anatomy and physiology chapter 8

What bones make up the pectoral girdle?

clavicle and scapula on each side of the body

How does the medial end of the clavicle articulate?

with the sternum

What is the function of the clavicle?

• braces the shoulders, keeping upper limbs away from the midline of the body

• transfers force from the arm to the axial skeleton

What is the role of the scapula in the pectoral girdle?

The scapula is attached to the thoracic cage only by muscle and articulates with the humerus.

What is the significance of the pectoral girdle's design?

offers extensive mobility of the upper limb but sacrifices stability

What is the anatomical position of the scapula?

a triangular bone that overlies ribs 2-7

What features of the scapula are important for muscle attachment?

• spine

• supraspinous and infraspinous fossa

• acromion

• coracoid process

What is the glenoid cavity?

a shallow socket that receives the head of the humerus

What are the three divisions of the upper limb?

• brachium (arm proper)

• antebrachium (forearm)

• hand

What is the primary bone of the brachium?

humerus

What articulates with the glenoid cavity?

hemispherical head of the humerus

What are the distal features of the humerus?

• capitulum

• trochlea

• radial fossa

• coronoid fossa

• olecranon fossa

• medial and lateral epicondyles

Where is the radius located in relation to the ulna?

lateral side of the forearm

What is the function of the radial tuberosity?

attachment point for the biceps brachii muscle

What is the olecranon?

bony point of the elbow located at the proximal end of the ulna

What is the role of the interosseous membrane?

connects the radius and ulna along their lengths.

How are the carpal bones arranged in the wrist?

two rows of four bones each.

What are the names of the carpal bones in the proximal row?

from lateral to medial, includes scaphoid, lunate, triquetrum, and pisiform.

What are the names of the carpal bones in the distal row?

from lateral to medial, includes trapezium, trapezoid, capitate, and hamate

How are the metacarpal bones numbered?

numbered I-V from lateral to medial.

How many phalanges does each finger have?

Each finger (except the thumb) has three phalanges: proximal, middle, and distal.

How many phalanges does the thumb have?

two phalanges: proximal and distal.

What is the pelvic girdle composed of?

two hip bones (ossa coxae) and the sacrum

What are the functions of the pelvic girdle?

• supports the trunk

• transfers force to the lower limbs

• protects the organs of the pelvic cavity

What are the three regions of each hip bone?

• ilium

• ischium

• pubis

What is the acetabulum?

hip socket where the three regions of the hip bone meet

What evolutionary changes in the pelvis allow for a smooth, efficient stride in humans?

positioning the body over the lower limbs

What is the primary function of the gluteus maximus in chimpanzees?

an abductor of the thigh

What are the general differences in appearance between male and female pelvises?

• males have a more massive and rougher pelvis

• females have a less massive and smoother pelvis

How does the tilt of the pelvis differ between males and females?

The upper end of the pelvis in males is relatively vertical, while in females, it is tilted forward.

What is the shape of the pelvic inlet in males compared to females?

• males are heart-shaped

• females are round or oval.

What is the subpubic angle in males compared to females?

Males typically have a narrower subpubic angle, usually 90° or less, while females have a wider angle, usually greater than 100°.

What is the longest and strongest bone in the human body?

The femur

What articulates with the acetabulum of the pelvis?

The spherical head of the femur

What are the two main bones of the leg?

tibia and fibula

Which bone of the leg is the only weight-bearing bone?

The tibia

What is the function of the calcaneus bone?

largest tarsal bone and forms the heel

What is the role of the patellar surface on the femur?

articulates with the patella

What adaptations of the foot are associated with bipedalism?

The great toe in humans is robust and adapted for the toe-off part of the bipedal stride.

What are the three types of arches in the human foot?

• medial and lateral longitudinal

• transverse

What is amelia in terms of limb pathology?

the complete absence of one or more limbs

What condition is characterized by webbed digits?

Syndactyly

What is polydactyly?

having extra fingers or toes

What is the role of the tibial tuberosity?

an attachment site for the quadriceps muscle group.

What is the significance of the medial malleolus?

the distal end of the tibia stabilizes the ankle.

What is the function of the fibula?

the lateral bone of the leg that helps stabilize the ankle.

How does the great toe of a chimpanzee differ from that of a human?

The great toe of a chimpanzee is prehensile and can grasp objects, while the human great toe is not prehensile and is adapted for bipedalism.

What is the role of the talus bone?

the second-largest tarsal bone and articulates with the tibia and fibula

What are the distal row bones of the foot?

• medial, intermediate, and lateral cuneiforms

• cuboid