UCI BioSci D170 The Appendicular Skeleton Williams
Reading: Chapter 8
What are the major parts of the appendicular skeleton?
The upper and lower limb bones as well as their girdles (belts
that encircle the body) make up the appendicular skeleton.
What four bones make up the pectoral girdle? Which of these bones
attach to the axial skeleton?
The anterior clavicles and posterior scapulas make up the
pectoral girdle. The medial end of the clavicle attaches to the
manubrium (sternum of axial skeleton), while the lateral end
attaches to the scapula.
Why is there great mobility in the pectoral girdle?
Only the clavicle is attached to the axial skeleton, thus the
scapula and arm move freely. The socket of the shoulder joint is
shallow, so it does not restrict the movement of the humerus (arm bone).
Describe the clavicles and their location, noting the acromial end and
sternal end. What are the functions of the clavicles?
The clavicle itself extends horizontally across the superior thorax on the
anterior surface. It is an S-shaped bone: the medial 2/3rds of the clavicle
convex anteriorly. The clavicle’s sternal end attaches to the manubrium
medially and the acromial end articulates w/ the scapula laterally.
Functions: provides attachment sites for muscles, holds the scapulae
and arms out laterally, and transmits compressions forces from the
upper limbs to the axial skeleton (pushing w/ hands).
Describe the scapulae (shoulder blades) and their location, noting the
following features. What is the function of the scapulae?
Shoulder blades are on the dorsal surface of the rib cage, b/w ribs 2 and 7. They consist of a
superior, medial, and lateral border.
Glenoid cavity – a shallow fossa found in the lateral angle. Articulates w/ the humerus, forming
the shoulder joint.
Inferior angle – at the junction of the medial and lateral borders.
Coracoid process – projects anterolaterally from the superior border. Attachment points for the
biceps muscle of the arm. Similar to a bent finger.
Spine – prominence on the posterior surface. End laterally in a...
, Alycia Edquilang, 4/17/20
Acromion – a flat projection on the lateral end of the spine. Articulates w/ the acromial end of
the clavicle -> acromio-clavicular joint.
Describe the structure and location of the humerus, including what bones it articulates with. Note the
following structures.
The humerus is the only bone in the arm; it articulates w/ the scapula at the shoulder and w/
the radius/ulna at the elbow.
Head – at the proximal end of the humerus, fitting in the glenoid cavity of the scapula.
Greater and lesser tubercle – lateral greater and medial lesser tubercles are attachment sites for
rotator cuff muscles (stabilize shoulder joint).
Intertubercular sulcus – separate the tubercles. Line that guides the biceps muscle to the
glenoid cavity attachment point. Bicipital groove.
Deltoid tuberosity – on the antero-lateral side of the shaft. Attachment site for the deltoid
muscle of the shoulder. Next to the posterior radial groove.
Trochlea – b/w 2 condyles at the distal end. Articulates w/ the ulna.
Capitulum* – lateral mound at the distal end, AND lateral to the trochlea from the posterior
view. Articulates w/ the radius.
Olecranon fossa – on the posterior surface of the humerus, superior to the trochlea.
*Area associated with a body structure is still a part of that body structure!
What two bones make up the forearm? How are they connected to one another along their length?
How are they arranged in the anatomical position? When the palms are facing posteriorly?
The forearm is made up of the radius and ulna; they are connected along their entire length by
a flat ligament called the interosseous membrane. In the anatomical position the radius lies
laterally and ulna medially. Vice versa when faced posteriorly.
Describe the structure and location of the ulna, including what bones it articulates with. Note the
following structures and their functions.
The longer ulna is the main bone forming the elbow joint w/ the humerus.
Reading: Chapter 8
What are the major parts of the appendicular skeleton?
The upper and lower limb bones as well as their girdles (belts
that encircle the body) make up the appendicular skeleton.
What four bones make up the pectoral girdle? Which of these bones
attach to the axial skeleton?
The anterior clavicles and posterior scapulas make up the
pectoral girdle. The medial end of the clavicle attaches to the
manubrium (sternum of axial skeleton), while the lateral end
attaches to the scapula.
Why is there great mobility in the pectoral girdle?
Only the clavicle is attached to the axial skeleton, thus the
scapula and arm move freely. The socket of the shoulder joint is
shallow, so it does not restrict the movement of the humerus (arm bone).
Describe the clavicles and their location, noting the acromial end and
sternal end. What are the functions of the clavicles?
The clavicle itself extends horizontally across the superior thorax on the
anterior surface. It is an S-shaped bone: the medial 2/3rds of the clavicle
convex anteriorly. The clavicle’s sternal end attaches to the manubrium
medially and the acromial end articulates w/ the scapula laterally.
Functions: provides attachment sites for muscles, holds the scapulae
and arms out laterally, and transmits compressions forces from the
upper limbs to the axial skeleton (pushing w/ hands).
Describe the scapulae (shoulder blades) and their location, noting the
following features. What is the function of the scapulae?
Shoulder blades are on the dorsal surface of the rib cage, b/w ribs 2 and 7. They consist of a
superior, medial, and lateral border.
Glenoid cavity – a shallow fossa found in the lateral angle. Articulates w/ the humerus, forming
the shoulder joint.
Inferior angle – at the junction of the medial and lateral borders.
Coracoid process – projects anterolaterally from the superior border. Attachment points for the
biceps muscle of the arm. Similar to a bent finger.
Spine – prominence on the posterior surface. End laterally in a...
, Alycia Edquilang, 4/17/20
Acromion – a flat projection on the lateral end of the spine. Articulates w/ the acromial end of
the clavicle -> acromio-clavicular joint.
Describe the structure and location of the humerus, including what bones it articulates with. Note the
following structures.
The humerus is the only bone in the arm; it articulates w/ the scapula at the shoulder and w/
the radius/ulna at the elbow.
Head – at the proximal end of the humerus, fitting in the glenoid cavity of the scapula.
Greater and lesser tubercle – lateral greater and medial lesser tubercles are attachment sites for
rotator cuff muscles (stabilize shoulder joint).
Intertubercular sulcus – separate the tubercles. Line that guides the biceps muscle to the
glenoid cavity attachment point. Bicipital groove.
Deltoid tuberosity – on the antero-lateral side of the shaft. Attachment site for the deltoid
muscle of the shoulder. Next to the posterior radial groove.
Trochlea – b/w 2 condyles at the distal end. Articulates w/ the ulna.
Capitulum* – lateral mound at the distal end, AND lateral to the trochlea from the posterior
view. Articulates w/ the radius.
Olecranon fossa – on the posterior surface of the humerus, superior to the trochlea.
*Area associated with a body structure is still a part of that body structure!
What two bones make up the forearm? How are they connected to one another along their length?
How are they arranged in the anatomical position? When the palms are facing posteriorly?
The forearm is made up of the radius and ulna; they are connected along their entire length by
a flat ligament called the interosseous membrane. In the anatomical position the radius lies
laterally and ulna medially. Vice versa when faced posteriorly.
Describe the structure and location of the ulna, including what bones it articulates with. Note the
following structures and their functions.
The longer ulna is the main bone forming the elbow joint w/ the humerus.
