MR imaging-anatomical-histological evaluation of the abdominal muscles, aponeurosis, and adductor tendon insertions on the pubic symphysis: a cadaver study.

PURPOSE: To perform an MR(magnetic resonance) imaging, anatomical, and histological evaluation of the abdominal muscles and adductor tendon insertions. METHOD: Four fresh cadaveric pelvis specimens were imaged at 3 T with the following imaging parameters: TE (echo time)/TR (repetition time): 20, 4090, slice thickness: 2 mm, FOV: 270 × 90, matrix size: 512. Anatomical slices were obtained with a band saw and photographed. MR images and photographs were evaluated by an anatomist and radiologist. Selected 3 mm thick slices were placed in formalin and decalcified, cut, placed on large slides, and stained with hematoxylin eosin stain (HES). RESULTS: The main adductor tendon insertions are: the anterosuperior aspect of the pubic bone for the adductor longus, the anteroinferior aspect of the pubic bone - for the adductor brevis, and the inferior aspect of the pubic bone for the adductor magnus. On histology, the adductor longus tendon fibers inserted perpendicularly into the bone at a fibrocartilage enthesis and cross connected along the anterior pubic ligament into the controlateral tendon. The rectus abdominis-pyramidalis unit was covered by a thin anterior and posterior aponeurosis. The posterior aponeurosis inserted into the superior aspect of the anterior pubic ligament, whereas the anterior aponeurosis fused distally with the adductor longus tendons. CONCLUSION: Our findings demonstrate the insertions of the adductor tendons, on the pubic ligament and pubic bone.Histologically, the adductor longus tendon fibers inserted perpendicularly into the bone through a fibrocartilage enthesis, and cross connected along the anterior pubic ligament into the contralateral tendon.

Double-Layered Patella (DLP) in Multiple Epiphyseal Dysplasia (MED).

Double-layered patella (DLP) is a rare form of bipartite patella, pathognomonic for a certain type of chondrodysplasia, named multiple epiphyseal dysplasia (MED). This patellar deformity may be asymptomatic, but it may also cause several complaints, including anterior knee pain and severe maltracking of the patella. We present the case of a young man with recurrent anterior knee pain, mainly provoked by movement, who was already known to have MED.

Shoulder Anatomy and Normal Variants.

The shoulder joint is functionally and structurally complex and is composed of bone, hyaline cartilage, labrum, ligaments, capsule, tendons and muscles. It links the trunk to the upper limb and plays an important biomechanical role in daily activities. Indications for imaging of the shoulder have considerably increased in the last few years. The article focuses mainly on Magnetic Resonance Imaging (MRI) as well as MR and CT arthrography, diagnostic procedures of choice for assessment of internal derangement of the shoulder. Bony components, rotator cuff tendons and muscles can be assessed on MR imaging without arthrographic technique, whereas the articular structures (including glenohumeral ligaments, capsulolabral structures and hyaline cartilage) require arthrography for more accurate assessment. Appropriate MR imaging protocols and sequences and applied MR anatomy of the shoulder (including normal variants) are proposed to help assist management and treatment of common shoulder pathologies encountered (such as rotator cuff tears, impingement syndromes, and instability as well as less frequent causes of shoulder pain). The most common variants and pitfalls are related to the anterosuperior aspect of the shoulder joint. Basic anatomy as well as recent findings are developed, including a new description of the attachment of supraspinatus and infraspinatus tendons at the superior aspect of the humerus, the rotator cable and the superior glenohumeral ligament complex.

Ultrasound of the elbow with emphasis on detailed assessment of ligaments, tendons, and nerves.

