A review of the coracoclavicular joint: Description, etiology, and clinical significance.

The coracoclavicular joint (CCJ) is a synovial joint that forms between the conoid tubercle of the clavicle and the coracoid process of the scapula in approximately 2.5% of the population. The number of bilateral to unilateral cases is almost equal. The number of right-sided and left-sided cases is also almost equal. It is found in both males and females but most often in male adults. Very few cases have been identified in juveniles. Found in populations all over the world, the highest frequencies of CCJ are in Asia. The etiology is unknown but it is most likely caused by metaplastic change of the trapezoid and surrounding tissue due to compression and friction of the coracoacromial ligament between the clavicle and coracoid process. Typically asymptomatic, but if so, the most common complaint is anterior should pain exacerbated by extreme abduction. Successful treatment includes steroid injection and surgical excision.

The anatomy and variation of the coracoid attachment of the subclavius muscle in humans.

The functions of the subclavius muscle (SM) are described as stabilization of the sternoclavicular joint (SCJ) and resisting elevation of the lateral end of the clavicle. During systematic cadaveric dissections, we observed additional fibrous structures, previously described as variants of the anatomy, extending from the SM and inserting into the coracoid process (CP). Due to the high incidence of these structures in our dissections, we hypothesized that the attachment at the CP is more common than appreciated and that, as a corollary, the function of the SM was (or has been) more complex than simply depressing the clavicle and generating stability at the SCJ. For our investigation, fifty-two upper extremities of 26 human cadavers were dissected. The SM was demonstrated from costal to clavicular attachment. We documented additional fibrous structures apparently derived from the SM inserting into the CP. Measurements of the length of the SM, the length of its attachment, and the length of the clavicle were taken in situ, with the specimens supine and the upper extremity in the anatomical position. Variations in the anatomy of the SM and its coracoidal attachment were recorded, and potential correlations were investigated. For documentation purposes photographs and video sequences of passive motion of the shoulder girdle of the specimens were taken. In 49 of the 52 specimens we found additional fibrous structures passing from the SM to the CP. We differentiated three types: (1) a strong cord-like structure; (2) a small or thin cord-like structure or structures; and (3) a planar twisted sheet-like structure. The SM and its extension to the CP appears to contribute to a 'functional scapular suspension system' together with the other muscles enveloped by the clavipectoral fascia (pectoralis minor, coracobrachialis and the short head of the biceps brachii). This system assists in the control of the position of the scapula in relation to the thorax, particularly in elevated positions of the upper extremity. We speculate that the differentiation of the fibrous structure depends on the functional demands of the individual. Level of Evidence: Basic science study.

Anatomy and Correlation of the Coracoid Process and Coracoclavicular Ligament Based on Three-Dimensional Computed Tomography Reconstruction and Magnetic Resonance Imaging.

BACKGROUND The anatomy of the coracoid process and coracoclavicular (CC) ligament have been described and the correlation between them has been assessed based on 3-dimensional computed tomography (CT) reconstruction and magnetic resonance imaging (MRI), which provide a guide for coracoclavicular ligament reconstruction. MATERIAL AND METHODS Data were collected from 300 patients who underwent both CT and MRI of the shoulder joint from January 2017 to January 2019 at the Jiang'an Hospital of Traditional Chinese Medicine. The coracoid process was observed and classified and parameters of the CC ligament were measured according to different corneal types. All of the statistics were collected and classified by 2 radiologists, and average values were determined.Measurements of segments were taken as follows: ab - In the coronal plane, the length of the CC ligament from the central point of the CC ligament at the clavicular attachment to the CC ligament at the center of the CC attachment); ac - The distance from the center point of the CC ligament at the supraclavicular attachment to the acromioclavicular joint; de - In the sagittal plane, the length of the CC ligament from the center of the clavicular attachment to the coracoid attachment point; fg - The maximum diameter of the CC ligament at the anterior and posterior margins of the clavicle attachment; hi - The largest diameter of the CC ligament at the anterior and posterior edge of the coracoid process attachment; dj - The distance of the coracoclavicular ligament from the center point of the coracoid process attachment to the coracoid process tip; kl - The distance in the supraclavicular plane from the coracoclavicular ligament to the subcoracoid process. RESULTS The analysis showed that there are 5 types of coracoid process: gourd (31%), short rod (20%), long rod (22.3%), wedge (10.3%), and water drop (6.3%). There were statistically significant differences between the lengths of the ac and hi segments in the among the wedge and gourd-type and the short rod and water drop-type coracoid processes. There were statistically significant differences between the lengths of the ab, de, and fg segments in the short rod, gourd, and long rod-type coracoid processes. There were statistically significant differences between the lengths of the ac, fg, hi, dj, and kl segments in the water drop, gourd, and long rod-type coracoid processes. CONCLUSIONS The present study indicated that measurement of the CC ligament and the different shapes of the coracoid process provide an anatomical basis for the diagnosis and treatment of shoulder diseases and the data can be used to improve the safety of CC ligament reconstruction.

