BMS Anatomy Asynchronous Lecture 2 PDF

BMS Anatomy Asynchronous Lecture 2 Joints of the vertebral Column and Thoracic Cage Dr. Karyn Lumsden BSc, M.Ed., DC Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II PhD FAAA (Author), Anne M. R. Agur BSc (OT) MSc PhD FAAA (Author), 9th ed. Back Chapter Pages 97 – 104 Thorax Chapter Pag...

BMS Anatomy Asynchronous Lecture 2 Joints of the vertebral Column and Thoracic Cage Dr. Karyn Lumsden BSc, M.Ed., DC Moore's Clinically Oriented Anatomy, by Arthur F. Dalley II PhD FAAA (Author), Anne M. R. Agur BSc (OT) MSc PhD FAAA (Author), 9th ed. Back Chapter Pages 97 – 104 Thorax Chapter Pages 304 – 306 Head Chapter 936 – 939 Intervertebral Joints 🞜 Bodies of the vertebrae articulate with the body of the upper and lower vertebra via intervertebral disc. Articulations of vertebral bodies are functionally amphiarthrodial and structurally cartilaginous symphysis joints. The individual vertebrae move only slightly on each other. When, however, this slight degree of movement between the pairs of bones takes place in all the joints of the vertebral column, the total range of movement is very considerable. Intervertebral Joints Each vertebra articulates with the upper and lower vertebrae in two ways: JOINT 1 Ligaments: The Anterior Longitudinal Ligament (ALL) a broad and strong band of fibers, which extends along the anterior surfaces of the bodies of the vertebrae, from the occipital bone to the sacrum. The ALL limits backward bending, and supports the anterior convexity in the lumbosacral area. The Posterior Longitudinal Ligament (PLL) is within the vertebral canal, and extends along the posterior surfaces of the bodies of the vertebrae, from the body of the axis, to the sacrum. The PLL does not attach to the body but covers a plexus of arteries, veins, and lymphatics and the nutrient foramina through which these vessels pass to the cancellous bone of the body. The PLL has a relatively low tensile strength and does not significantly restrict forward bending. Intervertebral disc: A fibrocartilaginous structure that intervenes between the bodies of the adjacent vertebrae and binds them together. It accounts for 20-25% of the length (height) of the vertebral column. It is made of two parts: 1. The nucleus pulposus fills the central part of the disc and is gelatinous in nature which absorbs compression forces between the vertebrae. 2. The annulus fibrosus is made of collagen fibres which form the peripheral part of the disc. Degenerative changes in annulus fibrosus can lead to herniation of nucleus pulposus. Posterolateral herniation can impinge on the roots of a spinal nerve in the intervertebral foramen. 🞻Degenerative changes in annulus fibrosus can lead to herniation of nucleus pulposus. Posterolateral herniation can impinge on the roots of a spinal nerve in the intervertebral foramen. ❖ JOINT 2: The articular processes of each vertebrae articulate with the upper and lower vertebrae articular processes. (Synovial planar joints called zygapophysial (facet) joints). ❖ The zygapophysial (facet) joints belong to the diarthrodial (synovial) variety = Planar joints allowing slide and glide motion ❖ They are enveloped by capsules lined by synovial membranes. The articular capsules are more extended and looser in the cervical than in the thoracic and lumbar regions. ❖ JOINT 2: ❖ The laminae, spinous and transverse processes are connected by the following ligaments: 1. The Ligamenta Flava connect the laminae of adjacent vertebrae, from the axis to the first segment (vertebra) of the sacrum. Their marked elasticity serves to preserve the upright posture, and to assist the vertebral column in resuming it after flexion. 2. The Supraspinous Ligament: A strong fibrous cord, which connects together the apices of the spinous processes from the seventh cervical vertebra to the sacrum. It is continued upward to the external occipital protuberance as the ligamentum nuchae. Goes from sacrum to C7 3. The Interspinous Ligaments thin and membranous, connect adjoining spinous processes and extend from the root to the apex of each process. 4. The Intertransverse Ligaments are interposed between the transverse processes. The Ligamentum Nuchae is a fibrous membrane, which, in the neck, represents the supraspinous ligaments of the lower vertebrae. It extends from the external occipital protuberance to the spinous process of the seventh cervical vertebra. 🞜 CVII (the seventh cervical vertebra) has the most prominent spinous process (not bifurcated) in the vertebral column called vertebral prominent. Craniovertebral Joints There are two sets of craniovertebral joints, the atlanto-occipital and the atlanto-axial joints. Atlantoaxial Joints; There are three atlantoaxial joints, two lateral and one median atlantoaxial joints. The lateral atlantoaxial joints are synovial gliding joints made between the lateral masses of the atlas and the superior articular processes of the axis. • The medial atlantoaxial joint is a synovial pivot joint between the odontoid process of the axis and the ring formed by the anterior arch and the transverse ligament of the atlas. This joint allows the rotation of the atlas (and, with it, the skull) upon the axis. The axis of motion is vertical through the dens, and approximately 50% of rotation in the cervical spine occurs at the atlantoaxial joint. Craniovertebral Joints ❒ Atlantoaxial Joints; • Supportive elements: • Anterior Atlantoaxial Ligament (membrane): This ligament is a strong membrane, fixed, above, to the lower border of the anterior arch of the atlas; below, to the front of the body of the axis. • Posterior Atlantoaxial Ligament (membrane): This ligament is a broad, thin membrane attached, above, to the lower