Skeletal System (In Part): The Appendicular Skeleton
Bruce G. Stewart
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Lecture Outline
The Appendicular Skeleton bones of the pectoral & pelvic girdles & upper & lower extremities
I. Pectoral Girdles attach bones of upper extremities to the axial skeleton
A. Components two bones; clavicle & scapula
1. articulation with axial skeleton only at sternum
B. Clavicle
1. anterior most bones (=collar bones)
a. double curvature
* medial convex anterior
* distal concave anterior
b. superior & anterior of thorax & horizontal
2. articulations
a. sternal extremity medial rounded & art. to sternum
b. acromial extremity broader, flat, lateral end that articulates with the scapula
* joint- acromioclavicular joint
3. other processes for ligament attachment
a. conoid tubercle inferior surface of the lateral end of bone
b. costal tuberosity inferior medial end
C. Scapulae (scapula is singular) shoulder blades
1. posterior large, flat , triangular bones
a. between levels of 2nd & 7th ribs
b. medial borders ca. 5 cm from vertebral Column
2. parts
a. body
* coracoid process (anterior lateral end)
* subscapular fossa (posterior depression)
b. spine diagonal ridge
* acromion lateral end of spine
# articulates with clavicle
* supraspinatous fossa (superior to the spine)
* infraspinatous fossa (inferior to the spine)
c. glenoid cavity inferior to spine
* articulates with humerus
II. Upper Extremity 60 bones
A. Humerus- arm bone
1. articulates with glenoid cavity & radius & ulna
2. parts of proximal end
a. head
b. anatomical neck (site of epiphyseal plate)
c. greater tubercle lateral & distal of neck
d. lesser tubercle anterior
e. intertubercular sulcus between tubercles
f surgical neck - distal to tubercles
3. parts of body (shaft) - cylindrical at proximal end but triangular then flattened & broad toward distal end
a. deltoid tuberosity
b. distal end
* capitulum art. with radius
* radial fossa art. / received head of radius when arm is flexed
* trochlea ulnar articulation (pully-like)
* coronoid fossa ant.
* olecranon fossa post.
* medial & lateral epicondyles
B. Ulna medial bone of forearm (little finger side)
1. proximal end
a. olecranon process art. with trochlea (elbow)
b. coronoid process art. with trochea notch
c. radial notch lateral & inferior to trochea notch
2. distal end
a. head has fibro. cart. disc at end & meets wrist
b. styloid medial
C. Radius lateral bone of forearm
1. proximal end
a. head art, with capitulum (humerus) & radial notch of ulna
b. radial tuberosity medial side ( insertion of biceps brachii)
2. distal end (concave)
a. styloid process lateral
b. ulnar process medial
c. also wrist articulation with lunate & scaphoid
D. Carpals, Metacarpals & Phalanges
1. carpus (wrist) - 8 bones united by ligaments
a. two transverse rows
b. scaphoid & lunate articulate with distal concave end of radius
# you do not have to know specific names of others
2. metacarpus 5
a. base, shaft & head (distal end)
b. I V (I articulates with thumb)
3. phalanges 14
a. base, shaft & head (distal end)
b. 3/digit except thumb (pollex) lacks middle
c. proximal, medial & distal rows
III. Pelvic (hip) girdle
A. components two coxal bones support lower extremities & connect to sacrum
B. pelvis general formed of sacrum, coccyx & coxal
1. brim of pelvis circumference of plane from sacral promontory to symphysis pubis
2. greater (false) pelvis superior expanded area * note anterior part has no bone
