Humerus Flashcards
What is the humerus?
The bone that forms the upper arm
What does the humerus do?
Joints the arm to the shoulder and forearm
What does the humerus articulate with?
The proximal region articulates with the scapula and clavicle
The distal region articulates with the forearm bones (radius and ulna)
What is formed when the humerus articulates with the scapula and clavicle?
The shoulder joint
What is formed when the humerus articulates with the forearm bones?
Elbow joint
What does the humerus act as?
The attachment site for many muscles and ligaments
What does the humerus’ role as an attachment site result in?
Various raised roughening on the bony surface
What does the proximal region of the humerus articulate with?
The scapula
What is formed when the humerus articulates with the scapula?
The glenohumeral (shoulder) joint
What are the important anatomical features of the proximal humerus?
The head Anatomical neck Surgical neck Greater and lesser tubercles Intertubercular sulcus
What is a tubercle?
A round nodule
What does a tubercle signify?
An attachment site of a muscle or ligament
Where does the head of the humerus project?
Medially and superiorly
What does the head of the humerus do?
Articulates with the glenoid cavity of the scapula
How is the head of the humerus connected to the tubercles?
By the anatomical neck
Describe the anatomical neck of the humerus?
Short in width, nondescript
Where is the greater tubercle of the humerus located?
Laterally
What does the greater tubercle of the humerus have?
An anterior and posterior face
What is the function of the greater tubercle?
It serves as attachment sites for three of the rotator cuff muscles
What muscles is the greater tubercle the attachment site for?
Supraspinatus
Infraspinatus
Teres minor
How does the lesser tubercle differ from the greater?
It is much smaller, and more medially located. It only has an anterior face
What is the purpose of the lesser tubercle?
It is the site of attachment for the last rotator cuff muscle- the subscapularis
What separates the two tubercles of the humerus?
A deep depression, called the intertubercular sulcus (or groove)
What runs through the intertubercular sulcus?
The tendon of the long head of the biceps brachii
What are the edges of the intertubercular sulcus known as?
Lips
What attaches to the lips of the intertubercular sulcus?
Tendons of the pectoralis major, teres major and latissimus dorsi
Where does the surgical neck of the humerus run?
From the tubercles to the shaft of the humerus
What is a frequent site of fracture of the proximal part of the humerus?
The surgical neck
How does a fracture of the surgical neck of the humerus occur?
By a direct blow to the area, or by falling on an outstretched hand