The Skeletal System PDF

Chapter II The Skeletal System We have already seen the importance of all 5 components of Fitness and how all of them are important to improve our Body’s functionality. Becoming fitter is all about improving the Body’s functionality or functioning capacity in the realm...

Chapter II The Skeletal System We have already seen the importance of all 5 components of Fitness and how all of them are important to improve our Body’s functionality. Becoming fitter is all about improving the Body’s functionality or functioning capacity in the realm of physical activity. To understand how we can improve the performance of the body's various systems & through that improve physical performance, we first need to know how each part or systems work in symphony with each other to perform the human body functions. Thus, this chapter is crucial as it deals with the study of the Normal Functioning of the various parts and Systems of the Human Body. This subject is called Physiology. Kinesiology is in many ways a branch of Physiology as it is the study of the human body movements (which is a part of the normal functioning of the human body). But before we understand how each System & the body part that constitute each system work, we need to know the body parts themselves. Where are they located? How do they look? What are they called? This study of the Human Body, its parts, and structures is called Anatomy. So, we shall now embark on a Study of Anatomy and Physiology to understand the various parts of the body and how they function. Only when we know the normal function of the various body parts (eg. Muscles), can we do something to make the part stronger and make it work better. And only when we know the normal functioning, can we judge if something abnormal is happening. Abnormal functioning is the antithesis of Physiology & is termed Pathology. It is like learning how to drive a car. First, we need to know the parts, the accelerator, brake, clutch, gear, etc (study of the parts - Anatomy), then we need to know how they work (functioning - Physiology). Only when we know these two things can we take steps to improve the functioning or get the desired results of improving the performance of the car. If we know the normal functioning of the car only then can we use it in a manner to zoom off really fast OR tune it in a manner to achieve maximum fuel efficiency. If we learn how to drive a car that makes abnormal sounds (Pathology), we would never know that something is not working properly if we did not know what the normal functioning (Physiology) of the car was. Hence Physiology as a science is very important to understand or detect Pathology. But this is for Medical professionals. For a Fitness professional, Physiology needs to be understood purely from the standpoint of making the body perform better physically. Therefore the 3 Sciences of Anatomy, Physiology & Kinesiology form the backbone of the knowledge base needed to be an effective, result-oriented Fitness Professional. Anatomy - The study of the human body is called Anatomy. Anatomy is studied in a particular sequence or method. Going back to the example of the car, if we have to study the car, we will first study the bigger components like the frame or body of the car, the engine of the car, etc. then the parts of these main components ie., parts of the body like the doors, the roof, the bonnet, etc. Similarly, when we study the engine, first we will look at the engine as a whole then its parts, and finally, the smaller units which make these parts. The human body is also studied in this sequential manner. In other words, the human body is constructed in a similar manner as bigger parts made of smaller parts, smaller parts made of still smaller parts, and these are further made of very minute parts. This arrangement of the Human Body is called as “Organization of the Human Body” The Human body is organized in the following manner Human Body made of different Systems ⇩ Systems made of parts called Organs ⇩ Organs made of Tissues ⇩ Tissues made of Cells The Human Body is made up of systems. The Human Body is made up of the following systems which work continuously in a harmonious manner like a symphony orchestra in total coordination and sync with each other. These systems are made up of various organs which in turn are made up of tissues, which in turn are made up of cells. A cell is the smallest functional unit of the entire body. e.g. Cardiovascular system is made up of blood vessels and heart (organs). Heart is made up of the cardiac muscle (Tissue) and Cardiac muscle is made up of the cardiomyocyte (cell). Let's take a look at the various systems that comprise the human body. Nervous System - Made up of