Fibrous Connection Between Cervical Nerve and Zygapophysial Joint and Implication of the Cervical Spondylotic Radiculopathy: An Anatomic Cadaveric Study.

STUDY DESIGN: Observational, anatomical, cadaveric study. OBJECTIVE: We anatomically investigated the fibrous connection between the cervical nerves and the zygapophysial joint capsules. SUMMARY OF BACKGROUND DATA: Cervical spondylotic radiculopathy is caused by the compression of the cervical nerves as the static factor and head and neck movements as the dynamic factor. To understand the dynamic pathology of cervical spondylotic radiculopathy, the anatomic relationship between the cervical nerves and the zygapophysial joints needs to be investigated in detail. METHODS: In 11 cadavers, we dissected both sides from the C5 to C7. For macroscopic examination, we observed structures connecting the cervical nerves and the zygapophysial joints in 18 cervical nerves from three cadavers. In 14 sides of eight cadavers, we histologically analyzed the fibrous structures and their attachments. RESULTS: Macroscopically, the fibrous band connected the cranial surface of the cervical nerve to the lateral and inferior aspects of the transverse process. In four of 18 nerves, the fibrous bands were divided into two fascicles by loose connective tissues. In addition, the fibrous bands extended along the dorsal aspect of the posterior tubercle of the transverse process and attached to the zygapophysial joint capsule. Histologically, densely stained fibrous tissues overlaid the zygapophysial joint capsule and extended to the recess between the posterior tubercle and inferior articular process on the cranial vertebral body. CONCLUSION: We macroscopically and histologically clarified the fibrous bands connecting the cervical nerve to the zygapophysial joint capsule. The fibrous bands may help clarify the pathology of cervical spondylotic radiculopathy associated with the zygapophysial joints as dynamic factors.Level of Evidence: N/A.

Morphology of the anterolateral ligament: a complex of fibrous tissues spread to the anterolateral aspect of the knee joint.

The anterolateral ligament (ALL) has recently received considerable attention as a key structure maintaining the rotational stability of the tibia. However, the morphology of the ALL, particularly the proximal attachment, is controversial. This study aimed to elucidate the morphological relationship between the ALL and its adjacent structures. A total of 25 knees from 22 cadavers were used in the current study. One knee was set at 30°, 60° and 90° of flexion. Stretched or winkled fibrous tissues were then observed with internal and external rotations of the tibia at each angle. In 22 knees, fibrous tissues that were attached to the lateroposterior area to the Gerdy's tubercle were macroscopically observed. In the other 2 knees, the fibrous tissues were histologically investigated and analyzed using computer-assisted three-dimensional reconstruction. A taut fibrous tissue was observed between the lateroposterior area to the Gerdy's tubercle and the posterosuperior area to the lateral epicondyle during an internal rotation of the tibia. A complex of fibrous tissues that were attached to the lateroposterior area to the Gerdy's tubercle spread to the anterolateral aspect of the knee as a sheet-like structure. This complex tissue was composed of the fascia lata and fibrous tissues continuous from the fabellofibular ligament, intermuscular septum, and tendon of the gastrocnemius. Three-dimensional reconstruction showed that each fibrous tissue formed a sheet. The structure recognized as the ALL could not be detected; therefore, the ALL that has been reported to date is considered to be a complex of fibrous tissues with a sheet-like structure.

An anatomic study on the origin of the long head of the triceps brachii.

BACKGROUND: Posterior shoulder instability was reported to be more common than had been previously reported. However, the detailed morphology of the origin of the long head of the triceps brachii (LHT), which is located at the posteroinferior part of the glenohumeral joint and associated with the stability of the head of the humerus, has been unknown. The purpose of the current study was to clarify the detailed morphology of the origin of the LHT. METHODS: A total of 64 specimens from 36 cadavers (11 males and 25 females) were used. After dissecting the origin of the LHT in 54 specimens of 27 cadavers, the width of the origin of the LHT was measured with a caliper by 2 observers. The origin of the LHT was also investigated histologically in 18 specimens. Sections were analyzed with Masson's trichrome staining and Safranin O staining. RESULTS: Some fibers of the LHT originated more from the cranial area than from the infraglenoid tubercle and descended along the posterior rim of the glenoid cavity. The width of the origin on the dorsal surface of the scapula was 31.2 mm. The origin from the bone had a developed uncalcified fibrocartilage histologically. In addition, the LHT was fused with the glenohumeral joint capsule and was attached to the glenoid labrum directly. CONCLUSIONS: The LHT could affect the glenohumeral joint capsule or the glenoid labrum because of their connections to each other and be associated with the posterior shoulder instability indirectly.

