Organization of the Skeleton

Axial Skeleton Appendicular Skeleton

Axial Skeleton is the “blue” Appendicular Skeleton is the “purple”

The Appendicular Skeleton

The appendicular skeleton is composed of the:

• pectoral girdle

• upper extremities

• pelvic girdle

• lower extremities

The Pectoral Girdle

Also called the “shoulder girdle,” the pectoral girdle contains four (4) bones. It functions to anchor and support the upper extremities and serves as animportant attachment site for a great number of muscles that help to move the arm. The bones of the pectoral girdle are as follows:

The Clavicles (2)

Also known as the “collarbones,” these act as anterior braces or struts, helping to prevent dislocations of the shoulder.

Bones of the Pectoral Girdle

The Scapula (2)

Also known as the “shoulder blades,” these contain the shallow sockets into which the head of the humerus fits.

Bones of the Pectoral Girdle

The Upper Extremities

The upper extremities or upper appendages, and commonly, but inappropriately, called the “arms,” contain a total of sixty (60) bones from regions commonly called the “upper arm,” “forearm,” “wrist,” and “hand.” The bones of the upper extremities listed proximally to distally are as follows:

Humerus

Bones of the Upper Extremities

Radius

Bones of the Upper Extremities

Ulna

Bones of the Upper Extremities

Reminder:A Comparison of the Radius to the Ulna

always “palm up,” palmar or supinated perspective

“Thumb”

“Pinkie”

Radius(on thumb side)

Ulna(on pinkie side)

5

1

23

4

43

2 1

5678

1 = Scaphoid

3 = Triangular2 = Lunate

4 = Pisiform

Proximal row of carpals – supinated (palmar) view; laterally to medially; or from below metacarpal 1 to metacarpal 5

Bones of the Upper Extremities

5 = Trapezium

6 = Trapezoid

7 = Capitate

8 = Hamate

Distal row of carpals – supinated (palmar) view; laterally to medially; or from below metacarpal 1 to metacarpal 5

5

1

23

4

43

2 1

5678

Bones of the Upper Extremities

1

23

45

Metacarpals

Bones of the Upper Extremities

1

23

45

Metacarpals

Naming the Metacarpals:

____________ metacarpal of the _________ hand.(1st, 2nd, 3rd, 4th, or 5th)

(Left or Right)

**Note: Counting for the metacarpals 1st through 5th goes from “thumb” to “pinkie.”

Reminder:

Bones of the Upper Extremities

1

23

45

P

P

M

D

D

P

M

D

P

M

D

Phalanges

P

M

D

1

23

45

Naming the Phalanges:

_______________ phalanx of the ___________ digit of the

_________ hand.(1st, 2nd, 3rd, 4th, or 5th)

(Left or Right)

(proximal, middle, or distal)

Proximal

Middle

Distal

**Note: The 1st digit, or thumb, has only proximal & distal phalanges – no middle.

P

P

M

D

D

P

M

D

P

M

D

Phalanges

P

M

D

Reminder:

Summary of Upper Extremities4. Metacarpals (10) – the

“palm” and/or the “back of the hand”

5. Phalanges (28) – (singular = phalanx) the “fingers”

1. Humerus (2) – the “upper arm”

2. Radius and Ulna (4) – the “forearm”

3. Carpals (16) – the ‘wrist”a. lunateb. hamatec. capitated. triangulare. trapeziumf. trapazoidg. scaphoidh. pisiform

The Pelvic Girdle

The pelvic girdle, also called the “pelvis,” functions to support and protect the soft, vital organs of the abdominal cavity, provide a stable support for the trunk of the body, and to provide attachments for the lower extremities (the legs). The bones of the pelvic girdle are as follows:

The Coxal Bones or Ossa Coxae

Also commonly called the “hipbones,” the coxal bones each consist of three parts which become fused

Bones of the Pelvic Girdle

in late adolescence to form a single bones. They articulate posteriorly with the sacrum and anteriorly to each other at the symphysis pubis joint.

The three subparts of the coxal bone which fuse in late adolescence are as follow:

a. The Ilium

b. The Ischium

c. The Pubis

Bones of the Pelvic Girdle

The Sacrum

Also a part of the vertebral column, it serves as a posterior anchor for the coxal bones and as a solid, posterior wall for the pelvic girdle.

Bones of the Pelvic Girdle

The Coccyx

Also known as the “tailbone.”

The Lower Extremities

The lower extremities or lower appendages, and commonly, but inappropriately, called the “legs,” contain a total of sixty (60) bones from regions commonly called the “thigh,” “shin,” “ankle,” and “foot.” The bones of the lower extremities listed proximally to distally are as follows:

Femur

Anterior View Posterior View

Bones of the Lower Extremities

Patella (2)

Tibia

Anterior View Posterior View

Bones of the Lower Extremities

Fibula

Anterior View Posterior View

Bones of the Lower Extremities

Right Leg – Anterior View

Tibia

Fibula

Lateral Medial

Right Leg – Posterior View

Fibula

Tibia

LateralMedial

Reminder: Comparison of the Tibia to the Fibula

1 2 34

5

7

654

3

2

1

Medial Lateral

1 = Calcaneus (heel bone)

3 = Navicular

2 = Talus (ankle bone)

4 = Medial Cuneiform

5 = Intermediate Cuneiform6 = Lateral Cuneiform

7 = Cuboid

Tarsals – dorsal view; Rt. foot

Bones of the Lower Extremities

Summary of Lower Extremities

1. Femur (2) – the “thighbone”

2. Patella (2) – the “kneecap”

3. Tibia (2) – the “shinbone”

4. Fibula (2) – the “calf bone”

5. Tarsals (14)

a. Talusb. Calcaneusc. Naviculard. Cuboide. Medial Cuneiformf. Intermediate Cuneiformg. Lateral Cuneiform

6. Metatarsals (10) – the “instep” or the “top of the foot”

7. Phalanges (28) – (singular = phalanx) – the “toes”