This report is to be written about the elbow complex (as a healthy joint)
Access strong academic information on a selected joint or region of the human body. Note that this joint will likely be associated with the injury that you will be covering in assessment 2B, but you may opt to do your healthy joint report on a joint/region that is not related to your injury report if you want to.
Organize the information into a coherent structure that explains the stabilizing factors and the factors that produce movement at the joint/region
Write a succinct and academically strong report on the joint or region
Week # 2 Summary Elbow
Structure
The elbow or humeroulnar joint is a uniaxial synovial hinge joint comprised of the distal humerus and
the proximal ulnar. Distally on the humerus is the trochlea, into which the hooked shaped proximal trochlea
notch of the ulna articulates and laterally the spherical capitulum interacts with the head of the radius. The
head of the radius in turn articulates with the ulnar via the radial notch of the ulna (Marieb, Wilhelm &
Mallatt, 2014). The radioulnar joint is a uniaxial, pivot joint and does not contribute directly to the hinge
mechanism of the elbow. Movement is complimented by the rotation of the radioulnar joint allowing
supination and pronation of the forearm. Posteriorly and distally on the humerus is olecranon fossa a deep
depression that accepts the olecranon of the ulnar as the elbow extends (Floyd & Thompson, 2001).
Anteriorly the radial and coronoid fossa accept the head of the radius and coronoid process as the elbow
flexes. The distal end of the humerus broadens from the main body with pronounced Medial and laterally
condyles (Marieb et al., 2014). Figure 1 highlights the prominent aspects of the humerus, ulnar and radius
that integrate to from the elbow joint.
Fig 1. Expanded view elbow joint
Stability
Primary stability is created by the the collateral ligaments, annular ligament and the articulating
profiles of the humerus and ulnar. The ulnar collateral ligament provides medial stability, resisting elbow
abduction while the radial collateral ligament and lateral ulnar collateral ligament provides lateral stability. As
the elbow approaches full extension the olecranon process’s interaction with the olecranon fossa locks the
joint increasing its stability, resisting lateral and medial loads (Floyd & Thompson, 2001). The annular ligament
secures the radioulnar joint to the ulnar, with fibres of the joint capsule extending into the fibres of the
annular and collateral ligaments (Marieb et al., 2014). Tension from the brachialis and pronators teres muscle
provide stabilization to the elbow joint (Owens & Binkley, 2011). Dynamic stabilization of the medial elbow
occurs through the action on the flexor, pronator muscles that originate from the medial epicondyle of the
humerus (Hamill, Knutzen & Derrick, 2015). Figures 2a and 2b illustrates the anterior, lateral and medial
ligaments and common tendon flexors and extensors that provide stability to the elbow joint.
2a
2b
Figures 2a and 2b. Anterolateral and medial view of elbow ligaments.
Muscles and movement
The elbow hinge structure allows uniaxial movement via flexion and extension. However along with
the radioulnar joint the elbow complex is able to provide pronation and supination the radius and ulnar (Floyd
& Thompson, 2001). The primary flexors of the humeroulnar joint are the biceps brachii, brachialis and
brachioradialis. Supination or pronation of the radioulnar joint occurs through actions of the either the biceps
brachii, brachioradialis, supinator muscle and the pronator teres, pronator quadratus respectively. Extension
is primarily through the triceps brachii with anconaeus muscle assists as a weak extensor of the elbow (Floyd
& Thompson, 2001). Figure 3a and 3b illustrate the anterior and posterior muscles primarily responsible for
flexion and extension of the elbow complex.
3a
3b
Figure 3a and 3b. Muscles in the anterior and posterior compartments of the humerus.
References
Anatomy.tv. 3D Human Anatomy, Primal Pictures (2020). [Computer software].
Retrieved from https://www-anatomy-tv.wallaby.vu.edu.au
Floyd, T. R. & Thompson, W. C. (2001). Manual of Structural Kinesiology (14th ed.).
New York McGraw-Hill
Hamil, J., Knutzen, M, K,. & Derrick, R, T,. (2015). Biomechanical Basis of Human Movement (4th ed.).
Philadelphia, United States: Williams and Wilkins
Marieb, N. E., Wilhelm, B. P., & Mallatt, B. J. (2014). Human Anatomy (7th ed.).
Essex, England: Pearson
Wise, S. L., Owens, D. S., & Binkley, H. M. (2011). Rehabilitating athletes with medial epicondylalgia. Strength
& Conditioning Journal, 33(2), 84-91.
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