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

Tarsal bones• Talus• Calcaneous

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)