Appendicular Skeleton

The Skeletal System Appendicular Skeleton

Appendicular Skeleton • Bones of extremities • Bones of shoulder and hip joints • 126 bones

Appendicular Skeleton • • • •

Pectoral girdle (shoulder joint) – 4 Upper extremities – 60 Pelvic girdle (hip joint) – 2 Lower extremities – 60

A. Pectoral Girdle and Upper Extremity

Pectoral Girdle (Shoulder Joint) • Clavicle • Scapula

Clavicle (superior) Lateral

medial

S-shaped bone Most frequently fractured bone in the human body

Clavicle

Scapula • Triangle-shaped bone • Medial, lateral and superior borders • Superior and inferior angles

Scapula (anterior)

Scapula (anterior)

Scapula (posterior)

Scapula (lateral)

posterior

anterior

Glenoid cavity (fossa)

Coracoid process (anterior)

Coracoid process (lateral)

posterior

anterior

Scapular Fossae (3)

Fossa -- a shallow depression

Scapular Fossae (3)

The Upper Extremity (Limb) • • • •

Consists of 30 bones 1 arm 2 forearm Remaining in wrist, palm and digits

The Upper Extremity (Limb)

The Arm • Only one bone • Humerus

Humerus Anterior view

Humerus Anterior view

Shoulder joint

Fractures often occur at this site Deltoid muscle attaches here

Humerus Anterior view Condyle – a smooth rounded surface or articular process 4. Capitulum (lat) 2. Trochlea (med)

Epi = above

Humerus

The Forearm • • • •

Two parallel bones Ulna & radius Ulna is medial Radial is lateral

Forearm

Forearm

lateral

medial

Ulna Anterior view

lateral

medial

Ulna

Ulna Anterior view

lateral

medial

Radius Anterior view

lateral

medial

Wrist (anterior)

Carpals 8 carpals

Carpal Tunnel Syndrome

Inflammation of tendons and nerve

Wrist

Metacarpals 5 metacarpals - palm

Phalanges 14 phalanges

A. The Pelvic Girdle (Pelvis) & Lower Extremity (Limb)

The Pelvis • 2 coxae bones • Sacrum and coccyx

Coxa • •

Left & right Formed from fusion of 3 bones 3. Ilium 4. Ischium 5. Pubis

1. Ilium ASIS

1. Ilium Iliac crest Iliac fossa

ASIS

Acetabulum

2. Ischium

2. Ischium

Ischial tuberosity

Ischial ramus

3. Pubis

3. Pubis

3. Pubis

Pubic arch – angle of inferior rami

Coxa (lateral) • All 3 bones contribute to acetabulum

Acetabulum • Accomodates head of femur

Pelvic Inlet • Formed by ilium, pubis and sacrum

Structural Differences Female vs Male • Differences in pelvis adapted for childbearing

1. Enlarged pelvic inlet in female

male

female

2. Sacrum doesn’t project into pelvic inlet

male

female

3. Iliac bones flare laterally in female

male

female

4. Pubic arch wider in female

male

female

X-ray of Hip Replacement

Femur • Only bone of thigh • Longest bone in body • Articulates w/ acetabulum and tibia

Femur Anterior view

right or left?

Femur Anterior view

Femur Posterior view

condyles

Femur Condyles

Patella

Patella

anterior

posterior

Leg Bones • Two leg bones • Tibia – medial lateral • Fibula - lateral

medial

Tibia

Fibula

lateral

Tibia articulates w/ femur— fibula does not

medial

Knee Articulation

Tibia and fibula • Major weight-bearing bone of leg

Tarsal Bones • • • 2.

7 bones talus - articulates with tibia Major weight bearing bone of foot calcaneous - heel bone

Tarsal Bones (7)

Metatarsals (5)

Phalanges (14)