the Brain, Spinal cord, and Nerves. Cardiovascular System - Made up of the Heart, Blood Vessels, and Blood. Respiratory System - Made up of the Nose, Windpipe, Lungs, and Respiratory Muscles. Muscular System - Made up of Muscles (Skeletal, Smooth, and Cardiac) and tendons. Skeletal System - Made up of Bones, Joints, Ligaments, and Cartilage. Endocrine or Hormonal System - Made up of Endocrine glands and Hormones that they secrete. Digestive or Gastrointestinal System - Made up of the entire Digestive Tract from the Mouth to the Anus and the Accessory Digestive Glands - the Salivary Glands, Liver and Pancreas. Urinary or Renal System - Made up of the Kidneys, Ureters, Urinary Bladder, and Urethra. Integumentary System - Made up of Skin, Hair and Nails. Immune or Immunological System - Made up of White Blood Corpuscles, the Lymphatic System, and protein substances called Antibodies. Reproductive System - Made up of Male and Female Reproductive Organs. Out of all the above systems, you will find that the K11 textbook will focus more on selected systems such as the Skeletal & Muscular System, Cardiovascular System, Respiratory System & Nervous System. The reason for this focus is that they have a direct relevance to exercise. In other words, physical activity directly impacts these systems & thus should be known to a fitness professional in detail. For instance, the simple act of walking, jogging, running, or engaging in resistance training of any kind directly involves the Nervous, Cardiovascular, Respiratory & musculoskeletal systems in equal measure. Hence these would be the most important systems for a fitness professional to understand. The Skeletal System The Skeletal System comprises the Bones, Joints, Ligaments and Cartilage. The bones of the skeleton are grouped into two divisions Axial Skeleton (bones that make the central support axis of the body) and Appendicular Skeleton (bones of the upper and lower limbs). There are 206 bones in the human body. A bone is a type of connective tissue made of cells, fiber and matrix. The skeletal system is divided into the Axial skeleton and the Appendicular skeleton. Axial Skeleton Consists of 80 bones from head to tail bone. Cranium (Skull), Vertebral Column (Spine), Sternum, and Rib Cage. Cranium or Skull Bone The skull is made up of the following bones Cranial Bones (8): Frontal, Parietal (2), Occipital, Temporal (2), Sphenoid(1), Ethmoid(1). Facial Bones (14): Maxilla (2), Zygomatic(2), Nasal(2), Lacrimal(2), Palatine(2), Inferior Nasal Concha(2), Vomer(1), Mandible(1). Vertebral Column or Spinal Column or Spine The Spine is a column of 26 bones and cartilage that extends from the base of the skull to the pelvis. It encloses and protects the organs and the nervous system (brain and spinal cord) and supports the trunk of the body. The Spine can be divided into 5 sections Cervical Vertebrae (Cervical Spine) Made of 7 cervical vertebrae (C1-C7) which also comprise the bony axis (most delicate of all the vertebrae) of the neck. The first vertebra (C1 - Atlas) supports and balances the head. The second vertebra (C2) is the Axis which lies in the ring of the Atlas. Thoracic Vertebrae (Thoracic Spine or Dorsal Spine) Made of 12 thoracic vertebrae (T1-T12) which are larger than the ones in the cervical region to which the ribs are attached. Lumbar Vertebrae (Lumbar Spine) Made of 5 vertebrae (L-L5) in the lower back. They are larger and stronger than the rest since they support more weight than the other vertebrae. Sacral Vertebrae (Sacrum) Sacrum is a large triangular bone comprising of 5 fused (S1-S5) vertebral bones (sacral vertebrae). Coccygeal Vertebrae (Coccyx) Also called the tail bone is a small triangular bone comprising 3-5 fused vertebral bones. It is a remnant of a vestigial tail. Cervical and Lumbar Regions - Maximum curvature and maximum movements, hence more postural problems in that region. Each pair of vertebrae is connected by a joint that stabilizes the vertebral column called the Intervertebral Joint. Between each pair of vertebrae is a disc called the Intervertebral Disc. Each disc is comprised of an outer tough encasing called Annulus Fibrosus made of layers of fibrocartilage which surrounds an inner soft central core called Nucleus Pulposus made of a gelatinous pulpy and jelly-like material. The Annulus Fibrosus distributes pressure evenly across the disc and also helps in anchoring the vertebrae to one another. The Nucleus Pulposus acts as a shock absorber, absorbing the impact of the body's daily activities and keeping the two vertebrae separated. Rib cage - The rib cage or thoracic cage is made of 12 pairs of ribs ( 24 ribs ) one pair attached to the thoracic vertebrae posteriorly. Anteriorly, the first