Copyright 2009 John Wiley & Sons, Inc.
Chapter 8 The Skeletal System: The Appendicular SkeletonCopyright 2009 John Wiley & Sons, Inc.
Appendicular SkeletonThe primary function is movement It includes bones of the upper and lower limbs Girdles attach the limbs to the axial skeleton
Copyright 2009 John Wiley & Sons, Inc.
Skeleton of the Upper LimbEach upper limb has 32 bones Two separate regions 1. The pectoral (shoulder) girdle (2 bones) 2. The free part (30 bones)
Copyright 2009 John Wiley & Sons, Inc.
The Pectoral (or Shoulder) Girdle Figure 8.1Copyright 2009 John Wiley & Sons, Inc.
Upper LimbThe pectoral girdle consists of two bones, the scapula and the clavicle The free part has 30 bones 1 humerus (arm) 1 ulna (forearm) 1 radius (forearm) 8 carpals (wrist) 19 metacarpal and phalanges (hand)
Copyright 2009 John Wiley & Sons, Inc.
Pectoral Girdle - ClavicleThe clavicle is “S” shapedThe medial end articulates with the manubrium of the sternum forming the sternoclavicular jointThe lateral end articulates with the acromion forming the acromioclavicular joint
Copyright 2009 John Wiley & Sons, Inc.
The Clavicle Figure 8.2Copyright 2009 John Wiley & Sons, Inc.
Pectoral Girdle - ClavicleThe clavicle is convex in shape anteriorly near the sternal junction The clavicle is concave anteriorly on its lateral edge near the acromion
Copyright 2009 John Wiley & Sons, Inc.
Clinical Connection - Fractured ClavicleA fall on an outstretched arm (F.O.O.S.H.) injury can lead to a fractured clavicle The clavicle is weakest at the junction of the two curves Forces are generated through the upper limb to the trunk during a fall Therefore, most breaks occur approximately in the middle of the clavicle
Copyright 2009 John Wiley & Sons, Inc.
Pectoral Girdle - ScapulaAlso called the shoulder blade Triangular in shape Most notable features include the spine, acromion, coracoid process and the glenoid cavity
Copyright 2009 John Wiley & Sons, Inc.
Features on the ScapulaSpine - a large process on the posterior of the scapula that ends laterally as the acromion Acromion - the flattened lateral portion of the spine of the scapula Coracoid process - a protruding projection on the anterior surface just inferior to the lateral aspect of the clavicle Glenoid cavity - shallow concavity that articulates with the head of the humerus
Copyright 2009 John Wiley & Sons, Inc.
Scapula Figure 8.3Copyright 2009 John Wiley & Sons, Inc.
Scapula Figure 8.3Copyright 2009 John Wiley & Sons, Inc.
Scapula - FeaturesThe medial (vertebral) border - closest to the vertebral spine Lateral border - closest to the arm Superior border - superior edge Inferior angle - where medial and lateral borders meet inferiorly Superior angle - uppermost aspect of scapula where medial border meets superior border
Copyright 2009 John Wiley & Sons, Inc.
Scapula - FeaturesSubscapular fossa - anterior concavity where the subscapularis muscle attaches Supraspinous fossa - posterior concavity superior to the scapular spine, attachment site for supraspinatus muscle Infraspinous fossa - posterior concavity inferior to the scapular spine, site of infraspinatus muscle
Copyright 2009 John Wiley & Sons, Inc.
Skeleton of the Arm - HumerusLongest and largest bone of the free part of the upper limb The proximal ball-shaped end articulates with the glenoid cavity of the scapula The distal end articulates at the elbow with the radius and ulna
Copyright 2009 John Wiley & Sons, Inc.
Humerus - Surface FeaturesThe head of the humerus has two unequal-sized projections The greater tubercle lies more laterally The lesser tubercle lies more anteriorly Between the tubercles lies the intertubercular groove or sulcus (bicipital groove) where the long head of the biceps brachii tendon is located
Copyright 2009 John Wiley & Sons, Inc.
