Joints, Muscles, and Spinal Nerves Lecture 3 PDF

Joints- muscles – spinal nerve By Dr. Mogeda Mahdy Prof. of Anatomy & Embryology Kasr Al-Ainy Faculty of Medicine Cairo University 2 Synovial Joint Characteristics (Structure )of synovial joint 1...

Joints- muscles – spinal nerve By Dr. Mogeda Mahdy Prof. of Anatomy & Embryology Kasr Al-Ainy Faculty of Medicine Cairo University 2 Synovial Joint Characteristics (Structure )of synovial joint 1 There is joint cavity containing synovial fluid. 2-Fibrous capsule connects the articulating bony ends. 3-The capsule is lined by synovial membrane. 4-The capsule is reinforced externally by ligaments. 3 Synovial Joint Characteristics (Structure )of synovial joint 5- The articulating surfaces are covered by hyaline cartilage. 6-Movements: are always possible. Structures which may be present inside the cavity of synovial joints: articular disc- menisci- ligament tendon.  Types of synovial joints Biaxial: non axial Uniaxial Polyaxial: (plane):  Uniaxial: A-hinge (horizontal axis) Elbow joint interphalangeal Humerus Ankle joint Radius ulna  B-pivot (vertical axis) superior radioulnar joint. 2 - Biaxial: has two perpendicular axes of movement. There 3 types: A- condylar e.g knee joint B- (ellipsoid) Joints : wrist joint 2 - Biaxial: C-Saddle Joints e.g Carpo metacarpal joint at the base of the thum Dr. Mogeda Mahdy 3- Polyaxial: called ball and socket allow all types of movements. e.g shoulder joint and hip joint Sunday, (Write 12 theOctober Name of13,the 2024 department) 4 – non axial (plane): Flat articular surfaces in which bones slide over each other Intercarpal and intertrasal ,. superior tibio-fibular joint MOVEMENTS OF JOINT  Flexion approximate two anterior surface Extension two anterior surface away from each other Abduction 🡪 moving a limb away from midline Adduction 🡪 moving a limb towards the midline  Circumduction 🡪 the combination in sequence of movements of flexion, abduction, extension & adduction. Rotation: Medial or lateral rotation of the limb around a vertical axis  Pronation 🡪 medial rotation of forearm which brings palm of hand to face posteriorly Supination🡪 lateral rotation of forearm which brings palm of hand to face anteriorly Sunday, (Write 17 theOctober Name of13,the 2024 department) Factors affecting the stability of the joint: Shape and fitting of articulating surfaces. Thickness and elasticity of the capsule. Position and strength of ligaments. Strength of muscles surrounding the joint. Factors affecting the range of movement: Tension of ligaments surrounding the joint. Contraction of the antagonistic muscles. Approximation and contact of the soft tissues around the joint. Nerve supply of joint: Hilton's Law: The joint is supplied by the same nerves which supply the muscles acting on this joint.  Muscles Types of muscle 1--Skeletal 2- Smooth 3- Cardiac  Types of muscles skeletal Cardiac smooth Site Attached to skeleton, In the myocardium of Walls of blood vessels the heart and viscera Contraction Voluntary Involuntary Involuntary Striations Present Present but less than in Absent skeletal muscle Nerve supply Somatic nerve Autonomic nerve Autonomic nerve Muscle cell (fiber) Multinucleated with Branch and fuse Spindle-shaped with peripheral nuclei together with single single nucleus nucleus.  Skeletal muscles 1- Attachment of skeletal muscles Skeletal muscles Origin: usually the most fixed attachment (proximal attachment). Insertion: usually the most mobile attachment (distal attachment). Types of attachment Attachment to bone (common type) Attachment to fibrous raphe Attachment to skin Attachment to intermediate tendon Attachment to cartilage Sunday, (Write 21 theOctober Name of13,the 2024 department) Form of Skeletal Muscles The muscle form depends on the arrangement of the muscle fibres in Muscles with parallel fibers relation to the line of pull (line extending between the origin & insertion). Sunday, (Write 22 theOctober Name of13,the 2024 department) Form of skeletal muscle Muscles with oblique fibers Types of muscle according to function: 1. Prime mover: The muscle responsible for producing a specific movement. 2. Antagonist: The muscle which helps the prime mover by relaxation. 3. Fixator (Stabilizer): The muscles which helps the prime mover by fixing the origin of the prime mover or stabilize the joint upon which prime mover acting. 4. Synergist: muscle which helps the prime mover by eliminating unwanted action. Sunday, (Write 24 theOctober Name of13,the 2024 department) BURSAE Definition: These are localized sacs filled with synovial fluids. Function: They minimize friction between opposing structures. Types: 1. Subcutaneous (adventitious) bursae: between skin and bones. 2. Subtendinous bursae: between tendons and bones. 3. Interligamentous bursae: between ligaments. 4. Submuscular bursae: between muscles and underlying structures.  Spinal Nerve Numbers: 31 pairs Arrangement: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral & one coccygeal. Roots: each spinal nerve has 2 roots: Dorsal root: Its fibres are sensory & has a dorsal root ganglion (DRG). Ventral: Its fibres are motor.  Nerve trunk: It is formed by the union of the dorsal & ventral roots. It leaves the vertebral canal through the intervertebral foramen. It divides into anterior & posterior rami. Rami: Anterior rami supply the skin & muscles of o Front of the trunk o Upper & lower limb Posterior rami supply the skin & muscles of the back of the trunk THANK YOU