Appendicular Skeleton Flashcards
the appendicular skeleton
pectoral girdle: attaches the upper limbs to the upper trunk
pelvic girdle: attaches the lower limbs to the lower trunk
upper and lower limbs differ in function but share a similar structural plan
the pectoral girdle
consists of the clavicle and the scapulae
do not encircle the body completely
medially: sternal end of each clavicle articulates with the manubrium and first rib of the axial skeleton
laterally: acromium end of the clavicle joins the scapula at the acromioclavicular joint
clavicles
provide attachment for muscles
articulate with the scapulae laterally
articulate with the sternum medially
transmit compression forces from the upper limbs to the axial skeleton
scapulae
lie on the superior dorsal surface of the rib cage
located between ribs 2-7
have three borders: superior, medial (vertebral), lateral (axillary)
have three angles: lateral (location of glenoid cavity), superior, inferior
the upper limbs
30 bones form each upper limb grouped into bones of the: arm: 1 bone (humerus) forearm: 2 bones (radius and ulna) hand/wrist: 27 bones
humerus
only bone in the arm
strongest bone in the upper limbs
articulates with the scapula at the shoulder
articulates with the radius and ulna at the elbow
proximal radius bone
interface with distal humerus
head of proximal radius bone interfaces with capitulum of distal humerus
radial tuberosity below head of radius
with elbow flexion, radial head moves into radial fossa of distal humerus
proximal ulna bone
interface with distal humerus
main bone responsible for forming the elbow hinge joint with the humerus
anterior coronoid process and posterior olecranon process of ulna interfaces with the trochlea of the distal humerus
with elbow flexion, coronoid process of ulna moves into coronoid fossa of distal humerus
with elbow extension, olecranon process of ulna moves into olecranon fossa of distal humerus
radius and ulna articulate with each other
at proximal and distal radioulnar joints proximal ulna has radial notch distal radius has ulnar notch interosseous membrane anatomical position: radius is lateral and ulna is medial
distal ulna
ulnar head and styloid process
distal ulna is separated from carpal bones by fibrocartilage
plays little to no role in hand movement
distal radius
articulates with carpal bones - scaphoid and lunate
when radius moves, the hand moves with it
ulnar notch of distal radius articulates with ulnar bone
styloid process
wrist and hand bones
carpals - wrist - 8 bones
metacarpals - palm - 5 bones
phalanges - fingers - 14 bones
pelvis
deep basin-like structure formed from the coxal bones, sacrum, and coccyx
pelvic girdle
consists of paired coxal bones (hip bones)
coxal bones unite anteriorly with each other at the pubic symphysis
coxal bones articulate posteriorly with the sacrum to form sacroiliac joints
supports visceral organs
attaches to axial skeleton by strong ligaments
acetabulum
deep socket on lateral coxal bone where head of the femur articulates
pelvis terms
pelvic brim (=pelvic inlet) - continuous oval ridge that runs from the pubic crest to around the sacral promontory pelvic inlet - delineated by the pubic brim pelvic outlet - inferior margins of true pelvis true pelvis - extends inferior from the pelvic brim and forms a deep bowl containing the pelvic organs false pelvis - superior to the pelvic brim and is actually part of the abdomen and contains abdominal organs
male vs. female pelves
female pelvis is adapted for childbearing
female pelvis is wider, with a wider pelvic inlet and outlet compared to males
pubic angle of pubic arch is > 80 degrees in females and < 60 degrees in males
the lower limbs
carries the entire weight of the erect body
bones of lower limb are thicker and stronger than those of the upper limb
divided into three segments - thigh (1 bone: femur), leg (2 bones: tibia and fibula), foot/ankle (26 bones)
femur
the single bone of the thigh
longest and strongest bone of the body
ball-shaped femoral head articulates with the acetabulum
patella
triangular sesamoid bone
embedded in the tendon that secures the quadriceps muscles
protects the knee anteriorly
improves leverage of the thigh muscles across the knee
leg
region of the lower limb between the knee and the ankle with the tibia and fibula bones
tibia: more massive medial bone of the leg that receives the weight of the body from the femur
fibula: stick-like lateral bone of the leg
interosseous membrane connects the tibia and fibula
the foot
composed of: tarsal bones (7) metatarsal (5) phalanges (14) functions: supports body weight, acts as a lever to propel body forward when walking, segmentation makes foot pliable and adapted to uneven ground
