Nancy H. McKee

Sonographic studies of human soleus and gastrocnemius muscle architecture : gender variability

Abstract The purpose of this study was to establish if there are gender differences in muscle architecture in relaxed human soleus and gastrocnemius muscles of normal, live subjects. Ultrasonography was used to measure fiber bundle length, muscle thickness, and angles of pennation in a total of ten predetermined sites in the medial and lateral heads of gastrocnemius and the anterior and posterior soleus in 19 males and 16 females. Percentage differences between males and females for each parameter were recorded. Gender differences were statistically analyzed using multivariate analysis of variance. In the gastrocnemius and soleus muscles of males and females the differences between the overall fiber bundle length, angle of pennation and muscle thickness were statistically significant (P < 0.05). Overall, females were found to have longer average muscle fiber bundle length and males thicker muscles and larger angles of pennation. The greatest percentage differences of the architectural parameters between males and females were in the posterior soleus: 13% difference in fiber length and 26% difference in angle of pennation in the midline of posterior soleus and 26% difference in muscle thickness of the lateral part of posterior soleus. No correlation was found between leg length and fiber length, angle of pennation or muscle thickness. Fiber length (decreased), angle of pennation (greater) and muscle thickness (greater) of most parts of the gastrocnemius and soleus muscles were significantly different in males and females. Leg length of males and females did not correlate to these architectural parameters.

Free muscle transplantation to provide active finger flexion

Free muscle transplatation is a procedure which involves the transfer of a skeletal muscle from one location in the body to another. Viability is maintained by microvascular anastomoses of the muscles artery and vein to a suitable artery and vein in the recipient site. Voluntary muscle contraction is obtained by suturing of the muscles motor nerve to an appropriate motor nerve in the recipient site. Two cases are presented; one using the gracilis and the other using the pectoralis major muscle. The indication for each transplantation was the traumatic loss of long flexor musculature to the digits. In both cases transplanted muscles survived and are functioning well. Excellent grip strength and nearly a full range of finger movement were provided by the transplanted muscle.

Exercise-enhanced satellite cell proliferation and new myonuclear accretion in rat skeletal muscle

The effects of increased functional loading on early cellular regenerative events after exercise-induced injury in adult skeletal muscle were examined with the use of in vivo labeling of replicating myofiber nuclei and immunocyto- and histochemical techniques. Satellite cell proliferation in the soleus (Sol) of nonexercised rats (0.4 +/- 0.2% of fibers) was unchanged after an initial bout of declined treadmill exercise but was elevated after two (1.0 +/- 0.2%, P < or = 0.01), but not four or seven, daily bouts of the same task. Myonuclei produced over the 7-day period comprised 0.9-1.9% of myonuclei in isolated fibers of Sol, tibialis anterior, and vastus intermedius of nonexercised rats. The accretion of new myonuclei was enhanced (P < or = 0.05) in Sol and vastus intermedius by the initial exercise followed by normal activity (to 3.1-3.4% of myonuclei) and more so by continued daily exercise (4.2-5.3%). Observed coincident with a lower incidence of histological fiber injury and unchanged fiber diameter and myonuclei per millimeter, the greater new myonuclear accretion induced by continued muscle loading may contribute to an enhanced fiber repair and regeneration after exercise-induced injury.

Comparing human skeletal muscle architectural parameters of cadavers with in vivo ultrasonographic measurements

The purpose of this study was to document and compare the architectural parameters (fibre bundle length, angle of pennation) of human skeletal muscle in cadaveric specimens and live subjects. The medial (MG) and lateral (LG) gastrocnemius, and posterior (PS) and anterior (AS) soleus were examined bilaterally in 5 cadavers (mean age 72.6, range 65–83 y) and 9 live subjects (mean age 76.3, range 70–92 y). Data were obtained from direct measurement of cadaveric specimens and from ultrasonographic scans of the live subjects. In cadaveric muscle, fibre bundles were isolated; their length was measured in millimetres and pennation angles were recorded in degrees. In live muscle, similar measurements were taken from ultrasonographic scans of relaxed and contracted muscle. For the scans of relaxed muscle, subjects were positioned prone with the foot at a 90° angle to the leg, and for scans of contracted muscle, subjects were asked to sustain full plantarflexion during the scanning process. Fibre bundle length and angle of pennation were compared at matched locations in both groups. It was found that the relationship between cadaveric and in vivo values for fibre length and angle of pennation varied between muscle parts. The cadaveric architectural parameters did not tend to lie consistently towards either extreme of relaxation or contraction. Rather, within MG, PS and AS, cadaveric fibre bundle lengths lay between those for relaxed and contracted in vivo muscle. Similarly both the anterior and posterior cadaveric fibre angles of pennation lay between the in vivo values within LG and PS. In summary, architectural characteristics of cadaveric muscle differ from both relaxed and contracted in vivo muscle. Therefore, when developing models of skeletal muscle based on cadaveric studies, the architectural differences between live and cadaveric tissue should be taken into consideration.

A Histochemical Method for the Simultaneous Demonstration of Capillaries and Fiber Type in Skeletal Muscle

A modified ATPase method for the simultaneous demonstration of capillaries and fiber types in skeletal muscle is presented. Muscle biopsies were obtained from mice, hamsters, rats, cats, and dogs, quick frozen, and sectioned at 8 microns in a cryostat. The frozen slides were fixed in a neutral formalin solution at 4 C for 5 min, and then incubated at 37 C for 1 hr in a medium containing ATP, Pb2+, and Ca2+ in a tris-maleate buffer (pH 7.2). Dilute (NH4)2S was used as a developer. To test the reliability of the proposed method, serial sections of each biopsy were stained separately for capillaries (amylase-PAS method) and for fiber types by a standard myosin ATPase (m-ATPase) method. Fiber type percent and capillary parameters were determined for each biopsy. No difference in results was observed for parameters determined using the modified ATPase method compared to the standard capillary and fiber type staining methods. This modified technique is therefore suitable for the simultaneous demonstration of capillaries and fiber types in skeletal muscle.