Origins, Courses, and Distributions of the Lumbar Arterial Branches in Relation to the Spinal Nerves: An Anatomical Study.

STUDY DESIGN: Observational, anatomical, cadaveric study. OBJECTIVE: To investigate the origins, courses, and distributions of the lumbar arterial branches in relation to the spinal nerves using Japanese cadavers. SUMMARY OF BACKGROUND DATA: Lumbar arterial branches to the spinal nerves can be damaged during posterior lumbar column osteotomy, leading to neurological complications. Spinal cord ischemia via arterial ligation has been reported to be a major cause of neurological complications in anterior thoracolumbar surgery. Although neurological deficits have been considered the most common complications in lumbar pedicle subtraction osteotomy, there is little information on the possible neurological deficits due to spinal nerve ischemia caused by damage to the lumbar arterial branches. METHODS: In total, 111 lumbar arteries (1 lumbar artery was damaged) from 14 embalmed cadavers (28 sides, L1-L4) were investigated. We examined the branching patterns and measured their diameter and length. Branches to the spinal nerves were classified as follows: radicular branch (Rb), spinal nerve branch (SNb), and plexus branch (Pxb). RESULTS: The Rb was identified most frequently at L1 (21.4%) and included the main branch to supply the spinal cord. The SNb diverged from the dorsal branch (59.4%) and was mainly detected at L2 (85.7%) and L3 (85.2%). The Pxb originated from the lumbar artery (56.1%) and was found most frequently at L4 (75%). The Pxb had a larger diameter and a longer length at L3 and L4 than the SNb. Both the L3 and L4 Pxbs were the main blood suppliers to the femoral nerve. CONCLUSION: The L3 and L4 Pxbs mainly supplied the femoral nerve. The Pxb is likely to exist in the medial side of the spinal nerve in the extraforaminal region. Thus, the Pxb should be recognized as a very important arterial branch during operation procedures. LEVEL OF EVIDENCE: 5.

Medial elbow anatomy: A paradigm shift for UCL injury prevention and management.

To improve the management outcomes and diagnostic accuracy of the ulnar collateral ligament (UCL) injury, the anatomy of the medial side of the elbow joint is necessary to be understood in terms of the periarticular surroundings rather than the specific ligaments. The aim of this study was to anatomically clarify the medial side of the elbow joint in terms of the tendinous structures and joint capsule. We conducted a descriptive anatomical study of 23 embalmed cadaveric elbows. We macroscopically analyzed the relationship between the flexor pronator muscles (FPMs) and the joint capsule in 10 elbows, histologically analyzed in 6 elbows, and observed the bone morphology through micro computed tomography in 7 elbows. The two tendinous septa (TS) were found: between the pronator teres (PT) and flexor digitorum superficial (FDS) muscles, and between the FDS and flexor carpi ulnaris (FCU) muscles. These two TS are connected to the medial part of the brachialis tendon, deep aponeurosis of the FDS, and FCU to form the tendinous complex, which linked the humeroulnar joint and could not be histologically separated from each other. Moreover, the capsule of the humeroulnar joint under the tendinous complex had attachment on the ST of 7 mm width. The two TS, the brachialis tendon, the deep FDS and FCU aponeuroses, and the joint capsule linked the humeroulnar joint. These anatomical findings could lead to a paradigm shift in the prevention, diagnosis, and treatment of UCL injuries in baseball players. Clin. Anat. 32:379-389, 2019. © 2018 The Authors. Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists.

An anatomic study on the attachment of the joint capsule to the tibia in the lateral side of the knee.

