Chapter 8
Skeletal System: Appendicular Skeleton
Pectoral girdle
Pelvic girdle
Upper limbs
Lower limbs
Pectoral (Shoulder) Girdle
Consists of scapula and clavicle
Clavicle articulates with sternum (sternoclavicular
joint)
Clavicle articulates with scapula (acromioclavicular
joint)
Scapula held in place by muscle only
Upper limb attached to pectoral girdle at shoulder (glenohumeral joint)
Clavicle (collarbone)
S-shaped bone with two curves
Extends from sternum to scapula above 1st rib
Fracture site is junction of curves
Ligaments attached to clavicle stabilize its position.
Posterior Surface of Scapula
Triangular flat bone found in upper back region
Scapular spine ends as acromion
process
a sharp ridge widening to a flat
process
Glenoid cavity forms shoulder
joint with head of humerus
Supraspinous & infraspinous fossa for muscular
attachments
Anterior Surface of Scapula
Subscapular fossa
filled with muscle
Coracoid process for muscle
attachment
Upper Extremity
Each upper limb = 30 bones
humerus
within the arm
ulna & radius within the
forearm
carpal bones within the wrist
metacarpal bones within the palm
phalanges in the fingers
Joints
shoulder (glenohumeral),
elbow, wrist, metacarpophalangeal, interphalangeal
Humerus --- Proximal End
Part of shoulder joint
Head & anatomical neck
Greater & lesser tubercles for muscle attachments
Intertubercular sulcus or bicipital groove
Surgical neck is fracture site
Deltoid tuberosity
Shaft
Humerus --- Distal End
Forms elbow joint with ulna and radius
Capitulum
articulates with head of radius
Trochlea
articulation with ulna
Olecranon fossa
posterior depression for olecranon process of ulna
Medial & lateral epicondyles
attachment of forearm muscles
Ulna & Radius --- Proximal End
Ulna (on little finger side)
trochlear
notch articulates with
humerus & radial notch with radius
olecranon
process forms point of elbow
Radius (on thumb side)
head articulates with capitulum of
humerus & radial notch of ulna
tuberosity
for muscle attachment
Elbow Joint
Articulation of humerus with ulna
and radius
Ulna articulates with trochlea of humerus
Radius articulates with capitulum
of humerus
Interosseous membrane between ulna
& radius provides site for muscle attachment
Ulna and Radius - Distal End
Ulna --styloid process
head separated from wrist joint by fibrocartilage disc
Radius
forms distal radioulnar
joint with head of ulna
8 Carpal Bones
(wrist)
Proximal row - lat to med
scaphoid
- boat shaped
lunate -
moon shaped
triquetrum
- 3 corners
pisiform
- pea shaped
Distal row - lateral to medial
trapezium - four sided
trapezoid - four sided
capitate
- large head
hamate -
hooked process
Carpal tunnel--tunnel of bone & flexor retinaculum
Metacarpals and Phalanges
Metacarpals
5 total----#1 proximal to thumb
base, shaft, head
knuckles (metacarpophalangeal
joints)
Phalanges
14 total: each is called phalanx
proximal, middle, distal on each
finger, except thumb
base, shaft, head
Pelvic Girdle and Hip Bones
Pelvic girdle = two hipbones united at pubic symphysis
articulate posteriorly
with sacrum at sacroiliac joints
Each hip bone = ilium, pubis, and ischium
fuse after birth at acetabulum
Bony pelvis = 2 hip bones, sacrum and coccyx
Ischium and Pubis
Ischium
ischial
spine & tuberosity
lesser sciatic notch
ramus
Pubis
body
superior & inferior ramus
pubic symphysis
is pad of fibrocartilage between 2 pubic bones
Iliac crest and iliac spines for muscle attachment
Iliac fossa for muscle attachment
Gluteal lines indicating muscle
attachment
Sacroiliac joint at auricular surface & iliac tuberosity
Greater sciatic notch for sciatic nerve
Pelvis
Pelvis = sacrum, coccyx & 2 hip bones
Pelvic brim
sacral promontory to symphysis pubis
separates false from true pelvis
false pelvis holds only abdominal
organs
Inlet & outlet
Pelvic axis = path of babies head
Female and Male Skeletons
Male skeleton
larger and heavier
larger articular
surfaces
larger muscle attachments
Female pelvis
wider & shallower
larger pelvic inlet & outlet
more space in true pelvis
pubic arch >90 degrees
Female
Male
Lower Extremity
Each lower limb = 30 bones
femur and patella within the thigh
tibia & fibula within the leg
tarsal bones in the foot
metatarsals within the forefoot
phalanges in the toes
Joints
hip, knee, ankle
proximal & distal tibiofibular
metatarsophalangeal
Femur and Patella
Femur (thighbone)
longest & strongest bone in
body
head articulates with acetabulum (attached by ligament of head of femur)
neck is common fracture site
greater & lesser trochanters, linea aspera, & gluteal tuberosity-- muscle attachments
medial & lateral condyles articulate with tibia
patellar surface anteriorly between condyles
Patella
triangular sesamoid
increases leverage of
quadriceps femoris tendon
Tibia and Fibula
Tibia
medial & larger bone of leg
weight-bearing bone
lateral & medial condyles
tibial tuberosity for patellar lig.
proximal tibiofibular
joint
medial malleolus
at ankle
Fibula
not part of knee joint
muscle attachment only
lateral malleolus
at ankle
Proximal region of foot (contains 7 tarsal bones)
Talus = ankle bone (articulates with tibia & fibula)
Calcaneus - heel bone
Cuboid, navicular
& 3 cuneiforms
Metatarsus and Phalanges
Metatarsus
midregion
of the foot
5 metatarsals (1 is most medial)
each with base, shaft and head
Phalanges
distal portion of the foot
similar in number and arrangement
to the hand
big toe is hallux
Arches of the Foot
Function
distribute body weight over foot
yield & spring back when weight
is lifted
Longitudinal arches along each side of foot
Transverse arch across midfoot
region
navicular,
cuneiforms & bases of metatarsals
Clinical Problems
Flatfoot
weakened ligaments allow bones of
medial arch to drop
Clawfoot
medial arch is too elevated
Hip fracture
1/2 million/year in US
osteoporosis
arthroplasty