Human Anatomy. Table of Contents. Introduction: What is the Structure of My Body? Chapter 2. Introduction

Transcription

1 Human Anatomy Chapter 2 Sport Books Publisher 1 Table of Contents Introduction Terms and Concepts Worth Knowing Anatomical Position Directional Terms Planes of the Body The Musculoskeletal System Bones Joints Muscles Sport Books Publisher 2 Introduction: What is the Structure of My Body? Human Anatomy: The study of the structures that make up the human body and how those structures relate lt to each other. Structure determines function: The structures of the human body are well-designed for efficient movement. Sport Books Publisher 3 1

2 Terms and Concepts Worth Knowing Sport Books Publisher 4 Anatomical Position Sport Books Publisher 5 Description Standing erect Facing forward Arms hanging at the sides Palms facing forward and the thumbs outward Legs straight Heels, feet and great toes parallel to each other The starting reference point for describing the human body It is universally accepted It is used in all anatomical descriptions Sport Books Publisher 6 2

3 Directional Terms Sport Books Publisher 7 Reminder: All directional terms are based on the assumption that the body is in the anatomical position. Sport Books Publisher 8 Midline Lateral-Medial Lateral Away from the midline of the body Lateral Medial Medial Toward the midline E.g., Your ears are lateral to your cheeks and your cheeks are medial to your ears Sport Books Publisher 9 3

4 Distal-Proximal Distal Further from some specified region Proximal Closer to some specified region E.g., With respect to the trunk, the hands are distal to the arms and the arms are proximal to the hands. E.g., With respect to nerves and blood vessels, proximal also means "toward the origin" and distal means "away from the origin" E.g., The colon is the distal portion and stomach is the proximal portion of the digestive tract Thigh is proximal to the leg Leg is distal to the thigh Leg is proximal to the foot Foot is distal to the leg Sport Books Publisher 10 Anterior-Posterior Anterior Skeleton Posterior Skeleton Anterior In front of or front of your body Posterior Behind or back of your body E.g., Your lips are anterior to your teeth and your teeth are posterior to your lips E.g., In the anatomical position, your palms are facing anteriorly Sport Books Publisher 11 Superior-Inferior Superior Above Inferior Below E.g., Your lips are superior to your chin and your chin is inferior to your lips The collar bone is superior to the rib cage The hip bone is inferior to the rib cage Sport Books Publisher 12 4

5 Supine Lying on the back E.g., Performing a bench press Prone Lying face down E.g., Preparing to perform a push-up Sport Books Publisher 13 Planes of the Body Sport Books Publisher 14 Planes Imaginary flat surfaces that divide the human body They are used to: divide the body for further identification of particular areas describe different movements or actions Always refer to the body in the anatomical position Sport Books Publisher 15 5

6 Median plane or midsagittal plane Median Plane A vertical plane that bisects the body into equal right and left halves Sagittal plane is any plane parallel to the median plane Sport Books Publisher 16 Coronal plane or frontal plane Coronal Plane A vertical plane that bisects the body into front and dback It is at right angles to the median plane Sport Books Publisher 17 Transverse plane or horizontal plane A horizontal plane that bisects the body into top and bottom It is at right angles to both the median and coronal planes Transverse Plane Sport Books Publisher 18 6

7 Center of gravity The point at which the median, frontal, and transverse planes intersect Sport Books Publisher 19 Movements Sport Books Publisher 20 Movement around a joint may be around any one (or more) of three axes Y Z X Most movements are found in pairs for every movement, there is generally a movement that is opposite to it Sport Books Publisher 21 7

8 Flexion-Extension Flexion reduces the angle between two bones at a joint Extension increases the angle between two bones at a joint Usually a sagittal plane movement E.g., Biceps curl Lifting the weight reduces the angle at the joint = flexion Lowering the weight increases the angle at the join = extension Flexion Extension Sport Books Publisher 22 Dorsiflexion-Plantar flexion Modified flexion with respect to the ankle joint Dorsiflexion bringing the top of the foot toward the lower leg or shin Dorsiflexion Plantar flexion planting the foot Plantar Flexion Sport Books Publisher 23 Abduction-Adduction Abduction moving a segment away from the midline of the body Adduction moving segment toward the midline of the body Frontal plane movement Abduction E.g., The motions of the arms and legs during a jumping jack Hint: Abduct = take away from the midline Adduct = add toward the midline Adduction Sport Books Publisher 24 8

