Intro to MSK Anatomy 6.pdf

13/09/2024...

13/09/2024 Musculoskeletal Element Introduction to 1 Week of Head and Neck, 4 Weeks of Limbs musculoskeletal Several lectures per week anatomy 1 lab per week Thursday morning Southwell Street VDR Pre-lab ‘flipped classroom’ – Familiarise yourself with the lab materials on Blackboard so that you come to lab prepared Southwell Street Vet Museum available as a study space and to work with potted/bony specimens. [email protected] Canine bone boxes available in the Medical library © School of Anatomy, University of Bristol. Not for distribution 1 2 The musculoskeletal system & bone Session ILOs classification – year 1 week 1 Discuss the structure of the skeletal system and Confidential and not for distribution. Copyright of School of Anatomy, University of classification of bones Discuss the simple classification of joints, giving Bone relevant examples of each type forms most of skeleton Describe the structure of bursae and explain their importance Cartilage Describe the characteristics of skeletal muscle and the forms some parts of skeleton (e.g. Bristol costal cartilage) process of contraction lines articular surfaces Explain the role of Ca2+ in skeletal muscle function and how muscle force is controlled Tendons and Ligaments Describe the length-tenson relationship in skeletal Tendons attach muscles, mostly to bone muscle Ligaments connect 2 or more bones or cartilage 5 6 The skeletal system & bone Bone classification classification Bones are classified according to their Axial skeleton shape Appendicular skeleton Cartilage Long Short Flat Irregular Other terms… Sesamoid Confidential and not for distribution. Copyright of School of Anatomy, University of Bristol Adapted from Chaveau, 1871 Pneumatic Splanchnic 7 8 1  13/09/2024 The Skeletal System: Bone articular Bone marrow epiphysis Cervical Pelvis (sacrum cartilage vertebrae Thoracic Lumbar hidden behind) vertebrae vertebrae metaphysis Bone marrow is found in the medulla and in the spaces between trabeculae of cancellous bone. Cancellous Confidential and not for distribution. Copyright of School of Anatomy, University of Bristol (trabecular) Scapula bone Hip joint Bone histology Shoulder joint cortical Femur bone As the name suggests compact (cortical) bone Humerus Stifle joint diaphysis endosteum has a much more dense structure than Olecranon (point of Calcaneus Elbow joint elbow) (point of cancellous (spongy) bone hock) Trabecular Ulna medulla strut osteon Tibia osteocytes Radius (fibula caudal aspect, not seen here) Tarsus periosteum 2 Bone Haversian canal marrow Carpus osteocytes Metacarpals Metatarsals Phalanges (digits) cancellous bone compact bone 9 10 © School of Anatomy, Fibro/cartilaginous joint classification University of Bristol. Not for distribution fibro- Fibrous joints connect the bones of the skull (sutures), connect bones in the Synovial joints Fibrous Joint bone cartilage bone body (syndesmosis) and hold the teeth CONFIDENTIAL AND NOT FOR DISTRIBUTION, COPYRIGHT OF UNIVERSITY OF BRISTOL. in the sockets (gomphosis). Shaped articular Primary Cartilaginous bone hyaline- bone Primary cartilaginous joints can be found at costochondral joints and growth plates cartilage surfaces cartilage Joint Joint capsule containing synovial fluid Secondary Secondary cartilaginous joints can be Cartilaginous bone bone found at the pubic symphysis and Supporting ligaments Joint intervertebral discs Supporting muscles and suture Growth tendons plate (1o) gomphosis Range of motion Synovial cavity Interosseous depends on a Capsule membrane (syndesmosis) Costochondral junction (1o) Intervertebral disc (2o) combination of all three Hyaline cartilage Fibrous Joints © School of Anatomy, University of Bristol. Not for distribution 11 12 Bursae The skeleton provides structure, support and protection, but movement functions in the limbs, Structures with a head and neck require active control from muscles capsule and synovial fluid but no ‘joint’ Muscles to maintain body ‘Antigravity’ (extensor) muscles posture of the limbs