Related Experiment Video
Updated: Jan 25, 2026
In Vivo Electrophysiological Measurement of the Rat Ulnar Nerve with Axonal Excitability Testing
Published on: February 6, 2018
The Effect of Humeral and Ulnar Bone Tunnel Placement on Achieving Ulnar Collateral Ligament Graft Isometry: A
Ajay C Lall1, David P Beason2, Jeffrey R Dugas1
1American Sports Medicine Institute, Birmingham, Alabama, U.S.A.
Purpose:
To assess simulated ulnar collateral ligament (UCL) graft length change, using surgically dissected anatomic landmarks, between multiple combinations of humeral and ulnar bone tunnels.
Methods:
Three equidistant humeral and ulnar tunnels were created at each UCL footprint of 10 cadaveric elbows. Suture was passed between 9 possible tunnel combinations for each elbow and affixed to an isometry gauge. Each elbow was moved through an arc of 0, 30, 60, 90, and 120° for each tunnel combination. Changes in isometry gauge spring displacement (and, in effect, tension) were recorded.
Results:
There was an overall significant effect (P < .0001) of tunnel placement at all degrees of flexion. Pairwise comparisons revealed increases in displacement between the central and posterior tunnel positions of the medial epicondyle, with significant differences (P = .0009) occurring when paired with both the central and posterior aspect of the sublime tubercle. Significant differences (P < .0001) were noted between the anterior and posterior humeral tunnel positions.
Conclusions:
Simulated UCL graft isometry is dependent upon optimal bone tunnel placement. No significant differences were noted between ulnar tunnel locations when paired with any given humeral tunnel. Conversely, deviation anterior or posterior from the centroid of the UCL footprint on the medial epicondyle significantly affected isometry at all degrees of flexion recorded with the greatest amount of displacement occurring with pairi4ng of posterior tunnels on both the humeral and ulnar footprints.
Clinical Relevance:
This anatomic study highlights the importance of medial elbow bone tunnel placement and its effect on simulated UCL graft isometry.
Related Concept Videos
01:27Sympathetic Pathways: Collateral Ganglia and Adrenal Medulla
Collateral Ganglia
Sympathetic preganglionic axons reach the collateral ganglia along the route of splanchnic nerves. These nerves bypass the sympathetic trunk and communicate with sympathetic postganglionic neurons housed in the prevertebral ganglia. These ganglia supply the organs of the abdominopelvic cavity.
The greater splanchnic nerve, formed by the...
01:27Secondary Motives: Power Motivation and Achievement Motivation
Power motivation is characterized by the desire to influence, control, or have an impact on others. It is shaped by an individual's experiences, social environment, and cultural context. People with high power motivation are...
01:09Spongy Bone
Spongy bone is more porous, and less dense compared to compact bone. It is composed of concentric lamellae that are arranged irregularly to form the trabecular network. In some bones, the spaces between trabeculae contain red marrow, where...
01:27Compact Bone
Compact bone, also called cortical bone, is the denser, stronger of the two types of bone tissue. It is found under the periosteum and in the diaphyses of long bones, where it provides support and protection. The microscopic structural unit of compact bone is called an osteon, or haversian system. Each osteon is composed of concentric rings of calcified...
01:29Bone Disorders
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
01:12The Hyoid Bone