Joints PDF

Joints  Articulation between two or more bone or rigid parts of the skeleton.  There are 186 joints in the body.  Joints exhibit a variety of forms and functions. Joints Joints can also be grouped according to the degree of movement possible at the bony junction Synarthrotic – Immovabl...

Joints  Articulation between two or more bone or rigid parts of the skeleton.  There are 186 joints in the body.  Joints exhibit a variety of forms and functions. Joints Joints can also be grouped according to the degree of movement possible at the bony junction Synarthrotic – Immovable joints Amphiarthrotic- Slightly moveable Diarthrotic- Freely movable  Classifications of the Joints classified by the type of tissue that binds the bones at each junction. (A) Fibrous joints: (B) Cartilaginous joints: (C) Synovial joint: suture and syndesmosis primary and secondary. knee joint A. Fibrous joint  The articulating surfaces of the bones are joined by fibrous tissue and thus very little or no movement is possible.  E.g. Sutures of skull. A. Fibrous joint Fibrous joint A. Fibrous joint A syndesmosis type of fibrous joint unites the bones with fibrous tissue sheet, either a ligament or a fibrous membrane. E.g. interosseous membrane between radius and ulna bones. B. Cartilaginous joint ❶ Primary cartilaginous joint : the bone are articulated by hyaline cartilage. such as epiphysial plate of long bone. ❷ Secondary cartilaginous joint: where the bones are Connected by fibrous cartilage. Such as intervertebral disc which connects the body of two vertebrae. Cartilaginous joint examples ❶ Primary cartilaginous joint ❷ Secondary cartilaginous joint Intervertebral disc C. Synovial joints  Are true mobile joints.  The articular surfaces of the bones are covered by hyaline cartilage separated by a joint cavity. This arrangement permits a great degree of freedom of movement. C. Synovial joints  The cavity of the joint is lined by synovial membrane, which extends from the margins of the articular surface to those of the other.  The synovial membrane is protected on the outside by a tough fibrous membrane called capsule of the joint. C. Synovial joints C. Synovial joints  The articular surfaces are lubricated by a viscous fluid called synovial fluid, which is produced by synovial membrane.  The capsule is strengthened by ligaments which unites the bones together.  Some ligaments lie within the capsule, some others lie outside it. Types of synovial joints According to the shape of articulating bones, and the type of movement the synovial joints are classified into the following: ❶ Plane joints: the articular surfaces are flat and this permits the bones to slide over one another. E.g. Acromioclavicular joint. ❷ Hinge joints: only flexion and extension are possible. E.g. Elbow, knee, and ankle joints. Types of synovial joints ❸ Pivot joints: in which a central bony axis is surrounded by a bony-ligamentous ring and rotation is the only movement possible. E.g. Atlanto-axial joint and superior radioulnar joints. ❹ Condyloid joints: in which there is two different convex surfaces articulate with two concave surfaces. Flexion, extension, abduction, adduction together with a small amount of rotation are possible, e.g. Metacarpophalangeal joints. Types of synovial joints ❺ Ellipsoid joints: an elliptical convex articular surface fits into an elliptical concave articular surface. Flexion, extension, abduction and adduction are possible with no rotation. Ex. Wrist joint. ❻ Saddle joint: in saddle joints, the articular surfaces are reciprocally concavo-convex and resemble a saddle on a horse's back. Flexion, extension, abduction, adduction and rotation are possible. E.g. Carpometacarpal joint of the thumb. Types of synovial joints ❼ Ball and socket joints: here a ball shaped convex surface fits into a socket like concavity. It permits free movement. ( flexion, extension, abduction, adduction, medial rotation, lateral rotation and circumduction). Ex. Shoulder and hip joints. Types of synovial joints Pivot joints TYPES OF SYNOVIAL JOINTS Joints of the head and neck ❶ Skull sutures. ❷ Temporo-Mandibular joint. ❸ Atlanto-Axial joint. ❹ Cervical Intervertebral joint. Sutures of the skull Coronal suture Sagittal suture ❶ Lambdoid suture Squmaous suture Sutures of the skull Intervertebral disc ❹ ❸ ❷ Joints of the Pectoral Girdle ❶ Sterno-clavicular Joint. ❷ Acromio-clavicular Joint. ❸ Gleno-humeral Joint. ❶ Sterno-clavicular Joint Articulation: occurs between the sternal end of the clavicle, the manubrium sterni, and the first costal cartilage. Type: Synovial double-plane joint. ❷ Acromioclavicular joint Articulation: This occurs between the acromion of the scapula and the lateral end of the clavicle. Type: Synovial plane joint ❸ Glenohumeral joint Type is a synovial ball and socket (multi-axial). Articulation between the head of the humerus and the glenoid cavity of the scapula, structurally is a weak joint?  