seven pairs of ribs articulate directly with the sternum via costal cartilage and are referred to as True Ribs. The next three pairs ( 8,9,10th pairs ) join together and attach via a common costal cartilage to the sternum, they are known as False ribs. The 11 and 12th pairs do not have any anterior attachment and are also referred to as the Free or Floating ribs. Sternum - The sternum of the chest bone has three parts, the manubrium of the sternum, the body of the sternum, and the xiphoid process (xiphisternum). Ear Bones(Ossicles) – Each ear has got three bones - Malleus, Incus, and Stapes. Hyoid Bone - The hyoid bone is a U-shaped bone located in the neck, serving as a point of attachment for muscles and playing a role in swallowing and speech. Appendicular Skeleton It is made up of 126 bones that lie in the lower and upper extremities of the body. 64 bones in the upper and 62 bones in the lower extremity. Bones of Upper Limbs (Upper Extremities) Clavicle (collar bone), Scapula (shoulder blade), Humerus (bone in arm), Radius (lateral bone in the forearm in line with the thumb), Ulna (medial bone in the forearm in line with the little finger), Carpals (8 small bones in the wrist), Metacarpals (5 bones in the palm from the wrist to fingers i.e. from the carpals to the phalanges), Phalanges (single Phalanx). 14 bones in the digits (fingers and thumb : 2 phalanges in the thumb and 3 phalanges in each finger). 8 Carpals + 5 Metacarpals + 14 Phalanges = 27 bones in each hand. The shoulder (pectoral) girdle is made up of bones that connect the upper limb to the axial skeleton viz. the clavicle and the scapula and it includes the Sternoclavicular joint, Acromioclavicular joint, and the Glenohumeral joint. Bones of the Lower Limbs (Lower Extremities) Hip Bone (Innominate bone or os coxa), Femur (thigh bone), Patella (knee cap), Tibia (also called shin is the anteromedial big bone of the leg in line with the great toe), Fibula (thin bone on the lateral aspect of the leg in line with the little toe), Tarsals (7 bones in the ankle), Metatarsals (5 bones from ankle to toes ie. from tarsals to phalanges), Phalanges (single Phalanx). 14 bones in the digits (toes: 2 phalanges in the great toe and 3 phalanges in each of the other toes. 7 Tarsals + 5 Metatarsals + 14 Phalanges = 26 bones in each foot. The Hip (Pelvic) Girdle is made of two hip bones that join the lower limb to the axial skeleton. The two large hip bones (os coxae) are bound by the Sacrum and Coccyx posteriorly at the rigid Sacroiliac joints and at the Symphysis Pubis anteriorly. Each hip bone is made of 3 bones Ilium, Ischium and Pubis. Classification of Bones Long Bones Most of the bones in the lower and upper extremities are long bones.Long bones are characterized by having a greater length than width. The long bones have two distinct ends called the Epiphyses (single epiphysis) and a shaft called the Diaphysis. The junction between the Epiphysis and Diaphysis is called the Metaphysis. The epiphyses are made up of spongy cancellous bone, covered by a thin layer of compact bone. Once the growth plate is turned into solid bone there is no scope for growth in bone length. The epiphyseal closure provides a fairly accurate estimate of age since each epiphysis closes at a definite age. The long bone is like a bamboo and is not a compact structure like an iron rod. Long bones are not completely hollow either. The diaphysis is primarily composed of compact bone, providing strength. However, it does contain a medullary cavity, a hollow space filled with bone marrow. The Spongy bone contains the red bone marrow and the medullary cavity contains the yellow bone marrow. The long bones are wider at the ends than the middle and so provide more stability and strength at the joints. The diaphysis is surrounded by the periosteum i.e. a connective tissue sheath. This outer layer is a site for muscular and tendon attachments and an inner layer comprising of osteoblasts which when facing a fracture work towards its repair. Both ends of the long bone are covered in hyaline cartilage to help protect the bone and aid shock absorption. Eg., humerus, femur, radius, fibula, metacarpals, metatarsals and phalanges. Short Bones Short bones are defined as being approximately as wide as they are long and have the primary function of providing support and stability with little movement. Examples of short bones are the Carpals and Tarsals - the wrist and foot bones. They consist of only a thin layer of the outer compact hard bone with cancellous bone (spongy bone) on the inside along with relatively large amounts of bone marrow. They lack the medullary cavity. Flat Bones They are hard with a spongy layer in between compressed anteroposteriorly. They are