A proposal for a new classification of coracobrachialis muscle morphology.

INTRODUCTION: The coracobrachialis muscle (CRM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. It inserts to the medial part of the humerus between the attachment of the medial head of the triceps brachii and the brachial muscle. Both the proximal and distal attachments of the CRM, as well as its relationship with the musculocutaneus nerve, demonstrate morphological variability. MATERIAL AND METHODS: One hundred and one upper limbs (52 left, and 49 right) fixed in 10% formalin solution were examined. RESULTS: Three main types, with subtypes, were identified. The most common was Type I (49.5), characterized by a single muscle belly with a classical origin from the coracoid process, medially and posteriorly to the tendon of the biceps brachii. Type II (42.6%), characterized by two heads, was divided into two subtypes (A-B) depending on its origin: Type IIA, where one head originated from the coracoid process posteriorly to the tendon of the biceps brachii and the second head from the short head of the biceps brachii, and Type IIB, in which both heads originated from the coracoid process; however, the superficial head fused with the insertion of a short head of the biceps brachii, while the deep head was directly originating. Finally, Type III (7.9%) was characterized by three heads: two originated from the coracoid process (superficial and deep), and the third from a short head of the biceps brachii. Two types of insertion and two types of musculocutaneous nerve (MCN) relative to CRM could be distinguished. CONCLUSION: An adapted classification is needed for all clinicians working in this area, as well as for anatomists. The CRM demonstrates morphological variability in both its proximal and distal attachments, as well as the variable course of the MCN relative to the CRM. WHAT IS KNOWN ABOUT THIS SUBJECT "AND" WHAT THIS STUDY ADDS TO EXISTING KNOWLEDGE: Not much is known about the variability of coracobrachialis muscle. The present paper introduces a completely new classification, both clinical and anatomical.

The Shoulder Trans-pectoralis Arthroscopic Portal Is a Safe Approach to the Arthroscopic Latarjet Procedure: A Cadaveric Analysis.

PURPOSE: To assess the proximity of neurovascular structures in a layered approach during medial portal placement and determine standardized measurements for establishing a portal medial to the coracoid used in arthroscopic Latarjet-type procedures. METHODS: Twelve shoulders (6 right and 6 left) in 6 fresh frozen cadaveric torsos were mounted in the modified beach-chair position. A standard posterior portal and 3 anterior portals-central, lateral, and medial-were used. A long spinal needle was placed along the path of the medial portal to the lateral tip of the coracoid, superficial to the conjoined tendon and pectoralis minor. A second long spinal needle was directed toward the medial base of the coracoid, penetrating the pectoralis minor. Superficial and deep plane dissections were performed, and distances to surrounding neurovascular structures were recorded. RESULTS: In the superficial plane, the cephalic vein and lateral pectoral nerve were located a mean distance (± standard deviation) of 4.6 ± 1.9 mm and 9.4 ± 2.6 mm from the spinal needle, respectively. In the deep plane, the axillary nerve was 24.9 ± 7.4 mm from the needle; the lateral cord of the brachial plexus, 25.5 ± 8.1 mm; the axillary artery, 34.1 ± 6.0 mm; and the musculocutaneous nerve, 42.2 ± 9.2 mm. The portal was consistently established 45.0 to 50.0 mm distal and 30.0 to 35.0 mm medial to the coracoid, which was a minimum distance of 10 mm to the lateral pectoral nerve. CONCLUSIONS: In a cadaveric model, the creation of a medial trans-pectoralis major portal used in the arthroscopic Bankart-Bristow-Latarjet procedure can avoid compromise of vital neurovascular structures, alleviating concerns of creating a portal medial to the coracoid. Portal placement 45.0 to 50.0 mm distal and 30.0 to 35.0 mm medial to the palpable tip of the coracoid process may be a safe approach to perform the arthroscopic Bankart-Bristow-Latarjet procedure. CLINICAL RELEVANCE: Creation of a portal medial to the level of the coracoid may pose a risk to neurovascular structures. This cadaveric study establishes a working zone for medial trans-pectoralis portal placement, which avoids vital neurovascular structures, and provides standardized measurements for establishing this portal for use in the arthroscopic Bankart-Bristow-Latarjet procedure.

