Exam #6: Anterior Arm & Forearm Flashcards
Review the bony landmarks of the humerus.
N/A
Review the bony landmarks of the radius & ulna.
N/A
Which is lateral, the radius or the ulna?
Radius
What does the radial head articulate with?
Capitulum of the humerus
What is the name for the proximal part of the ulna?
Olecranon process
What is the difference between the heads of the ulna and radius?
Radius= proximal Ulna= distal
What is the mechanism for a radius fracture?
Falling on an outstretched arm
*This can occur across the length of the shaft
What is the mechanism for ulna fracture?
- Falling on the forearm
- Defensive wounds
What is a nightstick fracture?
Ulnar fracture
What is an ulnar pseudoarthrosis?
Congenital or improperly set ulnar fracture that results in the formation of a “joint” midshaft in the ulna
Radiographically, how can you tell the difference between an ulnar fracture and a pseudoarthrosis?
Acute fracture= subtle
Pseudoarthrosis= prominent
What is the elbow joint proper? How many joints make the elbow? What types of joints are these?
Humeroradial & humeroulnar joints together
- Humeroradial= ball & socket
- Humeroulnar= hinge
What is the radio-ulnar joint? What is the function?
Annular ligament connects the radius & ulnar, which limits the humeroradial joint to a hinge joint
What are the ligaments of the elbow?
1) Annular ligament*****
2) Ulnar collateral ligaments
- Posterior
- Anterior
- Transverse
3) Radial collateral ligament
*****Most important ligament
What are the three main parts of the ulnar collateral ligaments? What is the clinical significance?
1) Posterior
2) Anterior
3) Transverse
*Baseball players rupture this ligament & ALL 3x of the components have to be replaced
Review the radiographic landmarks of the elbow.
N/A
What typically happens when you get a posterior dislocation of the elbow?
Fracture of the coronoid process
What is a nursemaid’s elbow?
Dislocated radial head i.e. rupture of the fibers of the annular ligament
What nerve innervates the anterior compartment of the arm?
Musculocutaneous n.
Which muscle of the anterior compartment has dual innervation? Why is this important?
Brachialis
*****Also innervated by the Radial N.; thus, if the musculocutaneous branch in damaged, you can still flex your arm at the elbow
What is the function of all the muscles of the anterior compartment?
Flexors
List the muscles of the anterior compartment or the arm.
1) Biceps brachii
2) Brachialis
3) Coracobrachialis
What are the origins of the Biceps Brachii?
Coracoid process
Supraglenoid tubercle
What are the insertions of the Biceps Brachii?
- Radial tuberosity
- Bicipital aponeurosis that blends with the antebrachial fasica, indirectly connecting to the ulna
What is the function of the Biceps Brachii?
Flexion of the shoulder
Flexion of the elbow
Supination
What is the origin of the Brachialis?
Anterior humerus
What is the insertion of the Brachialis?
Ulnar tuberosity
What muscle is the main flexor of the arm?
Brachialis
What is the function of the Brachialis?
Flexion of the elbow
*****This is where most of the power of flexion comes from i.e. MAIN FLEXOR
What are the origins of the Coracobrachialis?
Coracoid process
What is the insertion of the Coracobrachialis?
Medial humerus
What are the function of the Corachobrachialis?
1) Prevention of dislocation of the humerus
2) Flexion of the shoulder
3) Adduction of the arm
Anterior compartment of the forearm are innervated by what nerve?
Predominantly the median nerve with a few exceptions:
- Flexor carpi ulnaris (ulnar n.)
- Medial 1/2 of the flexor digitorum profundus (ulnar n.)
What are the muscles in the superficial group of the anterior compartment of the forearm?
Pronator teres
Palmaris longus
Flexor carpi radialis
Flexor carpi ulnaris
What is the origin of the Pronator teres?
Medial epicondyle of the humerus
What is the insertion of the Pronator teres?
Midshaft of the radius
What is the function of the Pronator teres?
Pronation