Week 21

A&P

MUST DO

Give an example of how the shape of a bone matches its function in the human body

The Appendicular Skeleton

Composed of 126 bones

•Limbs (appendages)

•Pectoral (Shoulder) girdle

•Pelvic girdle

The Appendicular Skeleton

Figure 5.6a

The Appendicular Skeleton

Figure 5.6b

The Pectoral (Shoulder) Girdle

Composed of two bones

•Clavicle—collarbone

•Scapula—shoulder blade

These bones allow the upper limb to have exceptionally free movement

Bones of the Shoulder Girdle

Figure 5.21a

Bones of the Upper Limbs

Humerus

•Forms the arm

•Single bone

Bones of the Upper Limbs

Figure 5.22a–b

Bones of the Upper Limbs

The forearm has two bones

•Ulna• Medial bone in anatomical position

•Radius • Lateral bone in anatomical position

Bones of the Upper Limbs

Figure 5.22c

Bones of the Upper Limbs

The hand

•Carpals—wrist

•Metacarpals—palm

•Phalanges—fingers

Bones of the Upper Limbs

Figure 5.23

The Appendicular Skeletona. Acromionb. Capitulumc. Carpalsd. Claviclee. Coracoid processf. Cornoid fossag. Cornoid processh. Deltoid tuberosityi. Greater tuberclej. Humerusk. Lateral epicondylel. Medial epicondylem.Metacarpalsn. Phalangeso. Radial tubersoityp. Radiusq. Scapular. Styloid process

(Radius)r2 Styloid process (Ulna)s. Trochelat. Ulna

a

b

c

de

f

g

h

i

j (3)

kl

m

n

o

p (4)

q

r r2

t (5)

s

2. Why is the clavicle at risk to fracture when a person falls on their shoulder?It is a slender bone3. Why is there generally no problem in the arm clearing the widest dimension of the thoracic cage?The clavicle serves as a brace to hold the arm clear of the thorax4. What are the total number of phalanges in the hand?145. What is the total number of carpals in the wrist?

8

Bones of the Pelvic GirdleFormed by two coxal (ossa coxae) bones

Composed of three pairs of fused bones

•Ilium•Ischium•Pubis

Bones of the Pelvic Girdle

The total weight of the upper body rests on the pelvis

It protects several organs

•Reproductive organs

•Urinary bladder

•Part of the large intestine

#15 Pelvic Girdle (Hip)

Figure 7.27a

The Pelvis: Right Coxal Bone

Figure 5.24b

Gender Differences of the Pelvis

Figure 5.24c

Comparison of Male and Female Pelves

Table 7.4.2

Pelvic Girdle6. Compare the pectoral and pelvic girdles for flexibility, security and weight-bearingPectoralFlexibility is most important, Insecure axial and limb attachment, moderate weight-bearing abilityPelvicModerate flexibility Secure axial and limb attachments, Massive Weight-bearing ability

#7 What organs are protected, at least in part, by the pelvic girdle?Bladder, small intestine and rectum and in females the uterus

Comparison of Male and Female Pelves

Table 7.4.1

#8 Distinguish between the true pelvis and the false pelvisThe true pelvis is the region inferior to the pelvic brim and is encircled by bone. The false pelvis is the area medial to the iliac bones and superior to the pelvic brim

#10 The pelvic bones of a four legged animal, such as a cat or pig are much less massive than those of a human being. Why?The quad-pedal pelvis does not carry as much weight as the bi pedal pelvis

#11 A person instinctively curls over their abdominal area when in danger. Why?Abdominal organs have the least protection by the skeletal system

#12 What does Fallen Arches mean?A weakening of the tendons and ligaments of the foot

#10 Label the parts of the pelvis and determine if the pelvis is male or female

This Pelvis is MALE, because the Acetabula are close together the pubic arch is less than 90 degrees the sacrum is narrow and the pelvic inlet is heart shaped

Bones of the Lower Limbs

The thigh has one bone

•Femur • The heaviest, strongest bone in the body

Bones of the Lower Limbs

Figure 5.25a–b

Bones of the Lower Limbs

The lower leg has two bones

•Tibia• Shinbone

• Larger and medially oriented

•Fibula• Thin and sticklike

Bones of the Lower Limbs

Figure 5.25c

Bones of the Lower Limbs

The foot

• Tarsals • Two largest tarsals

• Calcaneus (heelbone)

• Talus

• Metatarsals—sole

• Phalanges—toes

Bones of the Lower Limb

Figure 5.26

The foot supports body weight and acts as a lever to propel the body forward in walking and running