Analysis of the coracoid morphology with multiplanar 2D CT and its effects on the graft size in the Latarjet procedure.

PURPOSE: In this study, we aimed to reveal the individual differences regarding the size of the coracoid and their effects on the classical and modified Latarjet procedures. METHODS: Computed tomography images of 120 patients (mean age: 41.18 ± 12.01 years) without shoulder complaints or shoulder instability were evaluated retrospectively. The glenoid width, the surgical graft length, and the coracoid total length, width, and thickness were measured using the multiplanar reconstruction method on the Sectra Picture Archiving and Communications System (PACS) system. Age, gender, side, the dominant hand, and the height of the patients were recorded and the correlations between them were investigated. On the created hypothetical model, the current size of the coracoid was evaluated to determine what size of glenoid defects it could repair by employing the classical and the modified Latarjet techniques. RESULTS: There was no significant difference between the right-hand-dominant group and the left-hand-dominant group in terms of coracoid measurement results (p > 0.05). Again, there was no statistically significant difference between the right and the left side regarding the coracoid size (p > 0.05). A positive correlation could be detected only between age and the coracoid width and thickness (p < 0.05). A positive correlation was also found between the glenoid width and the coracoid width and thickness in both shoulders (p < 0.001). Coracoid thickness could fill in the defects that amounted to 40% of the glenoid width, while the coracoid width could fill in for the defects that were 50% of the glenoid width in both genders. CONCLUSION: Our study showed that hand dominance and side were not effective on the coracoid dimensions. In addition, it has been shown that the coracoid dimensions did not have a significant effect in the choice of Latarjet technique in terms of defect repair and that repair rates of up to 40% could be achieved in glenoid defects with both techniques.

Fractures of the Coracoid Process: Evaluation, Management, and Outcomes.

Fractures of the coracoid process are relatively rare, and current management guidelines remain unclear. Most coracoid fractures occur in conjunction with other shoulder injuries, including dislocations and fractures. Identifying coracoid fractures can be difficult because most fractures are nondisplaced and can be missed on radiographs or may be masked by other injuries. Management is largely guided by fracture location and displacement. Conservative treatment is preferred for fractures that are minimally displaced, whereas indications for surgical fixation include fractures that are displaced (>1 cm), have progressed to a painful nonunion, or are associated with the disruption of the superior shoulder suspensory complex. Although conservative treatment has been historically favored, satisfactory outcomes have been reported for both surgical and nonsurgical treatment. We provide a comprehensive review of diagnosis and management strategies for coracoid fractures.

Ecomorphological associations of scapulocoracoid form in Greater Antillean Anolis lizards.

External morphological metrics have featured prominently in comparative studies examining the morphological convergence that characterizes anoline ecomorphs. To what degree the appendicular-skeletal morphology of Greater Antillean island Anolis lizards tracks their diversity and ecological adaptation, however, remains relatively unexplored. Here we employ computed tomographic scanning techniques to visualize in situ the scapulocoracoid of ecomorph representatives (trunk-ground, trunk-crown, crown-giant, twig) from three islands (Jamaica, Hispaniola, and Puerto Rico), and compare its three-dimensional geometry using qualitative-descriptive and quantitative-morphometric techniques. In contrast to our previous, similarly-conducted study of the pelvic girdle of these same species, the form of the scapulocoracoid varies markedly both within and between species, with much of the variation relating to phylogenetic relationship, specimen size, and assigned ecomorph category. Morphometric variation that correlates with size and/or phylogenetic signal varies between species and cannot be eliminated from the data set without markedly reducing its overall variability. The discovered patterns of skeletal variation are consistent with the demands of locomotor mechanics imposed by the structural configuration of the microhabitat of these ecomorphs. Most pertinently the ecomorphs differ in the anteroposterior length of the coracoid, the dorsoventral height of the scapulocoracoid, the dorsoventral height of the scapula in relation to the height of the suprascapula, and the relative positioning of the borders of the scapulocoracoid fenestra. In the examined ecomorph categories these skeletal differences likely relate to microhabitat usage by permitting different degrees of tilting and displacement of the scapulocoracoid in the parasagittal plane and influencing the sizes of muscle origins and the vectors of their actions. These differences relate to the amount of humeral adduction applied during its protraction, and to the structural stability of the shoulder girdle during acrobatic maneuvers, thus influencing the perch diameter that can be effectively negotiated, a critical factor in the microhabitat structure of Anolis ecomorphs.

