Appendicular Bones

8.1 Pectoral (Shoulder) Girdle

1. Each of the body’s two pectoral (shoulder) girdles consists of a clavicle and

scapula.

2. Each pectoral girdle attaches an upper limb to the axial skeleton.

3. The clavicle (collarbone) lies horizontally across the anterior part of the

thorax superior to the first rib.

4. The medial end of the clavicle articulates with the manubrium of the sternum;

the lateral end of the clavicle articulates with the acromion of the scapula.

5. The scapula (shoulder blade) is situated in the superior part of the posterior

thorax between the levels of the second and seventh ribs.

6. The scapula articulates with the clavicle and the head of the humerus.

8.2 Upper Limb (Extremity)

1. Each of the two upper limbs (extremities) contains 30 bones.

2. The bones of each upper limb include the humerus, the ulna, the radius, the

carpals, the metacarpals, and the phalanges.

3. The humerus (arm bone) is the longest and largest bone of the upper limb.

4. The humerus articulates proximally with the scapula and distally with the

ulna and radius.

5. The ulna is located on the medial aspect of the forearm and is longer than

the radius.

6. The radius is the smaller bone of the forearm and is located on the lateral

aspect of the forearm.

7. The eight carpals are located in the proximal region of the hand.

8. The five metacarpals are located in the intermediate region of the hand.

9. The 14 phalanges are located in the distal part of the hand (fingers).

8.3 Pelvic (Hip) Girdle

1. The pelvic (hip) girdle consists of two hip bones.

2. Each hip bone consists of three parts: the ilium, pubis, and ischium.

3. The hip bones, sacrum, and pubic symphysis form the bony pelvis. It

supports the vertebral column and pelvic viscera and attaches the free lower

limbs to the axial skeleton.

4. The ilium is the superior portion of the hip bone.

5. The ischium is the inferior, posterior portion of the hip bone.

6. The pubis is the anterior and inferior part of the hip bone.

Chapter Review 259

Genu varum (JĒ-noo VAR-um; varum = bent toward the midline) A

deformity in which the knees are abnormally separated, there is a medial

angulation of the tibia in relation to the femur, and the lower limbs are

bowed laterally. Also called bowleg.

Hallux valgus (HAL-uks VAL-gus; hallux = great toe) Angulation of the

great toe away from the midline of the body, typically caused by wearing

tightly fitting shoes. When the great toe angles toward the next toe, there is

a bony protrusion at the base of the great toe. Also called a bunion.

8.4 False and True Pelves

1. The false pelvis is separated from the true pelvis by the pelvic brim.

2. The true pelvis surrounds the pelvic cavity and houses the rectum and

urinary bladder in both genders, the vagina and cervix of the uterus in females,

and the prostate in males.

3. The false pelvis is the lower portion of the abdomen that is situated superior

to the pelvic brim. It contains the superior portion of the urinary bladder

(when full) and the lower intestines in both genders and the uterus, uterine

tubes, and ovaries in the female.

8.5 Comparison of Female and Male Pelves

1. Bones of the male skeleton are generally larger and heavier than bones of

the female skeleton. They also have more prominent markings for muscle

attachments.

2. The female pelvis is adapted for pregnancy and childbirth. Sex-related

differences in pelvic structure are listed and illustrated in Table 8.1.

8.6 Lower Limb (Extremity)

1. Each of the two lower limbs (extremities) contains 30 bones.

2. The bones of each lower limb include the femur, the patella, the tibia, the

fibula, the tarsals, the metatarsals, and the phalanges.

3. The femur (thigh bone) is the longest, heaviest, and strongest bone in the body.

4. The patella (kneecap) is a small, triangular bone located anterior to the

knee joint.

5. The tibia (shin bone) is the larger, medial, weight-bearing bone of the leg.

6. The fibula is parallel and lateral to the tibia, but is considerably smaller.

7. The seven tarsal bones are located in the proximal region of the foot.

8. The five metatarsals are located in the intermediate region of the foot.

9. The 14 phalanges are located in the distal part of the foot (toes).

10. The bones of the foot are arranged in two arches, the longitudinal arch

and the transverse arch, to provide support and leverage.

8.7 Development of the Skeletal System

1. Most bones form from mesoderm by intramembranous or endochondral

ossification; much of the skeleton of the skull arises from ectoderm.

2. Bones of the limbs develop from limb buds, which consist of mesoderm

and ectoderm