The appendicular skeleton consists of the pectoral girdle, upper extremities, pelvic girdle, and lower extremities.

In this lecture we will focus just on the pectoral girdle and upper limbs

The pectoral girdle is not a complete girdle

The pectoral girdle provides for attachment of the arms and many of the arms’ associated muscles. It is a delicate structure.

The only bones that keep the scapulae and the shoulders laterally are the delicate clavicles.

Congenital absence of clavicles

Clavicle (collar bone)Inferior view

Superior view

Epaulettes were originally designed as armor to help protect the delicate clavicle.

Currently epaulettes are minimal and just used for attachment of symbols of military rank.

Sternoclavicular joint

Acromioclavicular joint (A-C joint).

Note the conoid tubercle on the inferior, lateral end of the clavicle that serves as an attachment site for several ligaments.

Superior view

Inferior view

Master Long is going to easily fracture his opponent’s right clavicle so his opponent will be unable to use that arm.

ACCORDING TO THE CLINICAL VIEW IN YOUR TEXT, WHY IS A POSTERIOR FRACTURE OF THE CLAVICLE POTENTIALLY MORE SERIOUS THAN AN ANTERIOR FRACTURE?

A MORE LIKELY TO BREAK THE SKIN

B MORE LIKELY TO DAMAGE BLOOD VESSELS

C MORE LIKELY TO ENTER HEART

D MORE LIKELY TO INJURE ULNAR NERVE

E MORE LIKELY TO TEAR DIAPHRAGM

The scapula normally lays over ribs #2-#7 on the posterior aspect of the rib cage.

Left scapula

Anterior Posterior

The head of the humerus articulates with the glenoid cavity.

Subscapular fossa on anterior surface of scapula.

Humerus

clavicle

Scapula

The humerus is the longest bone of the upper extremity.

groove

The distal end of the humerus is modified to articulate with the two bones of the forearm.

The radial fossa accommodates the head of the radius and the coronoid fossa of the humerus receives the coronoid process of the ulna when the elbow is flexed.

Anterior view

The olecranon fossa of the humerus receives the olecranon of the ulna when the elbow is extended

Posterior view

WHICH OF THE FOLLOWING IS CORRECT ABOUT THE DISTAL MEDIAL END OF THE HUMERUS?

A NEAR THE ULNAR NERVE

B SHAPED LIKE A PULLEY

C ARTICULATES WITH THE ULNA

D FORMS A FIRM HINGE JOINT WITH THE FOREARM

E ALL OF THE ABOVE

The antebrachium contains the ulna on the medial side and the radius on the lateral (thumb) side.

Note the head of the radius and the radial notch in nearby ulna

The radius is lateral to the ulna. Note the head, neck, the radial tuberosity, the shaft, and the styloid process on the lateral tip.

Trochlear notch

Note styloid processes on distal radius and ulna and ulnar notch on medial distal end of the radius

The proximal end of the ulna forms the trochlear notch. Note the anterior coronoid process and the posterior olecranon.

The radial notch, mentioned earlier, accommodates the nearby head of the radius

The distal end of the ulna is called the head. It has a medial projection called the styloid process. The distal ulna also once again articulates with the nearby radius.

Trochlear notch

The styloid processes of the distal ulna and radius create a “U-shaped” arrangement to help stabilize the bones of the wrist.

The interosseous membrane helps keep the radius and ulna a fixed distance from one another and also allows rotation of the forearm.

Crucifixion is NOT normally performed in the hand

Crucifixion is properly performed in the wrist or between distal ends of radius and ulna

The Governor of California shown properly crucified with nails in wrist or between distal end of radius and ulna. Note the vulture perched on arm that is soon to be lunch.

It damages median nerve

Shroud of Turin black and white image.

Color image of blood

In the Shroud of Turin the tibia and fibula are NOT broken.

There are 8 carpal bones in the wrist.

The bones of the manus at work on a keyboard

Kermit gets a surprise!

The palm of the manus is composed of 5 metacarpals numbered 1-5 with #1 leading to the thumb.

The fingers (digits) contain phalanges. All the digits have three phalanges, except for the thumb (finger #1) that only has two.

What specific phalanges have been “nailed”?

In this posterior x-ray of a child’s right hand, what specific bone has been fractured?

What specific bone(s) of this person’s left hand have been “forked”?

WHAT BONE IS ENCIRCLED BY A WEDDING RING?

A METACARPAL #3 OF RIGHT HAND

B PROXIMAL BONE OF POLLEX

C DISTAL PHALANX OF FINGER #5 OF RIGHT HAND

D BONE MEDIAL TO METACARPAL #4 AND MIDDLE PHALANX #4

E MIDDLE PHALANX OF FINGER #3 OF LEFT HAND

One of many ways to fracture the delicate clavicle.

Crack the whip

Left clavicular fracture

Matt Crivello’s fractured clavicle from football

Jagged ends of a fractured clavicle can easily damage underlying arteries and veins unless the injured arm is quickly immobilized.

Matt Crivello’s fractured clavicle from football after repair

Blows strong enough to fracture the scapula may also result in fracture of the underlying ribs.

Scapular fracture through the glenoid cavity

Blows or falls on the tip of the shoulder can lead to dislocation of the acromion process of the scapula from the clavicle (A/C separation).

When examining patient it is a good idea to palpate the normal shoulder and compare to bad shoulder.

Normal

Acromioclavicular separation (A/C separation) in the right shoulder

One way to reposition bones of a dislocated shoulder.

Fracture of the shaft of the humerus may damage nearby nerves.

Open fracture of humeral shaft.

Supracondylar fracture of the humerus.

Supracondylar fracture and midline fracture of distal humerus.

Anterior view of repair of fracture shown in previous slide

Lateral view of repair of fracture shown in previous slide.

Dislocation of the elbow.

The muscular tendons which attach to the lateral epicondyle of the humerus are put under tremendous stress during the backhand stroke.

Note vibration-stopping rubber bands on racquet and support band on forearm

A child who lived next door to me did this by falling off the trampoline

Colles’fracture. Fracture of the distal end of the radius causing a “silver fork” deformity.

Fracture of the distal end of the radius results in a characteristic “silver fork” deformity. This type of fracture is called a Colles’ fracture.

IF YOU WERE LAYING IN THE PARK PROPPED UP BY ONE FULLY EXTENDED ARM AND A HEAVY CHILD RAN INTO THE POSTERIOR OF THIS SAME EXTENDED ARM, WHAT WOULD MOST LIKELY OCCUR?

A FRACTURE OF THE OLECRANON

B A-C SEPARATION

C COLLES FRACTURE

D SCAPULAR FRACTURE

E FRACTURE OF A SESAMOID BONE