Radiological study of the Asian coracoid process and clavicle: Implications for coracoclavicular ligament reconstruction.

PURPOSE: Iatrogenic coracoid and clavicle fracture is a known complication of drilling bone tunnels during anatomic coracoclavicular ligament reconstruction (ACCR). This study aims to measure the dimensions of coracoid process and clavicle in an Asian population to evaluate the suitability of drilling coracoid and clavicle tunnels for ACCR in Asians. METHODS: Width measurements of 196 coracoids and 189 clavicles were obtained after reviewing all computed tomography (CT) scans of the shoulder performed over a 6 years period. Coracoid measurements were made on the CT slice which showed the maximum cross sectional width of the coracoid base. Medial to lateral measurements of the coracoid width were taken on an axial view, 4 mm above the identified junction of the coracoid base and glenoid base. Antero-posterior clavicle width was measured through a point directly above the midpoint of the coracoid and perpendicular to the long axis of the clavicle. RESULTS: The overall mean coracoid width was 14.8 mm ± 2.54 mm (range 9.2-23.3 mm) and clavicle width was 17.1 mm ± 2.72 mm (range 11.1-25.3 mm). CONCLUSION: The Asian coracoid process is smaller than its Western equivalent. More research is required to validate this conclusion as no cadaveric studies with equivalent measurement techniques have been performed on Asians. Given the potentially narrower dimensions of the Asian coracoid process, extra precautions are required to minimize the risk of iatrogenic coracoid and clavicle fractures.

Coracoid process fractures: anatomy, injury patterns, multimodality imaging, and approach to management.

The coracoid process of the scapula is in close proximity to major neurovascular structures, including the brachial plexus and the axillary artery and vein. In addition, it serves as a major site of attachment for multiple tendons and ligaments about the shoulder. Isolated coracoid fractures are rare; however, they can be easily overlooked on routine shoulder radiographs. Importantly, when these fractures go undiagnosed, they are at high risk for nonunion. In this paper, we will review the relevant anatomy of the coracoid process, classification schemes for coracoid fractures, mechanisms of injury how these fractures typically present, multimodality imaging findings, and associated injuries. Finally, we will briefly discuss the clinical management of these fractures.

'Superior biceps aponeurosis'-Morphological characteristics of the origin of the short head of the biceps brachii muscle.

PURPOSE: Our aim was to characterize the morphology of the proximal attachment of the biceps brachii short head. We hypothesize that it has an aponeurotic component that may affect shoulder joint biomechanics. METHODS: The coracoacromial region and the biceps brachii muscle were dissected in 30 cadaveric shoulders. The course and dimensions of the tendon and aponeurosis were evaluated. The cross-sectional area of the belly of the short head and the length of the whole muscle were measured. Correlations between the aponeurosis and dimensions of the muscle were tested with the Spearman's rank correlation coefficient. RESULTS: Aponeurosis was present in all specimens, although in 10 cases it was vestigial. The aponeurotic part of the muscle (mean length 90.7 ± 16.3 mm, mean width 12.5 ± 2.9 mm) branched off laterally and traveled to the acromion, blending with the coracoacromial ligament creating the aponeurotic membrane. We named this structure the "superior biceps aponeurosis". The mean length of the biceps brachii was 31.3 ± 2.1 cm and the mean cross-sectional area of the short head was 210.7 ± 54.3 mm2. The dimensions of the "superior biceps aponeurosis" correlated positively with the cross-sectional area of the muscle (R2 from 0.37 to 0.52, p from 0.014 to 0.001). CONCLUSION: The origin of the short head of the biceps brachii muscle has a varied aponeurotic component combining the aponeurotic part of the muscle and the aponeurotic membrane. Together, they create the "superior biceps aponeurosis". CLINICAL RELEVANCE: The morphology of the origin of the biceps brachii short head is relevant in Bristow/Latarjet procedures. This aponeurotic component may affect the shoulder joint biomechanics after the coracoid process transfer.

