Pectoral Girdle, Humerus, Forearm, and Hand Bones

(pages 158-161)

appendicular skeleton

composed of 126 bones of the limbs and the pectoral and pelvic girdles, which attach the limbs to the axial skeleton

shoulder girdle, or pectoral girdle

consists of two bones—a clavicle and a scapula

clavicle (klav′ ı̆-kl), or collarbone

a slender, doubly curved bone that attaches to the manubrium of the sternum medially and to the scapula laterally

scapulae (skap′u-le), or shoulder blades

triangular bones commonly called “wings”

acromion (ah-kro′me-on)

the enlarged end of the spine of the scapula

coracoid (kor′ah-koid) process

the beaklike process of the scapula that points over the top of the shoulder and anchors some of the muscles of the arm

acromioclavicular joint

where the acromion connects with the clavicle laterally

suprascapular notch

a large notch on the scapula that serves as a nerve passageway

glenoid cavity

a shallow socket in the lateral angle of the scapula that receives the head of the arm bone

sternoclavicular joint

the single point where each shoulder girdle attaches to the axial skeleton

Bones of the Upper Limbs

thirty separate bones that form the skeletal framework of each upper limb

humerus (hu′mer-us)

the single bone that forms the arm

anatomical neck

a slight constriction immediately inferior to the head of the humerus

greater and lesser tubercles

two bony projections anterolateral to the head of the humerus, separated by the intertubercular sulcus, which are sites of muscle attachment

surgical neck

the most frequently fractured part of the humerus

deltoid tuberosity

a roughened area in the midpoint of the humeral shaft where the deltoid muscle attaches

radial groove

runs obliquely down the posterior aspect of the humeral shaft, marking the course of the radial nerve

trochlea (trok′le-ah)

the medial, spool-like process at the distal end of the humerus

capitulum (kah-pit′u-lum)

the lateral ball-like process at the distal end of the humerus

coronoid fossa

a depression above the trochlea anteriorly

olecranon (o-lek′rah-non) fossa

a depression on the posterior surface of the humerus

medial and lateral epicondyles

flank the coronoid fossa and olecranon fossa

forearm

formed by two bones, the radius and the ulna

radius

the lateral bone of the forearm when the body is in the anatomical position (on the thumb side)

ulna

the medial bone of the forearm when the upper limb is in the anatomical position (on the little-finger side)

radioulnar joints

small joints where the radius and ulna articulate both proximally and distally

interosseous membrane

flexible membrane that connects the radius and ulna along their entire length

styloid process

projection found at the distal end of both the ulna and the radius

head of the radius

disc-shaped proximal end that forms a joint with the capitulum of the humerus

radial tuberosity

located just below the head of the radius, where the tendon of the biceps muscle attaches

coronoid process

anterior process on the proximal end of the ulna

olecranon

posterior process on the proximal end of the ulna

trochlear notch

separates the coronoid process and the olecranon, gripping the trochlea of the humerus

Hand

skeleton consists of the carpals, the metacarpals, and the phalanges

carpus

the part of the hand commonly called the wrist, composed of eight carpal bones

carpals

eight carpal bones arranged in two irregular rows of four bones each that form the wrist

metacarpals

five bones that form the palm of the hand

phalanges (fah-lan′jēz)

the 14 bones of the fingers

knuckles

the heads of the metacarpals when the fist is clenched