03- Arthrology Pdf Explaining joints in the human body

Joints

1. Chapter 2 Arthrology 1 、 The general description 2 、 Classification of the jionts 3 、 The diarthroses : Synovial joints 4 、 Movements of the synovial joints

2. The general description The joints are the junctions between the bones, by which the bones are interconnected to form the skeleton. The joints can be classified ['klæsɪfaɪd] either /'aɪðə; 'iː-/ by function or structure.

3. The functional classification According to the amount of movement allowed , The joints can be divided three types: the synarthroses [,sɪnɑː'θrəʊsiːz] are immovable [ɪ'muːvəb(ə)l] joints, the amphiarthroses /,æmfɪɑː' θ rəʊsiːz/ are slightly movable ['muːvəb(ə)l] joints the diarthroses [,daɪɑː'θrəʊsiːz] are freely movable joints.

4. The functional classification of the joints The diarthroses predominate  [prɪ'dɒmɪneɪt] in the limbs. the synarthroses and the amphiarthroses are restricted [rɪ'strɪktɪd] to the axial /ˈæksiəl/skeleton.

5. The structural classification of the joints The structural classification is based on the material [mə'tɪərɪəl] that binds the bones together. Structurally, joints are classified four types: The fibrous joints The cartilaginous [,kɑːtɪ'lædʒɪnəs] joints Synostosis [sinɔs'təusis] the synovial  /si'nəuviəl/ joints.

6. Classification of the joints The synarthroses (Immovable joint) The diarthroses ( Freely movable joints, Synovial joints ) ⑴ Fibrous joints ① Syndesmosis/,sɪndez'məʊsɪs ② Suture ⑵ Cartilaginous joints ① Synchondrosis/,siŋkɔn'drəusis/ ② Symphysis /'sɪmfɪsɪs/ ⑶ Synosteosis /,sinɔs'təusis/

7. The structural classification of the joints The fibrous joints In the fibrous joints, the bones are connected by the fibrous tissue. The amount of movement permitted by these joints depends on the length of the fibers. For example, the interosseous membrane of forearm connects the radius with the ulna. It permits limited movement between the two bones. Syndesmosis Suture

8. The structural classification of the joints The Cartilaginous   Joints In the cartilaginous [, kɑːtɪ'lædʒɪnəs ] joints the articulating bones are united [ jʊ'naɪtɪd ] by cartilage. This type of joints can be divided into the synchondrosis /, siŋkɔn'drəusis /  and the symphysis /' sɪmfɪsɪs / 

9. The structural classification of the joints The Cartilaginous   Joints The synchondrosis is formed by the hyaline [' haɪəlɪn ;]cartilage, in most cases, this is gradually   [' grædʒʊlɪ ; ossified [' ɔsifaid ] after puberty. For example ， the hip bone is originally [ ə'rɪdʒɪn (ə) lɪ ] 3 bones , which are connected by a synchondrosis . After puberty, the cartilage is ossified and the three bones fuse into one. The synchondrosis

10. The structural classification of the joints The Cartilaginous   Joints The epiphyseal [, epi'fiziəl ] plate between the epiphysis/ɪˈpɪfɪsɪs/ and the metaphysis /mi'tæfisis/ of long bones is also a good sample for the synchondrosis . The synchondrosis

11. The structural classification of the joints The Cartilaginous   Joints The symphysis is formed by the fibrocartilage ['faibrəu'kɑ:tilidʒ] It is unossified throughout life. Examples for this are the intervertebral disk between the bodies of two adjacent   [ə'dʒeɪs(ə)nt] vertebrae the pubic symphysis that connects the bilateral pubis.

12. The structural classification of the joints The synostosis   A synostosis /,sɪnɑs'tosɪs/ is a totally ['təʊtəlɪ] rigid bony fusion ['fjuːʒ(ə)n] between bones. They are usually formed by ossification [,ɒsɪfɪ'keɪʃən] of the synchondrosis ,or sometimes of fibrous joints. Synosteosis

13. The structural classification of the joints ⑴ Fibrous joints ① Syndesmosis /ˌsɪndesˈməʊsɪs/ ② Suture ⑵ Cartilaginous joints ① Synchondrosis ② Symphysis ⑶ Synostosis

14. The diarthroses : Synovial joint s In a synovial joint , the articulating bones are connected by a soft capsule /ˈkæps(ə)l/ the opposing surfaces are separated by a cavity The cavity contains some solution [ sə'luːʃ (ə)n] called the synovia [ sɪ'nəʊvɪə ]. The synovia can lubricate [' luːbrɪkeɪt ] articulating surfaces. The structural features [ˈ fiːtʃəz ] allow the joint to have a greater range of movements so ， the synovial joint is called the diarthrosis

15. Ⅰ) ★ Essential structures of the synovial joints ⑴ Articular surface ① Articular head ② Articular fossa ⑵ Articular capsule ① Fibrous capsule ② Synovial membrane ⑶ Articular cavity

16. i The articular surfaces The articular surfaces are the opposing   [ə'pəʊzɪŋ] surfaces of the articulating bones, One convex is called articular head One concave is termed articular fossa. They are covered by a layer articular cartilages. The opposing surfaces of the articular cartilages are slick and smooth Function to reduce friction and absorb shocks [ʃɔks] during movement at a joint.