9 Circumduction A cone of movement that does not include any rotation Occurs when flexion-extension movements are combined with abduction-adduction movements E.g., Tracing an imaginary circle in the air with your index finger The tip of your finger represents the base of the cone, while your knuckle forms the apex of this conical motion Sport Books Publisher 25 Rotation Turning a bone along its longitudinal axis Medial rotation rotation toward the midline Lateral rotation rotation away from the midline Sport Books Publisher 26 Pronation-supination Movements related to the forearm and hand Pronation when the palm is P ti moved to face posteriorly Pronation Supination when the palm is moved to face anteriorly (Hint: you can hold a bowl of soup) Supination Sport Books Publisher 27 9

10 Inversion-Eversion Movements related to the sole of the foot Inversion When the sole is turned inward (as when you "go over" on your ankle) Inversion Eversion When the sole is turned outward or away from the median plane of the body Eversion Sport Books Publisher 28 The Musculoskeletal System Sport Books Publisher 29 The Bare Bones of Human Anatomy Sport Books Publisher 30 10

11 The function of the skeletal system is to: provide a supporting framework protect body organs Bone is a living tissue complete with blood supply and nerves Sport Books Publisher 31 Bone Sport Books Publisher 32 Bone Shape The shapes of the bones allow them to perform specific functions more effectively Sport Books Publisher 33 11

12 Short Bones: Include bones of ankle (i.e., tarsals) and wrist (i.e., carpals) Serve as good shock absorbers Carpals Tarsals Sport Books Publisher 34 Long bones: Femur Humerus Include femur of the thigh, humerus of the upper arm, and others Any bone whose length greatly exceeds its diameter Provide levers for movement Sport Books Publisher 35 Flat bones: Include bones of the skull, scapula, ribs, sternum, and clavicle Largely protect underlying organs Sport Books Publisher 36 12

13 Irregular Bones: Include bones of your face and vertebrae Bones that cannot be placed in other groups Fulfill special functions Vertebrae Facial bones Sport Books Publisher 37 Sesamoid bones: Includes the patella Oval shape, like a pea, and found in tendons Patella Sport Books Publisher 38 Bone Composition Bone is very strong for its relatively light weight The major components of bone are: Calcium carbonate Calcium phosphate Collagen Water Cortical Bone Spongy Bone Medullary (marrow) cavity Sport Books Publisher 39 13

14 Bone Composition Calcium carbonate and calcium phosphate: Make up 60 to 70 percent of bone weight Provide much of the bone s stiffness and resistance to pressing or squeezing forces Collagen (a protein): Gives bone its characteristic flexibility and contributes to its ability to resist pulling and stretching forces With aging, collagen is lost progressively and bone becomes more brittle. Water Bone consists of much smaller proportion of water than other body parts Sport Books Publisher 40 Bone Classification According to the degree of porosity, bone can be classified into two general categories: Cortical bone (low porosity) Spongy or cancellous bone (high porosity) Sport Books Publisher 41 Porosity Cancellous bone Compact Bone High (Low mineral Low (High mineral content and high collagen) content and low collagen) Sport Books Publisher 42 14

15 Porosity Cancellous bone High (Low mineral content and high collagen) Compact Bone Low (High mineral content and low collagen) Structure Honey comb Compact Sport Books Publisher 43 Porosity Cancellous bone Compact Bone High (Low mineral Low (High mineral content and high collagen) content and low collagen) Structure Honey comb Compact Characteristic Provides more flexibility but is not as stress resistant Stiffer and can resist greater stress but less flexible Sport Books Publisher 44 Porosity Cancellous bone High (Low mineral content and high collagen) Compact Bone Low (High mineral content and low collagen) Structure Honey comb Compact Characteristic Function Provides more flexibility but is not as stress resistant Shock absorption due to its better ability to change shape Stiffer and can resist greater stress but less flexible Withstanding stress in body areas that are subject to higher impact loads Sport Books Publisher 45 15

