Chapter 8
The Appendicular Skeleton
Course objectives:
• List the bones of the appendicular skeleton
• Describe and identify the bones of the pectoral girdle
• Describe and identify the bones of the pelvic girdle

Appendicular Skeleton
• Includes the bones of the upper limb and their attachments to the axial skeleton at the pectoral girdle.
• Includes the bones of the lower limb and their attachments to the axial skeleton at the pelvic girdle.

Pectoral Girdle
• scapula – “shoulder blade”
-(triangular flat bone) articulates with humerus of arm at the glenoid fossa
• clavicle – “ collar bone"
-flat bone articulates with the acromion process of scapula and the manubrium of the sternum, thus forming the only bony link with the axial skeleton and pectoral appendicular skeleton

Scapula
• Thin triangular flat bone that forms the bulk of the shoulder
• Connects to the arm at the humerus via glenoid fossa
• Connects to the clavicle at the acromion process

Scapula landmarks
• Supraspinous and infraspinous fossa
• Suprascapular fossa
• Acromion
• Coracoid process
• Glenoid cavity
• Lateral and medial border

Clavicle landmarks
• Acromial end
• Sternal end
• Conoid tubercle
• Costoclavicular tuberosity

The clavicle

The Upper Limb
• Consists of 30 bones
• Grouped into bones of the arm, forearm and hand
• Arm = Humerus
• Forearm = Radius and Ulna
• Hand = Carpals (8), metacarpals (5) and phalanges (5)

“Arm or Brachium”

Humerus landmarks
• Head and body of humerus
• Greater and Lesser tubercles
• Anatomical neck and Surgical neck
• Medial and lateral supracondylar ridges
• Medial and lateral epicondyle
• Olecranon and radial fossa
• Coronoid process
• Deltoid tuberosity
• Capitulum
• Trochlea

Forearm “antebrachium”
• Consists of the Radius (lateral) and Ulna
(medial).
• Both are connected along their length by a ligament ( interosseous membrane )

Radius landmarks
• Head, neck and shaft
• Radial tuberosity
• Ulnar notch
• Styloid process
• Nutrient foramen

Ulna landmarks
• Olecranon process
• Coronoid process
• Trochlear notch
• Radial notch
• Head of the ulna
• Styloid process of ulna

The Hand
• Consists of:
• Carpals (8) “wrist”
• Metacarpals (5) “palm”
• Phalanges (5) “fingers”

Carpal bones
Eight bones makeup the wrist

Carpal bones

Metacarpals and Phalanges
• These bones are not named individually but are numbered 1-5.
• The thumb “pollex” is number 1.
• They are all long bones
• The base of the metacarpals articulate with the carpal bones at their base and the phalanges at their head.
• The phalanges consist of a proximal, middle and distal phalanx in all but the thumb .

Metacarpals and Phalanges

The Pelvic Girdle
• The “hips” form a much more solid and stable connection for the lower limbs to the axial skeleton than the pectoral girdle is to the upper limbs.
• The pelvic girdle is formed by the coxal bones
(a.k.a. hip bones, os coxae) which fuse posteriorly with the sacrum .
• The coxal bones are formed by the fusion of three separate bones ( ilium, ischium and pubis) during growth.

“Os Coxae” Hip bones
• Formed by the fusion of three bones
1. ilium, 2. ischium, and 3. pubis
• Attaches to the lower limb and spine at sacroiliac joint
• Supports the pelvic organs or viscera
• Attached to the axial skeleton by strong ligaments

Os coxae landmarks
• Iliac crest
• Anterior superior and ant. inferior iliac spine
• Posterior superior and post. inferior iliac spine
• Greater and lesser sciatic notch
• Iliac fossa
• Ischial spine and tuberosity; ramus of ischium
• Obturator foramen
• Superior and inferior ramus of pubis
• Pubic symphysis and pubic arch
• Acetabulum

Male vs Female Os coxae
• Significant differences exist between the male and female pelvis.
– ♀ pelvic outlet is enlarged due to in part greater separation of ischial spines
– ♀ less curvature of sacrum and coccyx which in males ♂ arcs into pelvic outlet
– ♀ wider more circular pelvic inlet
– ♀ relatively broad, low pelvis
– A broader pubic angle in ♀ between pubic bones
> 100 °

Male Female

True vs. False pelvis
• False pelvis = area within entire pelvic girdle
• True pelvis = area below pelvic brim

Lower limb
Consists of:
• Femur “Thigh” = hip to the knee
• Tibia and fibula “Leg” = knee to foot
• Foot

Femur “Thigh” landmarks
• Longest, strongest, largest bone in body
• Head
• Neck
• Greater and lesser trochanter
• Medial and lateral condyle
• Medial and lateral epicondyle
• Linea aspera

Patella “knee cap” landmarks
• Base
• Apex
• Articular surfaces

Lower leg
• technically the distance between the knee and ankle
• Bones of the leg: tibia (shin bone) and fibula
(lateral leg bone)
• Consists of the: Tibia (shin bone)
Fibula
• Interosseuos membrane connects tibia and fibula along their length

Tibia landmarks
• Medial and lateral condyle
• Tibial tuberosity
• Medial malleolus (medial bulge of ankle)
• Anterior border (crest) is the shin

Distal End of Tibia

Fibula landmarks
• Fibula is lateral bone of the leg
• Head
• Lateral malleolus (lateral bulge of ankle)

The foot
• Includes the bones of the;
-Tarsus
-Metatarsus
Phalanges
• Functions
-support of the body
-lever for walking or running

• Talus
• Calcaneous
Tarsal bones

Metatarsals and Phalanges
• Are all long bones
• Metatarsals numbered 1-5
• Phalanges consist of proximal, middle and distal bones in all but big toe
• Big toe or great toe is Hallux

Tarsal bones (Ankle)