Arthroscopic anatomy medial to the coracoid: an anatomic study of the axillary and musculocutaneous nerves.

PURPOSE: The purpose of this study was to provide arthroscopic measurements and orientations of the axillary and musculocutaneous nerves medial to the coracoid. METHODS: A retrospective chart review of 29 patients undergoing arthroscopic subscapularis repair and arthroscopic cadaveric dissection of 23 shoulders was used to analyze neuroanatomical distances to arthroscopic landmarks and to document the orientations of the axillary and musculocutaneous nerves using a clock face analogy. The clock face data was analyzed by separating the clock face into four quadrants and the frequency of any crossing nerve within each of the four quadrants was then determined. RESULTS: In vivo, the axillary nerve was found 1.5 ± 0.5 cm medial to the coracoid tip and the musculocutaneous nerve was found 1.6 ± 0.6 cm medial to the coracoid tip. In cadavera, the axillary nerve was found 2.0 ± 0.6 cm medial to the coracoid tip and the musculocutaneous nerve was found 1.5 ± 0.5 cm medial to the coracoid tip. The posterosuperior quadrant of the subcoracoid space contained a crossing nerve in 4 of 29 (13.8%) patients undergoing arthroscopic rotator cuff repair medial to the coracoid, compared to 9 of 23 (39.1%) cadavera undergoing arthroscopic dissection medial to the coracoid. The posteroinferior quadrant contained a crossing nerve in 16 of 29 (55.2%) patients compared to 17 of 23 (73.9%) cadavera. CONCLUSIONS: The axillary and musculocutaneous nerves run in close proximity to the coracoid tip and coracoid arch, most consistently within 1-2 cm medial to these structures, which is closer than has been previously documented in the literature. Crossing nerves are least frequently encountered within the posterosuperior quadrant of the subcoracoid space medial to the coracoid, followed by the posteroinferior quadrant. Arthroscopic dissection of this space should begin in the posterosuperior quadrant and carefully progress to the posteroinferior quadrant to decrease the risk of intraoperative nerve injury. Given the close proximity and frequently encountered nerves in this area, extreme caution must be exercised when working arthroscopically within the subcoracoid space.

Proximity of the Coracoid Process to the Neurovascular Structures in Various Patient and Shoulder Positions: A Cadaveric Study.

PURPOSE: To examine and compare the distances from the anteromedial aspects of the coracoid base and the coracoid tip to the neurovascular structures in various patient positions. METHODS: The experiment was conducted in 15 fresh-frozen cadavers. We dissected 15 right and 15 left shoulders to measure the distances from the anteromedial aspects of the coracoid base and the coracoid tip to the lateral border of the neurovascular structures in the horizontal, vertical, and closest planes. The measurements were performed with the cadavers in the supine, lateral decubitus, and beach-chair positions. With cadavers in the beach-chair position, we evaluated 5 arm postures (arm at side, 45° of abduction, 90° of abduction, 45° of forward flexion, and 90° of forward flexion). RESULTS: The shortest distance from the coracoid base to the neurovascular structures was found in the beach-chair position with arm at side in the horizontal plane (27.4 ± 4.9 mm) and 90° of abduction in the vertical (21.8 ± 4.2 mm) and closest (19.5 ± 4.2 mm) planes. The distances in each plane were statistically significant compared with the supine and lateral decubitus positions (P < .005). Between the coracoid tip and the neurovascular structures, the shortest distance was found in the beach-chair position with 90° of abduction, with 29.3 ± 7.7 mm, 20.8 ± 4.9 mm, and 18.5 ± 5.1 mm in the horizontal, vertical, and closest planes, respectively. The distances were statistically significant in all planes compared with the supine and lateral decubitus positions (P < .005). CONCLUSIONS: Shoulder surgery in the area of the coracoid process is safe, especially with the patient in the supine position. The distance from the coracoid process to the neurovascular structures was closest in the beach-chair position with 90° of arm abduction. CLINICAL RELEVANCE: This study determined the distances between the coracoid process and the neurovascular structures during surgery around the coracoid process.