Humerus - Surface FeaturesJust distal to the head is the anatomical neck The surgical neck is where the tubular shaft begins and is a common area of fracture About mid-shaft on the lateral aspect is a roughened area, the deltoid tuberosity where the deltoid tendon attaches Capitulum - a round knob-like process on the lateral distal humerus Trochlea - medial to the capitulum, is a spool-shaped projection on the distal humerus
Copyright 2009 John Wiley & Sons, Inc.
Humerus - Surface FeaturesCoronoid fossa - anterior depression that receives the coronoid process of the ulna during forearm flexion Olecranon fossa - posterior depression that receives the olecranon of the ulna during forearm extension The medial and lateral epicondyles are bony projections to which the forearm muscles attach
Copyright 2009 John Wiley & Sons, Inc.
Humerus and Glenohumeral Joint Figure 8.4
Copyright 2009 John Wiley & Sons, Inc.
Skeleton of the Forearm - UlnaThe longer of the two forearm bonesLocated medial to the radiusOlecranon - the large, prominent proximal end, the “tip of your elbow”Coronoid process - the anterior “lip” of the proximal ulnaTrochlear notch - the deep fossa that receives the trochlea of the humerus during elbow flexionStyloid process - the thin cylindrical projection on the posterior side of the ulna’s head
Copyright 2009 John Wiley & Sons, Inc.
Copyright 2009 John Wiley & Sons, Inc.Right humerus in relation to scapula, ulna, and radius-- Figure 8.5
Copyright 2009 John Wiley & Sons, Inc.
Articulations formed by the ulna and radius -- Figure 8.7Copyright 2009 John Wiley & Sons, Inc.
RadiusLies lateral to the ulna (thumb side of the forearm) The head (disc-shaped) and neck are at the proximal end The head articulates with the capitulum of the humerus and the radial notch of the ulna Radial tuberosity - medial and inferior to neck, attachment site for biceps brachii muscle Styloid process - large distal projection on lateral side of radius
Copyright 2009 John Wiley & Sons, Inc.
Ulna and Radius
The shaft of these bones are connected by an interosseus membrane There is a proximal radioulnar joint and a distal radioulnar joint Proximally, the head of the radius articulates with the radial notch of the ulna Distally, the head of the ulna articulates with the ulnar notch of the radius
Copyright 2009 John Wiley & Sons, Inc.
Right ulna and radius in relation to the humerus and carpals -- Figure 8.6Copyright 2009 John Wiley & Sons, Inc.
Skeleton of the HandThe carpus (wrist) consists of 8 small bones (carpals) Two rows of carpal bones Proximal row - scaphoid, lunate, triquetrum, pisiform Distal row - trapezium, trapezoid, capitate, hamate Scaphoid - most commonly fractured Carpal tunnel - space between carpal bones and flexor retinaculum
Copyright 2009 John Wiley & Sons, Inc.
Articulations formed by the ulna and radius -- Figure 8.7Copyright 2009 John Wiley & Sons, Inc.
Metacarpals and PhalangesFive metacarpals - numbered I-V, lateral to medial 14 phalanges - two in the thumb (pollex) and three in each of the other fingers Each phalanx has a base, shaft, and head Joints - carpometacarpal, metacarpophalangeal, interphalangeal
Copyright 2009 John Wiley & Sons, Inc.
Right wrist and hand in relation to ulna and radius -- Figure 8.8
Copyright 2009 John Wiley & Sons, Inc.
Skeleton of the Lower LimbSkeleton of the Lower Limb Two separate regions 1. A single pelvic girdle (2 bones) 2. The free part (30 bones)
Copyright 2009 John Wiley & Sons, Inc.
Pelvic (Hip) GirdleEach coxal (hip) bone consists of three bones that fuse together: ilium, pubis, and ischium The two coxal bones are joined anteriorly by the pubic symphysis (fibrocartilage) Joined posteriorly by the sacrum forming the sacroiliac joints (Fig 8.9)
Copyright 2009 John Wiley & Sons, Inc.
Right Hip Bone Figure 8.10Copyright 2009 John Wiley & Sons, Inc.
Bony Pelvis Figure 8.9Copyright 2009 John Wiley & Sons, Inc.
The Ilium
Largest of the three hip bones Ilium is the superior part of the hip bone Consists of a superior ala and inferior body which forms the acetabulum (the socket for the head of the femur) Superior border - iliac crest Hip pointer - occurs at anterior superior iliac spine Greater sciatic notch - allows passage of sciatic nerve
Copyright 2009 John Wiley & Sons, Inc.
