Chapter 8: The Skeletal System: The Appendicular Skeleton Flashcards
What are the general functions of the axial and appendicular skeletons?
The general function of the axial skeleton is the protection of internal organs; the primary function of the appendicular skeleton is movement.
Identify the bones of the pectoral (shoulder) girdle, their functions, and their principal markings.
The human body has two pectoral (shoulder) girdles that attach the bones of the upper limbs to the axial skeleton. Each of the two pectoral girdles consists of a clavicle and a scapula.
The clavicle, or collarbone, is the anterior bone and articulates at the medial end, called the sternal end, with the manubrium of the sternum at the sternoclavicular joint. The broad, flat, lateral end, the acromial end, articulates with the acromion of the scapula to form the acromioclavicular joint.
The scapula, or shoulder blade, articulates with the clavicle at the acromioclavicular joint and with the humerus at the glenohumeral (shoulder) joint. A prominent ridge called the spine runs diagonally across the posterior surface of the scapula. The lateral end of the spine projects as a flattened, expanded process called the acromion easily felt as the high point of the shoulder.
Identify the bones of the upper limb and their principal markings.
Each upper limb (upper extremity) has 30 bones in three locations - (1) the humerus in the arm; (2) the ulna and radius in the forearm; and (3) the 8 carpals in the carpus (wrist), the 5 metacarpals in the metacarpus (palm), and the 14 phalanges (bones of the digits) in the hand.
The humerus, or arm bone, is the longest and largest bone of the upper limb.
The ulna is located on the medial aspect (the little-finger side) of the forearm and is longer than the radius. The radius is the smaller bone of the forearm and is located on the lateral aspect (thumb side) of the forearm. In contrast to the ulna, the radius is narrow at its proximal end and widens at its distal end.
The carpus (wrist) is the proximal region of the hand and consists of eight small bones, the carpals, joined to one another by ligaments.
The metacarpus, or palm, is the intermediate region of the hand and consists of five bones called metacarpals. Each metacarpal bone consists of a proximal base, an intermediate shaft, and a distal head.
The phalanges, or bones of the digits, make up the distal part of the hand. There are 14 phalanges in the five digits of each hand. Each phalanx consists of a proximal base, an intermediate shaft, and a distal head. The thumb (pollex) has two phalanges called proximal and distal phalanges. The other four digits have three phalanges called proximal, middle, and distal phalanges.
What are the locations of the greater and lesser tubercles and lateral and medial epicondyles on the humerus?
Greater Tubicle - proximal, lateral
Lesser Tubicle - proximal, medial
Lateral Epicondyle - distal, lateral
Medial Epicondyle - distal, medial
What are the names of the 8 carpals?
The carpals are arranged in two transverse rows of four bones each. Their names reflect their shapes.
The carpals in the proximal row, from lateral to medial, are the:
- scaphoid (boatlike)
- lunate (moon-shaped)
- triquetrum (three-cornered)
- pisiform (pea-shaped)
The carpals in the distal row, from lateral to medial, are the:
- trapezium (four-sided figure with no two sides parallel)
- trapezoid (four-sided figure with two sides parallel)
- capitate (head-shaped)
- hamate (hooked)
Identify the bones of the pelvic girdle and their principal markings.
The pelvic (hip) girdle consists of the two hip bones, also called coxal, or pelvic bones, or os coxa. The hip bones unite anteriorly at a joint called the pubic symphysis. They unite posteriorly with the sacrum at the sacroiliac joints. The complete ring composed of the hip bones, pubic symphysis, sacrum, and coccyx forms a deep, basin-like structure called the bony pelvis.
The ilium, the largest of the three components of the hip bone, is composed of a superior ala and an inferior body.
The ischium, the inferior, posterior portion of the hip bone, comprises a superior body and an inferior ramus.
The pubis, meaning pubic bone, is the anterior and inferior part of the hip bone.
The pubic symphysis is the joint between the two pubes of the hip bones. The acetabulum is a deep fossa formed by the ilium, ischium, and pubis. It functions as the socket that accepts the rounded head of the femur.
Distinguish between the false and true pelves.
The bony pelvis is divided into superior and inferior portions by boundary called the pelvic brim that forms the inlet into the pelvic cavity from the abdomen. The portion of the bony pelvis superior to the pelvic brim is referred to as the false (greater) pelvis. The portion of the bony pelvis inferior to the pelvic brim is the true (lesser) pelvis.
The space enclosed by the false pelvis is part of the lower abdomen; it contains the superior portion of the urinary bladder (when it is full) and the lower intestines in both genders and the uterus, ovaries, and uterine tubes of the female.
The true pelvis contains the rectum and urinary bladder in both genders, the vagina and cervix of the uterus in females, and the prostate in males. Not only does the true pelvis surround the pelvic cavity, but it forms the birth canal through which a baby passes during delivery.
Compare the principal differences between female and male pelves.
Identify the bones of the lower limb and their principal markings.
Each lower limb (lower extremity) has 30 bones in four locations - (1) the femur in the thigh; (2) the patella (kneecap); (3) the tibia and fibula in the leg; and (4) the 7 tarsals in the tarsus (ankle), the 5 metatarsals in the metatarsus, and the 14 phalanges (bones of the digits) in the foot
Identify the bones of the lower limb and their principal markings.
Each lower limb (lower extremity) has 30 bones in four locations - (1) the femur in the thigh; (2) the patella (kneecap); (3) the tibia and fibula in the leg; and (4) the 7 tarsals in the tarsus (ankle), the 5 metatarsals in the metatarsus, and the 14 phalanges (bones of the digits) in the foot.
The femur, or thigh bone, is the longest, heaviest, and strongest bone in the body. The greater trochanter and lesser trochanter are projections from the junction of the neck and shaft that serve as points of attachment for the tendons of some of the thigh and buttock muscles.
The patella, or kneecap, is a small, triangular bone located anterior to the knee joint.
The tibia, or shin bone, is the larger, medial, weight-bearing bone of the leg. The proximal end of the tibia is expanded into a lateral condyle and a medial condyle.
The fibula is parallel and lateral to the tibia, but it is considerably smaller. The distal end of the fibula has a projection called the lateral malleolus that articulates with the talus of the ankle.
The tarsus (ankle) is the proximal region of the foot and consists of seven tarsal bones. They include the talus (ankle bone) and calcaneus (heel) located in the posterior part of the foot. The calcaneus is the largest and strongest tarsal bone. The anterior tarsal bones are the navicular, three cuneiform bones called the third (lateral), second (intermediate), and first (medial) cuneiforms, and the cuboid.
The metatarsus, the intermediate region of the foot, consists of five metatarsal bones numbered I to V (or 1–5) from the medial to lateral position.
The phalanges comprise the distal component of the foot and resemble those of the hand both in number and arrangement. The toes are numbered I to V (or 1–5) beginning with the great toe, from medial to lateral. Each phalanx (singular) consists of a proximal base, an intermediate shaft, and a distal head. The great, or big, toe has two large, heavy phalanges called proximal and distal phalanges. The other four toes each have three phalanges - proximal, middle, and distal.
Name the 2 arches of the foot.
The longitudinal arch and the transverse arch.