Tissue on the Transferred Coracoid Graft After Latarjet Procedure: Histological and Morphological Findings.

BACKGROUND: Anterior shoulder instability is a debilitating condition that can require stabilization via a Latarjet procedure. PURPOSE: The aim of this study was to characterize the histological composition of the articular-sided surface of the coracoid bone graft after Latarjet procedure. Specific features of cells isolated from the coracoid and graft tissues were assessed. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Tissue samples were harvested from 9 consecutive patients undergoing arthroscopic debridement and screw removal after arthroscopic or open Latarjet procedure. Tissues were processed histologically. In 2 patients, the samples were analyzed to assess specific cellular properties. RESULTS: Safranin O staining indicated that glenoid tissues contained variable amounts of glycosaminoglycan (GAG) and round chondrocytic cells mainly organized in clusters. Graft tissues contained less GAG and were more cellular but were not organized in clusters and had variable morphological features. An association appeared to exist between the cartilage quality of glenoid tissues and that of the graft tissues. Cells isolated from glenoid and graft tissues exhibited similar proliferation capacity. CONCLUSION: The results of our analysis show that cells located at the articular-sided surface of transferred coracoid grafts demonstrate fibrocartilaginous properties and may have the capacity for chondral proliferation. Further studies are needed to confirm this observation and future application.

Anatomical study of the position and orientation of the coracoclavicular ligaments: Differences in bone tunnel position by gender.

BACKGROUND: Reconstructing both coracoclavicular ligaments following acromioclavicular dislocation has recently been reported to restore the function of the acromioclavicular joint better than traditional procedures. Knowing the appropriate position and orientation of the bone tunnels and the potential risks of neurovascular injuries leads to safe reconstruction. We aimed to answer the following questions: what is the difference in the accurate clavicular bone tunnel positions (BTPs) during coracoclavicular ligament reconstruction between sex, and what are the potential risks for neurovascular injuries? HYPOTHESIS: The BTPs differ by sex at the site of coracoclavicular ligament reconstruction. PATIENTS AND METHODS: We introduced two Kirschner wires into 25 cadaver shoulders (17 male, 8 female), one through the insertion center of the trapezoid ligament and one through the conoid ligament, and measured the distance from the respective Kirschner wire insertion points to the bony landmarks of the clavicle and the oblique angle of each Kirschner wire. The shortest distance from the insertion point of each Kirschner wire to the suprascapular nerve and artery was also measured. RESULTS: While the distance from the acromioclavicular joint to the respective Kirschner wire insertion points tended to be longer in males, the ratio of these insertion points to total clavicle length was constant. Other measurements for respective Kirschner wire insertions to the bony landmarks and neurovascular structures were comparable, as were abduction and retroversion angles. The distance from the suprascapular nerve to the insertion point of the conoid ligament at the coracoid process was 13.8±4.0mm, while the distance from the suprascapular artery was 7.1±3.3mm. DISCUSSION: Appropriate position and orientation of the bone tunnels, and the ratio of the BTPs to the total clavicular length, aid surgeons in performing the reconstruction. The conoid ligament insertion on the coracoid was just proximal to the suprascapular artery, so surgeons should be careful with conoid insertion. LEVEL OF EVIDENCE: V, cadaver study.

Anatomic considerations for arthroscopic glenoid reconstruction using iliac crest grafts: a radiologic study.

BACKGROUND: Arthroscopic glenoid reconstruction using autografts is an advanced procedure that requires experience and preparation. Knowledge about anatomic pitfalls is therefore important to establish well-positioned portals and prevent neurovascular damage. METHODS: We included 43 computed tomography scans from 43 patients. The distance between the tip of the coracoid process and a perpendicular line representing the anteroinferior glenoid was measured. From these results an anteroinferior working portal was designed, and the angulation needed for screw insertion to fixate a hypothetical graft was measured. In a second step, 9 patients underwent magnetic resonance imaging scans 34 ± 10 months after glenoid reconstruction, and the distance between the screw approach path and the neurovascular bundle was measured. RESULTS: In the analyzed scans, average defect size was 23%, and the coracoid process to the anteroinferior glenoid distance was 32 ± 7 mm. We thus hypothesized that a corridor 20 to 30 mm inferior to the coracoid process would be the ideal position for a working portal. Through this portal, 85% of screws could be applied with 0° to 30° angulation. When the postoperative scans were analyzed, the distance from the neurovascular bundle showed an average of 26 ± 6 mm for the superior screw and 21 ± 5 mm for the inferior screw. CONCLUSIONS: The ideal distance between the coracoid process and an anteroinferior working portal is 32 mm. Having established the portal, instruments should not be inserted pointing in a medial direction of the coracoid process due to the proximity of the neurovascular bundle.

