2 IntroductionThe framework of bones and cartilage that protects our organs and allows us to move is called the skeletal system.The branch of medicine that deals with the preservation and restoration of the skeletal system, articulations (joints), and associated structures is called orthopaedics.
3 The skeletal system performs the following functions: SupportProtection (for internal organs)MovementMineral storageStorage of blood cell-producing cellsStorage of energy
4 Types of Bones There are five principal types of bones based on shape 1. Long bones (e.g. thighs, legs, toes, arms, forearms, and fingers)greater length than widthconsist of a shaft and extremities (ends)slightly curved for strengthconsist mostly of compact bone (dense bone with few spaces) but also contain considerable amounts of spongy bone (bone with large spaces)
5 2. Short bones (e.g. wrist, ankle bones) Somewhat cube-shaped and nearly equal in length and widthSpongy except at the surface where there is a thin layer of compact bone
6 3. Flat bones (e.g. cranial bones, sternum, ribs, scapulas) Generally thin and composed of two more or less parallel plates of compact bone enclosing a layer of spongy boneFlat bones afford considerable protection and provide extensive areas for muscle attachment
7 Irregular bones (e.g. vertebrae, and certain facial bones) Have complex shapes and cannot be grouped into any of the other three categoriesThey vary in the amount of spongy and compact bone
8 5. Sesamoid bonesAre small bones in tendons where considerable pressure develops, for instance, the wristTheir number varies greatly from person to personAll people have at least two sesamoid bones: the patella (kneecap)
9 Divisions of the Skeletal System The adult human skeleton consists of 206 bones grouped as the axial skeleton and the appendicular skeleton.The axial division consists of the bones of the skull, auditory ossicles, hyoid bone, ribs, breastbone, and the backbone.The appendicular division consists of the bones of the upper and lower extremities (limbs), plus the bones called girdles, which connect the extremities to the axial skeleton.There are 80 bones in the axial division and 126 in the appendicular. Listed below are the divisions of the skeletal system.
10 Anatomical Position (AP) AP is the reference position used to describe the location of anatomical parts and to describe and explain human movement.The subject is:standing upright with feet flat on the floorarms at the side of the bodyfacing the observerpalms are facing forward (supinated)
12 Directional TermsNote: the midline is an imaginary vertical line that divides the body into equal left and right sidesSuperior: nearer the heade.g. the heart is superior to the liverInferior: farther away from the heade.g. the stomach is inferior to the lungs
13 Directional TermsAnterior (ventral): nearer to or in front of the bodye.g. the sternum is anterior to the heartPosterior (dorsal): nearer to or at the back of the bodye.g. the esophagus is posterior to the trachea
14 Directional Terms Medial: closer to the midline of the body e.g. the ulna is on the medial side of the forearmLateral: farther away from the midline of the bodye.g. the ear is lateral to the nose in all individuals
15 Directional TermsProximal: nearer to the attachment of an extremity (limb) tothe trunk; nearer to the point of origine.g. the humerus is proximal to the radiusDistal: farther from the attachment of an extremity (limb) to thetrunk; farther away from the point of origine.g. the phalanges are distal to the carpals (wrist bones)
16 Directional Terms Superficial: on or near the surface of the body e.g. the skin is the most superficial organ of the bodyDeep: farther away from the surface of the bodye.g. the ribs are deep to the skin of the chest
17 Planes of Motion and Axes Biomechanics is the study of human movements through the use of physics. As such, biomechanics has its own language and terminology. The language of biomechanics establishes a common reference system of standard terms. Planes and axes of motion are an important part of this language.