PURPOSE: The purpose of the current study was to examine the width, area, and histological characteristics of the capsular attachment to the tibia in the lateral side of the knee. METHODS: A total of 27 knees were used in this study. The joint capsule of the knee was peeled away from the tibia and the width of the capsular attachment to the tibia was measured by two independent observers using a caliper. Interclass correlation coefficients for each value were calculated to evaluate the validity of the measurement. The capsular attachment to the tibia of the seven knees was histologically analyzed using Masson's trichrome staining. RESULTS: At the posterior border of Gerdy's tubercle, the capsular attachment was wide; the average width was 8.6 mm (SD 3.0). Toward the posterolateral aspect of the knee, the capsular attachment gradually tapered. Finally, the capsular attachment was linear at the apex of the head of the fibula. Histological analysis at the posterior border of Gerdy's tubercle revealed developed uncalcified fibrocartilage on the capsular attachment. In contrast, at the apex of the head of the fibula, the joint capsule was adhered to the capsule of the proximal tibiofibular joint. Fibrous connective tissue was directly attached to the calcified fibrocartilage. CONCLUSIONS: The attachment width of the knee joint capsule at the lateral side varied according to location. We consider that this finding on the capsular attachment will facilitate an understanding of the pathology or mechanism of diseases on the lateral side of the knee joint.

The extended bundle of the tensor veli palatini: Anatomic consideration of the dilating mechanism of the Eustachian tube.

OBJECTIVE: The aim of this study was to analyze the topographical structures of the muscles surrounding the Eustachian tube. MATERIALS AND METHODS: We conducted macroscopic and histological studies of 24 halves of 12 heads from Japanese cadavers. RESULTS: The main findings were as follows: 1) the infero-lateral muscle bundles of the tensor veli palatini didn't turn medially at the pterygoid hamulus but were distributed laterally and continuous with the buccinator; 2) the tensor veli palatini attached laterally to the membranous part of the Eustachian tube; 3) the superior pharyngeal constrictor was not only adjacent to the buccinator at the pterygomandibular raphe but also had muscular continuation with it laterally and 4) some bundles of the superior pharyngeal constrictor adhered with the palatine aponeurosis. CONCLUSION: We believe that the cooperation of the muscles contributes to the dilating mechanism of the Eustachian tube, due to the complex topographical structures of the surrounding muscles: the tensor veli palatini, the levator veli palatini, the superior pharyngeal constrictor and the buccinator.

A morphological comparison of the extraforaminal ligament between the cervical and thoracic regions.

PURPOSE: The current study was conducted to clarify the morphology of the extraforaminal ligament (EFL) at the cervicothoracic junction and to compare the attachment of the EFL and the positional relation between the EFL and the spinal nerves, additionally to clarify the details within the connecting bundles at the cervicothoracic junction. MATERIALS AND METHODS: The EFLs from the 4th cervical to the 4th thoracic vertebrae were dissected in 56 sides of 28 Japanese cadavers (11 males, 17 females). The range of age was 62.0-99.0 years. In addition, connecting bundles were analyzed by histological examination. RESULTS: Ventral to the spinal nerve, the capsulotransverse ligament (CTL), transforaminal ligament (TFL) and the ligament between the 7th cervical vertebra and the 1st rib were attached to the transverse process and rib. The EFL ventral to the 1st thoracic nerve was not observed in all sides. Dorsal to the spinal nerve, the anterior part of the superior costotransverse ligament (ASCL) and the ligament homologous to the ASCL were attached to the transverse process and rib. The superior radiating ligament (SRL) and the ligament homologous to the SRL were identified. The connecting bundles identified between the 7th cervical and the 1st thoracic nerve were histologically confirmed to consist of nerves and vessels. CONCLUSIONS: The EFLs at the cervicothoracic junction were found to be homologous. The connecting bundles were observed between the 7th cervical and the 1st thoracic nerve. Interestingly, the 1st thoracic level alone might be a unique level at the cervicothoracic junction.

The malaris muscle: its morphological significance for sustaining the intraorbital structures.

