Joints: Structural and Functional Classification (Nursing)

00:01 In this lecture we will be discussing the joints of the body.

00:06 So what is a joint? A joint can be a point of contact between either two or more bones, cartilage and bone, or in the case of the mouth, the teeth and the bones underneath.

00:19 We classify joints in two different ways.

00:22 Structurally, we asked, does the joint have a cavity associated with it? And also what type of connective tissue is involved in the joint? We can also classify joints by their function or their degree of movement.

00:39 The first structural classification of joints it's going to be the fibrous joints.

00:43 This type of joint does not have a cavity.

00:47 In this joint, the articulating bones are held together by a dense fibrous connective tissue.

00:55 This joint permits very little if any movement at all.

01:01 Examples of fibrous joints can be found in the skull.

01:05 We have the sutures, which are going to connect the different bones of the skull.

01:11 We also have syndesmosis.

01:13 This is the joint between the tooth and the underlying bone.

01:20 A third type of fibrous joint is going to be the joint between two bones that are next to each other, such as the ulna and radius of the arm or the tibia and fibula of the leg.

01:34 A second structural classification of joints are cartilaginous joints.

01:39 Like fibrous joints, cartilaginous joints also lack a cavity.

01:44 The articulating bones are held together with a cartilage connective tissue.

01:50 And also like fibrous joints, these permit very little if any movement at all.

01:57 There are two main types of cartilaginous joints in the body.

02:01 We have synchondroses, which are like what you find in the ribs, as well as symphysis, which are found in areas of the body, such as the pubic symphysis of the pelvic bone.

02:15 The third structural classification of joints is the synovial joint.

02:20 The synovial joint does have a cavity and we refer to this cavity as the synovial cavity.

02:28 Unlike the other two structural classifications of joints, this joint does permit a large range of different movements.

02:36 In the synovial joint, the two articulating bones are covered with articular cartilage at the end of their epiphysis.

02:45 They are also held together by ligaments, which are a type of connective tissue.

02:52 Inside of the cavity, we also have a gelatinous fluid known as synovial fluid.

03:01 The synovial joint also contains a blood supply as well as a nerve supply.

03:08 And on the outside portion of this joint, you have an articular fibrous capsule.

03:16 Some synovial joints also have other structures associated with them.

03:21 These structures are usually there to help reduce friction during movement.

03:25 The two types of structures that you can also find in the synovial cavity include bursa and tendon sheaths.

03:34 Bursa are sac like structures that are filled with synovial fluid and are there to cushion the movement of one body part over another.

03:43 An example of this can be found in the knee.

03:48 A second structure is the tendon sheaths.

03:52 These are like bursa except they are shaped like the tube instead of like a sack.

03:57 They usually wrapped around the tendon and again, are subject to great deal of friction.

04:03 An example of this can be found in the wrist or the hands.

04:10 So now that we've gone through all the structural classifications of joints, let's talk about the functional classifications of joints.

04:18 We classify joints functionally by their ability to move.

04:23 A joint that is a synarthroses allows no movement.

04:28 Examples of this include the sutures in the skull, as well as the gomphosis in the teeth.

04:36 The second functional classifications of joints is going to be amphiarthroses.

04:42 In this classification, there's very little movement.

04:46 And you can find this in places such as the pubic symphysis of the pelvic bone, or the intervertebral disk of the spine.

04:55 The third functional classification is diarthroses.

04:59 In diarthroses you have free movement.

05:03 This is going to be characteristic of joints such as the hip joint, the knee joint, shoulder joint, and elbow joint.

05:12 In fact, most synovial joints are diarthroses.