Ch 8 - Chapter 8 study notes PDF

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Chapter 8 The Skeletal System: The Appendicular Skeleton Identify the names, locations and major surface markings of the bones of the pectoral (shoulder) girdles. -

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primary function of the appendicular skeleton, is movement pectoral girdles or shoulder girdles (2) o attach the bones of the upper limbs to the axial skeleton o consists of a clavicle and a scapula clavicle or collarbone o anterior bone and articulates with the manubrium of the sternum at the sternoclavicular joint o scapula articulates with the clavicle at the acromioclavicular joint o with the humerus at the glenohumeral (shoulder) joint o slender S shape  medial half is convex anteriorly (curves toward you when viewed in the anatomical position), and the lateral half is concave anteriorly (curves away from you)  rougher and more curved in males o lies horizontally across the anterior part of the thorax superior to the first rib o medial end, called the sternal end, is rounded and articulates with the manubrium of the sternum to form the sternoclavicular joint. o The broad, flat, lateral end, the acromial end, articulates with the acromion of the scapula to form the acromioclavicular joint scapula or shoulder blade p234 o large, triangular, flat bone situated in the superior part of the posterior thorax between the levels of the second and seventh ribs o spine  prominent ridge, runs diagonally across the posterior surface of the scapula  lateral end of the spine projects as a flattened, expanded process called the acromion, easily felt as the high point of the shoulder  acromion articulates with the acromial end of the clavicle to form the acromioclavicular joint  Inferior to the acromion is a shallow depression, the glenoid cavity, that accepts the head of the humerus (arm bone) to form the glenohumeral (shoulder) joint  The thin edge of the scapula closer to the vertebral column is called the medial (vertebral) border

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The thick edge of the scapula closer to the arm is called the lateral (axillary) border  medial and lateral borders join at the inferior angle superior edge of the scapula, called the superior border, joins the medial border at the superior angle scapular notch is a prominent indentation along the superior border through which the supra- scapular nerve passes lateral end of the superior border of the scapula is a projection of the anterior surface called the coracoid process  tendons of muscles (pectoralis minor, coracobrachialis, and biceps brachii) and ligaments (coracoacromial, conoid, and trapezoid) attach Superior and inferior to the spine on the posterior surface of the scapula are two fossae:  The supraspinous fossa is a surface of attachment for the supraspinatus muscle of the shoulder  infraspinous fossa serves as a surface of attachment for the infraspinatus muscle of the shoulder On the anterior surface of the scapula is a slightly hollowed-out area called the subscapular fossa, a surface of attachment for the subscapularis muscle.

Identify the names, locations and major surface markings of the bones of the upper limbs. upper limbs or upper extremities (2; details in the Exhibits) -

30 bones in three locations— (1) the humerus in the arm; (2) the ulna and radius in the forearm; and (3) the 8 carpals in the carpus (wrist), the 5 metacarpals, 14 phalanges Humerus p235 o longest and largest bone of the upper body o articulates proximally with the scapula and distally with two bones, the ulna and the radius, to form the elbow joint o proximal end of the humerus features a rounded head that articulates with the glenoid cavity of the scapula to form the glenohumeral joint o Distal to the head is the anatomical neck, which is visible as an oblique groove  former site of the epiphyseal (growth) plate in an adult humerus  most laterally palpable bony landmark of the shoulder region and is immediately inferior to the palpable acromion of the scapula o lesser tubercle projects anteriorly o Between the two tubercles there is a groove named the intertubercular sulcus o surgical neck is a constriction in the humerus just distal to the tubercles, where the head tapers to the shaf  it is so named because fractures ofen occur here. o body (shaft) of the humerus is roughly cylindrical at its proximal end, but it gradually becomes triangular until it is flattened and broad at its distal end

