Download Muscles of the Elbow

Myology 2
(HS 201)
Lecture 3
Myology of the
Elbow
1
Distal Humerus
• Anatomy:
– Capitulum: rounded knob that articulates with the head of the
radius
– Radial fossa: anterior depression that receives the head of the
radius when the forearm is flexed
– Trochlea: spool-shaped surface that articulates with the ulna
– Coronoid fossa: anterior depression that receives the coronoid
process when the forearm is flexed
– Olecranon fossa: posterior depression receiving the olecranon
process of the ulna when the forearm is extended
– Medial and lateral epicondyles: projections on either side for
attachment of many forearm muscles.
2
Anatomical Review Distal Humerus
3
Ulna
• Ulna located on the medial forearm
• Longer than the radius
• Anatomy:
– Olecranon process: large process on the proximal end of the
elbow
– Coronoid process: an anterior projection of bone that with the
olecranon receives the trochlea of the humerus
– Ulnar tuberosity: ridge of bone inferior to the coronoid process
– Trochlear (semilunar) notch: large curved area between the
olecranon and the coronoid process
– Radial notch: depression on the lateral humerus that receives
the head of the radius
– Head: rounded distal end of the ulna
– Styloid process: small projection distal to the head of the ulna
4
Radius
• Located on the lateral side of the forearm
• Anatomy:
– Head: disc shaped proximal end of the radius which articulates
with the capitulum of the humerus.
– Neck: constricted area distal to the head
– Radial tuberosity: roughened area on the proximal medial shaft
for attachment of the biceps brachii muscle
– Shaft: widens distally to articulate with the scaphoid and lunate
bones of the wrist
– Styloid process: small bony projection at the distal end of the
radius
– Ulnar notch: depression on the medial side of the radius for
articulation with the distal end of the ulna
5
Anatomical Review Proximal Ulna
and Radius
6
Articular Anatomy of the Elbow
• Elbow is a hinge joint formed by the articulation of the distal
humerus and proximal radius and ulna
• Made up of three joints:
– Humeroradial: joint between the capitulum and the head of
the radius
– Humeroulnar: joint between the trochlea and the trochlear
notch of the ulna
– Radioulnar: joint between the head of the radius and the
radial notch of the ulna
7
Soft Tissue of the Elbow
Interosseous Membrane: A broad, flat
fibrous connective tissue that joins the
shafts of the radius and ulna
Articular Capsule: Extends from
distal humerus to proximal radius and
ulna (enveloping the entire joint)
Ulnar Collateral Ligament: Thick
triangular ligament extending from
medial epicondyle of the humerus to the
coronoid process and olecranon of the
ulna
8
Soft Tissue of the Elbow
Radial Collateral Ligament: Strong
triangular ligament extending from
the lateral epicondyle of the humerus
to the annular ligament of the radius
and radial notch of the ulna
Radial Annular Ligament: Ligament
encircling the head/neck of the radius and
radial notch of the ulna
Olecranon Bursa: Fluid filled sac lining
the olecranon process. Lubricates the
joint
9
Elbow Ranges of Motion
Each student should be able to describe and
demonstrate the following movements:
1.
2.
3.
4.
Elbow flexion
Elbow extension
Pronation
Supination
10
Palpation of the elbow
Olecranon Process: Sitting; Shake hands with your partner and palpate large prominence of the
elbow. Passively flex and extend the elbow observe how the olecranon moves.
Olecranon Fossa: Sitting; Locate the olecranon process again. Roll your finger proximally around
the top of the process, pressing through the triceps tendon and into the fossa.
Humeral epicondyles: Sitting; Again locate the olecranon process. Slide your fingers medially and
laterally off the olecranon feeling the prominences. Note that the medial is larger.
Supracondylar ridges: Sitting; Locate the epicondyles, slide your fingers proximally toward the
shoulder feeling the medial and lateral supracondylar ridges. Roll your fingers back and forth to feel
the edges.
Shaft of the ulna: Sitting; Again, locate the olecranon process and then slide your hand distally
along the shaft of the ulna (remember the ulna is medial). Follow it along the length of the forearm.
Ulnar Head: Sitting; Slide your finger along the shaft of the ulna. Just proximal to the wrist the shaft
will bulge to become the ulnar head.
Ulnar styloid process: Sitting; Find the posterior aspect of the ulnar head then slide distally off the
head and palpate the ulnar styloid process.
11
Palpation of the elbow (cont.)
Radial Head: Sitting; Locate the lateral epicondyle and slide distally. Notice a small depression
between the humerus and radius. The distal side of the depression is the radial head. Have your
partner pronate and supinate the forearm feeling the radial rotate.
Radial Shaft: Sitting; Supinate and flex your partner’s elbow, find the radial head again and slide
your fingers distally along the radial shaft.
Radial styloid process: Sitting: Find the distal radial shaft to the end feeling the lateral side of the
radius to the tip of the styloid process.
12
Muscles that move the Elbow
Biceps Brachii
Brachialis
Brachioradialis
Triceps Brachii
Anconeus
Pronator Teres
Pronator Quadratus
Supinator
13
Biceps Brachii
O:
Long Head: Supraglenoid tubercle of the
scapula
Short Head: Corocoid process of the scapula
I: Radial tuberosity
A: Shoulder: Flexes the arm
Elbow: Flexes the elbow and assists in
supination when power is required.
**Note: the long head can cause abduction of
the arm, while the short head can cause
adduction
N: Musculocutaneous nerve
14
Brachialis
O: Anterior aspect of the
humeral shaft
I: Coronoid process of the ulna
A: Flexion of the forearm
N: Musculocutaneous nerve
Brachialis is located deep to the
biceps brachii
15
Brachioradialis
O: Lateral supracondylar ridge of the
humerus
I: Styloid process of the radius
A: Flexion of the elbow in the neutral
position (shaking hands). Also
assists in supination and pronation
of the forearm.
N: Radial nerve
16
Triceps Brachii
O:
Long Head: Infraglenoid tubercle of
the scapula
Lateral Head: Posterior aspect of the
shaft of the humerus (proximal ½)
Medial Head: Posterior aspect of the
shaft of the humerus (distal ½)
I: Olecranon Process of the Ulna
A: Shoulder: Extends the arm
Elbow: Extends the elbow
** Note: the long head can cause
adduction of the arm
N: Radial nerve
17
Anconeus
O: Lateral epicondyle of the
humerus
I: Olecranon process of the
ulna
A: Extension of the elbow
(weak)
N: Radial nerve
18
Pronator Teres
O:
Humeral Head: medial epicondyle (via
common flexor tendon) of the humerus
Ulnar Head: Coronoid process of the ulna
I: Lateral aspect of the shaft of
the radius
A: Pronates the forearm and flexes the elbow.
Assists in flexion of the elbow
N: Median nerve
19
Pronator Quadratus
O: Distal ¼ of the Ulna
I: Distal ¼ of the Radius
A: Pronation of the forearm
N: Median nerve
20
Supinator
O: Lateral epicondyle of the
humerus and proximal ulna
I: Proximal anterior radius
A: Supination of the forearm
(for slow non-resisted
supination the supinator is
sufficient. When speed or
resistance is required, the
biceps brachii is recruited.
N: Radial Nerve
21