16 Porosity Cancellous bone High (Low mineral content and high collagen) Compact Bone Low (High mineral content and low collagen) Structure Honey comb Compact Characteristic Function Provides more flexibility but is not as stress resistant Shock absorption due to its better ability to change shape are important Stiffer and can resist greater stress but less flexible Withstanding stress in body areas that are subject to higher impact loads Location e.g., vertebrae Long bones (e.g., bones of the arms and legs) Sport Books Publisher 46 Effect of Fitness on Bone When bones are subjected to regular physical activity and habitual loads, they tend to become more dense and more mineralized E.g., Right forearm bones of right-handed tennis players are more dense than their left ones due to more frequent use Inactivity works in the opposite direction, leading to a decrease in weight and strength. E.g., Loss of bone mass has been noted in bed-ridden patients, inactive senior citizens, and astronauts Sport Books Publisher 47 The Human Skeleton Sport Books Publisher 48 16

17 Axial Skeleton Sport Books Publisher 49 Axial Skeleton Skull Sternum Ribs Vertebral Column Sport Books Publisher 50 Skull Divided into two parts: a) Calvaria b) Face Sport Books Publisher 51 17

18 a) Calvaria Frontal Bone Parietal Bone Occipital Bone Temporal Bone Sport Books Publisher 52 Calvaria May be fractured in blows to the skull (e.g., being checked and hitting the skull on the ice in hockey) Temporal bone: Most fragile of the calvaria bones Overlies one of the major blood vessels If fractured and displaced internally = medical emergency (picture) Sport Books Publisher 53 b) Facial Bones Lacrimal Bone Nasal Bone Zygomatic Bone Maxilla Bone Mandible Bone Sport Books Publisher 54 18

19 Facial Bones Often broken in contact sports due to rough impact Some fractures of the maxilla (upper jaw) can leave the lower face separated from the upper face Sport Books Publisher 55 Vertebral Column 7 Cervical Vertebrae (of the neck) Lumbar vertebra, superior view 12 Thoracic Vertebrae (of the chest) 5 Lumbar Vertebrae (of the lower back) Sacrum (mid-line region of buttocks) Lumbar vertebra, lateral view Coccyx (4 or 5 fused vertebrae of the tail bone) Sport Books Publisher 56 Vertebral Column Vertebrae are arranged in a cylindrical column interspersed with fibrocartilaginous (intervertebral) discs Function: Provides strong and flexible support for the body and the ability to keep the body erect The point of attachment for muscles of the back Protects the spinal cord and nerves Absorbs shock through the intervertebral discs without causing damage to other vertebrae Sport Books Publisher 57 19

20 Ribs Twelve pairs Made up of : Bone Cartilage, which strengthens the chest cage and permits expansion Curved and slightly twisted, making them ideal for protecting the chest area Sport Books Publisher 58 Ribs All 12 pairs of ribs articulate with the twelve thoracic vertebrae posteriorly Classified into three groups based on anterior attachment: True ribs 1-7 attach to both the vertebrae and the sternum False ribs 8-10 attach only to the sternum indirectly, through 7 th rib Floating ribs 11 and 12 attach only to the vertebral column Sport Books Publisher 59 The Ribs Manubrium Sternal Body True Ribs (1-7) Xiphoid Process Costal Cartilages Floating Ribs (11-12) False Ribs (8-10) Sport Books Publisher 60 20

21 Sternum Mid-line breast bone The clavicles and ribs one to seven articulate with the sternum Sternum comprised of the manubrium, sternal body, and xiphoid process Sport Books Publisher 61 Appendicular Skeleton Sport Books Publisher 62 Appendicular skeleton Consists of: 1. The pectoral girdle (chest) 2. The upper limb 3. Pelvic girdle (hip) 4. The lower limb Sport Books Publisher 63 21

22 1.Pectoral Girdle Consists of: Scapula (shoulder blade) Clavicle (collar bone) Allows the upper limb great mobility The sternoclavicular joint is the only point of attachment between the axial skeleton and the pectoral girdle Sport Books Publisher Upper Limb Humerus The arm bone Shoulder to elbow Rdi Radius and dulna The forearm bones Elbow to wrist Radius is located on the thumb side of the hand When you pronate the forearm, the radius is actually crossing over the ulna try it yourself Sport Books Publisher 65 Upper Limb Carpals Proximal Phalanx Metacarpals Distal Phalanx Middle Phalanx Phalanges Sport Books Publisher 66 22

