Joints and Ligaments of the Back

00:01 Now we're going to take a look at the joints and ligaments of the back that allow the back to move in so many different combinations of movements.

00:11 We'll start with a lateral view here of an intervertebral disc connecting the adjacent vertebral bodies.

00:20 This is a special type of joint called a symphysis.

00:23 And it's not the highly movable joint that you expect in what we call synovial joint, such as the elbow or the knees.

00:32 But it also provides a lot of support and a lot of shock absorption.

00:40 If we look more posterior in the vertebral arch, we see the inferior articular facet of one vertebra interacting with the superior articular facet of the vertebra below.

00:52 And together these facets form the facet joint or is like apophyseal joints. And these are synovial joints.

01:04 Synovial joints are joints that have a capsule and a cavity filled with joint fluid.

01:12 We call that the synovial cavity in the synovial fluid.

01:16 And these synovial joints are the ones that have a greater degree of movement.

01:22 So here we see these joints together in action.

01:26 We have flexion, which is really bending forward and extension just really bending backward.

01:32 And we have lateral flexion in either direction.

01:35 And they're fairly limited in their movement.

01:39 That's because we have the spinal cord.

01:41 We don't want to bend too far in any one direction, because then we cause damage to the spinal cord or its nerves.

01:49 So that brings us to ligaments to help provide structure and strength and stability.

01:55 So if we look at the base of the skull, going all the way down to the anterior surface of the sacrum inferiorly.

02:04 All of the anterior surface of the vertebral bodies and the intervertebral discs are covered by the anterior longitudinal ligament.

02:14 So it's a very descriptive term tells us where it is in which direction it's running.

02:19 Similarly, there's a structure up in the top of the cervical vertebra called the tectorial membrane.

02:27 And all along the posterior surfaces of the intervertebral discs and bodies run the posterior longitudinal ligament.

02:35 Really just the equivalent of the anterior longitudinal ligament on the other side of the vertebral bodies.

02:42 If we zoom in from a posterior point of view, and we look at adjacent laminae, which again, are the structures that connect the spinous process to the rest of vertebral arches.

02:54 We have these ligaments called ligamentum flavum.

02:57 It's a funny name and it's actually shown here in yellow because flavum means yellow, and it gets this yellowish appearance because of the presence of elastin fibers.

03:07 We swim around to a lateral view.

03:10 We see adjacent spinous processes connected by interspinous ligaments.

03:17 And if we look very, very posterior to the posterior most tips of the spinous processes, we see a ligament running along those tips called the supraspinous ligament.

03:30 As we move superiorly towards the cervical region, we see the spinous processes of the lower cervical vertebra here, going all the way up to the base of the skull.

03:42 And there's this free edge of ligament forming something about triangular shape.

03:46 And we call this the ligament of nuchae a referring to neck and as you might guess as you follow it down it becomes continuous with the supraspinous ligament.