Appendicular Skeleton

The *pelvic girdle* is composed of 2 hip (coxal) bones called the

*ossa coxae* that attach the lower limb to the axial skeleton.

The bone surface markings formed by the *ilium, ischium*, and *pubis*.

-*acetabulum* = deep indentation, or cup, for head of the femur. -*obturator foramen* = largest foramen in the skeleton.

The bone surface markings of the *radius (lateral bone of forearm)*

-*head* = flat, disc-shaped proximal end. -*radial tuberosity* = rough, anterior projection on medial side just distal to the head. -*styloid process* = slender, pointed projection; distal end.

The bone surface markings of the femur (thigh bone)*

-*head* = large, rounded, knob-like proximal end. -*neck* = narrower, constrictiion distal to end. -*greater trochanter* = large and roughened superior projection; lateral to neck. -*lesser trochanter* = smaller, posterior-medial prominence distal to greater trochanter. -*medial condyle* = rounded, medial process on posterior side of distal end. -*lateral condyle* = similar to medial condyle on lateral side. -*intercondylar fossa* = deep fossa between medial and lateral condyles. -*medial epicondyle* = bump-like projection superior to medial condyle. -*lateral epicondyle* = bump-like projection superior to lateral condyle; a little smaller. -*gluteal tuberosity* = posterior surface of body of femur; roughened projection inferior to lesser trochanter. -*linea aspera* = vertical ridge on posterior surface.

The bone surface markings of the *humerus (arm bone)*

-*head* = rounded, proximal end. -*anatomical neck* = constriction immediately distal to head. -*greater tubercle* = lateral projection distal to anatomical neck. -*lesser tubercle* = smaller, anterior projection distal to anatomical neck. -*intertubercular sulcus* = groove between the two tubercles. -*surgical neck* = constriction distal to the tubercles. -*deltoid tuberosity* = raised area on lateral side between the proximal and disstal ends of humerus. -*trochlea* = spool-shaped medial condyle on the distal end. -*capitulum* = rounded, knob-like condyle lateral to trochlea. -*medial epicondyle* = rough projection above trochlea. -*lateral epicondyle* = rough projection above capitulum; smaller than medial epicondyle. -*radial fossa* = anterior depression that receives the radial head with flexed forearm. -*coronoid fossa* = shallow anterior depression on distal end. -*olecranon fossa* = largest depression on posterior, distal end.

The appendicular skeleton

has larger bones than the axial skeleton and bears more weight.

The *elbow joint*

is formed by the articulation of the coronoid process and olecranon process of the ulna into the coronoid and olecranon fossae of the humerus and by the trochlea of the humerus with the trochlear notch of the ulna.

The *male pelvis*

is more vertical and narrower, has a pelvic inlet that is heart-shaped, and has a 90 degree or less pubic arch angle.

The phalanges

make up the fingers or digits. The fingers are also numbered I to V from the thumb to the little finger. The thumb has 2 phalanges, proximal and distal. Digits II through V each have *proximal, middle,* and *distal phalanges*.

The *shoulder joint*

that connects the upper limb to the pectoral girdle is formed by the head of the humerus, articulating with the glenoid cavity of the scapula.

The upper limb consists of

the *humerus*, *ulna*, *radius*, *carpals*, *metacarpals*, and *phalanges*.

Each *os coxa* is formed by the fusion of 3 separate bones:

the *ilium*, *ischium*, and *pubis* bones. These 3 bones are identifiable as separate bones in children.

The bones of the appendicular division are separated into four main areas:

the *pectoral girdles*, the *upper limbs (extremities)*, the *pelvic girdle* and the *lower limbs*.

The bone surface markings of the *ulna (medial bone of forearm)*

-*olecranon* = large, curved, lip-like projection on posterior side of proximal end. -*coronoid process* = smaller, curved, lip-like projection on anterior side of proximal end; distal to olecranon. -*trochlear notch* = deep, curved area between olecranon and coronoid process. -*styloid process* = slender, pointed projection on distal end. -*radial notch* = depression on proximal end where head of radius articulates with ulna.