23 3. Pelvic Girdle Formed by pair of os coxae (hip bones) Supports the bladder and abdominal contents Attachment: Posteriorly join with the sacrum Anteriorly join to each other Laterally join to the head of thigh bone (femur) in a cup-shaped acetabulum Sport Books Publisher Lower Limb Femur Thigh bone From hip to knee Patella Knee cap Sesamoid bone in the tendon of the quadriceps (thigh) muscles Sport Books Publisher 68 Lower Limb Tibia and Fibula Leg bones From knee to ankle Tibia is medial and fibula is lateral Medial malleolus and Lateral malleolus The distal ends of the tibia and fibula, respectively Commonly referred to as the "ankle bones" Can be easily palpated Lateral malleolus Medial malleolus Sport Books Publisher 69 23

24 Lower Limb Talus Tarsals Ankle bones Calcaneus or heel bone Talus Calcaneus Metatarsals 5 bones of the foot Unite with the toes Metatarsals Phalanges Toe bones Three per toe, except the big toe proximal, middle, and distal Tarsals Phalanges Sport Books Publisher 70 Joints of the Human Body Joint Classification Synovial Joints Characteristics of synovial joints Types of synovial joints Naming Joints: Pectoral Girdle Upper Limb Pelvic Girdle Lower Limb Sport Books Publisher 71 A joint is a point of connection between two bones Strands of connective tissue and ligaments hold the bones together and ensure the stability of joints Sport Books Publisher 72 24

25 Joint Classification Joints are classified according to their motion capabilities: Synarthroses Immovable Amphiarthroses Slightly movable Diarthroses Allow the greatest amount of motion Sport Books Publisher 73 Joint Classification Joints are further classified by the material that joins them: Fibrous joints Allow no movement E.g., sutures of the skull Cartilaginous joints Allow limited movement E.g., intervertebral discs Synovial joints Allow large range of movements E.g., knee joint Sport Books Publisher 74 Characteristics of Synovial Joints Hyaline cartilage A protective layer of dense white connective tissue that covers the ends of the articulating bones Joint cavity Synovial membrane Covers joint cavity, except over the surfaces of the articular cartilage Secretes the lubrication fluid Synovial fluid Lubricates the joint Capsule May or may not have thickenings called intrinsic ligaments Extrinsic ligaments Support the joint and connect the articulating bones of the joint Sport Books Publisher 75 25

26 Types of Synovial Joints There are three basic types of synovial joints: Unilateral (rotation about only one axis) Biaxial joints (movement about two perpendicular axes) Multiaxial joints (movement about all three perpendicular axes) Sport Books Publisher 76 Types of Synovial Joints Synovial are further classified into: 1. Hinge Joint 2Pi 2. Pivot tjit Joint 3. Condyloid Joint 4. Saddle-shaped joint 5. Ball and Socket Joint 6. Plane Joint Sport Books Publisher Hinge (Ginglymus) Joint Uniaxial Has one articulating surface that is convex, and another that is concave E.g., humero-ulnar elbow joint, interphalangeal joint Sport Books Publisher 78 26

27 Pivot Joint Uniaxial One bone rotates around one axis E.g., head of radius rotating against ulna Sport Books Publisher 79 Condyloid (Knuckle) Joint Biaxial (flexion-extension, abduction-adduction) The joint surfaces are usually oval One joint surface is an ovular convex shape, and the other is a reciprocally shaped concave surface E.g., metacarpophalangeal joint Sport Books Publisher 80 Saddle Joint Biaxial (flexion-extension, abduction-adduction) The bones set together th as in sitting on a horse E.g., carpometacarpal joint of the thumb Sport Books Publisher 81 27

28 Ball and Socket Joint Multiaxial (rotation in all planes) A rounded bone is fitted into a cup-like receptacle E.g., shoulder and hip joints Sport Books Publisher 82 Plane (Gliding) Joint Uniaxial (permits gliding movements) The bone surfaces involved are nearly flat E.g., intercarpal joints and acromioclavicular joint Sport Books Publisher 83 Joints of the Pectoral Girdle Sport Books Publisher 84 28

