATLAS ▸ The atlas is the first cervical vertebra and articulates with the occiput of the head and the axis (C2) ▸ It differs from the other cervical vertebrae in that it has no vertebral body and no spinous process ▸ Instead, the atlas has lateral masses which are connected by an anterior and posterior arch ▸ Each lateral mass contains a superior articular facet (for articulation with occipital condyles), and an inferior articular facet (for articulation with C2) ▸ The anterior arch contains a facet for articulation with the dens of the axis ▸ This is secured by the transverse ligament of the atlas – which attaches to the lateral masses ▸ The posterior arch has a groove for the vertebral artery and C1 spinal nerve
- 8. BONES OF THE NECK CERVICAL SPINE: AXIS ▸ The axis (C2) is easily identifiable due to its dens (odontoid process) which extends superiorly from the anterior portion of the vertebra ▸ The dens articulates with the anterior arch of the atlas, in doing so creating the medial atlanto-axial joint ▸ This allows for rotation of the head independently of the torso ▸ The axis also contains superior articular facets, which articulate with the inferior articular facets of the atlas to form the two lateral atlanto-axial joints
- 10. BONES OF THE NECK CERVICAL SPINE: JOINTS ▸ The joints of the cervical spine can be divided into two groups ▸ those unique to the cervical spine ▸ those that are present throughout the vertebral column ▸ There are two joints unique to the cervical spine ▸ atlanto-axial (x3) ▸ atlanto-occipital (x2)
- 11. BONES OF THE NECK CERVICAL SPINE: JOINTS - UNIQUE TO THE CERVICAL SPINE ▸ The atlanto-axial joints are formed by the articulation between the atlas and the axis: ▸ Lateral atlanto-axial joints (x2) ▸ formed by the articulation between the inferior facets of the lateral masses of C1 and the superior facets of C2 ▸ are plane type synovial joints ▸ Medial atlanto-axial joint ▸ formed by the articulation of the dens of C2 with the articular facet of C1 ▸ a pivot type synovial joint
- 12. BONES OF THE NECK CERVICAL SPINE: JOINTS - UNIQUE TO THE CERVICAL SPINE ▸ The atlanto-occipital joints consist of an articulation between the spine and the cranium ▸ They occur between then superior facets of the lateral masses of the atlas and the occipital condyles at the base of the cranium ▸ These are condyloid type synovial joints, and permit flexion at the head i.e. nodding
- 13. BONES OF THE NECK CERVICAL SPINE: JOINTS - PRESENT THROUGHOUT THE VERTEBRAL COLUMN ▸ There are two different joints present throughout the vertebral column: ▸ Between vertebral bodies ▸ adjacent vertebral bodies are joined by intervertebral discs, made of fibrocartilage ▸ a type of cartilaginous joint, known as a symphysis ▸ Between vertebral arches ▸ formed by the articulation of superior and inferior articular processes from adjacent vertebrae ▸ a synovial type joint
- 14. BONES OF THE NECK CERVICAL SPINE: LIGAMENTS ▸ There are six major ligaments to consider in the cervical spine ▸ The majority of these ligaments are present throughout the entire vertebral column Present throughout Vertebral Column ▸ Anterior and posterior longitudinal ligaments – long ligaments that run the length of the vertebral column, covering the vertebral bodies and intervertebral discs ▸ Ligamentum flavum – connects the laminae of adjacent vertebrae ▸ Interspinous ligament – connects the spinous processes of adjacent vertebrae
- 15. BONES OF THE NECK CERVICAL SPINE: LIGAMENTS Unique to Cervical Spine ▸ Nuchal ligament ▸ a continuation of the supraspinous ligament ▸ attaches to the tips of the spinous processes from C1-C7 and provides the proximal attachment for the rhomboids and trapezius ▸ Transverse ligament of the atlas ▸ connects the lateral masses of the atlas, and in doing so anchors the dens in place ▸ (Note: Some texts consider the interspinous ligament to be part of the nuchal ligament)
- 17. BONES OF THE NECK CERVICAL SPINE: ANATOMICAL RELATIONSHIPS ▸ The cervical spine has a close relationship with several neurovascular structures in the neck ▸ The transverse foramina of the cervical vertebrae provide a passageway by which the vertebral artery, vein and sympathetic nerves can pass ▸ The only exception to this is C7 – where the vertebral artery passes around the vertebra, instead of through the transverse foramen ▸ The spinal nerves are intimately related to the cervical vertebrae ▸ They extend from above their respective vertebrae, through the intervertebral foramen created by the joints at the articular processes ▸ Again, C7 is an exception – it has a set of spinal nerves extending from above (C7) and below (C8) the vertebra ▸ Therefore, there are eight spinal nerves associated with seven cervical vertebrae
- 23. THE HYOID BONE
- 24. BONES OF THE NECK THE HYOID BONE ▸ The hyoid bone is a ‘U’ shaped structure located in the anterior neck ▸ It lies at the base of the mandible (approximately C3) ▸ It acts as a site of attachment for the anterior neck muscles https://teachmeanatomy.info/neck/bones/hyoid-bone/
- 25. BONES OF THE NECK THE HYOID BONE: STRUCTURE ▸ The hyoid is composed of a body, two greater horns and two lesser horns: ▸ Body ▸ the central part of the bone ▸ has an anterior convex surface and a concave posterior surface ▸ Greater horn ▸ projects from each end of the body in a posterior, superior and lateral direction ▸ acts as a site of attachment for numerous neck muscles ▸ Lesser horn ▸ arises from the superior aspect of the hyoid bone, near the origin of the greater horn ▸ projects superoposteriorly (toward the styloid process of the temporal bone) ▸ stylohyoid ligament attaches to the apex of the lesser horn
- 27. BONES OF THE NECK THE HYOID BONE: MUSCULAR ATTACHMENTS ▸ The hyoid bone is unique ▸ it does not articulate with any other bones ▸ is suspended in place by the muscles and ligaments that attach to it ▸ it acts as a site of attachment for many muscles in the neck
- 28. BONES OF THE NECK THE HYOID BONE: LIGAMENT ATTACHMENTS ▸ There are three main ligaments that attach to the hyoid bone ▸ stylohyoid, thyrohyoid and hyoepiglottic ▸ act to support the position of the hyoid in the neck ▸ Stylohyoid ligament ▸ extends from the styloid process of the temporal bone to the lesser horn of the hyoid bone ▸ Thyrohyoid membrane ▸ originates from the superior border of the thyroid cartilage and attaches to the posterior surface of the hyoid bone and the greater horns ▸ Hyoepiglottic ligament ▸ connects the hyoid bone to the anterior aspect of the epiglottis
- 30. References ▸ These slide reflect a summary of the contents of TeachMeAnatomy.info and are to be used for educational purposes only in compliance with the terms of use policy. Specific portions referenced in this summary are as follows: ▸ https://teachmeanatomy.info/neck/areas/ Additional sources are referenced on the slide containing that specific content.