SKELETAL SYSTEM (APPENDICULAR SKELETON) AND ARTICULATIONS

Transcription

1 5-1 LAB 5: SKELETAL SYSTEM (APPENDICULAR SKELETON) AND ARTICULATIONS In this lab you will continue to study the skeletal system. appendicular skeleton and associated articulations (joints) The focus of this lab is the Prelab Complete p 1, 5, 9, 13-16, 21-22, 25, 27 Complete the flashcards by identifying the labeled structures on p 3, 7, 11, 17, 19 Label the diagram of the knee on p. 23 Objectives 1. the names of the bones and the bone landmarks (bumps and depressions), as indicated for each bone 2. the location of the bones in the body, and the structural relevance of the landmarks 3. identify bone landmarks on the body surface by palpation 4. the difference between left and right bones in the appendicular skeleton 5. the names of the joints (articulations) and their structural / functional classification Learning the skeletal system in detail will require continual review. Refer to the flash cards, locate the bones and landmarks on your own body, handle the bones in the lab. APPENDICULAR SKELETON The appendicular skeleton consists of the girdle and the arm bones girdle and the leg bones Review the bones of both the axial and appendicular skeleton before beginning this lab

2 5-2 PART I : UPPER LIMB BONES STATION 1 PECTORAL GIRDLE Examine the scapula and clavicle both on the disarticulated and articulated skeletons. Note the "landmarks" (specific bumps and depressions) as requested. 1. Clavicle Acromial end (flat) Sternal end (cone shaped) NOTE: Inferior surface is rougher than superior 2. Scapula Identify the following on the bones and label on the diagrams; palpate structures indicated with a * on your body or your lab partner s body Spine: Site of attachments of trapezius and deltoid muscles, laterally becomes acromion process. * Supraspinous fossa: supraspinatus muscle arises from this area. Infraspinous fossa: infraspinatus muscle arises from this area Acromion process: tip of the shoulder (no muscle) * Coracoid process: three muscles attach here. - coracobrachialis, pectoralis minor, short head of the biceps brachii. Glenoid fossa: head of the humerus fits here. NOTE: practice differentiating left from right scapulae.

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5 5-5 STATION 2 ARM / FOREARM 1. Humerus Head: articulates with of scapula Surgical neck: common fracture site. Greater tubercle: 3 rotator cuff muscles attach here. Lesser tubercle: subscapularis muscle inserts here. Intertubercular groove: for the tendon of biceps brachii (see orthopaedic skeleton and shoulder joint model) Deltoid tuberosity: deltoid muscle inserts at this site. * Medial epicondyle: origin of flexor muscle group of forearm. * Lateral epicondyle: origin of extensor muscle group in forearm. * Trochlea: (means "pulley") articulates with ulna. Capitulum: articulates with radius 2. Ulna Identify: Olecranon process: triceps brachii inserts here. (forms the elbow ) * Trochlear notch: articulates with trochlea of humerus. Styloid process of ulna: surface landmark * 3. Radius. Identify: Head: articulates with capitulum of humerus. Neck: held to the ulna by an annular ligament. Radial tuberosity: biceps brachii insets here. Styloid process of radius: surface landmark. *

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9 5-9 HAND Carpal, metacarpal and phalanx bones make up the carpus (wrist), metacarpus (palm), and phalanges (fingers) of the hand. 1. Carpal Bones: (carpals) There are a total of eight carpal bones, you are NOT responsible for differentiating the individual carpal bones. What is the classification (as to shape) of these bones? NOTE: The scaphoid and lunate bones articulate with the radius, so, in a fall on the hands (using the hands to break a forward fall) the force of a sudden stop is almost directly placed on these two bones. Thus, of all the carpals, these are the ones most commonly fractured. 2. Metacarpals These bones form the palm of your hand. They are numbered from lateral to medial (in anatomical position). Locate metacarpals 1 through 5 on the articulated hand the base of each metacarpal the distal head of each metacarpal What is the classification (as to shape) of these bones)? 3. Phalanges. (singular: phalanx) Numbered 1-5 from lateral (thumb) to medial, like the metacarpals. Note that the thumb has only proximal and distal phalanges while all the fingers have proximal, middle and distal phalanges. Locate: the proximal and distal phalanges of the thumb (I proximal phalanx and I distal phalanx) II, III, IV, and V proximal, middle and distal phalanges What is the anatomical term for the thumb?