thin and bent or curved, e.g., vault of the skull, ribs, sternum, scapulae and part of the hip bone. Irregular Bones Irregular bones, as the name suggests have no symmetry or regularity in shape and size. They have different shapes designed for their specific purposes, e.g. the vertebrae, hip bones and many bones of the base of the skull. They are made of an outer thin layer of compact bone lining an inner spongy bone. Sesamoid Bones This is a unique bone that is embedded within a tendon, e.g. patella (knee cap) develops within the tendon of the quadriceps muscle. Sesamoid bones are named so to their resemblance to sesamoid seeds. Functions of the Skeletal System Protects the vital organs of the body Provides attachments for skeletal muscles, which are linked together by joints. Acts as a reservoir for minerals such as Calcium, Phosphorous, Sodium, Potassium, etc. The red marrow of the bone is responsible for the production of red blood cells, some types of white blood cells, and platelets. Role in movement and locomotion Joints or Articulations An articulation or joint is the connection between two or more bones, regardless of whether they allow movement or not. Function of Joints Mobility and Stability The stability provided by a Joint will depend on The shape of bones involved in the joint. The tone of the muscles surrounding the joint. Ligaments. Classification of Joints Joints are classified in two ways Based on the cementing or packing material at the joint Based on the extent of movement possible at the joint Based on Packing Material (Structure) Based on Movement (Function) Fibrous Joint Synarthroses or Immovable Articulations This is joint where 2 bones at a joint are Fibrous joints are also called Synarthroses as connected by thick, fibrous connective tissue, they don’t allow any appreciable movement e.g. Cranial sutures, joining the bones of the These include all those joints in which the cranium ( skull ). So there is no movement surfaces of the bones are in almost direct possible here. contact, held together by dense fibrous connective tissue. e.g., Joints between the bones of the skull ( except the mandible with skull). Cartilaginous Joint Amphiarthrosis or Partially / Slightly Movable Articulations This is a joint where there is cartilage between 2 bones. There is very little movement possible Cartilaginous joints are also called e.g. The joint between the 2 vertebrae - the Amphiarthrosis since they allow slight intervertebral joint where between the vertebrae movement. E.g., joints between the bodies of is the intervertebral disc made of fibrocartilage, the vertebrae. and the joints between any of the ribs and the sternum where the material connecting the rib to the sternum is costal cartilage (a type of hyaline cartilage). So, there is very little movement possible here. Synovial Joint Diarthrosis or Freely Movable Joints This is a joint where there is a fluid (liquid) - Synovial joints are also called Diarthrosis Synovial fluid in the joint cavity. There is an because they allow free movement. All the joints outer joint capsule covering the articular from the shoulder to the fingers(including the surfaces of the bones. This capsule on the inside shoulder joint, elbow joint, wrist joint, and the is lined by the delicate Synovial membrane various joints of the hand) are all classified as which secretes the synovial fluid. Most mobile synovial joints. Similarly, the joints from the hip joints, e.g. elbow, wrists, hips, etc. So there is to the toes (including the hip joint, knee joint, maximal or free movement possible here. ankle joint, and the various joints of the foot) are also classified as synovial joints. These joints allow for a wide range of movement. The Diarthroses Or Synovial joints. Diarthroidal Joints (Freely Movable Joints) are further classified as Type of Joint Description Hinge Joint (Ginglymus or A hinge joint is formed when the convex end of one bone fits Ginglymoid) into the concave end of another bone. This joint type is considered uniaxial as it allows movement along a single axis. Typically, this axis enables flexion and extension. Common examples of hinge joints in the human body include the elbow, knee, ankle, and interphalangeal joints. Also, knee joint and ankle joints although they may be less typical as they allow a slight degree of rotation or side-to-side movement also. Pivot joint (rotary joint, or A pivot joint is an articulation within a ligamentous ring trochoid joint) between the rounded end of one bone and another bone. This type of joint is uniaxial because, although the bone rotates within this ring, it does so around a single axis. Examples are the atlantoaxial joint between C1 (Atlas) and C2 (Axis) of the vertebrae, and