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Laterally, at the middle portion of the shaf, there is a roughened, V-shaped area called the deltoid tuberosity  This area serves as a point of attachment for the tendons of the deltoid muscle  posterior surface of the humerus is the radial groove, which runs along the deltoid tuberosity and contains the radial nerve capitulum is a rounded knob on the lateral aspect of the bone that articulates with the head of the radius radial fossa is an anterior depression above the capitulum that articulates with the head of the radius when the forearm is flexed (bent) trochlea: located medial to the capitulum spool-shaped surface that articulates with the trochlear notch of the ulna coronoid fossa is an anterior depression that receives the coronoid process of the ulna when the forearm is flexed olecranon fossa is a large posterior depression that receives the olecranon of the ulna when the forearm is extended medial epicondyle and lateral epicondyle are rough projections on either side of the distal end of the humerus to which the tendons of most muscles of the forearm are attached The ulnar nerve may be palpated by rolling a finger over the skin surface above the posterior surface of the medial epicondyle  This nerve is the one that makes you feel a very severe pain when you hit your elbow, which for some reason is commonly referred to as the funny- bone

Ulna p.237 o located on the medial aspect (the little-finger side) of the forearm and is longer than the radius  p.u (pinky,ulna) o At the proximal end of the ulna is the olecranon, which forms the prominence of the elbow o With the olecranon, an anterior projection called the coronoid process articulates with the trochlea of the humerus o trochlear notch is a large curved area between the olecranon and coronoid process that forms part of the elbow joint o Lateral and inferior to the trochlear notch is a depression, the radial notch, which articulates with the head of the radius o Just inferior to the coronoid process is the ulnar tuberosity, to which the biceps brachii muscle attaches o distal end of the ulna consists of a head that is separated from the wrist by a disc of fibrocartilage o styloid process is located on the posterior side of the ulna’s distal end radius o Smaller bone of the forearm and is located on the lateral aspect (thumb side) of the forearm

In contrast to the ulna, the radius is narrow at its proximal end and widens at its distal end o The proximal end of the radius has a disc-shaped head that articulates with the capitulum of the humerus and the radial notch of the ulna o Inferior to the head is the constricted neck o roughened area inferior to the neck on the anteromedial side, called the radial tuberosity, is a point of attachment for the tendons of the biceps brachii muscle o The shaf of the radius widens distally to form a styloid process on the lateral side, which can be felt proximal to the thumb  provides attachment for the brachioradialis muscle and for attachment of the radial collateral ligament to the wrist o Fracture of the distal end of the radius is the most common fracture in adults older than 50 years, typically occuring during a fall o The ulna and the radius connect with one another at three sites  a broad, flat, fibrous connective tissue called the interosseous membrane joins the shafs of the two bones  The ulna and radius articulate directly at their proximal and distal ends  Proximally, the head of the radius articulates with the ulna’s radial notch (proximal radioulnar joint)  Distally, the head of the ulna articulates with the ulnar notch of the radius (distal radioulnar joint)  distal end of the radius articulates with three bones of the wrist—the lunate, the scaphoid, and the triquetrum—to form the radiocarpal (wrist) joint. carpal bones (Note: You are expected to learn the names of the carpals and major features, but o

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not their precise positions) p.240

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carpus (wrist) is the proximal region of the hand and consists of eight small bones, the carpals, joined to one another by ligaments articulations among carpal bones are called intercarpal joints The carpals are arranged in two transverse rows of four bones each Their names reflect their shapes The carpals in the proximal row, from lateral to medial, are the  Scaphoid  70% carpal fractures only this bone is broken  All the force on an outstretched hand is transmitted from the capitate through the scaphoid to the radius  Lunate  Triquetrum  pisiform The proximal row of carpals articulates with the distal ends of the ulna and radius to form the wrist joint The carpals in the distal row, from lateral to medial, are the  Trapezium  trapezoid  capitate

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largest carpal bone rounded projection (head) articulates with the lunate

hamate  large hook like projection on its anterior surface metacarpal bones (in the anatomical position, the first metacarpal is the lateral bone) o metacarpus, or palm, is the intermediate region of the hand and consists of five bones called metacarpals o Each metacarpal bone consists of a proximal base, an intermediate shaf, and a distal head o metacarpal bones are numbered I to V (or 1–5), starting with the thumb, from lateral to medial o The bases articulate with the distal row of carpal bones to form the carpometacarpal joints. o The heads articulate with the proximal phalanges to form the metacarpophalangeal joints. o The heads of the metacarpals, commonly called “knuckles,” are read- ily visible in a clenched fist. Phalanges (14) o make up the distal part of the hand o digits are numbered I to V (or 1–5), beginning with the thumb, from lateral to medial o A single bone of a digit is referred to as a phalanx o Each phalanx consists of a proximal base, an intermediate shaf, and a distal head o The thumb (pollex) has two phalanges called proximal and distal phalanges o The other four digits have three phalanges called proximal, middle, and distal phalange o The proximal phalanges of all digits articulate with the metacarpal bones o The middle phalanges of the fingers (II–V) articulate with their distal phalanges o Joints between phalanges are called interphalangeal joints. 