The orbicularis oculi muscle, an important mimetic muscle, was investigated to ascertain its anatomical relation to facial aging-especially its orbital part (Oo). Previous studies of the distinct muscle bundles frequently found inferior to the Oo have provided various definitions, including that of the malaris muscle. This study aimed to examine these muscle bundles and clarify their function in facial aging. Twelve heads of Japanese cadavers (average age: 82.5 years old) were dissected to observe the muscles, focusing in particular on those in the periorbital region. Six specimens were further dissected from the inner surfaces to examine the patterns of facial nerve branches under the operating microscope. Histological examinations of two head halves were carried out to investigate the relationship between the muscle bundles and the intraorbital structures. Muscle bundles consisting of lateral, medial, and U-shaped suspending bundles were observed in the region inferior to the Oo. Lateral and suspending bundles were found in all specimens, while the medial bundles were noted in only 9 of 22 specimens. Some branches of the facial nerve penetrated through the lateral, medial, and suspending bundles. The relationship between the suspending bundles and the protruding orbital fat was assessed. The muscle bundles found in this study were regarded as the malaris muscle-a transitional muscle between the superficial and deep facial layers. The suspending bundle may play a role in sustaining the intraorbital structures.

Morphology of the region anterior to the anal canal in males: visualization of the anterior bundle of the longitudinal muscle by transanal ultrasonography.

PURPOSE: The anterior bundle of the longitudinal muscle in the region anterior to the anal canal in males has been described, although the anatomical details remain unclear. The present study was undertaken to clarify the precise morphology of the anterior bundle of the longitudinal muscle and its relationship to the surrounding structures, and to visualize the anterior bundle of the longitudinal muscle via transanal ultrasonography. METHODS: Histological examination was carried out using seven male cadavers; an additional three male cadavers were used for transanal ultrasonography, and the ultrasonography images were compared with the actual sagittal sections. In addition, transanal ultrasonography images of 50 male patients at Tokatsu-Tsujinaka Hospital were studied. RESULTS: The region anterior to the anal canal consisted of smooth muscles and skeletal muscles. The anterior bundle of the longitudinal muscle was situated between the bulbospongiosus and the external anal sphincter, and consisted of smooth muscle. The bundle was identified in the transanal ultrasonography of cadavers by comparison with the actual sections. Transanal ultrasonography images of living bodies showed the anterior bundle of the longitudinal muscle as a hypoechoic layer of approximately 17.7 mm in length. CONCLUSIONS: The detailed anatomical findings of the anterior bundle of the longitudinal muscle suggested "an alternate arrangement of smooth muscles and skeletal muscles" in the region anterior to the anal canal and facilitated the visualization of the anterior bundle of the longitudinal muscle in transanal ultrasonography.

Joint capsule attachment to the coronoid process of the ulna: an anatomic study with implications regarding the type 1 fractures of the coronoid process of the O'Driscoll classification.

BACKGROUND: The attachment of the anterior joint capsule on the ulnar coronoid process is not yet completely understood. The purpose of this study was to clarify the anatomic relationship between the anterior capsule of the elbow joint and the tip of the coronoid process. METHODS: Seventeen embalmed elbows were used for this anatomic study. The anterior capsule of the elbow joint was reflected, and the attachment of the capsule on the coronoid process was exposed. The attachment of the joint capsule on the coronoid process was macroscopically and histologically observed, its relationship to the coronoid tip was assessed, and the length of the attachment of the joint capsule was measured. RESULTS: The length of the capsule attachment at the radial side of the coronoid (11.9 mm) was greater than that at the ulnar side (6.1 mm). The bone thickness on the coronoid tip from the proximal edge of the joint capsule attachment was 1.9 mm; together, the cartilage and bone thickness was 4.7 mm. At the radial side of the coronoid, the thickness of the joint capsule at the proximal aspect of the attachment of 2 samples was 0.6 mm and 0.3 mm, and that at the tip of the coronoid was 2.6 mm and 1.7 mm, respectively. CONCLUSIONS: The anterior capsule of the elbow joint had a substantial attachment on the radial side of the coronoid process. The subtype 2 tip fractures of the O'Driscoll classification included the joint capsule attachment, joint cartilage, and subchondral bone.