Intraoperative and anatomic dimensions of the coracoid graft as they pertain to the Latarjet-Walch procedure.

BACKGROUND: Our objective was to study the anatomic and intraoperative coracoid measurements with an aim to closely replicate the Latarjet-Walch technique and find the similarities and dissimilarities in our population. METHODS: In the cadaveric study, 20 shoulders in 10 fresh cadavers were dissected, and the coracoid length, width, and thickness were measured. In the intraoperative study, 10 patients underwent the classic Latarjet procedure according to the Walch technique. The harvested coracoid graft was analyzed for the length of the coracoid, the distance of the inferior hole from the lateral margin of the coracoid graft, and the width of the coracoid graft at the inferior and superior hole. RESULT: The average distance from the tip of the coracoid to the trapezoid insertion was 25.4 mm (standard deviation [SD], 1.7 mm). The mean width of the undersurface of the coracoid was 14.2 mm. The average length of the graft after harvesting was 25.1 mm (SD, 1 mm). The average distance between the lateral border and the inferior hole was 5.5 mm (SD, 1.1 mm). We used 25-mm malleolar screws in 3 shoulders and 30-mm malleolar screws in 7 shoulders. CONCLUSION: The"7-mm" rule of Walch could be followed in our population. The medial surface width of the coracoid in our Indian morphology was an average of 7 mm; hence, malleolar screws of 30 and 25 mm were used to fix the graft on the glenoid.

Análisis morfométrico de la apófisis coracoides mediante tomografía computarizada en Chile / Morphometric coracoid process analysis by computed tomography in Chile

OBJETIVO: Determinar la morfometría de la apófisis coracoides (Cor) mediante tomografía computarizada de hombro (TC hombro) en población chilena. MÉTODO: 162 TC hombro (90 género femenino y 72 masculino), edad promedio 55,9 20,2 años, fueron analizadas mediante sistema computacional IMPAX. RESULTADOS: Largo total Cor promedio de 41,0 2,5 mm. Largo promedio del pilar superior de 20,5 2 mm. Altura media pilar superior de 9,2 1,2 mm. Ancho promedio pilar superior de 10,3 1,5 mm. Altura media de la base de 13,4 1,8 mm. CONCLUSIÓN: En nuestra población el pilar superior es más ancho que alto y el largo total de Cor es aproximadamente el doble del largo del pilar superior. Todas las dimensiones de Cor son mayores en el género masculino versus femenino. Al comparar la morfometría de Cor, nuestra población es similar a otros grupos étnicos según lo descrito en la literatura. Nivel de evidencia: III.

PURPOSE: Define the morphometric measurements of the coracoid process (Cor) in Chilean population through the analysis of shoulder computed tomography (shoulder CT) METHOD: 162 shoulder TC (90 females and 72 males), average age 55.9 20.2 years, were analyzed by IMPAX software. RESULTS: The mean total Cor length was of 41.0 2.5 mm. Average upper pillar length was 20.5 2 mm. The mean upper pillar height was 9.2 1.2 mm. The mean upper pillar width was 10.3 1.5 mm. Average base height was 13.4 1.8 mm. CONCLUSIONS: In our population, upper pillar is wider than high and the total Cor length is approximately twice than upper pillar length. All Cor dimensions are greater in males versus females. The Cor morphometric measurements in our population is similar to other ethnic groups as described in the literature. Level of evidence: III.

Quantitative Assessment of the Coracoacromial and the Coracoclavicular Ligaments With 3-Dimensional Mapping of the Coracoid Process Anatomy: A Cadaveric Study of Surgically Relevant Structures.

