The union or meeting point of two or more than two bones or parts of the bones is called as Joint

Articulation Means pertaining to the joint e.g. articular surface of the bone, articular artery, articular nerve

Classification of the Joints Fibrous Synovial Cartilaginous Joints are classified according to the tissues that lie between the bones

In fibrous joints the bones are united by tissue consisting of collagen fibers which run between the bones Very little movement is possible The degree of movement depends on the length of the collagen fibers No joint cavity Fibrous Joint Sutures

There are three subtypes of fibrous joints: 1.Suture: Bones are held together by a thin layer of dense fibrous tissue and also by interlocking projections of the bones. The connecting fibers holding bones together are short. This type of joint occurs only in the skull: cranial sutures.

2. Syndesmoses: Bones are held together by a cord or sheet of dense fibrous connective tissue. The connecting fibers holding bones together are long. The tibia/fibula joint and the interosseous membrane connecting the radius and ulna along their length are syndesmosis.

3.Gomphosis: It is a peg-in-socket fibrous joint. The only examples are the articulations of teeth (the peg) with their alveolar sockets in the mandible or the maxillae. The thin fibrous membrane that hold teeth inside their alveolar sockets is called the periodontal ligament.

Cartilaginous Joint In cartilaginous joints the bones are united with each other by cartilage. Again, there is NO JOINT CAVITY.

There are two subtypes of cartilaginous joints: 1.Primary cartilaginous joints (synchondroses):Primary cartilaginous joints A plate of hyaline cartilage connects the bones at the joint. Only hyaline cartilage is involved, not moveable. An example is the cartilaginous epiphyseal plate which separates the epiphysis from the diaphysis in long bones during growth. These joints are immoveable (synarthroses) and are obliterated by bone in the adult.

2. Secondary cartilaginous joints (symphyses)Secondary cartilaginous joints It involves both hyaline and fibrocartilage. The articular surface of each bone is covered with a thin layer of hyaline cartilage, and fibrocartilage unites these two layers. Limited movement is permitted at such joints, depending on the thickness of the fibrocartilage pad which can be compressed or stretched. Two important examples are the pubic symphysis and the intervertebral discs.

majority of articulations between bones are synovial joints. freely moveable joints. characterized by PRESENCE OF A closed space or CAVITY between the bones: the joint cavity (= synovial cavity). articulating surfaces are covered by hyaline cartilage, lubricated by a highly viscous the synovial fluid secreted by the synovial membrane which lines the cavity. to reduces friction. Joint cavity is enclosed by a double layered synovial membrane & the articular capsule. Synovial joints are reinforced by a number of ligaments. Ligaments are bands of dense regular connective tissue proper that connect bones to other bones. Synovial Joint

Synovial joints are classified according to the shape of the articulating surfaces which, in turn, determines the range of movement permitted They can be classified into six major categories: 1. Plane (gliding) Plane (gliding) Opposite bone surfaces are flat or slightly curved. Only sliding motion in all directions are allowed. Since there is no bone movement around an axis, the joints are nonaxial.

2. HingeHinge Convex surface of one bone fits smoothly into concave surface of the second bone. T he joints are uniaxial.

3. Pivot Pivot A rounded, or conical surface of one bone is inserted into a ring made partly of another bone and partly of a ligament. Since the only movement allowed is the rotation of one bone around its own axis, the Joints are uniaxial.

4. Ellipsoidal (condyloid) Ellipsoidal (condyloid) Oval-shaped surface fits into an oval- shaped cavity (ellipse means oval). The movements allowed are flexion/extension, adduction/abduction and circumduction but NO ROTATION. Since bones can move in both planes: side to side and back and forth movements the joints are biaxial.

5. Saddle Saddle First bone's articular surface is concave in one direction and convex in the other while the second bone is just the opposite (or one bone is shaped like a saddle, and the other is shaped like its rider). The saddle joint is similar to the Ellipsoidal Joint but the movements are freer. The movements allowed are flexion/extension, adduction/abduction and circumduction but NO ROTATION. Since bones can move in both planes: side to side and back and forth movements the joints are biaxial.

6. Ball and socket Ball and socket Ball-shaped head fits into a cup-shaped depression These joints are the most freely moving of all synovial joints. The movements are allowed in all axes and planes: flexion/extension, adduction/abduction, circumduction and rotation. These joints are multiaxial.

Introduction to the nervous system Nervous System (NS) Peripheral NS Central NS Autonomic NS Somatic NS Sympathetic NS Parasympathetic NS Brain Spinal Cord Functional Division 12 pairs of Cranial nerves & 31 pairs of spinal nerves Structural Division Classification

Nervous system consists of two main cell type a. Neurons b. Neuroglia (Non neuronal cells) Neurones Neurons are the functional & structural units of nervous system

NERVE Bundle of axons NUCLEUS Collection of nerve cell bodies in the CNS TRACT Bundle of nerve fibers connecting nuclei GANGLION Collection of nerve cell bodies in the PNS

CRANIAL NERVES Exit the cranial cavity through foramina 12 pairs of cranial nerves. Olfactory I Optic II Oculomotor III Trochlear IV Trigeminal V Abducens VI Facial VII Auditory (Vestibulocochlear) VII Glossopharyngeal IX Vagus X Spinal Accessory XI Hypoglossal XII

SPINAL NERVES 31 Pair Exit the vertebral column through intervertebral foramina

Sympathetic Thoracolumber Division Parasympathetic Craniosacral Division