18 Planes of MotionA plane of motion can be defined as the two dimensional space cut by a moving body or the plane along which movements occur. There are generally three planes used to describe segmental and body movements in physical activity. These are:Sagittal planea vertical plane that cuts the body into right and left sidesFrontal planevertical plane that cuts the body into anterior (front) and posterior (back) partsTransverse planehorizontal plane that cuts the body into superior and inferior parts
20 Anatomical AxesAn axis is the point about which rotation of a body or of a body segment occurs. There are three axes of rotation. Each axis is associated with a plane of motion and the axis is perpendicular to that plane.Horizontal axis (…think East and West)passes through the body from side to sideperpendicular to the sagittal planeAntereoposterior axis (axis)passes through the body from front to backperpendicular to the frontal planeLongitudinal axis (…think North and South pole)passes through the body from top to bottomperpendicular to the transverse plane
21 Planes & MovementsMovements in the sagittal plane around a horizontal axis(e.g. front roll, back roll, cycling, running)Flexionflexion at a joint results in a decrease of the angle between the two segments that meet at that jointExtensionextension at a joint results in an increase of the angle between the two segments that meet at that jointif the movement occurs beyond the extended position, the action is called hyperextension
22 Examples of flexion and extension shoulder flexion and extensionelbow flexion and extensionwrist flexion and extensionfingers flexion and extensionhip flexion and extensionknee flexion and extensionankle dorsi flexion and plantar flexiontilt of pelvis underDorsi flexion: bringing the toes toward the shinPlantar flexion: pointing the toes away from the shin (toward the floor)
23 Planes & MovementsMovements in the frontal plane around a antereoposterior axis(e.g. cartwheel, jumping jacks, galloping)Abductionoccurs when a body part is moved away from the midline of the bodye.g. shoulder, hip, fingersAdductionoccurs when a body part is moved toward the midline of the bodyremember “add to your midline”
24 Movements & Planes Inversion Turning the sole of the foot inward at the ankle (so the sole of the foot faces toward the midline)Eversionturning the sole of the foot outward at the ankle (so the sole of the foot faces away from the midline)Elevationraising a part to a superior positione.g. raising your shoulders toward your ears; closing your jawDepressionlowering a part to an inferior positione.g. lowering your shoulders to normal or lower than normal position; lowering your jaw to an open position
25 More… Protraction Sticking jaw out (pouting) Retraction Bringing jaw back to anatomical positionLateral bendingbending of the spinal column in the frontal plane to the left or righte.g. bending side to side at the waist
26 And More… Movements in the transverse plane around a longitudinal axis (e.g. twist, pirouette)Rotationthe movement of a bone around its own axis; this is also known as a pivote.g. the head, neck, and trunk can pivot around the longitudinal axisInternal (medial) rotationRotation towards the midlineE.g. turning forearn in towards bodyExternal (lateral) rotationRotation away from midlineE.g. turning forearm away from body
27 More…Pronationrotation of the forearm and hand to the palms down positionSupinationrotation of the forearm and hand to the palms up position (remember holding a cup of “soup”)ProtractionShoulder rounding (hunching shoulders)RetractionBringing shoulders back to anatomical position, or squeezing shoulder blades together at back
28 Special movements Circumduction a combination of abduction, adduction, flexion and extensionthis action describes a circlee.g. moving the shoulder in a circle (swimming, windmill throw in baseball); can also be done at the hip jointOppositionBringing thumb towards fingersRepositionReturning thumb back to anatomical position
29 Skeletal Surface Markings The surfaces of bones have various structural features adapted to specific functions. These features are called surface markings. Long bones that bear a great deal of weight have large, rounded ends that can form sturdy joints, for example. Other bones have depressions that receive the rounded ends.
30 Depressions and Openings Foramenan opening through which blood vessels, nerves, or ligaments passExample:Meatusa tubelike passageway running within a boneParanasal sinusan air-filled cavity within a bone connected to the nasal cavityFossaa depression in or on a bone
31 Processes that form Joints Condylea large, rounded articular prominenceExample:Heada rounded articular projection supported on the constricted portion (neck) of a boneFaceta smooth, flat surface
32 Processes to which tendons, ligaments and other connective tissues attach Tuberositya large, rounded, usually roughened processExample:Spinous processa sharp, slender projectionTrochantera large, blunt projection found only on the femurCresta prominent border or ridge