Movements Flexion, extension, abduction, adduction, medial rotation, lateral rotation, and circumduction are possible. Clinical notes Dislocation of Glenohumeral Joint  Caused excessive abduction or lateral rotation of the arm.  The head of the humerus drived inferiorly. Joints of the forearm ❶ Elbow joint. ❷ Superior Radio-Ulnar Joint. ❸ Radio-Ulnar Joint. ❹ Distal Radio-Ulnar Joint. ❶ Elbow joint  Articulation: This occurs between the trochlea and capitulum of the humerus and the trochlear notch of the ulna and the head of the radius.  Type: Synovial hinge joint  It permits only flexion and extension ❷The radio-ulnar joints  The two ends (upper and lower ends) of the radius and ulna are jointed to each other at the superior and inferior radioulnar joints.  The shaft of the two bones are united by the interosseous membrane (some time called middle radioulnar joint). ❸ Superior (proximal) radio-ulnar joint  Articulation: The head of the radius with the radial notch of the ulna. The radial head is held in position by the anular ligament of the radius  Type: Synovial pivot joint  Possible movements are pronation and supination. ❹ Distal (inferior) radio-ulnar joint Articulation: Between the rounded head of the ulna and the ulnar notch on the radius. Type: Synovial pivot joint. Possible movements are pronation and supination. Clinical notes Subluxation and Dislocation of Radial Head Wrist joint (Radio-Carpal joint)  Articulation: Is between the distal end of radius and the articular disc of ulna above, and the scaphoid, lunate and triquetral bones below.  Type: it is a synovial ellipsoid joint).  It allows flexion, extension, abduction and adduction, with no rotation. Joints of the hands Other hand joints include: ❶ Intercarpal joints, ❷ Carpometacarpal joints, ❸ Metacarpophalangeal joints, ❹ Interphalangeal joints. ❶ Hip joint  Type: Is a synovial ball and socket joint.  Articulation: between the head of the femur and acetabulum  Movements: flexion, Extension, abduction, adduction, lateral and medial rotation ,and circumduction ❷Knee joint  Is the most complex joint of the body.  Articulation: Between two rounded condyles of femur above and two condyles of the tibia and their cartilaginous menisci.  Types: Between the femur and tibia is a synovial hinge variety, Between the patella and femur is synovial plane gliding variety. Extracapsular ligament A-Lateral collateral ligament: separates from (i) lateral meniscus by the tendon of the (ii) popliteal A muscle. ii B-while the medial collateral B ligament: is firmly attached to the i (iii) medial meniscus so injury of iii ligament lead to damage of medial meniscus. Intracapsular ligament B The intracapsular ligament are A two cruciate ligament. A. Anterior crusciate ligament B. Posterior crusciate ligament B A The menisci of the knee joint They are two fibro-cartilaginous discs A. Medial meniscus is C shaped. B. Lateral meniscus circular shape. B A Clinical note Knee Joint Injuries  Tibio-fibular Joints The tibia and fibula are connected by two joints: ❶ the superior(proximal) tibiofibular joint and, ❷ the tibiofibular syndesmosis (inferior (distal tibiofibular) joint. ❸In addition, an interosseous membrane joins the shafts of the two bones. Proximal Tibio-Fibular joint Type is a plane type of synovial joint. Articulation between the lateral condyle of the tibia and head of the femur. Distal Tibio-fibular Joint Articulation: Articulation is between the fibular notch a of the tibia and the lower end of the fibula. Type: The distal tibiofibular joint is a fibrous joint. Ankle Joint Articulation: Articulation is between the lower end of the tibia, the two malleoli, and the body of the talus. Type: The ankle is a synovial hinge joint. Movements: a. Dorsiflexion (toes pointing upward) and b. plantar flexion (toes pointing downward) are possible. The movements of inversion and eversion take place at the tarsal joints and NOT at the ankle joint.