The high resolution and dynamic capability of ultrasound make it an excellent tool for assessment of superficial structures. The ligaments, tendons, and nerves about the elbow can be fully evaluated with ultrasound. The medial collateral ligament consists of an anterior and posterior band that can easily be identified. The lateral ligament complex consists of the radial collateral ligament, ulnar insertion of the annular ligament, and lateral ulnar collateral ligament, easily identified with specialized probe positioning. The lateral ulnar collateral ligament can best be seen in the cobra position. On ultrasound medial elbow tendons can be followed nearly up to their common insertion. The pronator teres, flexor carpi radialis, palmaris longus, and flexor digitorum superficialis can be identified. The laterally located brachioradialis and extensor carpi radialis longus insert on the supracondylar ridge. The other lateral tendons can be followed up to their common insertion on the lateral epicondyle. The extensor digitorum, extensor carpi radialis brevis, extensor digiti minimi, and extensor carpi ulnaris can be differentiated. The distal biceps tendon is commonly bifid. For a complete assessment of the distal biceps tendon specialized views are necessary. These include an anterior axial approach, medial and lateral approach, and cobra position. In the cubital tunnel the ulnar nerve is covered by the ligament of Osborne. Slightly more distally the ulnar nerve courses between the two heads of the flexor carpi ulnaris. An accessory muscle, the anconeus epitrochlearis can cover the ulnar nerve at the cubital tunnel, and is easily identified on ultrasound. The radial nerve divides in a superficial sensory branch and a deep motor branch. The motor branch, the posterior interosseous nerve, courses under the arcade of Frohse where it enters the supinator muscle. At the level of the dorsal wrist the posterior interosseous nerve is located at the deep aspect of the extensor tendons. The median nerve may be compressed at various sites, including the lacertus fibrosis, between the pronator teres heads, and the sublimis bridge. These compression sites can be identified with ultrasound.

Distal insertions of the semimembranosus tendon: MR imaging with anatomic correlation.

OBJECTIVE: The purpose of this study is to investigate the distal insertions of the semimembranosus tendon with MR imaging, correlated with findings in cadavers. MATERIALS AND METHODS: Four fresh cadaveric specimens were studied with 3-T MR imaging. Sequences included proton density (PD) sequences (TE, 13; TR, 4957; FOV, 170 × 170; matrix, 424 × 413; NA, 2; slice thickness, 2.5 mm) in the axial, coronal, and sagittal planes and 3D fast field echo (FFE) sequences (TR 9.4; TE 6.9; FOV, 159 × 105; matrix, 200 × 211; NA, 2; slice thickness, 0.57 mm). One specimen was dissected and three specimens were sectioned with a bandsaw in the axial, coronal, and sagittal plane. The sections were photographed and correlated with MR images. To standardize the analysis, the semimembranosus muscle and tendon were assessed at seven levels for the axial sections, and at three levels for the coronal and sagittal sections. RESULTS: Anatomic dissection revealed six insertions of the distal semimembranosus tendon: direct arm, anterior arm, posterior oblique ligament extension, oblique popliteal ligament extension, distal tibial expansion (popliteus aponeurosis), and meniscal arm. Axial MR images showed five of six insertions: direct arm, anterior arm, oblique popliteal ligament extension, posterior oblique ligament extension, and distal tibial expansion. Sagittal MR images showed four of six insertions: direct arm, anterior arm, oblique popliteal ligament arm, and distal tibial expansion. Sagittal MR images were ideal for showing the direct arm insertion, but were less optimal than the axial images for showing the other insertions. The anterior arm was seen but volume averaging was present with the gracilis tendon. Coronal MR images optimally revealed the anterior arm, although magic angle artifact was present at its posterior aspect. The common semimembranosus tendon and meniscal arm were also well depicted. The division in anterior arm, direct arm, and oblique popliteal ligament arm was poorly seen on coronal images due to volume averaging. CONCLUSIONS: Although the anatomy of the distal semimembranosus tendon is complex, six different semimembranosus insertions can be identified on routine proton density and FFE sequences at 3 T. Analysis of images at defined levels in the three imaging planes simplifies MR interpretation of the anatomy of the distal semimembranosus tendon.

Pathology of extrinsic ligaments: a pictorial essay.

The role of the extrinsic ligaments, together with the intrinsic ligaments, appears to be much more important than previously thought in the setting of carpal stability. The anatomy and pathology of the extrinsic wrist ligaments is complex. Magnetic resonance imaging (MRI) with thin slices is essential for visualization. This article describes the pathological appearance of the extrinsic palmar and dorsal radiocarpal and ulnocarpal ligaments on MRI, correlated with arthroscopy (performed by two skilled hand surgeons), clinical findings, and follow-up. High-resolution MRI, especially using isotropic three-dimensional sequences with orthogonal multiplanar reconstructions on 3T MR systems, allows detailed depiction of many of the extrinsic ligaments affected in carpal injuries. Recognition of ligament abnormalities is improved by intra-articular or intravenous injection of contrast before the examination. Both techniques may help to determine the precise localization, size, and extent of dorsal and palmar radiocarpal and ulnocarpal ligament lesions. Further experience with these techniques is needed to define the place of MRI in the management of traumatic wrist injuries.