29 Sternoclavicular Joint Connects the clavicle to the sternum The only joint connecting the pectoral girdle to the axial skeleton True synovial joint strengthened by an intracapsular disc and extrinsic ligaments Sport Books Publisher 85 Acromioclavicular Joint Unites the lateral end of the clavicle with the acromion process of the scapula Where shoulder separations often occur in sports such as hockey, baseball, and football Sport Books Publisher 86 Glenohumeral Joint Connects the upper limb and the scapula Typical multiaxial joint Wide range of movement at this joint Compromise = relative lack of stability Sport Books Publisher 87 29

30 Joints of the Upper Limb Sport Books Publisher 88 Elbow Joint There are three joints at the elbow: Humero-ulnar joint Medial Between the trochlea of the humerus and the olecranon process of the ulna Humero-radial joint Lateral Between the capitulum of the humerus and the head of the radius Radio-ulnar joint Between the radius and the ulna Sport Books Publisher 89 Elbow Joint Humerus Humero-Radial Joint Humero-Ulnar Joint Radius Radio-Ulnar Joint Ulna Anterior View Posterior View Sport Books Publisher 90 30

31 Joints of The Wrist Radio-carpal joint Between distal end of the radius and the carpals Movements: Flexion-extension and abductionadduction Sport Books Publisher 91 Joints of the Hand Intercarpal joints Between the bones of the carpus Gliding joints Carpometacarpal joint Between carpals and metacarpals The characteristics of carpometacarpal joint of the thumb allows the range of movement necessary for opposition Sport Books Publisher 92 Joints of the Hand Metacarpophalangeal joints Joints between metacarpals and carpals The knuckles Movements: Flexionextension and abductionadduction Interphalangeal joints Joints between the phalanges Permit flexion-extension Sport Books Publisher 93 31

32 Joints of the Pelvic Girdle Sport Books Publisher 94 Hip Joint - Between the head of the femur and the cup (acetabulum) of the hip bone (os coxae) Like the shoulder joint, the hip joint is a: ball and socket joint multiaxial joint that allows flexion-extension, abductionadduction, and circumduction Sport Books Publisher 95 Hip Joint Unlike the shoulder, the hip joint is very stable The most stable synovial joint due to: deepened socked (via lip or fibrocartilaginous labrum ) an intrinsic and very strong extrinsic ligaments Dislocation in sports is not common, but can occur in car collisions Dislocate the head posteriorly or drive it through the posterior lip of the actetabulum Sport Books Publisher 96 32

33 Lower Limb Joints Sport Books Publisher 97 Knee Joint Tibiofemoral or knee joint Incredible range of movement (flexion extension) Sport Books Publisher 98 Knee Joint The knee joint is relatively stable due to additional structural supports from: Menisci Shock-absorbing bi fibrocartilaginous il i discs Anterior and posterior cruciate ligaments Located in the center of the joint Lateral and medial collateral ligaments Extend from the sides of the femur to the tibia and fibula Musculature that surrounds it Sport Books Publisher 99 33

34 Knee Joint Movements: Primary action is flexion-extension (e.g., squat or jump) When flexed, medial and lateral rotation can also occur Sport Books Publisher 100 Ankle Joint Talocrural or ankle joint Includes several bones: Medial and lateral malleoli of the tibia and fibula Head of the talus Calcaneus (heel bone) Calcaneus Lateral malleolus Medial malleolus Talus Sport Books Publisher 101 Foot and Toe Joints Intertarsal joints Between tarsals Transverse tarsal joint Between the proximal and distal row of tarsal bones Movement: inversion-eversioneversion of the sole of the foot This action enables you to adjust to uneven ground when walking or running Tarsals Sport Books Publisher

35 Foot and Toes Joints As in the hand, there are joints between the tarsal bones, metatarsals, and phalanges: Tarsometatarsal Metatarsophalangeal Interphalangeal Strengthened by plantar ligaments, which aid in maintaining the arch of the foot Tarsometatarsal Metatarsophalangeal Interphalangeal Sport Books Publisher 103 Muscles of the Human Body Sport Books Publisher 104 Over 600 muscles in the human body Allow the skeleton to move Both ends of a muscle must be attached to bone to create movement Origin or proximal attachment: the attachment closer to the center of the body Insertion or distal attachment: the attachment away from the center of the body Sport Books Publisher