and spine Help to smooth Muscles to move the limb joints Flexor and extensor muscles passage of bones, Muscles to move the jaw Muscles of mastication tendons, ligaments (trigeminal muscles) during movement Muscles to shape the lips Muscles of facial expression Can become Muscles to move food into the Palatine and pharyngeal muscles inflamed ‘bursitis’ © School of Anatomy, University of Bristol. Not for distribution digestive tract Muscles to support the Abdominal muscles abdominal organs 13 14 2  13/09/2024 Skeletal muscle is organised Muscle attachments into muscle-tendon units Origin – the ‘start’ of the muscle. Contractile, muscular portion (‘belly’) with visible Typically proximal, generally fascicles (each comprising multiple muscle fibres) ‘moves less’ Non-contractile fibrous/elastic portion (‘tendon’) Insertion – the ‘end’ of the The proportion of each depends on function muscle. Typically distal, generally Share a name eg Biceps brachii refers to both the ‘moves more’ muscle and the tendon These are mostly attachments to bone *but* can be to e.g. fascia Can be multiple origins and Eg Biceps brachii insertions per muscle Origin: supraglenoid tubercle Determine leverage of muscle Insertion: proximally Intrinsic = within the limb, on the radial extrinsic = from limb to body tuberosity and ulna CONFIDENTIAL AND NOT FOR DISTRIBUTION, COPYRIGHT OF UNIVERSITY OF BRISTOL. 15 16 Skeletal muscles Tendons and ligaments © School of Anatomy, Striated, cylindrical Tendons connect muscle and University of Bristol. Not for distribution cells, multinucleate, bone, ligaments bone to bone voluntary control Both dense regular connective Contraction comes tissue, ligaments generally have a greater elastic from the sarcomere Table 4.15a, Seeley et al, Anatomy & Physiology, McGraw Hill component Fibers arranged into Tendons act as strings or visible fascicles – springs parallel and pinnate For a tendon to act as a spring, attached muscle fibres ‘Motor unit’ – a motor need to develop force so that neuron and the skeletal the tendon can be stretched muscle fibers it Reduced muscle fibre content (eg equine sdf) reduces this innervates at the need for energy From: Clayton and Flood, Large Animal neuromuscular junction Applied Anatomy, 1996, Mosby 17 18 19 Skeletal Muscle Structure Endomysium (between muscle fibres) Muscle activation and contraction Skeletal muscle (surrounded by Muscle fibre epimysium or deep fascia) Fasicles (surrounded by Tendon perimysium) One sarcomere Bone Myofibrils Figure 9.3a,b&c Seeley et al, Anatomy & Physiology, McGraw Hill 19 20 3  13/09/2024 Seeley et al, Anatomy & Physiology, McGraw Hill Ca2+ and the control of contraction 21 22 The length:tension relationship Seeley et al, Anatomy & Biomechanics – forces, loads and levers Physiology, McGraw Hill Muscle tension Levers are the cornerstone of Muscle the body’s ability to move activation is A muscle can only deliver so Muscle length not all or much force Actin is purple nothing! Levers can change the force Myosin is green required to move a set mass Or they can increase the speed of movement for a given force, making that movement more powerful Just like the length-tension curve, there are optima for this! They do this by altering the lengths of the lever arms 23 24 Useful movement terminology Session ILOs -essential for communication! Flexion/Extension Discuss the structure of the skeletal system and Abduction/Adduction classification of bones Pronation/supination Discuss the simple classification of joints, giving External Rotation/Internal rotation relevant examples of each type Axial/abaxial Describe the structure of bursae and explain their importance Eccentric, concentric, isometric Describe the characteristics of skeletal muscle and the process of contraction Translation Explain the role of Ca2+ in skeletal muscle function and Valgus/Varus how muscle force is controlled (Sub)luxation Describe the length-tenson relationship in skeletal Avulsion muscle Transection http://emcocala.com/news-info/equine-information/angular-limb-deformities 25 26 4