Mediastinoscopic subaortic and tracheobronchial lymph node dissection with a new cervico-hiatal crossover approach in thiel-embalmed cadavers.

The use of mediastinal surgery for minimally invasive esophagectomy (MIE) has been proposed; however, this method is not performed as radical surgery because it has been thought to be impossible to perform complete upper mediastinal dissection, including the left tracheobronchial lymph nodes (106tbL). We herein describe a new method for performing complete dissection of the upper mediastinum. We developed a method for performing complete mediastinoscopic esophagectomy as radical surgery via the bilateral transcervical and transhiatal approach in 6 Thiel-embalmed human cadavers. The lower and middle mediastinal lymph nodes are dissected via the transhiatal approach. The dorsal side of the left recurrent nerve is dissected up to the aortic arch and left recurrent nerve lymph nodes (106recL) are dissected under pneumomediastinum. Next, the right recurrent nerve lymph nodes (106recR) are dissected. The cartilage of the left main bronchus is dissected and pushed downward, thereby obtaining a good view between the aortic arch and left main bronchus via the transhiatal approach. The 106tbL lymph nodes are dissected until the aortic arch is reached. Simultaneously, the lymph nodes are dissected via a right cervical incision. This method is termed the "cross-over technique." We herein demonstrated that the upper mediastinal lymph nodes, including the 106tbL nodes, can be dissected using the bilateral transcervical and transhiatal approach under pneumomediastinum and named this method "mediastinoscopic esophagectomy with lymph node dissection" (MELD). MELD is therefore considered to be a useful modality based on our experience with Thiel-embalmed human cadavers.

An anatomic study of the structure and innervation of the pronator quadratus muscle.

The pronator quadratus muscle is composed of the superficial and deep heads. However, to date there is no consensus on the variations of each head. To add to this enigma, the innervation patterns of each head have not been thoroughly studied. The present study was conducted to clarify the structure and innervation of the pronator quadratus muscle by minute dissection of 46 forearms from 26 cadavers. The origin, insertion, shape, and direction of the muscle fascicles in each head were observed. The intramuscular distribution and the innervation patterns to each head were investigated. The attachment of the deep head was examined using Masson's trichrome staining technique. Each head consisted of various muscle fascicles which differed in shape and direction. The most distal muscle fascicle extended toward the head of the ulna. On microscopic study, this most distal fascicle was observed to reach the base of the ulnar styloid process. The nerves innervating the superficial head penetrated through the deep head and ran on the anterior surface of the radius from medial to lateral. This tendency was common to all of the forearms studied. We confirmed that each head of the pronator quadratus muscle consisted of various muscle fascicles. The attachment to the base of the ulnar styloid process is considered to be an important structure that prevents the head of the ulna from impacting against the carpal bones. Knowledge of the innervation pattern to each head is critical for preserving the function of the pronator quadratus muscle during surgery for distal radial fracture.

Human fetal topographical anatomy of the femoral triangle in relation with change in the hip joint position.

Fetal hip joint is characterized by its highly flexion and lateral rotation although adult anatomy of the femoral nerve and iliofemoral ligament suggested the medial rotation. To investigate topographical anatomy of the femoral nerve, artery and vein in the femoral triangle, we histologically examined 11 fetuses (15-37 weeks). The nerve-vessel topographical relation was basically similar to that in adults, but the fan-like nerve division was seen in the horizontal plane in the smaller specimens in contrast to that included in the sagittal plane in the larger specimens. The medial or internal rotation of the nerve division seemed to occur in late stage fetuses, at birth and at infancy. Blood supply to the head of the femur might be also accelerated by changes in the hip joint position.

Rare case of femoral artery ramification and origin of the obturator artery.

We observed two rare patterns of femoral artery ramification in the bilateral thighs of an 83-year-old male cadaver. In the right thigh, the lateral circumflex femoral and deep circumflex iliac arteries formed a common trunk, while in the left, the medial circumflex femoral, inferior epigastric, and obturator arteries formed a common trunk. In the left pelvis, the obturator artery comprised branches from the inferior epigastric, superior gluteal, and inferior gluteal arteries. We describe this rare case and discuss the genesis and clinical significance of these variations.