APPENDICULAR SKELETON

CHAPTER 8(9/30/08)

THE PECTORAL GIRDLE

Pectoral or Shoulder Girdle

Consists of two bones, the anteriorly positioned clavicle and the posteriorly positioned scapula

Pectoral girdle is a loosely attached, held in place largely by musculature attached to the thorax and the vertebral column

Only direct ligament attachment exists at the sternoclavicular joint

Frees girdle to move over the thorax as the need arises

Pectoral Girdle

Flexible and Mobile Pectoral girdle is very light to allow the upper limb flexibility and mobility not allowed anywhere else in body

This is possible because only the sternal end of clavicle is attached to axial skeleton thus allowing the scapula to move across thorax and the arm with it

The socket of the shoulder joint is shallow and poorly reinforced

Although this arrangement does not restrict movement it is less stable

Clavicles

Clavicles are double curved bones extending along the superior thorax

Attached on the sternal end to sternum and the acromial to the scapula

Attachment site or muscles of the thorax and shoulder

Position scapula away from thorax

Right ScapulaAnterior Aspect

Bone markings are related to– Joint structures

– Muscle attachments

– Nerve and blood vessels

Right Scapula

Posterior Aspect

Bone markings are related to– Joint structures

– Muscle attachments

– Nerve and blood vessels

Right ScapulaLateral Aspect

Schematic representation of its orientation

THE UPPER LIMB

SECTION V

The Upper Limb Arm

– Humerus Forearm

– Ulna– Radius

Hand Wrist (8 carpal bones) Palm (5 metacarpal bones) Fingers (14 phalanges)

The Humerus

Radius and Ulna

Ulna is involved in elbow flexion

Radius is involved with supination and pronation

Elbow Joint

Olecranon process pivots around the Trochlea to allow for elbow flexion and extension

Elbow Joint

Olecranon process and coronoid process grips the trochlea of the humerus

Elbow Joint

Olecranon process of ulna fits into the olecranon fossa of humerus to limit extension

Wrist Joint

Scaphoid and lunate bones articulate with the radius

Wrist Joint

Palpation to locate the distal styloid processes of the radius and ulna

Colles’ Fractur

e An impact fracture caused by falling on an outstretched hand

Note characteristic bending of tissue

Carpals, Metacarpals, & Phalanges

Carpal Bones The carpal bones appear in two irregular rows (proximal arch and distal row)

Mnemonic; proximal row - lateral to medial

Sally Left The Party To Take Carmen Home

Scaphoid is the most frequently fractured carpal bone often resulting from falling on an outstretched hand

Carpals, Metacarpals, & Phalanges

THE PELVIC GIRDLE

SECTION VI

The Pelvic (Hip) Girdle

Attaches the lower limbs to axial skeleton

Transfers the weight of the torso, head, and upper extremities to lower limbs

Supports the visceral organs of the pelvis

Secured by strong ligaments and deep sockets the joint is reinforced for stability

Less range of motion in all planes of movement

Female pelvic structure to facilitate childbearing

Pelvis

Pelvis Pelvic girdle is formed by a pair of coxal bones, each called an os coxae

Each os coxae unites anteriorly at the pubic symphysis and with the sacrum posteriorly

Each coxa is formed by the ilium, ischium and pubic which were separate during childhood but fused in adulthood

Collectively the os coxae, sacrum and coccyx is called the pelvis

Os Coxa Ilium

– Superior

Ishium– Posterior

Pubis– Anterior

Os Coxa Ilium

– Superior

Ishium– Posterior

Pubis– Anterior

Ischium

Sacrospinous ligament anchors the coccyx to the sacrum

Sacro-tuberous ligament runs from sacrum to each ishial tuberosity

False Pelvis The false pelvis lies superior to the pelvic brim

The area is bounded by the alae of the iliac bones

Actually part of the abdomen and contains abdominal organs

True Pelvis The true pelvis lies inferior to the pelvic brim

It forms a deep bowl that contains the pelvic organs

Pelvic Structure and Childbearing

The female pelvis reflects modifications for child bearing

It tends to be wider, shallower, lighter, and rounder than the male

Pelvic modifications accommodate the growing fetus as well as providing a birth canal wide enough to allow the infants head to exit at birth

Pelvic inlet and outlet are critical to delivery

Male and Female Pelvic Structures

Male and Female Pelvic Structures

Male and Female Pelvic Structures

THE LOWER LIMB

SECTION VII

The Lower Limb Thigh

– Femur Leg

– Tibia– Fibula

Foot (7 Tarsal bones) Instep (5 Metatarsal bones) Toes (14 Phalanges)

Bones of Bones of Right FootRight Foot

Right Foot - Medial View

Right Foot - Lateral View

Arches of the Foot

DEVELOPMENTAL ASPECT OF THE SKELETON

SECTION VIII

The Appendicular Skeleton Throughout

Life Long Bone Ratio

The Fetal Skull