Ischium and PubisIschium - inferior and posterior part of the hip bone Most prominent feature is the ischial tuberosity, it is the part that meets the chair when you are sitting Pubis - inferior and anterior part of the hip bone
Copyright 2009 John Wiley & Sons, Inc.
False and True PelvesPelvic brim - a line from the sacral promontory to the upper part of the pubic symphysis False pelvis - lies above this line (Fig 8.9b) Contains no pelvic organs except urinary bladder (when full) and uterus during pregnancy True pelvis - the bony pelvis inferior to the pelvic brim, has an inlet, an outlet and a cavity Pelvic axis - path of baby during birth
Copyright 2009 John Wiley & Sons, Inc.
True and False Pelvis Figure 8.11Copyright 2009 John Wiley & Sons, Inc.
Copyright 2009 John Wiley & Sons, Inc.
Comparing Male and Female Pelves
Copyright 2009 John Wiley & Sons, Inc.
Comparing Male and Female Pelves Table 8.1Copyright 2009 John Wiley & Sons, Inc.
Comparing Male and Female Pelves Table 8.1Copyright 2009 John Wiley & Sons, Inc.
Copyright 2009 John Wiley & Sons, Inc.Right Lower Limb Figure 8.12
Copyright 2009 John Wiley & Sons, Inc.
Skeleton of the Thigh - Femur and PatellaFemur - longest, heaviest, and strongest bone in the body Proximally, the head articulates with the acetabulum of the hip bone forming the hip (coxal) joint Neck - distal to head, common site of fracture Distally, the medial and lateral condyles articulate with the condyles of the tibia forming the knee joint Also articulates with patella
Copyright 2009 John Wiley & Sons, Inc.
Femur
Greater and lesser trochanters are projections where large muscles attach Gluteal tuberosity and linea aspera - attachment sites for the large hip muscles Intercondylar fossa - depression between the condyles Medial and lateral epicondyles - muscle site attachments for the knee muscles
Copyright 2009 John Wiley & Sons, Inc.
Right Femur Figure 8.13Copyright 2009 John Wiley & Sons, Inc.
PatellaLargest sesamoid bone in the bodyForms the patellofemoral jointSuperior surface is the baseInferior, narrower surface is the apexThick articular cartilage lines the posterior surfaceIncreases the leverage of the quadriceps femoris musclePatellofemoral stress syndrome - “runner’s knee”
Copyright 2009 John Wiley & Sons, Inc.
Patella Figure 8.14Copyright 2009 John Wiley & Sons, Inc.
Tibia (shin bone)The larger, medial weight-bearing bone of the leg The lateral and medial condyles at the proximal end articulate with the femur It articulates distally with the talus and fibula Tibial tuberosity - attachment site for the patellar ligament Medial malleolus - medial surface of distal end (medial surface of ankle joint)
Copyright 2009 John Wiley & Sons, Inc.
Fibula
The smaller, laterally placed bone of the leg Non-weight bearing The head forms the proximal tibiofibular joint Lateral malleolus - distal end, articulates with the tibia and the talus at the ankle
Copyright 2009 John Wiley & Sons, Inc.
Tibia and Fibula Figure 8.15Copyright 2009 John Wiley & Sons, Inc.
Tibia and Fibula Figure 8.15Copyright 2009 John Wiley & Sons, Inc.
Skeleton of the Foot - Tarsals, Metatarsals, and PhalangesSeven tarsal bones - talus (articulates with tibia and fibula), calcaneus (the heel bone, the largest and strongest), navicular, cuboid and three cuneiforms Five metatarsals - (I-V) base, shaft, head 14 phalanges (big toe is the hallux) Tarsus = ankle
Copyright 2009 John Wiley & Sons, Inc.
Right Foot Figure 8.16Copyright 2009 John Wiley & Sons, Inc.
Arches of the FootTwo arches support the weight of the bodyProvide spring and leverage to the foot when walkingThe arches flex when body weight appliedFlatfoot - the arches decrease or “fall”Clawfoot - too much arch occurs due to various pathologies