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Identify the names, locations and major surface markings of the bones of the pelvic (hip) girdle. -

pelvic girdle or hip girdle p.240 o consists of the two hip bones, also called coxal or pelvic bones or os coxa o coxal bone or hip bone (or os coxa)  The hip bones unite anteriorly at a joint called the pubic symphysis  They unite posteriorly with the sacrum at the sacroiliac joint  complete ring composed of the hip bones, pubic symphysis, sacrum, and coccyx forms a deep, basin- like structure called the bony pelvis  Functionally, the bony pelvis provides a strong and stable support for the vertebral column and pelvic and lower abdominal organs

pelvic girdle of the bony pelvis also connects the bones of the lower limbs to the axial skeleton Each of the two hip bones of a newborn consists of three bones separated by cartilage: a superior ilium, an inferior and anterior pubis, and an inferior and posterior ischium o By age 23, the three separate bones fuse together o Although the hip bones function as single bones, anatomists commonly discuss each hip bone as three separate bones Ilium p.241 o largest of the three components of the hip bone o composed of a superior ala and an inferior body o body is one of the components of the acetabulum, the socket for the head of the femur  deep fossa formed by the ilium, ischium, and pubis  Together, the acetabulum and the femoral head form the hip (coxal) joint o The superior border of the ilium, the iliac crest, ends anteriorly in a blunt anterior superior iliac spine o Below this spine is the anterior inferior iliac spine o Posteriorly, the iliac crest ends in a sharp posterior superior iliac spine o Below this spine is the posterior inferior iliac spine o The spines serve as points of attachment for the tendons of the muscles of the trunk, hip, and thighs o Below the posterior inferior iliac spine is the greater sciatic notch, through which the sciatic nerve passes, along with other nerve and muscles o The sciatic nerve is the longest nerve in the body, passes o medial surface of the ilium contains the iliac fossa, a concavity where the tendon of the iliacus muscle attaches o Posterior to this fossa are the iliac tuberosity, a point of attachment for the sacroiliac ligament ischium o inferior, posterior portion of the hip bone o comprises a superior body and an inferior ramus o The ramus is the portion of the ischium that fuses with the pubis o Prominent ischial spine o lesser sciatic notch, below the spine o rough thickened ischial tuberosity  Because this prominent tuberosity is just deep to the skin, it commonly begins hurting afer a relatively short time when you sit on a hard surface o the ramus and the pubis surround the obturator foramen, largest foramen in the skeleton  even though blood vessels and nerves pass through it, it is nearly completely closed by the fibrous obturator membrane pubis (pubic bone) o anterior and inferior part of the hip bone o A superior ramus, an inferior ramus, and a body between the rami make up the pubis. 

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anterior, superior border of the body is the pubic crest, and at its lateral end is a projection called the pubic tubercle o tubercle is the beginning of a raised line, the pectineal line, which extends superiorly and laterally along the superior ramus to merge with the arcuate line of the ilium  These lines, as you will see shortly, are important landmarks for distinguishing the superior (false) and inferior (true) portions of the bony pelvis o pubic symphysis is the joint between the two pubes of the hip bones. o Inferior to this joint, the inferior rami of the two pubic bones converge to form the pubic arch hip or coxal joint o The bony pelvis is divided into superior and inferior portions by a boundary called the pelvic brim that forms the inlet into the pelvic cavity from the abdomen o false (greater) pelvis: The portion of the bony pelvis superior to the pelvic brim  bordered by the lumbar vertebrae posteriorly, the upper portions of the hip bones laterally, and the abdominal wall anteriorly o true (lesser) pelvis: The portion of the bony pelvis inferior to the pelvic brim  It has an inlet, an outlet, and a cavity  bounded by the sacrum and coccyx posteriorly, inferior portions of the ilium and ischium laterally, and the pubic bones anteriorly  pelvic inlet: The superior opening of the true pelvis, bordered by the pelvic brim  pelvic outlet: inferior opening of the true pelvis o pelvic axes: The pelvic axis is an imaginary line that curves through the true pelvis from the central point of the plane of the pelvic inlet to the central point of the plane of the pelvic outlet  During childbirth the pelvic axis is the route taken by the baby’s head as it descends through the pelvis o

