CT and MRI do not detect fibrous bands, but are good to exclude other causes Electrophysiology: to exclude CTS
Characteristics: low or absent sensory NCV of ulnar and medial cutaneous nerves.
EMG abnormalities of muscles lower trunk Paraverterbrals are normal.
1. Conservative treatment: posture correction, stretching may relieve problems.
2. Orthosis to elevate shoulder
3. Surgery: resection of the first rib
Due to cervical rib and vascular involvement (subclavian artery compression with poststenotic compression, or subclavian artery aneurysm). Clinically may present with weakness and pain: resulting in unilateral hand and finger ischemia and pain.
Minor vascular involvement results in reduced arterial pulse during hyper-abduction of the arm.
Occurs in young athletes and swimmers, from throwing, occlusion, stenosis, aneurysm, or pseudoaneurysm. Humeral head may compress axillary artery. With (or without) cervical rib.
No rib changes. Symptoms, but no objective changes of TOS. Symptoms are variable: pain and paresthesias in the lower trunk distribution, supraclavicular tenderness. Stable and non-progressive.
Treatment: disputed, potentially the removal of the anterior scalene muscle. Females with low set shoulders and long necks.
Symptoms: pain and paresthesias in upper neck, shoulder, head, sometimes bilateral.
Reduced by passive shoulder elevation, increased by downward arm traction. Electrodiagnosis: normal.
Bonney G (1965) The scalenus medius band: a contribution to the study of the thoracic References outlet syndrome. J Bone Joint Surg Br 47: 268-272
Katirji B, Hardy RW Jr (1995) Classic neurogenic thoracic outlet syndrome in a competitive swimmer: a true scalenus anticus syndrome. Muscle Nerve 18: 229-233 Roos DB, Hachinski V (1990) The thoracic outlet syndrome is underrated/overdiagnosed. Arch Neurol 47: 327-330
Swift DR, Nichols FT (1984) The droopy shoulder syndrome. Neurology 34: 212-215
Thoracic outlet syndromes: Arterial
Disputed neurogenic TOS
Droopy shoulder syndrome
Three nerve plexus are commonly termed the "lumbosacral" plexus: lumbar, Anatomy sacral and coccygeal plexus (see Fig. 7 through 10).
Formed by the ventral rami of the first to fourth lumbar spinal nerves. Rami pass Lumbar downward and laterally from the vertebral column within the psoas muscle, where dorsal and ventral branches are formed.
The dorsal branches of L2-4 rami give rise to the femoral nerve, which emerges from the lateral border of the psoas muscle. The femoral nerve passes through the iliacus compartment and the inguinal ligament.
The obturator nerve arises from the ventral branches of L2-4 and emerges from the medial border of the psoas, within the pelvis.
Communication with the sacral plexus occurs via the lumbosacral trunk (fibers of L4 and all L5 rami).
The trunk passes over the ala of the sacrum adjacent to the sacroiliac joint.
The sacral plexus is formed by the union of the lumbosacral trunk and the Sacral ventral rami of S1-S4. The plexus lies on the posterior and posterolateral walls of the pelvis, with its components converging toward the sciatic notch. Sacral ventral rami divide into ventral and dorsal branches. The lateral trunk arises from the union of the dorsal branches of the lumbosacral trunk (L4, 5), and the dorsal branches of the S1 and S2 spinal nerves. The lateral trunk forms the peroneal nerve.
Fig. 10. Topical relations of lumbar (1) and sacral (2) plexus
Other nerves originating in the plexus include the superior and inferior gluteal nerves, the pudendal nerve, the posterior cutaneous nerve of the thigh and several small nerves for the pelvis and hip.
Autonomic fibers are found within lumbar and sacral nerves.
Lumbar plexus injury can be mistaken for L2-L4 radiculopathies, or for femoral mononeuropathies. Pain radiates into the thigh, with sensory loss in the ventral thigh, and weakness of hip flexion and knee extension.
In sacral plexus injury sensation is disturbed in the gluteal region and somewhat in the external genitalia. All lower limb muscles display weakness, except those innervated by the femoral and obturator nerves.
Motor loss in some pelvic muscles, gluteus muscles, tensor fasciae latae, hamstrings, and all muscles of the leg and foot can be caused by sacral plexopathies with L5/S1 radiculopathies, or proximal sciatic neuropathies.
Lumbar plexus lesions may have pain radiating into the hip and thigh. The motor deficit causes either loss of hip flexion, knee extension, or both. Adductors can be clinically spared, but usually show spontaneous activity in EMG. Sensory loss is concentrated at the ventral thigh, but the saphenous nerve can be involved. In acute lesions, patients have the hip and knee flexed.
The sacral plexus pain resembles sciatic nerve injury. Depending on the lesion of the sacral plexus, motor symptoms are concentrated in L5, S1, resulting in weakness of the sciatic nerve muscles. Proximal muscles that exhibit weakness include the gluteus maximus muscle, but the gluteus medius muscle is usually spared. Sensory symptoms may also involve proximal areas, such as the distributions for the pudendal nerve and the posterior cutaneous nerve of the thigh. Sphincter involvement can occur.
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