Appendicular Skeleton (Ch 8) Flashcards
Pectoral Girdle
attaches to upper limb
includes: L/R scapula, L/R clavicle
Clavicle
*collarbone
-spans superior throat
-S-shaped
-sternal end: attaches to manubrium of sternum (medial)
-acromial end: attaches to acromial process of scapula (lateral)
Functions: muscle attachment, acts as brace for scapula/arms
–> ligaments are strong- most likely to break, not dislocate
Scapula
-does NOT join to axial skeleton, attached by muscles/ligaments
-loose connection to clavicle
-lots of movement/flexible but not stable
-located on posterior surface of rib cage
Includes:
-scapular spine: on posterior side
-glenoid cavity (fossa) articles with humerus to form shoulder joint
-corocoid process: attachment to bicep muscle
-acromion attaches with acromial end of clavicle
Upper Limb
- 30 bones
- Arm: one bone, humerus
- Forearm: two bones, ulna and radius
- Hand (+wrist): 27 bones, carpals/metacarpals/phalanges
Humerus
- longest bone of upper limb
- head articulates with scapula at glenoid cavity
- distal end articulates with radius/ulna
- greater/lesser tubercles: sites of muscle attachment
- -> deltoid tuberosity: attachment of deltoid
Where do most fractures of humerus occur?
at surgical neck (1) or mid shaft spiral fracture (2)
–> nerves run through an can be damaged, possibly permanent upper limb dysfunction
Ulna
- trochlea of humerus articulates w/trochlear notch of ulna = hinge
- coronoid process of ulna fits into coronoid fossa when forearm BENDS
- olecranon fossa of humerus receives olecranon process of ulna when forearm EXTENDS
- lateral/medial epicondyles on humerus are attachment sties for forearm muscles
Radius
- capitulum of distal humerus articulates w/head of radius
- radial head also articulates w/radial notch of ulna (proximal radioulnar joint) to form pivot joint –> elbow can bend/forearm can twist
- ligaments that anchor the wrist attach to radial/ulnar styloid processes
Supination
palms up
-radius parallel to ulna
Pronation
palms down
-radius crosses over ulna
Wrist fractures
- typically distal radius while catching self during fall –> scaphoid (bad blood supply–> severe fracture = necrosis of bone)
- common in older females
- “dinner fork” presentation
- may lead to nerve damage/dysfunction
Carpals
*8 in wrist, two rows
-gliding movements
-endochondrial bone ossification
hamate-capitate-trapezoid-trapezium
pisiform-triquetrum-lunate-scaphoid
Metacarpals/Phalanges
- 5 digits, numbered I-V (thumb to pinkie)
- each has a metacarpal
- digits II-V have 3 phalanges (proximal, middle, distal)
- -> thumb/pollex only has two (no middle)
Pelvis
“hip bones” + sacrum + coccyx
- includes appendicular and axial skeletal bones
- attaches lower limbs to spine (body weight basses through girdle) and support viscera
- strong attachment to axial skeleton at SI joint (stable)
- less freedom of movement compared to pectoral girdle
Ox Coxae
“hip bones”
- acetabulum: lateral sockets where head of femur articulates (composed of all 3 pelvic bones)
- two os coxae join anteriorly at pubic symphysis
Pelvic Inlet
space between pelvic and abdominal cavities (true and false pelves)
Pelvic Brim
edge of pelvic inlet
Pelvic Outlet
inferior opening defined by ischial tuberosities (bony future you sit on)
Pelvic differences in males/females
Males- narrower, inlet = more heart shaped
Females- wider/shallower
*different angles
Lower Limb
- carry weight of body
- bones are thicker/stronger than upper limb
- femur is largest/strongest bone in body
Femur
- head of femur carried on neck that angles laterally to join the shaft
- -> neck is weakest part
- greater/lesser trochanters are sites of muscle attachment
- lateral/medial condyles articulate with tibia (include lateral/medial epicondyles = raised part of condyle)
- linea aspera: ridge along posterior diaphysis, used for muscle attachment
- condyles are separated anteriorly by patellar surface and posteriorly by intercondylar fossa
Patella
- sesmoid bone (formed within CT) enclosed in the tendon of the quad muscle
- protects knee joint/improves leverage of quad
Tibia
- large/more sturdy than fibula
- located medially
- articulates with femur (at knee) and talus (at ankle)
- transmits weight body weight to foot
- medial/lateral condyles articulate with condyles of femur
- diaphysis is triangular with sharp anterior border (shin)
- distal end is flattened for articulation with talus
- medial malleolus projects to form ankle bone
- superior/inferior articulations connected by interosseous membrane
Fibula
- smaller/thiner than tibia
- located laterally
- NO articulation with femur, only for stabilization at ankle
- head on superior end, lateral malleolus in inferior end (ankle bone)
- does NOT bear weight
- superior/inferior articulations connected by interosseous membrane
Ankle Fractures
- common in sports, skiing, running
- typically result of rolling/twisting
- ligaments crossing the joint are strong –> usually remain intact but bones fracture
Foot
-includes: tarsals, metatarsals, phalanges (hallux=big toe)
Functions:
1. supports weight of body
2. acts as lever for moving body (walking/running)
Tarsals
-body weight mostly carried by talus and calcaneus
-talus articulates with tibia/fibula anteriorly and calcaneus inferiorly
talus, calcaneus, acicular, cuboid, lateral cuneiform, intermediate cuneiform, medial cuneiform
calcaneus
“heel”
-achilles tendon attaches to posterior surface and enables extension of foot
Metatarsals/Phalanges
- 5 digits, numbered I-V
- 5 metatarsals
- 3 Phalanges for each digit (II-V): proximal, middle, distal
- -> hallux (big toe) has no middle phalange
Arches of Foot
- Transverse: side to side between longitudinal arches
- Medial (Internal) Longitudinal: talus is key
- Lateral (External) Longitudinal: cuboid is key
- -> supports/distributes body weight, 1/2 to heel, 1/2 to metatarsals
- bones, ligaments, and tendons work together to maintain these
- tendons can fail with time (over/underuse) –> fallen arches