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Compare the principal structural differences between female and male skeletons, especially those that pertain to the pelvis.

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Most differences are adaptions for pregnancy and childbirth Female: wider and more shallow o more space in true pelvis, especially in inlet and outlet

Identify the names, locations and major surface markings of the bones of the lower limbs. lower limbs or lower extremities (2); - Each lower limb (lower extremity) has 30 bones in four locations—(1) the femur in the thigh; (2) the patella (kneecap); (3) the tibia and fibula in the leg; and (4) the 7 tarsals in the tarsus (ankle) the 5 metatarsals in the metatarsus, and the 14 phalanges (bones of the digits) in the foot -

femur or thighbone o longest, heaviest, and strongest bone in the body o proximal end articulates with the acetabulum o distal end with the tibia and patella o body or shaft  angles medially and, as a result, the knee joints are closer to the midline than the hip joints. o proximal end of the femur consists of a rounded head that articulates with the acetabulum of the hip bone to form the hip (coxal) joint o The neck of the femur is a constricted region distal to the head

“broken hip” is more ofen associated with a fracture in the neck of the femur than with fractures of the hip bones greater trochanter and lesser trochanter are projections from the junction of the neck and shaf that serve as points of attachment for the tendons of some of the thigh and buttock muscle  Greater trochanter: prominence felt and seen anterior to the hollow on the side of the hip  Lesser trochanter: inferior and medial to the greater trochanter Between the anterior surfaces of the trochanters is a narrow intertrochanteric line  ridge called the intertrochanteric crest appears between the posterior surfaces of the trochanters Inferior to the intertrochanteric crest on the posterior surface of the body of the femur is a vertical ridge called the gluteal tuberosity  blends into another vertical ridge called the linea aspera  Both ridges serve as attachment points for the tendons of several thigh muscles The expanded distal end of the femur includes the medial condyle and the lateral condyle  These articulate with the medial and lateral condyles of the tibia Superior to the condyles are the medial epicondyle and the lateral epicondyle, to which ligaments of the knee joint attach patellar surface is located between the condyles on the anterior surface 

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o patella o small, triangular bone located anterior to the knee joint o broad proximal end of this sesamoid bone, which develops in the tendon of the quadriceps femoris muscle, is called the base; the pointed distal end is referred to as the apex o posterior surface contains two articular facets, one for the medial condyle of the femur and an- other for the lateral condyle of the femur o patellar ligament attaches the patella to the tibial tuberosity o The patellofemoral joint, between the posterior surface of the patella and the patellar surface of the femur, is the intermediate component of the tibiofemoral (knee) joint. o patella increases the leverage of the tendon of the quadriceps femoris muscle, maintains the position of the tendon when the knee is bent (flexed), and protects the knee joint tibia or shin bone o larger, medial, weight-bearing bone of the leg o tibia means flute, because the tibial bones of birds were used in ancient times to make musical instruments o tibia articulates at its proximal end with the femur and fibula, and at its distal end with the fibula and the talus bone of the ankle o The tibia and fibula, like the ulna and radius, are connected by an interosseous membrane o The proximal end of the tibia is expanded into a lateral condyle and a medial condyle.  These articulate with the condyles of the femur to form the lateral and medial tibiofemoral (knee) joints

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inferior surface of the lateral condyle articulates with the head of the fibula tibial tuberosity on the anterior surface is a point of attachment for the patellar ligament Inferior to and continuous with the tibial tuberosity is a sharp ridge that can be felt below the skin, known as the anterior border (crest) or shin The medial surface of the distal end of the tibia forms the medial malleolus  his structure articulates with the talus of the ankle and forms th...