Ch 8 appendicular skeleton

articulates with trunk

-supports the upper limbs

-clavicles and scapulae

•The scapula moves across thorax and arm moves with it

S-shaped bone

Sternal end articulates medially with the manubrium of sternum -acromial end articulates laterally with the acromion of the scapula

Conoid tubercle and costal tuberosity are ligament attachment sites

Glenoid cavity articulates with head of humerus

•Supraglenoid tubercle and infraglenoid tubercle superior and inferior edges of glenoid cavity, respectively

Other features (for muscle and ligament attachment):

•Posterior bony ridge is the spine

•Supraspinous fossa is superior to it and infraspinous fossa inferior to it

•Lateral: acromion process

•Anterior projection: coracoid process

•Subscapular fossa is anterior surface

•Head: articulates with glenoid cavity of scapula

Shaft contains deltoid tuberosity (deltoid)

•Anatomical and surgical necks

•Greater and lesser tubercles: for muscle attachment

•Intertubercular sulcus: for passage of biceps brachii tendon and muscle attachment

•Capitulum: articulation with radius

•Trochlea: medial, articulation with ulna

muscle attachments

•Radial fossa (anterior): accommodates head of radius

•Coronoid fossa (anterior): coronoid of ulna

•Olecranon fossa (posterior): olecranon of ulna

forearm

•In the anatomic position, they are parallel = in supination

•The radius is lateral to the ulna

•Pronation involves the radius crossing over the ulna

•Palm faces posteriorly

•Proximal features:

•Head: articulates with capitulum of humerus

•Neck: narrowest region

•Radial tuberosity: for biceps brachii muscle attachment

•Distal features:

•Styloid process: lateral “wrist bump”

•Ulnar notch: medial indentation for articulation with head of ulna

•Proximal features:

•Trochlear notch: accommodates trochlea of humerus

•Olecranon: projection that forms the posterior “bump” of the elbow; attachment site for triceps brachii

•Coronoid process: inferior lip of trochlear notch

•Radial notch: lateral; accommodates head of radius

Distal features:

•Head: knoblike end

•Styloid process: posteromedial “wrist bump”

Proximal Row

(lateral to medial)

1.Scaphoid

2.Lunate

3.Triquetrum

4.Pisiform

Distal Row

(lateral to medial)

5.Trapezium

6.Trapezoid

7.Capitate

8.Hamate

Roman numerals I–V

•I thumb, V little finger

•Proximal phalanx, middle phalanx, and distal phalanx

(pollex)Proximal and distal phalanges only (no middle phalanx)

pelvis-left and right ossa coxae, sacrum and coccyx

pelvic girdle-only the left and right ossa coxae

The “hip bone”

•Fusion of ilium, ischium, and pubis between 13 and 15 years of age

Articulations:

•Posteriorly -sacrum

•Laterally - femur at lunate surface of acetabulum

•All three bones of os coxa contribute to its acetabulum (socket)

superior portions of os coxa and acetabulum

•Ala: wide, fan-shaped portion

•Arcuate line: ridge along inferior border of the ala

•Iliac fossa: large depression on medial surface

•Anterior, posterior, and inferior gluteal lines: lateral sites of muscle attachments

•Iliac crest: superior ridge

•Anterior and posterior, superior and inferior iliac spines: projections along iliac crest

•Greater sciatic notch: for sciatic nerve entering lower limb

•Auricular surface: medial articulation with sacrum

The ilium fuses with the ischium at the superior and posterior margins of the acetabulum

Features:

•Ischial spine: prominent medial process

•Ischial tuberosity: rough inferior projection that

-weight of body when seated

•Ramus: extends from tuberosity to pubis

pubis fuses with the ilium and ischium at the acetabulum

Features:

•Superior pubic ramus and inferior pubic ramus: extend between acetabulum and ischial ramus

•Obturator foramen: large space bordered by pubic and ischial rami

•Pubic crest: rough ridge on anterosuperior of superior ramus; ends as pubic tubercle

•Pectineal line: ridge on medial surface of pubis continuing from arcuate line of ilium

Pelvic brim: continuous oval ridge formed by pubic crest, pectineal line, arcuate line, and sacral promontory

•True pelvis: inferior to pelvic brim containing pelvic organs

•False pelvis: superior to pelvic brim bound by ilia laterally and abdominal wall anteriorly

Pelvic inlet: superior entrance to true pelvis, at pelvic brim (space)

Pelvic outlet: exit of true pelvis, defined by coccyx, ischial tuberosities, and inferior border of pubic symphysis

Most reliable indicator of the sex -ossa coxae

Female-

- less massive, has less prominent markings

- ilia laterally flared = wider pelvis

- pelvic inlet = wide oval; male’s = heart-shaped

- preauricular sulcus

•subpubic angle is wider: greater than 100° compared to less than 90° in males

Longest, strongest, and heaviest bone

Proximal features:

•Head: articulates with os coxa at acetabulum

•Fovea: pit on head for ligament attaches to acetabulum

•Neck: constricted region just distal to head

•Greater trochanter and lesser trochanter: massive processes for attachment of powerful hip and thigh muscles

•Intertrochanteric line: anterior between trochanters marking distal edge of hip capsule

•Gluteal tuberosity: posterior rough region for attachment of gluteus maximus muscle

•Linea aspera: ridge on posterior shaft for attachment of many thigh muscles

•Distally, linea aspera splits into medial and lateral supracondylar lines

Distal features of femur:

•Medial condyle and lateral condyle: smooth, rounded articular surfaces for articulation with tibia

•Medial epicondyle and lateral epicondyle: projections just superior to the condyles for muscle and ligament attachment

•Intercondylar fossa: deep posterior depression that separates the condyles; ligament attachment site

•Patellar surface: smooth anterior region between condyles where patella articulates with the femur

Kneecap”

•Triangular with broad superior base and inferiorly pointed apex

•Articulates with patellar surface of femur

•an interosseous membrane

•Tibia is medial to fibula

•Tibia is the only weight-bearing bone

•Medial and lateral condyles: smooth surfaces for articulation with femur

•Fibular articular facet: articulation site for head of fibula

•Tibial tuberosity: rough anterior projection inferior to condyles

•Attachment site of patellar ligament

•Anterior border: ridge along anterior surface

•Commonly known as the “shin”

•Medial malleolus: inferiormost prominent medial process; stabilizes ankle joint

•Inferior articular surface: for articulation with talus (a tarsal bone)

•Proximal head with flat articular facet for articulation with the tibia

•Narrow neck and slender shaft

•Distal end expands into lateral malleolus, which stabilizes ankle joint

•Calcaneus: largest; forms the heel

•Talus: superiormost; weight-bearing; articulates with tibia

•Navicular: on medial side of ankle

•Cuneiforms: Wedge-shaped bones

•Medial, intermediate, and lateral cuneiform bones

•Cuboid: lateral side of ankle

between tarsals

And phalange

Roman numerals I–V from medial to lateral

•Proximal, middle, and distal phalanges for toes 2–5

•Great toe (hallux) has only two phalanges

•Proximal and distal phalanges only (no medial phalanx)

•Medial longitudinal arch: from heel to hallux; highest arch

•Lateral longitudinal arch: from heel to fifth toe; lowest arch

•Transverse arch: perpendicular to other arches; along distal row of tarsals

Skeletal mass and density decline

osteoporosis

•Begins in middle age

Osteoarthritis

Pubic symphysis changes with age

•Rough in early adulthood

•Develops concavities with arthritis in elderly

Upper limb develops a few days ahead of lower limb during weeks 4-8