36 Facial Muscles Sport Books Publisher 106 Various functions of the facial muscles: Enable you to change expression and display emotions visibly Allow you to close your eyes and blink Essential for opening and closing the mouth for: keeping food in the mouth chewing forming words Tongue Functions: allows you move food around in your mouth and get it to a position to be swallowed allows you to pronounce words and speak intelligibly Sport Books Publisher 107 Neck Muscles Sport Books Publisher

37 Neck Muscles There are muscles posterior, lateral, and anterior to the neck or cervical region These muscles: Maintain the position of the head on the 1st cervical vertebra (atlas), i.e., they hold up our head Also permit a wide range of movement Sport Books Publisher 109 Sternocleidomastoids The most important anterior pair of muscles Movements: Acting together, they flex the head toward the chest Individually, each muscle tilts the face up and toward the opposite side Sport Books Publisher 110 Erector spinae muscles Important posterior neck muscles Attach to sacrum inferiorly and to the skull superiorly Maintain your erect position Also called anti-gravity muscles When someone faints, these muscle no longer function and the body falls face forward to the ground Sport Books Publisher

38 Trapezius, upper fibers Important lateral neck muscles Movements: Acting alone, tilt the head to the one side Together, assist in neck extension Trapezius upper fibers Sport Books Publisher 112 Muscles of the Pectoral Girdle Sport Books Publisher 113 Muscles acting to hold the pectoral girdle to the chest wall: Anterior Pectoralis Major Pectoralis Minor Subclavius Serratus Anterior Posterior Trapezius Latissimus Dorsi Levator Scapulae Rhomboids Major Rhomboids Minor Sport Books Publisher

39 Pectoral Girdle Anterior Pectoralis Minor Pectoralis Major Serratus Anterior Sport Books Publisher 115 Pectoral Girdle Posterior Trapezius (upper fibers) Trapezius (middle fibers) Rhomboids Teres Major Trapezius (lower fibers) Latissimus Dorsi Sport Books Publisher 116 Muscles that attach from the scapula to the humerus and act across the shoulder joint: Anterior Subscapularis Posterior Supraspinatus Infraspinatus Teres Minor Teres Major Lateral Deltoid Sport Books Publisher

40 Anterior Lateral Subscapularis Deltoid (anterior fibers) Deltoid (middle fibers) Deltoid (posterior fibers) Sport Books Publisher 118 Superior and Posterior Supraspinatus Infraspinatus Teres Minor Combined with Subscapularis, these muscles are the rotator cuff muscles Can be remembered by using the mnemonic SSIT Sport Books Publisher 119 Muscles of the Arm Sport Books Publisher

41 Anterior Compartment Biceps Brachii Attaches: proximally to distal part of humerus (short head) distally to proximal part of ulna (together with long head) Biceps Brachii Movements of the arm: Flexor of the elbow joint Supinator of the forearm Sport Books Publisher 121 Anterior Compartment Brachialis Attaches: proximally to the anterior surface of the humerus distally to the coronoid process of the ulna Movements of the arm: Powerful flexor of the elbow joint Works with the biceps brachii Brachialis Sport Books Publisher 122 Posterior Compartment Triceps Brachii Attaches: proximally to humerus (medial and lateral head) distally to the olecranon process of the ulna (together with long head) Triceps Movement of the arm: Elbow extensor Sport Books Publisher

42 Muscles of the Forearm Sport Books Publisher 124 Forearm muscles act on the elbow, wrist, and digits (fingers) Flexor-pronator group Attached to the medial epicondyle of the humerus Extensor-supinator Attached to the lateral epicondyle of the humerus Sport Books Publisher 125 Flexors of the forearm Extensors of the forearm Anterior View Posterior View Sport Books Publisher

43 Muscles of the Pelvic Girdle Sport Books Publisher 127 Anterior Muscles Iliopsoas Sport Books Publisher 128 Posterior and Lateral Muscles Gluteals Include 3 muscles: Gluteus maximus Largest of the three muscles Principal extensor of the hip Gluteus medius and minimus Assist in hip extension Abduct the hip Gluteus Medius Gluteus Maximus Lateral or external rotators of the hip Six little muscles Sport Books Publisher

