Bill 110: Lecture 9: The Appendicular Skeleton

What bones make up the Appendicular Skeleton

Pectoral Girdle; Upper Limb; Pelvic Girdle; Lower Limbs

What bones make up the Pectoral Girdle

The clavicle and scapula

What is the function of the pelvic girdle

-positions the shoulder joint

-provides a base of arm movement (major muscles attach here)

-maximizes the range of motion

Clavicles are shaped how?

-s shaped

Clavicles are the only direct bony connection between the pectoral girdle and the axial skeleton

The sternal end of the clavicle articulates with the manubrium of the sternum forming the sternoclavicular joint

Clavicles have two ends

the Acromial End and the sternal end

The sternal end of the clavicle articulates with the

manubrium of the sternum (forming the sternoclavicular joint)

The acromial end of the clavicle articulates with the

acromion or acromial process of the scapula (forming the acromioclavicular joint)

The superior surface of the clavicle is smooth

The inferior surface of the clavicle contains the conoid tubercle (near acromial end) and costal tuberosity (near sternal end)

The conoid tubercle and costal tuberosity are attachment sites for

ligaments

the sternoclavicular joint is the only bone that connects the

arm to the body

Scapula has three borders (posterior view)

Superior border, medial border, lateral border (posterior view)

Why are the superial, medial, and lateral borders important?

they are attachment sites for muscles

scapular spine of the scapula

a ridge that runs across the posterior side

Why is the scapular spine important

attachment site for muscles (ex: deltoid and trapezius)

acromion (acromial process) of the scapulae

projects anteriorly at a 90⁰ angle from the lateral end of the scapular spine

acromion (acromial process) of scapula lateral view

acromion (acromial process) of scapula anterior view

why is the acromion important

the acromion of the scapula articulates with the acromial end of the clavicle, forming the acromioclavicular joint

the coracoid process of the scapula

also called “crows beak”

projects anteriorly & laterally (means it can primarilly be seen from the anterior/ lateral view)

Subscapularis fossa of the scapula

smooth concave surface on the anterior side of scapula

supraspinous fossa from the posterior view of the scapula

a depression superior to scapular spine (posterior view bc scapular spine is on posterior side of scapula)

importance of the supraspinous fossa?

attachments sit for supraspinatus muscle (posterior view)

Infraspinous fossa (posterior view)

a depression inferior to scapular spine (posterior view bc scapular spine is on posterior side of scapula)

why is the infraspinous fossa important?

attachment site for infraspinatus muscle

glenoid cavity of the scapula

on lateral side, cup-shaped

posterior view of glenoid cavity of the scapula

anterior view of glenoid cavity of the scapula

why is the glenoid cavity of the scapula important

where the head of the humerus articulates

The user limbs of the appendicular skeleton include:

Humerus; radius; ulnal; carpals; metacarpals; phalanges

Humerus

head of humerus articulates with the scapula at the glenoid cavity

Head of humerus importance

articulates with glenoid cavity of the scapula to form the glenohumeral joint

Head of humerus is smooth and round and located at the

medial portion of the proximal epiphysis of the humerus

Greater tubercle of the humerus

where is the greater tubercle of the humerus

On the lateral edge of the head of the humerus (lateral edge of the epiphyses of the humerus)

Why is the Greater tubercle of the humerus important?

attachment site for muscles

Lesser tubercle of the humerus

Where is the lesser tubercle of the humerus

on the anterior & medical surface of the epiphyses of the humerus

why is the lesser tubercle important?

the tendon of biceps brachii runs along it

The intertubercular sulcus or groove

why is the inter tubercular sulcus or groove important

it separates the 2 tubercles

Body or shaft of the humerus is the

long, cylindrical middle part of the humerus

Deltoid tuberosity

an elevation that runs ½ way down the lateral surface of the humerus

Why is the deltoid tuberosity important

deltoid muscles insert here

Medial Epicondyle of the Humerus

FUNNY BONE feeling is her

Importance of the medial epicondyle of the humerus?

attachment site for muscles

what nerve crosses the medial epicondyle of the humerus posterior side?

the ulnar nerve

Trochlea of the humerus

the “pulley”

importance of the trochlea of the humerus?

Articulates with the trochlear notch of the ulna, forming the elbow joint

Capitulum of the humerus

“capit” = head

Importance of the capitulum of the humerus

The capitulum of the humerus articulates with the head of the radius, forming the humeroradial joint

Ulna

The ulna is the medial forearm bone

trochlear notch of the ulna

importance of the trochlear notch of the ulna?

the trochlear notch of the ulna articulates with the trochlea of the humerus, forming the elbow joint

Olecranon process of the ulna

the olecranon process of the ulna makes up the superior or inferior lip of the trochlear other of the ulna?

The superior lip

Olecranon process of ulna located on posterior part of elbow (can only be seen from posterior view)

olecranon and trochlear notch of ulna

olecranon process makes the

point of your elbow

radial notch of ulna

head of the radius

The head of the radius articulates with the radial notice of the ulna at the

proximal end

the olecranon process of the ulna enters into the

olecranon fossa of the humerus when the elbow is extended

The coronoid process enters the

coronoid fossa of the humerus when the elbow is flexed

The head of the radius articulates with the

capitulum of the humerus

The head of the radius enters into the

radial fossa of the humerus when the elbow is fixed

Head of ulna

distal

disc shaped

Styloid process of ulna

Medial

Radius

Lateral forearm bone

Head of radius

The head of the radius articulates with the

capitulum of the humerus

Neck of the radius

The radial tuberosity

Importance of the radial tuberosity

Attachment site for biceps brachii

ulnar notch