the Radioulnar joint in the forearm. Condyloid Joint A condyloid joint is an articulation between the shallow (Ellipsoidal Joint) depression of one bone and the rounded structure of one or more other bones. This type of joint is biaxial because it permits two axes of movement: flexion/extension and abduction/adduction. E.g., wrist joint (radiocarpal joint between the radius and carpals). Saddle Joint (Sellar Joint) In a saddle joint, the articulating surfaces of the bones have a shape resembling a saddle, with one concave surface and one convex surface. This unique shape allows the bones to fit together in a way that enables a wide range of movement. Saddle joints allow for movement in two axes typically flexion/extension and abduction/adduction. E.g. carpometacarpal joint of the thumb. Ball and Socket Joint A ball and socket joint is characterized by a rounded (Enarthrosis or Spheroidal bone end(ball) fitting into a cup-shaped socket of Joint) another bone. It is classified as a multiaxial joint. Ball and socket joints allow for movement in multiple axes, including flexion/extension, abduction/adduction, and rotation and circumduction. This gives them a wide range of motion and makes  them highly mobile. Examples of ball and socket joints in the human body include the shoulder joint (glenohumeral joint) and the hip joint (acetabulofemoral joint). Gliding Joint A planar joint, or gliding joint, is defined as an (Arthrodial or Plane Joint) articulation between two bones that are both flat and of similar size. This type of joint is multiaxial because it permits many movements; however, surrounding ligaments usually restrict this joint to a small and tight motion. Examples include intercarpal joints, intertarsal joints, and the acromioclavicular joint. The Growth Of Bones Bones initially form as solid masses of minerals, eventually developing hollow centers that house red marrow responsible for blood cell production. A newborn has more bones than an adult, with approximately 270 bones that gradually fuse together over time. Soft spots on the baby's skull, known as fontanelles, allow flexibility during birth and typically close as the baby grows. The skeletal framework of a child contains more flexible cartilage, which gradually hardens into the bone through ossification. Bone growth occurs through the lengthening of the arm, leg, and backbones, primarily at the growth plates located at their ends. These growth plates are responsible for the production of new bone tissue, enabling an increase in bone length. Cartilage Cartilage is a smooth and tough connective tissue that is primarily found in joints and covers the ends of bones. Its structure varies depending on its location and specific function within the body. Cartilage is composed of a matrix comprising cells and fibers made up of proteins called collagen and elastin. Different types of cartilage, such as hyaline cartilage, fibrocartilage, and elastic cartilage, have distinct compositions and arrangements. The matrix of cartilage provides support and flexibility to the tissue. It consists of chondrocytes, which are cells embedded within a gel-like substance known as the ground substance. The ground substance contains fibers, primarily collagen and elastin, that contribute to the structural integrity and elasticity of cartilage. One notable characteristic of cartilage is its avascularity, meaning it lacks blood vessels. Instead, it receives nutrients and oxygen through diffusion from nearby blood vessels in the surrounding tissues. The perichondrium, a connective tissue covering that surrounds some types of cartilage, plays a role in the nourishment of cartilage by facilitating this diffusion process. Overall, cartilage is a crucial component of the body's skeletal system, providing smooth and flexible support at joint surfaces and aiding in the proper functioning of bones and joints. Types of Cartilage Hyaline Cartilage It is a bluish-white translucent tissue and has the fewest cells and fibres of the three. The existent fibres are made of collagen. It forms the embryo of the skeleton and is capable of growth allowing a baby to grow into adulthood. After growth, it remains a thin layer across the ends of the bones lining the surfaces of bones and joints. Also found in the respiratory tract, at the end of ribs, and in the larynx. Fibrocartilage It is made of lots of bundles of collagen, thus providing it with its toughness, and ability to withstand compression. In the backbone, each vertebra is separated from the other by a disc of fibrocartilage. It helps to avoid the vertebrae from grating against each other acting as a shock absorbent. The lubricated surface of the disk prevents the bones from being worn away