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13 5-13 STATION 3 JOINTS OF UPPER LIMB Examine the shoulder and elbow joint models and the articulated arm and locate the following. i) Glenohumeral joint articulating surfaces of the meeting bones: the of the scapula articulates with the of the humerus ii) Elbow joint Examine the following articulating points. Of the 2 bones of the forearm, the ulna contributes most to movements at the elbow joint. humeroulnar trochlea of fits into trochlear notch of radiohumeral capitulum of glides over superior surface of the head of the radius iii) Radioulnar joint The radius and ulna articulate with each other both proximally and distally at small radioulnar joints, and are connected along their length by a flexible interosseous membrane (see photo). In anatomical position, the radius lies laterally (on the thumb side) and the ulna lies medially (supinated position). When the hand is rotated so the palm faces posteriorly (pronated position), the radius crosses over the ulna and the two bones form an X. TRY THIS: Place the index finger and thumb of the right hand on the edges of the radius and ulna (about half way up the forearm). Now, rotate the forearm so you switch from supination to pronation. Can you feel the two bones cross over one another?

14 5-14 PART II : LOWER LIMB BONES STATION 4 PELVIC GIRDLE: COXAL BONES Coxal bones - from the Latin: Ossa coxae (hip bones) Each of the coxal bones starts out as three separate bones which are separated by cartilage until about age 14 then gradually fuse until, by approximately age twenty-two, they become one bone. Name the 3 bones that make up each coxal bone: Identify the following structures on the coxal bones: iliac crest - easily found on yourself (*locate by palpation) iliac fossa - large muscles arise here acetabulum What bone articulates here? ischial tuberosity - you sit on them (muscles of the hamstring group originate here) obturator foramen a large nerve runs through this hole symphyseal surface - joins with opposite pubic bone to form the pubic symphysis CONSIDER: Is the pelvic bone you are examining a left or right coxal bone? Is the skeleton at station 10 male or female? COMPARE THE MALE VS FEMALE PELVISES: Describe 4 ways in which the female pelvis differs from the male pelvis:

15 5-15 STATION 5 LEG BONES 1. Femur Identify the following structures on the femur: head - articulates with of hip neck - often a site of fracture greater trochanter - insertion site for gluteus medius and minimus and deep lateral rotator muscles lesser trochanter - site of attachment for iliopsoas muscle gluteal tuberosity - where gluteus maximus inserts patellar surface - where patella articulates medial femoral condyle * lateral femoral condyle * CONSIDER: The femur is the longest and heaviest bone in the body. It is secured in the acetabulum by a ligament (ligamentum teres) arising from a small pit (the fovea capitis) in the center of the ball-like head of the femur How do you differentiate a right femur from a left femur? 2. Patella The patella protects the knee joint anteriorly and improves the leverage of the thigh muscles. The patella also prevents friction from occurring where the quadriceps tendon crosses the joint. How would you classify the patella by shape?

16 Tibia Be able to identify right from left tibias by noting the following (structures indicated with an asterisk, you should be able to palpate): lateral tibial condyle * medial tibial condyle * tibial tuberosity * medial malleolus * (medial ankle bone ) 4. Fibula head (articulates with what bone? ) lateral malleolus * (lateral ankle bone ) Why is the fibula thinner and smaller than the other leg bones? (You are not responsible for distinguishing right from left fibulas). BONES OF THE FEET tarsals (ankle bones) There are a total of 7 tarsal bones. The only tarsal you need to know by name is the calcaneus (or heel bone ): metatarsals - five, numbered 1 5 from the great toe - locate the base and head of each metatarsal. phalanges (singular: phalanx) - there are only two phalanges (proximal and distal) in the great toe or hallux (phalanx #1), and 3 in each of the other toes; a proximal, middle and distal phalanx. CONSIDER: What structure makes up the ball of the foot?