An anatomical study of the pectoralis major muscle as related to functioning free muscle transplantation

The prerequisites for a functioning free muscle transplant are reviewed. A method for studying the anatomy of the pectoralis major muscle is presented, giving special attention to the detail of the neurovascular structures. Fifteen meticulous dissections, documented by sketches and photographs, provide the data base. This work is summarized in Table I and Figure 3. The variability is stressed in Table II. None of the variations observed preclude the use of the inferior four-fifths of the sternocostal muscle as a functioning free muscle transplant. The length and bulk of this muscle are advantages for its use in replacing forearm flexors. The multiple innervations may be an advantage or disadvantage, depending on the availability of the motor nerves in the recipient site. The time-consuming dissection is a disadvantage. With this knowledge, the reconstructive surgeon can assess the advisability of using the pectoralis major muscle as a functioning free muscle transplant.

Bone and cartilage allotransplantation. A review of 14 years of research and clinical studies.

The authors review their experience of over 14 years in the field of osteochondral allotransplantation. Experimental studies demonstrated the immunogenicity of bone and cartilage, immunosuppression in skeletal transplantation models, and a subset of myeloid cells within bone marrow with strong immunogenic properties. Clinical results of knee joint resurfacing with fresh small-fragment osteochondral allografts have been best in posttraumatic joints. Experience with allograft reconstructions of skeletal defects after tumor surgery has been gratifying as a limb salvage procedure. Microvascular fibular autografts have been an important adjunct in massive reconstructive osteochondral transplantation.

Reconstruction of skeletal deficits at the knee. A comprehensive osteochondral transplant program.

From 1971 to 1982, 110 osteochondral transplants with follow-up evaluation were performed for treatment of skeletal deficits caused by degenerative, traumatic, and neoplastic diseases largely involving the knee joint. Seventy-eight small-fragment fresh allografts were transplanted for repair of old tibial plateau osteochondral fractures, osteonecrosis, and unicompartmental osteoarthritis. Thirty-two large-fragment grafts were performed following en bloc excision of bone tumors. Of these, 22 were allografts, three were vascularized fibular autografts, and seven were a combination of allografts and vascularized fibular autografts. In this large-fragment group, three grafts have been removed for tumor recurrence, two for infection, and one for a stress fracture. The results of these transplants have proved particularly rewarding in the old plateau fractures, for traumatic loss of bone and cartilage (osteonecrosis), and after en bloc excision of giant cell tumors.

An isolated skeletal muscle model suitable for acute ischemia studies

A modified isolated canine gracilis model of acute complete muscle ischemia was developed and then tested metabolically and histologically in 25 animals to assess its validity. In each dog, both gracili were isolated on their major vascular pedicles. One muscle underwent ischemia and reperfusion by placing and removing microvascular clips on the artery and vein. The other gracilis muscle was used as a control. Total muscle blood flow measurements, blood samples, and muscle biopsies were taken every other hour for up to 11 hr after preparation. The fiber-type profile of the gracilis was determined bilaterally using a myosin ATPase stain (n = 10). The results verified these hypotheses: after surgical preparation, the right and left muscles in the same dog are equivalent metabolically, after a 2-hr stabilization period, gracilis blood flow, oxygen and glucose uptake, lactate release, and tissue glycogen, lactate, phosphocreatine, and ATP levels remain within normal limits and unchanged for the next 9 hr, the surgical isolation of the gracilis muscle on a single vascular pedicle does not result in significant metabolic changes, in this model, a 2-hr ischemia is reversible, but a 7-hr ischemia results in irreversible ischemic injury. As well, fiber-type profile, muscle blood flow, and metabolic parameters can very significantly among animals supporting the necessity of a contralateral control. Therefore, this modified gracilis muscle model with its contralateral muscle as a control is suitable for acute skeletal muscle ischemia experiments of at least 9-hr duration.

Isometric contractile function recovery following tourniquet ischemia

The purpose of this study was to document the recovery of isometric contractile function following tourniquet ischemia. Male Wistar rats (N = 27) were subjected to unilateral hindlimb tourniquet ischemia of 0 hr (control, N = 6), 1 hr (N = 5), 2 hr (N = 5), 3 hr (N = 5) and 4 hr (N = 3). Following a 2-week recovery period, isometric force measurements were made from both gastrocnemii of each rat with the contralateral limb acting as the control side. Each muscle was analyzed for maximal twitch (Pt, N/g), maximal rate of rise of twitch tension (DP/dt, N/sec), time to peak tension (TPT, msec), half relaxation time (RT 1/2, msec), maximal tetanus (P0, N/g, at 100 Hz), and fatigue (Burke Fatigue Protocol). Pt, P0, and DP/dt were significantly different from control values (P less than 0.05) for all hours of tourniquet ischemia. A strong negative correlation (P less than 0.001) was found for twitch (R = -0.84), tetanus (R = -0.78), and maximal rate of force development (R = -0.83) with respect to increasing hours of ischemia. The recovery of isometric twitch and tetanic function following tourniquet ischemia is inversely related to the ischemic interval. This study quantified the relationship between muscle ischemia and recovery of function following a 2-week interval and stresses the functional physiological changes which occur in skeletal muscle following tourniquet ischemia.