17. ii The articular capsule The articular capsule is a soft envelope ['envələʊp/ surrounding the articulating bones. It consists of two layers, an outer fibrous capsule and an inner synovial membrane. The fibrous capsule attaches onto the circumference [sə'kʌmf(ə)r(ə)ns] of the articular head and fossa, and continues with the periosteum/ˌperɪˈɒstɪəm/ 外 层 （ 纤维层 ） 内 层 （ 滑膜层 ）

18. ii The articular capsule The synovial membrane lines the inner surface of the joint except the areas covered by the articular cartilage. The membrane can produce synovia [sɪ'nəʊvɪə]. 外 层 （ 纤维层 ） 内 层 （ 滑膜层 ）

19. iii The articular cavity The articular cavity   [' kævɪtɪ ] is a space enclosed by the synovial membrane and the opposing [ ə'pəʊzɪŋ ] surfaces of the articular cartilages. It is filled by synovia. when pressure [' preʃə ] is applied [ ə'plaɪd ] across a joint, the opposing articular cartilages do not touch with each other, but are separated by a thin film [ fɪlm ] of synovia. From this, you can imagine/ ɪ'mædʒɪn /how appropriate [ ə'prəʊprɪət ] amount of synovia is important for the joint. Function: 1.lubricate the joint 2.protect and nourish [' nʌrɪʃ ] the articular cartilages.

20. Ⅱ ） ★ Accessory structures of the synovial joints Ligaments ① Extracapsular ligaments ② Intracapsular ligaments Articular disc The articular labrum The synovial bursae

21. i The ligaments The ligaments are bundles [' bʌnd (ə) lz ]of dense connective tissue that interconnect the articulating bones to enhance stability of the joint. Two types of ligaments are classified. The extracapsular /ˌekstrəˈkæpsələr/ ligaments cross the joint outside the articular capsule. The intracapsular /ˌɪntrəˈkæpsjʊlə(r)/ ligaments are covered with a synovial membrane that separates them from the joint cavity through which they run. Where are the intracapsular ligaments ？

22. ii The articular disc The articular disc is a fibrocartilaginous [,faibrəu,kɑ:ti'lædʒənəs] cushion/ˈkʊʃ(ə)n/ existing [ɪɡ'zɪstɪŋ] in some synovial joints. It is located between the opposing articular surfaces to improve their congruity [kɒŋ'ɡruːɪtɪ]. A disc extends internally from the capsule and completely or partly divides the joint cavity in two.

23. ii The articular disc An example for this is the lateral and medial discs in the knee joint. Each disc is thick at its outer edge and tapers to the inner edge. This shape conforms to the space between the articular surfaces of the femur and the tibia Where are articular discs?

24. iii Articular labrum /ˈleɪbrəm, ˈlæb-/ The articular labrum is a fibrocartilaginous ring that surrounds the edge of an articular fossa Function: to increase its depression area

25. ⅳ Synovial fold and Synovial bursae Synovial fold synovial surface area is greater than the fiber layer Synovial overlapping /, əʊvə'læpɪŋ / roll fold, and to the joint cavity to form a Synovial fold , which contain fat and blood vessels, which become the synovial membrane fat pad . In movement, the shape of the articular cavity, volume, pressure change, synovial membrane fat pad can be adjusted up or filling, but also enlarge the area of the synovial membrane this is advantageous / ædvən'teɪdʒəs / to the synovial fluid absorption and secretion Synovial bursae The synovial fold Synovial bursae The synovial

26. ⅳ Synovial fold andSynovial bursae The synovial bursae ['bə:si:] In some areas （ in the absence of a fibrous membrane or a weak place) the synovial membrane is sacs/sæks/ filling between the tendon and the bone surface forming a synovial capsule that reduces the friction between the muscle activity and the bone   Synovial bursae The synovial fold

27. ★ Movements of the synovial joints ⅰ The movements of a synovial joint are various and sometimes complex ⅱ They can be simplified into two forms ⅲ the plane movement ⅳ the angular movement

28. ⅰ Movements of the synovial joints 1.the plane [pleɪn] movement ⑴ The gliding (slipping) movement In this movement, the opposing articular surfaces glide past one another. 2. the angular ['æŋgjʊlə] movements ⑵ Flexion and extension Flexion and extension ⑶ Adduction and abduction Adduction and abduction ⑷ Rotation Rotation ⑸ Pronation ans supination Circumduction Circumduction

29. Flexion and extension Flexion is a motion that reduces the angle between the articulating bones ， moves the distal bones anteriorly The extension is a motion that increases the angle between the articulating bones For example, a flexion or an extension at the elbow joint reduces or increases the angle between the upperarm and the forearm. A flexion at the shoulder and hip joints moves the limbs anteriorly, and a extension brings them posteriorly

30. Flexion and extension An exception for this is the movements at the ankle joint where elevation/ˌelɪˈveɪʃ(ə)n/ of the dorsum of the foot toward the anterior aspect of the leg is called dorsiflexion the opposite movement is plantar ['plæntə] flexion.

31. Adduction and abduction The angular movements on the sagittal axis of a joint Abduction is a motion away from the median plane of the body.Adduction refers to a motion that pulls a structure or part toward the midline of the body, or towards the midline of a limbs. An exception   for this is the movements of the fingers and toes, Spreading  the fingers or toes is abduction, and bringing them back to the middle finger or to the second toe is adduction. For the vertebral column, the sagittal axial movement is called lateral flexion.

32. Rotation The movements on the vertical axis of a joint are called rotation. For the vertebral column, you can do right or left rotations. rotation towards or away from the center of the body For the limbs, rotating the anterior surfaces toward the median plane of the body is called the medial rotation

33. Pronation and supination A special rotation can take place in the forearm Turning the wrist and hand from palm-facing-front to palm-facing-back is called the pronation the opposite movement is the supination

34. Circumduction The circumduction, the distal end of bone moves in a circle while the proximal end slides [slaɪdz] along the articular fossa repeatedly on the coronal and sagittal axes. In other words, the circumduction is a complex ['kɒmpleks] movement that combines   [kəm'baɪn] the flexion, the abduction, the extension, and the adduction in succession   [sək'seʃ(ə)n].