44 Thigh Muscles Sport Books Publisher 130 Medial Compartment Pectineus Gracilis Adductors: Adductor longus Adductor brevis Adductor magnus Primary action: adduct the thigh toward the midline Pectineus Adductor Brevis Adductor Longus Adductor Magnus Gracilis Sport Books Publisher 131 Anterior Compartment Quadriceps Rectus femoris Vastus lateralis Vastus intermedius Vastus medialis Sartorius Lies anterior to the quads Used to sit cross-legged Primary knee extensors Sartorius and Rectus femoris also aid in flexion of the hip Sartorius Vastus Lateralis Vastus Intermedius Rectus Femoris (cut) Vastus Medialis Sport Books Publisher

45 Posterior Compartment Hamstrings composed of three muscles: Biceps femoris (2 heads) Semitendinosus Semimembranosus Attach: proximally to the ischial tuberosity distally, biceps femoris to the head of the fibula and semitendinosus and semimembranosus to the tibia Primary flexors of the knee Also extend the hip Long Head of Biceps Femoris Short Head of Biceps Femoris Semitendinosus Semimembranosus Sport Books Publisher 133 Leg Muscles Sport Books Publisher 134 Anterior Compartment Tibialis anterior Extensor hallucis longus (deep) Extensor digitorum (deep) Arise from: anterolateral surface of the tibia interosseous membrane between the tibia and the fibula anterior surface of the fibula Cross anterior to the ankle joint Attach distally to: medial side of the foot distal phalanges of the digits Movements: Primary dorsiflexors of the ankle Extensors of the toes Tibialis anterior further inverts the foot Peroneus tertius assists in eversion Tibialis Anterior Sport Books Publisher

46 Lateral Compartment Peroneus longus Peroneus brevis Attach proximally to the lateral surface of the tibia Pass behind the lateral l malleolus Attach distally to the foot Movements: Plantar flexors Evert the sole of the foot Peroneus Longus Peroneus Brevis Sport Books Publisher 136 Posterior Compartment Superficial group Gastrocnemius has two proximal heads attaches proximally to the medial and lateral epicondyles of the distal femur Soleus attaches proximally to proximal ends of tibia and fibula Gastrocnemius and soleus come together to form the Achilles tendon Principal plantar flexors of the ankle Gastrocnemius Soleus Achilles Tendon Sport Books Publisher 137 Posterior Compartment Deep group Pi Primary role is flexion of fthe toes Assist in plantar flexion of the ankle Sport Books Publisher

47 Muscles of the Abdomen Sport Books Publisher 139 Obliques External oblique Internal oblique Internal oblique Transversus abdominis Reach from the vertebral column, ribs, and hip bone posteriorly Meet in the midline anteriorly through rectus abdominis Functions: Lateral bending of the abdomen Rotation of the abdomen Extension of the abdomen during forced inspiration Allow the development of a pregnant uterus Contract to help expel fecal contents from the rectum External oblique Transversus abdominis Sport Books Publisher 140 Rectus Abdominis Paired midline muscles Rectus Sheath Powerful flexor of the anterior abdominal wall Strengthening of the abdominal muscles is a very important part of back therapy, because the abdominals act to support the back Rectus Abdominis Linea alba Sport Books Publisher

48 Summary Human anatomy deals with the structures that make up the human body (structure determines function) The bones, joints, and muscles that make up the musculoskeletal system allow numerous movements to occur, with varying degrees of: Motion capabilities Strength Flexibility Bones provide the structural framework necessary for support Muscles supply the power Joints supply the mechanism that allows human movement to occur Sport Books Publisher 142 Discussion Questions 1. Describe the anatomical position and discuss its relationship to the directional terms of the body. 2. What are the four major planes that bisect the body? Provide an example of a movement that occurs in each plane. 3. Define three types of movement and give an example of each. 4. Name the three types of muscle. How do slow twitch and fast twitch fibbers differ? 5. Differentiate among agonists, antagonists, and synergists. What role is played by the fixators? 6. Which synovial joints allow the greatest amount of movement? The least? 7. Outline the components and roles of the axial and appendicular skeletons. 8. What structures present at the knee provide additional support to this joint? 9. What type of joint is the knee? 10. What muscles are primarily responsible for maintaining an upright posture? 11. The posterior group of leg muscles are commonly called the hamstrings. What three muscles combine to form the hamstrings? What role do they play? Sport Books Publisher