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21 5-21 STATION 6 JOINTS OF THE LOWER LIMB Using the skeleton, orthopaedic skeleton, joint models and diagrams, study the following joints of the lower limb. 1. Pelvic Joints (articulated skeletons and male and female pelvises). i) Sacroiliac Joint between and of coxal bone ii) Pubic Symphysis The superior rami of both pubic bones join at their symphyseal surfaces with cartilage to form the pubic symphysis Classify this joint: What type of cartilage forms this joint? 2. Hip Joint - refer to joint model, skeletons, and photographs. Identify the following in the hip joint model : acetabulum head of the femur ligaments reinforcing the capsule (three on each side) In a typical hip replacement surgery, what is actually replaced? In a typical hip fracture (common in elderly individuals with osteoporosis), what bone is actually fractured? what part of this bone is vulnerable to fracture?

22 Knee Joint - refer to knee joint model, articulated skeleton and photographs Identify: articular capsule medial meniscus lateral menisci What type of cartilage forms the menisci? The lateral and medial menisci function to anterior cruciate ligaments posterior cruciate ligaments The cruciate ligaments function to medial (tibial) collateral ligament stabilize joint medially and lateral (fibular) collateral ligament stabilize joint laterally NOTE: Tendons of a number of muscles also reinforce the knee joint: CONSIDER: The knee joint is the most complex joint in the body and is subject to more than usual wear and tear due to the weight-bearing loads put on it throughout life. THINK: Knee injury commonly occurs when an individual receives a blow to the lateral side of the knee. What ligaments would most likely be torn in this type of injury? LABEL THE DIAGRAM OF THE KNEE JOINT WHICH FOLLOWS

23 5-23 THE KNEE JOINT

24 5-24 STATION 7 PART III. ARTICULATIONS (JOINTS) When skeletal muscle contracts, bones move. This movement occurs at joints or articulations. Many different types of supportive connective tissues come together at joints. JOINT CLASSIFICATION Joints can be classified on the basis of the range of motion that occurs at the joint. i) Synarthoses (singular synarthrosis) Define: ii) Amphiarthroses (singular amphiarthrosis) Define: iii) Diarthroses (singular diarthrosis) Define: Joints are also classified on the basis of structure ( how are bones held together and with what tissues). i) Fibrous joints Distinguish between the following suture syndesmosis gomphosis Examine a suture on the skull provided. Observe the interosseous membrane between the radius and ulna ii) Cartilagenous joints Distinguish between the following synchondrosis symphysis

25 5-25 iii) Synovial joints Synovial joints are classified by the number of axes along which movement occurs. Monaxial Biaxial Triaxial Various names are used to describe the different types of synovial joints. Give 1 example of each of the following types of synovial joints Planar (gliding) Hinge Pivot Condylar (ellipsoidal) Saddle Ball and socket JOINT ASSIGNMENT Five joints have been labelled on the skeleton at this station. Complete the joint assignment which was handed out at the beginning of class by classifying these 5 joints and completing the table provided. You and your lab partner(s) will hand this assignment in for grading.

26 5-26 STATION 8 SYNOVIAL JOINT STRUCTURE The majority of joints are diarthrotic and synovial. Recall the basic structure of a synovial joint: Articular cartilage composed of tissue Joint cavity filled with Articular capsule composed of two layers: Outer fibrous capsule composed of tissue Inner layer the secretes Recall the accessory structures by completing the following table: structure tissue function Ligaments Tendons Menisci Fat pads Bursa Tendon sheath DISSECTED BEEF LEG JOINT Examine the beef leg joint and locate the following structures: articular cartilage, synovial membrane, articular (joint) capsule, adipose tissue, ligament, tendon (if muscle is present)

27 5-27 Examine the photograph of a human hip joint below. Using your textbook as a reference, identify the following features: articular (fibrous) capsule, synovial cavity, articular cartilage, ligamentum teres (at head of femur), ischiofemoral ligament

28 5-28 STATION 9 REVIEW Identify the 10 loose bones (by name), indicate whether each is part of the axial or appendicular skeleton, and determine whether the bone is from the left or right side of the body (if possible)