Biology

CHAPTER 8

Appendicular skeleton

-126 bones

-movement

-“appendages” refer to upper/lower limbs

Pectoral(shoulder)girdle

1. Clavicle(collar bone)

-S shaped

-medial(sternal) end articulates w/ manubrium of scapula

-lateral(acromial) end articulated w/ acromion of scapula

1. Scapula(shoulder blade)

-triangular flat bone located in superior part of posterior thorax b/w 2nd and 7th ribs

-glenoid cavity→attachment point for humerus

*humerus + scapula = shoulder joint

UPPER LIMB EXTREMITIES

1. Humerus

-articulates w/ scapula proximally (head into glenoid cavity)

-articulated w/ radius & ulna distally in forearm

*biggest bone of upper extremity

    2. Ulna(pinkie)

        -olecranon & coronoid process at proximal end of ulna    

         form the trochlear notch which wraps trochlea of humerus  

         which makes up elbow

1. Radius(thumb)

-articulation of its head w/ capitulum of humerus & w/ ulna allow forearm to rotate

1. Carpal(wrist)

-8 small bones connected by ligaments

-2 rows of 4 bones

→proximal row-scaphoid, lunate, triquetrum, pisiform (articulate with distal radius/ulna)

→distal row-trapezium, trapezoid, capitate, hamate

(articulate with metacarpals)

1. Metacarpals

-5 hand bones that make up palm/back of hand

-bases articulate w/ distal carpals

-heads articulate w/ proximal phalanges(bones of fingers) *56 phalanges

1. Pelvic hip girdle (3 growth centers)

-made up of 2 bones (os coxa & coxal) that articulate w/ sacrum posteriorly

-each hip bone has 3 bones that fuse into 1 by 23 years old

1.ilium

2.ishium

3.pubis

-2 bones (ilium & ishium) articulate anteriorly at pubic bones(pubic symphysis) w/ disc of fibrocartilage in b/w

-head of femur articulates with acetabulum (ilium,ishium,pubis) of hip bone as ball & socket joint