during movement and the fluid acts as a natural shock absorber. At the hip girdle, it joins both parts of the hip together anteriorly at the joint known as the symphysis pubis. Elastic Cartilage It is made up of collagen as well as elastin giving it its distinct yellow color. It forms the flap of tissue called the epiglottis, the springy part of the outer ear and supports the walls of the canal leading to the middle ear, and the Eustachian tubes that connect each ear with the back of the throat. Also found in the larynx with the hyaline cartilage. Connective Tissue - Packing, filling material between 2 organs/structures Located all around the muscle and its fibres are connective tissues. Connective tissue is composed of a base substance and two kinds of protein-based fibre. The two types of fibre are collagenous connective tissue and elastic connective tissue. Collagenous connective tissue consists mostly of collagen (hence its name) and provides tensile strength. Elastic connective tissue consists mostly of elastin and (as you might guess from its name) provides elasticity. The base substance is called mucopolysaccharide and acts as both a lubricant (allowing the fibres to easily slide over one another), and as a glue (holding the fibres of the tissue together into bundles). The more elastic connective tissue there is around a joint, the greater the range of motion in that joint. Connective tissues are made up of tendons, ligaments, and the fascial sheaths that envelop or bind down, muscles into separate groups. Tendons These are white, glistening fibrous cords, varying in length and thickness, sometimes round, sometimes flat and devoid of much elasticity. They consist almost entirely of white fibrous tissue, the fibrils of which have an undulating course parallel to each other and are firmly united together. They have a relatively poor blood supply. Nerves supplying tendons have special modifications of their terminal fibres named Golgi Tendon Organs. Aponeuroses Aponeuroses are broad, flat, and wide ribbon-shaped connective tissue structures that serve as attachments between muscles and movable structures such as bones, cartilages, ligaments, and fibrous membranes. They are similar in structure to tendons but have a wider and flatter shape. Aponeuroses provide strength and stability to the muscles they connect, distributing the forces generated by muscle contractions over a broader area. They allow for efficient transmission of muscular forces, aiding in movement and providing support to the surrounding structures. Examples include the Aponeurosis of external and internal oblique muscles. Fascia Fascia is a dense and fibrous connective tissue that surrounds and separates muscles, organs, and other structures within the body. It forms a three-dimensional network of fibers that provides support, protection, and compartmentalization. Fascia is composed of collagen, elastin, and other proteins, giving it strength and flexibility. Fascia can be found throughout the body, forming layers that envelop muscles, tendons, ligaments, and bones. It helps to hold organs in place and provides a framework for the transmission of forces generated by muscle contractions. Fascia also plays a role in maintaining proper alignment and coordination between different body structures. There are different types of fascia, including superficial fascia located just beneath the skin, deep fascia that surrounds muscles and groups them into functional units, and visceral fascia that wraps around internal organs. Fascia is highly interconnected, allowing for the transmission of tension and force across different regions of the body. In addition to its structural role, fascia also has important sensory functions. It contains nerve endings and proprioceptors that provide feedback on position, movement, and tension, contributing to the body's sense of spatial awareness and coordination. Overall, fascia is a vital component of the body's connective tissue system, providing structural integrity, support, and coordination between different body structures. Kinesiology Kinesiology can be defined as a science that deals with the study of the human body in motion. The human body movements take place in 3 planes. Coronal Plane - Divides the body into anterior/posterior (front/back) Transverse Plane - Divides the body into superior/inferior halves (top/bottom) Sagittal Plane - divides the body into right/left These planes are imaginary planes and DO NOT EXIST IN THE BODY. Anatomical Reference Terms Anatomical Position - Standing in a neutral position with feet and palms facing forward. Anterior - Front of body or segment. Posterior - Back of body or segment. Lateral - That section that is further away from the