The bone surface markings of the *pelvis*

-*pelvic brim* = divides the false pelvis from the true pelvis; beings at the sacral promontory and extends laterally and inferiorly to end at the pubic symphysis. -*false pelvis* = portion of pelvis superior to pelvic brim; wide area extending to top of iliac crest. -*true pelvis* = portion of pelvis inferior to pelvic brim; surrounds the pelvic cavity. -*pelvic inlet* = superior opening of true pelvis; bordered by pelvic brim. -*pelvic outlet* = inferior opening of true pelvis; bordered by the coccyx, ischial spines, and ischial tuberosities.

The bone surface markings of the *scapula (shoulder blade)*

-*spine* = sharp ridge located on posterior side -*acromion* = flattened process at lateral end of spine. -*glenoid cavity* or *fossa* = depression inferior to acromion -*coracoid process* = superior and medial to glenoid cavity; projects anteriorly. -*supraspinous fossa* = depression superior to spine. -*infraspinous fossa* = depression inferior to spine. -*subscapular fossa* = depression on anterior surface of scapula. -*lateral* or *axillary border* = margin near axilla. -*medial* or *vertebral border* = margin near vertebral column.

The bone surface markings of the *clavicle (collar bone)*

-*sternal end* = blunt, medial end. -*acromial end* = broader, flat, roughened, lateral end.

Of the 30 bones in each upper limb,

1 is in the arm, 2 in the forearm, and the other 27 are in the hand (includes wrist).

Of the 30 bones in each lower limb,

4 are in the thigh and leg, and the other 26 are in the foot (including ankle).

The *metacarpal* bones, the palm of the hand (or metacarpus) is composed of

5 bones, making up the palm of the hand. They are numbered as Roman numerals I to V from the metacarpal of the thumb (lateral side) to the little finger side. The metacarpals articulate with the carpals proximally and with the phalanges distally.

The *carpal* bones, the wrist (or carpus), is composed of

8 bones, which are lined up to form a proximal and a distal row of bones. Two of the carpal bones articulate with the radius, but there is no articulation of the carpal bones with the ulna.

The bone surface markings of the *ilium (of the os coxa)*

The *ilium* is the largest and most superior of the three components of the os coxa. -*iliac crest* = superioer border of ilium. -*anterior superior iliac spine* = anterior end of iliac crest. -*anterior inferior iliac spine* = below the anterior superior iliac spine. -*posterior superior iliac spine* = posterior end of iliac crest. -*posterior inferior iliac spine* = below the posterior superior iliac spine. -*greater sciatic notch* = large notch on posterior side. -*iliac fossa* = depression on anterior surface.

The bone surface markings of the *ischium (of the os coxa)*

The *ischium* is the inferior, posterior portion of the os coxa. -*ischial tuberosity* = large, roughened projection on posterior and inferior edge. -*ischial spine* = posterior projection between greater and lesser sciatic notches. -*lesser sciatic notch* = depression on anterior surface.

The bone surface markings of the *pubis (of the os coxa)*

The *pubis* is the anterior inferior portion of the os coxa. -*pubic symphysis* = joint where the two pubic bones join anteriorly.

There are 2 pectoral girdles, and each attaches an upper limb to the axial skeleton. Each *pectoral* (or shoulder) *girdle* is composed of

a *scapula* and a *clavicle*.

The *sacroiliac joints*

are where the pelvic girdle articulates with the axial skeleton. The sacroiliac joints are located where the articulated ossa coxae unite posteriorly with the sacrum.

The lower limb consists of

bones of the *femur*, *patella*, *tibia*, *fibula*, *tarsals*, *metatarsals*, and the *phalanges*.

The ____ is the largest and strongest bone in the human skeleton. This bone is bowed anteriorly in a slight curve.

fermur

The *female pelvis*

generally has more space in the true pelvis for childbirth and is tilted backward and flared. The pelvic inlet is round or oval, the angle of the pubic arch is generally greater than 90 degrees, and the angle of the sciatic notch is wider.