border of the posterior arch of the atlas; below, to the upper edges of the laminae of the axis. It supplies the place of the ligamentum flavum. The Transverse Ligament of the Atlas is a thick, strong band, that arches across the ring of the atlas, and retains the odontoid process in contact with the anterior arch. It is firmly attached on either side to a small tubercle on the medial surface of the lateral mass of the atlas. As it crosses the odontoid process, a small fasciculus is prolonged upward, and another downward, from the superficial or posterior fibers of the ligament. The superior band is attached to the basilar part of the occipital bone, the inferior band is fixed to the posterior surface of the body of the axis; hence, the whole ligament is named the cruciate ligament of the atlas. • Ligaments Connecting the Axis with the Occipital Bone: • Tectorial membrane is situated within the vertebral canal. It covers the odontoid process and its ligaments and appears to be a prolongation upward of the posterior longitudinal ligament of the vertebral column. • Ligaments Connecting the Axis with the Occipital Bone: The Alar ligaments arise one on either side of the upper part of the odontoid process and, passing obliquely and lateral upward. They are inserted into the medial sides of the condyles of the occipital bone. • In addition to the ligaments which unite the atlas and axis to the skull, the ligamentum nuchae must be regarded as one of the ligaments connecting the vertebral column with the cranium. Atlanto Occipital Joint Articulation of the atlas with the occipital bone consists of a pair of synovial condyloid (condylar) joints. The ligaments connecting the bones are: The articular capsules surround the condyles of the occipital bone and connect them with the superior articular surfaces of the lateral masses of the atlas. they are thin and loose. The Anterior Atlantooccipital Membrane passes between the anterior margin of the foramen magnum above, and the upper border of the anterior arch of the atlas below The Posterior Atlantooccipital Membrane is connected above, to the posterior margin of the foramen magnum; below, to the upper border of the posterior arch of the atlas. Movements.—The movements permitted in this joint are (a) flexion and extension, which give rise to the ordinary forward and backward nodding of the head, and (b) slight lateral flexion (bending) and rotation. ❖ Uncovertebral “ joints” or cleft (of Luschka's joints): synovial planar joints formed between uncinate processes of the cervical vertebrae. They are located in the cervical vertebrae between C3 and C7. Two lips project upward from the superior surface of the vertebral body below and one projects downward from the inferior surface of vertebral body above. They allow for flexion and extension and limit lateral flexion in the cervical spine. Costovertebral Joint Articulations of the head of the ribs constitute a series of synovial planar (gliding) joints (diarthrodial joints). They are formed by the articulation of the head of the typical ribs with the facets on the sides of the bodies of the thoracic vertebrae and with the intervertebral discs between them. The 1st , 10th, 11th, and 12th ribs each articulates with a single vertebra. The ligaments of these joints are: • Radiate ligament of head of rib connects the anterior part of the head of each rib with the side of the bodies of two vertebrae, and the intervertebral disc between them. • The Intra-articular ligament of head of rib: is situated in the joint’s interior. It attaches on one end to the crest separating the two articular facets on the head of the rib, and on the other end to the intervertebral disc. It divides the joint into two cavities. ❒ Costotransverse joints are formed between the tubercle of the rib with the articular surface on the adjacent transverse process (diarthrodial joint). • The superior costotransverse ligament is attached below to the upper border of the neck of the rib and to the transverse process immediately above. • The costotransverse ligament connects the rough surface on the back of the neck of the rib with the anterior surface of the adjacent transverse process. • The lateral costotransverse ligament passes obliquely from the tip of the transverse process to the rough non-articular tubercle of the rib. Joints of Thoracic Cage Posterior Joints: Summary of posterior joints: • Each rib touches 2 vertebral bodies and 1 transverse process • Example: 7th rib forms articulation with bodies of T7 and T6 and the TVP of T7 LATERAL view SUPERIOR view 19 ❒ Sternocostal & Costochondral joints The articulations of the cartilages of the true ribs with the sternum are synovial joints, except for the first rib, in which the cartilage is directly united with the sternum and which is, therefore, a synchondrosis articulation. The ligaments connecting them are: The anterior and posterior radiate sternocostal ligaments consist of broad and thin membranous bands that radiate from the front and back of the sternal ends of the cartilages of the true ribs to the anterior and posterior surfaces of the sternum. Movements.—Slight gliding movements are permitted in the sternocostal joints. Costochondral articulations.—The lateral end of each costal cartilage is received into a depression in the sternal end of the rib, and the two are held together by the periosteum. They are all synchondrosis types of the joint (structurally are synarthrosis). Joint movement: Sternocostal + Costotransverse and Costovertebral work together to move the ribs in a superior and lateral direction This is known as “bucket handle” motion Sternocostal alone also pulls the sternum in a superior direction This is known as “pump handle” motion