3. lesser ( true) pelvis inferior & posterior of brim
a. formed by inferior portion of ilia & sacrum, the coccyx & pubis
b. pelvic inlet superior opening
c. pelvic outlet inferior opening
d. pelvimetry measurement
C. pelvis bones, etc.
1. coxal bones ilium, ischium & pubis
a. unfused in babies; fused in adults
b. acetabulum point of fusion where it articulates with femur (2/5 ilium, 2/5 ischium, 1/5 pub)
2. ilium
a. iliac crest
* anterior superior iliac spine
* posterior superior Iliac spine
* abductor. muscles attachment to spine
b. greater sciatic notch inferior to the post. Sup. Iliac spine
c. iliac fossa
d. auricular surface
3. ischium inferior posterior portion
a. ischial spine
b. lesser sciatic notches below spines
c. ischial tuberosity inferior
d. ramus partly around obturator foramen
4. pubis anterior & inferior
a. superior & inferior rami
b. body to symphysis pubis
c. symphysis pubis fibrocartilage pad & joint
IV. Lower Extremeties 60 bones
A. Femur thighbone longest & heaviest bone in body
1. proximal end
a. head art. acetabulun
b. neck
c. greater trochanter lateral
d. lesser trochanter medial posterior
2. body
a. linea aspera - vertical ridge on posterior surface - muscle attachment
3. distal
a. medial condyle artic. with tibia
b. lateral condyle artic. with tibia
c. medial epicondyle & lateral epicondyle
d. patellar surface between condyles on anterior surface
B. Patella
1. broad superior end (base)
2. pointed inferior (apex)
3. posterior surface (two articular facets) that articulate with condyles
C. Tibia & Fibula
1. Tibia larger
a. proximal
* lateral condyle & medial condyle
* intercondylar eminence rise between condyles
* tibial tuberosity anterior surface for attachment of patellar ligament
* distal
# medial malleolus art. with talus bone
# fibular notch articulates with fibula
2. Fibula lateral to tibia & smaller
a. proximal end
* head art. with inferior surface of lateral condyle of femur
b. distal end
* lateral malleolus articulates with talus bone.
D. Tarsals, Metatarsals & Phalanges
1. tarsus 7 bones (know the following two by name)
a. talus articulates with fibula & tibia
* medial malleolus of tibia
* lateral malleolus of fibula
b. calcaneus heel bone
2. metatarsus I-V
a. connecters with a base (proximal end), shaft, head (distal end)
3. phalanges 3 per toe except hallux
4. arches
a. longitudinal arch
* medial part (flatfoot)
# Calcaneus through talus (keystone) to through other tarsals through 3 medial metatarsals
* lateral part
# Calcaneus through cuboidal through 2 lateral metatarsals (bunions)
b. transverse arch
V. Homeostatic Imbalances of the Skeleton in General
A. Herniated (Slipped) Disc
1. rupture of fibrocartilage allowing nucleus pulposus to become herniated
2. often slips posteriorly toward spinal cord & nerves
a. can cause acute pain
b. if sciatic nerve is involved pain can extend down leg
3. treatment
a. traction & bed rest
b. surgical decompression or removal followed by bone graft and fusion
c. percutaneous laser disc decompression (an out patient treatment)
B. Abnormal curves
1. scoliosis lateral bending often congenital
a. can result in malformation, chronic sciatica, paralysis of back muscles, poor posture, one shorter leg
2. kyphosis exaggeration of the thoracic curve. Causes include:
a. intervertebral disc degeneration
b. rickets
c. bad posture
3. Lordosis exaggeration of lumbar curve. Causes include:
a. obesity
b. poor posture
c. rickets
d. pregnancy
C. Spinabifida congenital defect where laminae fail to unite
1. 50% in lumbar region
2. mild cases affect urinary problems minor
3. serious cases meninges protrusion occurs paralysis, loss of urinary control
4. prenatal diagnosis mothers blood, sonography, amniocentesis
D. Fractures often of T5, T6, T9 L2
E. Various problems require marrow biopsy
1. Marrow aspiration by
sternal puncture is a common method
Reminder about Textbook Study
As with other topics, your textbook has excellent presentations of the materials on the appendicular skeleton of the skeletal system. While you should focus on the specific material in the Notes on the Web, you should always use your textbook as a resource for illustrations and for understanding content that your notes cover.
As with all materials throughout the semester, you will have opportunities to ask questions or ask that any relevant material from your assignments be discussed in class.
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