midline of the body or segment in its anatomical position. Medial - That side that is closest to the midline of the body or segment body in its anatomical position. Lateral flexion of the vertebral column - Bending or tilting of the trunk from side to side. Superior - A body part lying above another. Inferior - A body part lying below another. Supine - Body lying facing upwards. Prone - Body lying facing downwards. Proximal - The end of the bone lying closest to the body. Distal - The further end of the bone from the body. Ipsilateral - Refers to a position on the same side of the body Contralateral - Refers to a position on the opposite side of the body. Superficial - Towards or on the surface Deep (Internal) - Away from the surface The terms given above are interchangeable, i.e. it depends upon the frame of reference. Types Of Joint Movement 1. Flexion - Movement of part of the body bringing 2 body parts close to each other (reducing the angle at a joint). 2. Extension - Movement of part of the body that takes 2 body parts away from each other (increasing the angle at a joint) Flexion/Extension generally occurs in the SAGITTAL plane. 3. Hyperextesnion - Taking the body into extension beyond the anatomical position. 4. Abduction - Movement AWAY from the center line of the body that divides the body into right and left. 5. Adduction - Movement TOWARD the center line of the body that divides the body into right and left. Abduction/Adduction generally occurs in the FRONTAL (CORONAL) plane. 6. Circumduction - Movement in a circular pattern that involves several joint movements successively. Circumduction occurs in all 3 planes SAGITTAL/FRONTAL (CORONAL) HORIZONTAL (TRANSVERSE). 7. Medial Rotation- An inward ROTATING movement at a ball and socket joint. 8. Lateral Rotation - An outward ROTATING movement at a ball and socket joint. Foot movements (8,9,10,11) 9. Inversion - Movement of the foot TOWARD the midline of the body at the ankle joint. 10. Eversion - Movement of the foot AWAY from the midline of the body at the ankle joint. 11. Plantanflexion - EXTENSION of the foot at the ankle joint. 12. Dorsiflexion - FLEXION of the foot at the ankle joint. 13. Elevation - Moving upwards Scapular movements. 14.Depression - Moving downwards Scapular movement. Hand movements (14,15) 15. Pronation - Rotating hand and wrist from elbow joint so that the palm is facing BACKWARD/DOWNWARD. 16. Supination - Rotating hand and wrist from elbow joint so that the palm is facing FORWARD/UPWARD Levers And Lever Movements A lever is a rigid structure that moves about a fixed point called a fulcrum. In producing body movements, the long bones and skeletal system act as levers. The joints act as fulcrum for these levers. The lever is acted upon by two forces RESISTANCE (R) - The force that must be overcome. It is usually the weight of the body part to be moved or gravity or a handheld weight. EFFORT (E] - The force exerted to overcome the resistance. It is the contraction of the muscle or group of muscles working to move the resistance. Types Of Levers Levers can be categorized into 3 types, determined by the different placement of the EFFORT (E) and RESISTANCE (R). First Class Levers Here the fulcrum (F) is placed between the EFFORT(E) and RESISTANCE (R), e.g. seesaw, scissors. Second Class Levers Here the FULCRUM (F) is at one end, EFFORT (E) at the other end and RESISTANCE (R) in the middle, e.g. a wheelbarrow. Third Class Levers This is seen most commonly in human body movements. The FULCRUM (F) is at one end, RESISTANCE (R) is at the other end and EFFORT (E) is in the middle e.g. forceps. NOTE When analysing the placement of effort, fulcrum and resistance in human movements, look at the attachment of the muscle when examining effort (E). Since most levers in the human body act as third-class levers, they are at a great disadvantage in force, i.e. a muscle must provide far more force to move an object than the weight of the object. At the same time, third-class levers have an advantage in range of motion and speed of movement, e.g. the hamstrings must provide far more force to move the leg and foot than their weight. However, if the knee is flexed, the foot moves a greater linear distance than the attachment of the hamstrings. The effectiveness of the muscle to move a bone, changes, as the bone-muscle angle changes. The most effective position is when the bone-muscle angle is 90 degrees. However, as most muscles cannot achieve this, the bone-muscle angle closest to 90 degrees, is the right angle, at which they are most effective. The class of the lever changes, the moment you change the position of any of the variable factors (fulcrum {F}, effort {E} or resistance {R}). So this is interchangeable.