PURPOSE: To perform a quantitative anatomic evaluation of the (1) coracoid process, specifically the attachment sites of the conjoint tendon, the pectoralis minor, the coracoacromial ligament (CAL), and the coracoclavicular (CC) ligaments in relation to pertinent osseous and soft tissue landmarks; (2) CC ligaments' attachments on the clavicle; and (3) CAL attachment on the acromion in relation to surgically relevant anatomic landmarks to assist in planning of the Latarjet procedure, acromioclavicular (AC) joint reconstructions, and CAL resection distances avoiding iatrogenic injury to surrounding structures. METHODS: Ten nonpaired fresh-frozen human cadaveric shoulders (mean age 52 years, range 33-64 years) were included in this study. A 3-dimensional coordinate measuring device was used to quantify the location of pertinent bony landmarks and soft tissue attachment areas. The ligament and tendon attachment perimeters and center points on the coracoid, clavicle, and acromion were identified and subsequently dissected off the bone. Coordinates of points along the perimeters of attachment sites were used to calculate areas, whereas coordinates of center points were used to determine distances between surgically relevant attachment sites and pertinent bony landmarks. RESULTS: The CAL had a single consistent acromial attachment (mean area 77 mm [51.9, 102.2]) and then bifurcated into 2 bundles, anterior and posterior, that separately inserted on the lateral aspect of the coracoid. The footprint areas were 54.4 mm2 [31.7, 77.2] and 30.6 mm2 [23.4, 37.7] for the anterior and posterior CAL bundles, respectively. These anterior and posterior bundles attached 10.6 mm [8.4, 12.9] and 24.8 mm [12.3, 27.4] medial and proximal to the apex of the coracoid process, respectively. The minimum distance between the coracoid apex and the trapezoid ligament was 25.1 mm [22.1, 28.1] and was noted to be different in males (28.1 mm [25.1; 31.2]) and females (22.0 mm [18.2, 25.9]). The most lateral insertion of the CC ligaments on the clavicle the AC joint was 15.7 mm [13.1, 18.3]. The distance between the most medial to the most lateral point of the CC ligaments on the clavicle was 25.6 mm [22.3, 28.9], which accounted for 18.2% [15.8, 20.6] of the clavicle length. CONCLUSIONS: In contrast to previous findings, 2 different coracoid attachments (anterior and posterior bundles) of the CAL were consistently identified in all specimens. Moreover, a coracoid osteotomy for a bone graft for the Latarjet procedure should be performed at less than 28.1/22 mm from the apex of the coracoid in male/female patients, respectively. The CC ligaments' attachments on the clavicle were located 15.7 mm from the AC joint, which should be considered for reconstruction. CLINICAL RELEVANCE: During the Latarjet technique, to maintain the integrity of the CC ligaments, precise knowledge of differences between male and female anatomy is necessary during a coracoid osteotomy. Furthermore, when reconstructing the AC joint, the distance from the lateral aspect of the clavicle and the size of the attachments areas should be considered to better replicate the native anatomy.

Surgical anatomy of the radial nerve in the deltopectoral approach for revision shoulder arthroplasty and periprosthetic fracture fixation: a cadaveric study.

BACKGROUND: Radial nerve injury is a rare but clinically significant complication of revision shoulder arthroplasty and fixation of native and periprosthetic proximal humeral fractures. Understanding of the anatomic relationship between the radial nerve as it enters the humeral spiral groove and anterior shoulder landmarks in a deltopectoral approach is necessary to avoid iatrogenic radial nerve injury. METHODS: Eight forequarter cadaveric specimens were dissected through a deltopectoral approach. Distances between the radial nerve entry into the proximal spiral groove and the coracoid process, distal lesser tuberosity/inferior subscapularis insertion, superior latissimus insertion, and inferior latissimus insertion were measured. Means, standard deviations, and ranges were determined for each distance. RESULTS: The radial nerve entry into the proximal spiral groove averaged 133.1 mm (range, 110.3-153.0 mm) from the coracoid process, 101.9 mm (range, 76.5-124.3 mm) from the distal lesser tuberosity/inferior subscapularis insertion, 81.0 mm (range, 63.4-101.5 mm) from the superior latissimus insertion, and 39.6 mm (range, 25.5-55.4 mm) from the inferior latissimus insertion. The proximal spiral groove was distal to the inferior latissimus insertion in all specimens. CONCLUSION: The risk of iatrogenic injury to the radial nerve at the spiral groove may be minimized through proper identification and protection or avoidance of circumferential fixation. However, if encircling fixation with cerclage cables is necessary, instrumentation proximal to the inferior edge of the latissimus dorsi insertion may reduce the risk of radial nerve injury.